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HUMANBODY HUMAN

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DLEBACK’S

Human Body

Copyright © 2008 by Saddleback Educational Publishing

All rights reserved. No part of this book may be reproduced in any form or by

any means, electronic or mechanical, including photocopying, recording, or by

any information storage and retrieval system without the written permission of the

publisher.

ISBN-10: 1-59905-234-2

ISBN-13: 978-1-59905-234-2

eBook: 978-1-60291-596-1

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Weight of BrainThe brain weighs less than 2.5% of our total body weight, but it burns oxygen and glucose at ten times the rate of other body organs.

• Healthy people can live with only

one kidney.

• There are three types of blood vessels:

arteries, veins, and capillaries.

• Blood vessels provide two important

means of measuring vital health

statistics: pulse and blood pressure.

• The tooth is the only part of the human

body that cannot repair itself.

• For humans, the normal pulse is 70

heartbeats per minute.

• It takes more muscles to frown than it

does to smile.

• The brain is more active and thinks

more at night than during the day.

• The human brain is 80% water.

• Your fingernails grow almost four times

as fast as your toenails.

Length of IntestineThe small intestine in human beings is 19.68 feet long.

Human Body

The human body is an organized collection of several body systems, which perform specialized functions.

Some of these body systems, such as nervous, skeletal, and muscular are found throughout the body, while some systems, such as digestive, urinary, and endocrine are located in smaller areas.

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The human body is made up of billions of cells. Cells are the basic structural and

functional units of the human body. Tissues are an organization of several similar cells along with various intercellular substances between

them. Organs are an organization of several different kinds of tissues arranged

together to perform special functions.

Largest OrganSkin is the largest organ of the human body.

Dissimilar Person Similar DNAAny two unrelated strangers anywhere on the planet share 99.9 percent of the same DNA.

Cells, Tissues, and Organs

• Intercellular matrix is a non-living material, which

fills the space between the cells.

• Epithelial cells may be squamous, cuboidal, or

columnar in shape and may be arranged in

single or multiple layers.

• Nerve cells or neurons are cells in nervous tissue

that generate and conduct impulses.

• There are about 210 different types of cells in the

human body.

• Human cells are made of several smaller

organelles, such as nucleus, endoplasmic

reticulum, golgi complex, lysosomes, and

mitochondria.

• There are four types of tissues in the human

body: epithelium, connective, muscles, and

nervous tissues.

• Epithelium tissues cover organ surfaces and serve

as protection and absorption.

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Body systems are the most complex components of the human body. They are an organization of several

organs that perform complex functions for the body. The major body systems include circulatory, digestive, endocrine, immune, lymphatic, muscular, nervous, reproductive, respiratory, skeletal, and urinary.

Combined Body Systems The functions of many body systems often overlap. For instance, the muscular and skeletal systems function together. As a result, both are sometimes combined and studied under the musculoskeletal system.

• The muscular system allows

the human body to move.

• The circulatory system moves

substances to and from the

body cells.

• The lymphatic system or

immune system defends the

body against diseases.

• The skeletal system supports

the human body and protects

its internal organs.

• The nervous system carries

messages from the body to the

brain and from the brain to

the body.

• The digestive system digests

food and extracts energy and

nutrients from it.

• The respiratory system controls

the gaseous exchange in the

human body.

• The endocrine system controls

the secretion of hormones.

Body Systems

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• The skeleton is the internal

structure that holds the human

body up and with the help of the

muscular system, allows us to

move.

• Bones are the most important

part of the skeletal system.

• The longest bone of the skeletal

system is the thighbone or femur.

• The stirrup bone inside the ear is

the smallest bone of the skeletal

system.

• Muscles hold the bones together

and allow them to move.

The skeletal system provides support to the human body. It also protects delicate internal organs. The skeletal system is

made of individual or joined bones. These bones are supported by ligaments, tendons, muscles, and cartilage. The skeleton

continues to change its composition over a lifespan. On average, an adult human has 206 bones, but a baby is born with

approximately 270 bones.

Types of SkeletonThere are two types of skeleton in the human body: the axial skeleton and the appendicular skeleton.

Blood Forming TissueThe skeleton contains bone marrow, the blood forming tissue.

Skeletal System

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Bones are hard endoskeletal connective tissues. They support body structures

and protect internal organs. There are two types of bone tissues: compact

and spongy. They differ in density. Most bones contain both types of

tissues.

Types of Bones There are four categories of bones: long, short, flat, and irregular bones.

Producer and StoreBones manufacture blood cells and store for useful minerals.

• The bone that is broken

most often is the collarbone.

The scientific name for the

collarbone is the clavicle.

• The hyoid bone in the throat

is the only bone in the body

that is not attached to any

other bone.

• The human hand has 27

bones; your face has 14!

• There are over 230 movable

and semi-movable joints in

the body.

• Bones in men tend to be

larger and heavier than in

women.

• The place where two bones

meet is called a joint. Some

joints move and others

don’t.

Bones are ActiveBone cells rely on blood to keep them alive.

Bone

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• The lower part of the upper jaw

holds the upper teeth.

• Baby teeth start appearing at the

age of 6 or 7 months.

• The real name for baby teeth is

milk teeth.

• The hardest thing in the body is

the enamel.

• The first permanent teeth appear

at about the age of six.

• Human adults have 32 teeth

called permanent teeth.

• Human beings have three kinds

of teeth: incisors, canines, and

molars.

• A tooth is fixed into the bony

jaw socket and held in place by

cement.

• Digestion starts in mouth with

teeth.

Teeth are hard structures attached to the jaws. They are used for grinding

and chewing food. The jaw is made up of two opposed bony structures that form the entrance of the mouth. The jaw consists of the upper and lower jaw. The upper jaw is known as the maxilla and the lower jaw is known as the mandible. The upper jaw is fixed while the lower jaw can move.

Working Mechanism of JawsThe movement in the jaw is brought with the help of several muscles that are known as muscles of mastication.

Permanent TeethAn adult has 32 permanent teeth that start to grow at about the age of 5–6 years.

Teeth and Jaw

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Ligaments are also found in many organs, such as the uterus, bladder, liver, and diaphragm. Ligaments are fibrous bands

that are made of collagen. They keep the joints stable and allow flexibility and movement. Tendons are the fibrous connective tissues. They connect muscles to bones.

Ligament System in SpineThere are two primary ligament systems in the spine: intrasegmental and intersegmental systems.

• Bones are connected to each other

by ligaments.

• The muscles are attached to the

bones with the help of tendons.

• Ligaments and tendons may take

a long time to heal after an injury

because their blood supply is

limited.

• Tendons carry tensile forces from

muscles to bones.

• The word “ligament” comes

from the Latin word ligamentum,

meaning a band or tie.

• If a ligament is made up of several

thick bands of fibrous branches, it is

called a “collateral ligament.”

Ligaments and Tendons

Desmology“Desmology” is the study of ligaments.

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• Nails grow at a rate of .019–

.047 inches per day.

• Hair grows more quickly in summer

than winter, and more slowly at night

than during the day.

• There are no blood vessels in the

epidermis, that is why a small scratch

does not cause bleeding.

• The larger part of the nail, the nail

plate, looks pink because of the

network of tiny blood vessels in the

underlying dermis.

• It is normal to lose 100 hairs per day

from the scalp.

Hair is the thread-like growth in the epidermis of the skin. It

provides body covering and is found only in mammals. Nails are protective coverings on the upper surface of the fingers and toes. They are formed from dead cells. These dead cells contain keratin, which is a fibrous protein.

Hair and Nails

Scalp HairThere are around 100,000 hairs in the human scalp.

Fastest Growing TissueHair is the fastest growing tissue in the human body after bone marrow.

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Muscular System

The muscular system is the network of muscles found in the human body. The system facilitates and allows

movement of the body. The muscular system is also responsible for the functioning of important organs in the body such as heart and lungs. It also helps in keeping the body warm.

Smallest MuscleStapedius is the smallest muscle that measures 1/20

th of an inch.

Busiest Muscle in the Body Eye muscles are the busiest muscle in the body. They may move more than 100,000 times a day.

• Muscles can only pull; they

cannot push.

• The largest muscle in the

body is the gluteus maximus found in the buttocks.

• There are 630 active muscles

in your body and they act in

groups.

• Massete muscles are the

strongest muscles of the body

found on each side of jaw.

• A smile uses 17 muscles while

a frown uses 43.

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There are more than 600 muscles in the human body. These muscles are found

all over the body. Muscles that are attached to the skeletal system are divided into two

groups: axial muscles and appendicular muscles. Axial muscles are muscles found from the head to waist. Appendicular muscles are muscles of the limbs.

• Muscles need oxygen and food

for energy from blood in order to

work properly.

• Skeletal muscles make up 50%

of body weight and there are

640 individually named skeleton

muscles.

• Skeletal muscle is made up of

thousands of cylindrical muscle

fibers often running all the way

from origin to insertion.

• Cardiac muscles are found in the

heart.

• A single muscle cell is called a

muscle fiber.

• Smooth muscles are of two types:

multiunit smooth and single unit

smooth.

• Strains, sprains, cramps (charley

horse), and repetitive stress

injuries are the most common

injuries of muscles.

Requirement of MusclesTo work

systematically, muscles need proper oxygen and food from blood.

Types of MusclesHuman muscles are divided into three categories: skeletal, cardiac, and smooth muscles.

Muscles in Our Body

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• Weight of the skin: 7 pounds.

• Skin is thickest on the palms and soles

(.04–.18 inches) and thinnest on the lips

and around the eyes.

• Facial skin is approximately .004 inches

thick and on the body is about .02 inches.

• Length of the skin of an adult: 20 square

feet of skin.

• Humans shed about 600,000 particles

of skin every hour—about 1.5 pounds

a year. By 70 years of age, an average

person will have lost 105.8 pounds of

skin.

• Each square half inch of the skin has

6 million cells, 5,000 sensory points, 100

sweat glands, 15 sebaceous glands, 10

hairs, and .03 inches of tiny blood vessels.

Skin is the outer covering of the human body. On

average, the skin covers about 2 square yards of surface area. The primary job of the skin is to protect the body from external dangers. It also defends the body against infections and acts as a sensory organ detecting temperature, touch, and vibration.

Body Temperature ControlBy distributing heat through the skin and by preventing dehydration, skin helps to control body temperature.

Regeneration of SkinSkin is frequently regenerated and completely renews itself every 3–5 weeks.

Skin

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The nervous system is the information system of the body. It collects, stores, and analyzes all the information received by

the body. The nervous system is the control system of the body. It is divided into two parts – the central nervous system

and the peripheral nervous system. The entire nervous system is made of nervous tissues.

Nerve ImpulsesA nerve cell can transmit 1,000 nerve impulses each second.

Blood TransportationThe carotid artery carries blood to the head and neck.

Nervous System

• The human nervous system consists of

around a hundred billion nerve cells or

neurons.

• The nervous system is made up of brain,

brain stems, and nerves.

• Most of the thinking takes place in the

frontal lobe.

• The entire surface of the central nervous

system is covered with a fluid called

cerebrospinal fluid (CSF).

• In 1860 the average weight of a male brain

was 2.99 pounds. Now a male brain weighs

an average of 3 1/8 lbs.

• The left side of human brain controls the

right side of the body and the right side of

the brain controls the left side of the body.

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The brain is a part of the central nervous system, located

inside the head. It controls and coordinates bodily activities and the senses. The brain is divided into two halves or hemispheres. Both hemispheres communicate with each other through a bundle of nerve fibers known as corpus callosum. The brain is made of several parts, such as cerebrum, cerebellum, brain stem, hypothalamus, thalamus, limbic system, and midbrain.

Measurement of BrainThe average human brain is 6.57 inches long, 5.6 inches wide, and 3.72 inches high.

Technique to Record Brain ActivityElectroencephalogram, or EEG, is a non-invasive technique used to record small changes of electrical activity in the brain, with surface electrodes on the scalp.

Brain

• An average adult male brain weighs

about 3 pounds and a female brain is

about 2.8 pounds.

• A newborn baby’s brain grows almost

3 times during the course of its first

year.

• The biggest part of the brain is the

cerebrum. It makes up 85% of the

brain’s weight.

• The brain receives about 100 million

pieces of information at one moment

that reaches the nervous system

through receptors in the skin.

• The adult human brain is about 2% of

the total body weight.

• One human brain generates more

electrical impulses in a single day

than all of the world’s telephones put

together.

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The spinal cord is a part of the central nervous system. It is a bundle of nerves that carries messages between the brain and the other parts

of the body. The spinal cord is protected by a spinal column. The spinal column is made up of bones called vertebrae. The spinal cord is covered

with three layers of protective membrane known as meninges. The space between the layers of meninges is filled with a fluid, which is called the cerebrospinal fluid. The cerebrospinal fluid is a clear and

colorless liquid that protects the spinal cord.

Dimension of Spinal CordThe human spinal cord is about 16.92–17.71 inches long and approximately as wide as a human finger.

Structure of Spinal CordThe human spinal column is made up of 33 bones: 7 vertebrae in the cervical region, 12 in the thoracic

region, 5 in the lumbar region, 5 in the sacral region, and 4 in the coccygeal region.

Spinal Cord

• The base of the spinal

cord has a cluster of

nerves, which are the most

sensitive.

• There are 31 pairs of nerves

in the the spinal cord.

• The male spinal cord is

longer than the female

spinal cord.

• The first bone or vertebrae

of the cervical region of

spinal cord is called the

atlas.

• The spinal cord develops

before other parts of the

body.

• Receptors in the skin send

the information to the spinal

cord through the spinal

nerves.

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Neurons are the nerve cells. They are specialized cells

that carry messages through the nerves. The German scientist Heinrich Wilhelm Gottfried von Waldeyer-Hartz coined the term neuron in 1891. Each neuron has several extensions known as the dendrites. These dendrites bring information to the neuron from other neurons.

• Neurons vary in size from .004 mm to

100 microns or .1 mm in diameter. Their

length varies from a fraction of an inch to

several feet.

• A typical neuron communicates with

1,000–10,000 other neurons, muscle

cells, glands, etc.

• Neurons cannot regrow after being

damaged.

• There are about 100 billion neurons in

the brain.

• Neurons can be divided into three

major categories: sensory, motor, and

interneuron.

• Neurons grow at a rate of 250,000

neurons per minute during the

development of the fetus.

Neurons in BrainThere are about 100 billion neurons in the brain.

Controller for NeuronThe nucleus is essentially the “brain” or control center for the neurons that hold all of the genetic information.

Neurons and Dendrites

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The central nervous system is one of

the major divisions of the nervous system. It consists of the brain and spinal cord. The central nervous system acts as the control system of the entire body. Some of the body functions controlled by the nervous system include muscle control, eyesight, breathing, and memory.

Composition of BrainThe brain is made up of 77–78 percent water, 10–12 percent lipids, 8 percent fat, 1 percent carbohydrate, 2 percent soluble organic substances, and 1 percent inorganic salts.

Division of Spinal CordThe spinal cord is divided into 31 segments.

• There are two different

types of regions in the central

nervous system: grey matter and

white matter.

• The central nervous system does not

include the peripheral nerves in the

arms, legs, muscles, and organs.

• The brain is made up of three

main sections: the forebrain, the

midbrain, and the hindbrain.

• The brain contains about 100 billion

nerve cells (neurons) and trillions of

“support cells” called glial cells.

• Cerebrospinal fluid flows

uninterrupted throughout the central

nervous system.

Central Nervous System

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The immune system works to fight against diseases and infections that

affect the body. They produce antibodies that fight against antigens or disease

causing bacteria, viruses, and pathogens. The lymphatic system is also associated with providing immunity to the body. It consists of the lymph vessels, lymph nodes, and lymphatic organs.

Lymphatic/Immune System

Lymph and Fat Lymph mixed with fat is called the chyle. Chyle is transported to the blood.

Autoimmune DiseasesSometimes the immune system fails to recognize body cells. It starts destroying them. This can lead to autoimmune diseases.

• Our immune system is an amazing

network of cells that function from

very basic to highly complex levels.

• The immune system is divided

into three parts: antigen-specific,

systemic, and memory.

• The antigen-specific immune

system acts against a particular

antigen.

• The systemic immune system works

throughout the body.

• The memory immune system can

fight against the same antigen

even after a long period of time.

• Multiple sclerosis, arthritis, and

diabetes are autoimmune diseases.

• The immune system of a young

child has the capacity to respond

to 10,000 different immune

challenges.

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• Lymph nodes are surrounded

by a fibrous capsule.

• Lymph nodes range in size

from a few millimeters to

about .3–.7 inches in their

normal state.

• White blood cells are located

within honeycomb structures

of the lymph nodes.

• Spleen and tonsils are large

lymphoid glands. Their

functions are similar to lymph

nodes.

• Lymph nodes also produce

phagocytes that destroy

bacteria and poisonous

substances.

Lymph nodes are bean-shaped

organs that filter the lymph fluid. There are about five hundred lymph nodes in the body.

DistributionThe human body has about 500 to 600 lymph nodes. They are mostly found in the underarms, groin, neck, chest, and abdomen.

Enlargement of Lymph Nodes When the body is infected, it increases the production of white blood cells. This leads to the enlargement of lymph nodes.

Lymph Nodes

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Virus

Antigens and Antibodies

Antigens are molecules, often found on foreign substances such as bacteria or viruses.

They cause diseases in the body. The immune system fights against

these invading particles by the production of antibodies. They tag, destroy, or neutralize antigens or disease causing

molecules.

• Antibodies are protein

molecules known as

immunoglobulin.

• Antibodies are y-shaped

molecules.

• Antibodies inactivate the

antigen.

• Antigens include bacteria,

viruses, and mycoplasma

as well as chemicals, food

proteins, pollen grains, and

dust particles.

• Antibodies are produced

by white blood cells to fight

against antigens.

B-lymphocytesB-lymphocytes secrete antibodies to defend the body against parasites.

T-lymphocytes T-lymphocytes protect the body against virus infection by killing the virus infected cells.

Antigens

Bacteria

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Circulatory System

The circulatory system is made up of the heart, blood, and blood vessels. It transports nutrients, water, and oxygen

to the body’s cells. It also carries away waste, such as carbon dioxide produced by the body’s cells. The circulatory system of an adult human has over 59,987 miles of blood vessels.

The circulatory system is divided into three parts: pulmonary circulation, coronary circulation, and systemic circulation.

• Except the heart and lungs,

all the other parts of the body

receive their blood supply

from the aorta.

• The aorta is the largest artery

of the body.

• The pulmonary vein is the only

vein in the human body that

carries oxygenated blood,

while all the other veins in the

body carry de-oxygenated

blood.

• The red blood cells circle the

whole body in 20 seconds.

• The kidneys filter much of the

waste from the blood.

Quantity of BloodAn average human has about 1.47 gallons of blood in the body.

Blood is ColorlessHemoglobin, pigment present in the red blood cells, is responsible for the red color of the blood.

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Blood

Blood is a fluid that carries oxygen and nutrients to the

body’s tissues and removes waste from them. Blood consists of plasma—a watery liquid— and three specialized cells. The specialized cells of the blood are: red blood cells, white blood cells, and platelets. Red blood cells carry oxygen throughout the body, white blood cells protect the body from diseases, and platelets help in the clotting of the blood.

Blood GroupsHuman blood is grouped into four types: A, B, AB, and O.

Identifier of Blood TypeThe Rh factor is a term for substances found on the surface of the red blood cells, and is named after the rhesus monkey, in which it was originally found.

• Blood is grouped into four types: A, B,

AB, and O.

• The average healthy adult contains

between 5 and 6 quarts of blood.

• A cubic millimeter of human blood

contains about 5 million red blood

cells.

• Red blood cells are formed in the bone

marrow.

• Abnormal reduction in the number of

red blood cells is known as anemia.

• Medical terms related to blood often

begin with hemo- or hemato- from the

Greek word haima for “blood.”

• Blood cells are produced in the bone

marrow; the process is termed as

hematopoiesis.

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Blood Vessels

Construction of ArteriesArteries are tough on the outside and smooth on the inside so the blood can flow easily.

Coronary ArteryCoronary arteries are the blood vessels that carry blood to the heart muscle.

• Sinusoids are extremely small

vessels located within the liver,

spleen, and bone marrow.

• The blood vessels provide two

important means of measuring

vital health statistics: pulse and

blood pressure.

• The largest artery of the body is the

aorta.

• Arteries and veins run parallel

throughout the body, with a

web-like network of capillaries

connecting them.

Blood vessels are tube-like canals that circulate blood to and from all parts of the body. There are four main

types of blood vessels: arteries, veins, capillaries, and sinusoids. A blood vessel is divided into several parts, such as lumen, intima, media, and adventitia. Lumen is the hollow part of the vessel through which the blood flows. It is followed by a layer of tissues known as the intima. The intima is followed by another layer of tissues known as the media. The adventitia is the outermost layer of a blood vessel.

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The heart is a hollow, muscular organ. It is located

to the left of the middle of the chest. The heart is of the size of a fist. It acts like a pump. It receives impure blood from the veins and pumps the pure blood into the arteries. It is made of cardiac muscles.

Heart Beats Per MinuteThe human heart beats 72 times per minute.

Blood Vessels of the HeartArteries carry blood away from the heart and veins carry blood back to the heart.

• The human heart continues to beat

even after it is taken out of the

body.

• A heartbeat is nothing but the

sound produced by the closure of

valves of the heart when the blood

is pushed through its chamber.

• The heart muscles will stop working

only when we die.

• A woman’s heartbeat is faster than

that of a man.

• The pumping of the heart is called

the cardiac cycle.

• During an average lifetime, the

human heart will beat more than

2.5 billion times.

• The aorta, the largest artery in the

body, is almost the diameter of a

garden hose.

• The heart pumps more quickly

during running and more slowly

during sleeping.

Heart

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Ears are the organs of

hearing. They are also responsible for providing balance to the body. There are three parts of the ear: the outer ear, the middle ear, and the inner ear. These parts function together so that we can hear and process sounds.

Produces the WaxThe ear canal is about 1 inch long and produces wax that keeps the canal clean and protects the ear from infection.

Ear

Between Outer and Middle EarThe eardrum separates the outer ear from the middle ear. It is also known as the tympanic membrane.

• The stirrup is the smallest bone in

the human body. It is about .098 to

0.129 inches long.

• Ears are made of cartilage.

• Humans can hear sounds between

20–20,000 Hz.

• Tinnitus is a symptom associated with

many forms of hearing impairment and

noise exposure.

• The number of vibrations that are

produced per second is called frequency.

• The pinna, the outer part of the ear,

serves to catch the sound waves.

• Ossicles are the tiniest bones found in

the middle ear.

• Cochlea is the part of the inner ear filled

with liquid. It contains hair cells that help

in creating nerve signals for the brain.

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Eyes are organs of vision. They are small in size—about .98 inches

wide and .98 inches deep. Eyes are found in a hollow area of the skull called the eye socket. The front part of the eye is protected by the eyelid, which keeps the eyes moist and clean.

Non-transferableEyes are connected to the brain by the optic nerve and cannot be reconnected once it has been severed.

Size of EyesEyes remain the same size throughout life.

• The eye is the only part of the human

body that can function at 100% ability

at any moment, day or night, without

rest.

• The human eyeball measures only

about .98 inches.

• The Ishihara test is a test used to

detect your ability to see colors.

• The human eye blinks an average of

4,200,000 times a year.

• The retina is responsible for

converting light signals into electrical

impulses.

• Eyelashes work with eyelids to keep

dirt and other unwanted stuff out of

your eyes.

• The biggest part of the eye sits behind

the lens and is called the vitreous

body.

Eye

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Odors enter the nose in the form of chemicals. They activate the hair cells located inside the nose. These

hair cells are sense receptors that convert smell into electric signals and send them to the brain. The brain interprets theses signals as smell. When food enters the

mouth, it passes through the tongue. The tongue has more than 10,000 taste buds. Taste buds contain taste receptor cells called microvilli. These cells react to different types of tastes found in the food and send nerve impulses to the brain. The brain interprets these impulses and identifies different tastes.

• Children are likely to have much

more subtle sense of smell than

parents or grandparents.

• Smells are detected in the nose by

the specialized receptor cells of

the olfactory epithelium. These are

called olfactory receptor neurons.

• The average human being is

able to recognize approximately

10,000 different odors.

• A diminished sense of taste is

known as hypogeusia.

• Flavor is what people commonly

call the “taste” of food.

• There are five basic tastes: salt,

sour, sweet, bitter, and umami.

• Humans have seven primary odors

that help them determine objects.

Smell is Not the SameNo two people smell the same odor the same way.

Loss of Sense of SmellAnosmia is the total loss of the sense of smell resulting from various causes.

Odor Example

Camphoric Mothballs

Musky Perfume/Aftershave

Floral Roses

Peppermint Mint Gum

Etheral Dry Cleaning Fluid

Pungent Vinegar

Putrid Rotten Eggs

Smell and Taste

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Water LossWe lose half a liter of water a day through breathing.

Breathing DisordersAsthma is an increasingly common disease that causes coughing and makes it hard to breathe.

Respiratory System

• At rest, a person breathes about 14

to 16 times per minute. After exercise,

it could increase to over 60 times per

minute.

• Newborn babies at rest breathe

between 40 and 50 times per minute.

By the age of five it decreases to

around 25 times per minute.

• Each lung contains 300–350 million

respiratory units called alveoli, making

it a total of 700 million in both the

lungs.

• Smoking makes it harder for our lungs

to absorb oxygen.

• The common cold is an infection of

the lining of the nasal cavity and other

parts of the respiratory system caused

by viruses.

• The level of oxygen in the blood

is monitored by specialized nerve

cells known as the peripheral

chemoreceptors.

The respiratory system is responsible for supplying oxygen to the blood. This is done

through breathing. The body inhales oxygen and exhales carbon dioxide. The respiratory system is divided into two subgroups: the upper respiratory tract and lower respiratory tract. The upper respiratory tract includes body organs such as the nose, sinuses, and throat. The lower respiratory tract includes body organs such as the trachea and lungs.

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Smell FingerprintA smell fingerprint is the unique odor identity of every person.

Nose

• A woman’s sense of smell is

keener than a man’s.

• The human body can recall

smells with a 65% accuracy

after the age of one year.

• The cartilage gives shape and

support to the outer part of the

nose.

• Rhinitis is an inflammation of

the mucous membrane of the

nose.

• Memory is often associated

with smell.

• Rhinoplasty is a surgery

through which the nose can be

altered.

Nose as a FilterThe nose filters all the air that passes through it.

The nose is the organ of smell. The sense of smell

is also known as olfaction. The nose helps in respiration. It lets the air enter into the lungs. In a day, about 21,140 quarts of air passes through the nose of an adult human.

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There are two lungs in the human body. Lungs are 9.84–11.81 inches

in length and are separated by a structure called the mediastinum. The lungs are protected by the rib cage. The diaphragm is located at the end of the lungs. It helps the lungs inhale and exhale air. The lungs are protected by a covering of membrane, which is called the pulmonary pleura.

Lungs Can Float in WaterLungs are the only organ in the human body that can float in water.

Lungs

• Male lungs average 2.3 lbs, while

female lungs average 2.05 lbs.

• The right lung is slightly larger than

the left.

• Women and children have faster

breathing rates than men.

• Yawning brings more oxygen to the

lungs.

• The total surface area of the alveoli

(tiny air sacs in the lungs) is the size

of a tennis court.

• The lungs are protected by the ribs.

• An estimated 90% of the lung is

filled with air and only 10% is hard

tissue.

• Lungs are composed of smooth,

shiny lobes.

Weight of LungsMale lungs weigh around 2.3 pounds, whereas female lungs weigh around 2.05 pounds.

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The trachea is a pipe that connects the mouth and nose to the lungs. It is also known as the windpipe. Bronchi

are the divisions of the trachea that lead to each lung. Each bronchus (singular of bronchi) is further subdivided into several branches that terminate into tiny air sacs called alveoli.

Trachea, Bronchi, and Alveoli

• The trachea is made of 16 to 20

rings of cartilage that are connected

by ligaments.

• The alveoli are found in the

respiratory zone of the lungs.

• Lungs contain about 300 million

alveoli.

• The trachea divides into two main

bronchi—the left and the right.

• The right main bronchus is wider,

shorter, and more vertical than the

left main bronchus.

• Bronchitis is a viral or bacterial

infection of the bronchi.

• The bronchi tubes are responsible

for cleaning the lungs.

Structure of TracheaThe trachea is flexible, stretching to between 4 and 5 inches long and about one inch in diameter.

Structure of AlveoliAlveoli have radii of about 0.1 mm and wall thickness of about 0.2 mm.

Trachea

Bronchi

Alveoli

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The breathing mechanism is related to the inhaling and

exhaling of the air. The body uses oxygen from the inhaled air and gives off carbon dioxide through the exhaled air. Several body organs such as the nasal cavity, larynx, trachea, bronchus, alveoli, and lungs help in breathing. Normal breathing is controlled by the medulla oblongata of the brain.

Breathing Mechanism

• Inspiration is inhaling of air inside

the body.

• The diaphragm and intercostal

muscles contract during

inspiration.

• The lungs expand during

inspiration.

• This expansion of the lungs lowers

the pressure of the air inside the

lungs compared to the air outside.

As a result, air from outside flows

into the lungs.

• Expiration is exhaling of air from

the body.

• The diaphragm and intercostal

muscles relax during expiration.

• The lungs relax during expiration.

• This relaxation of the lungs

increases the pressure of the air

inside the lungs compared to the

air outside. As a result, air flows

Composition of Inhaled Air Inhaled air contains about 78 percent nitrogen, 20.8 percent oxygen, 0.04 percent carbon dioxide, and 1.2 percent water vapor.

Composition of Exhaled AirExhaled air contains 76 percent nitrogen, 15.3 percent oxygen, 4.2 percent carbon dioxide, and 6.1 percent water vapor.

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Male urinary system

• All the blood in our body passes

300 times through each kidney

everyday.

• Nephrons are the structural unit of

kidneys.

• Nephrons send about six cups of

urine to the bladder per day.

• The urinary bladder can hold

around 2 cups of urine for about 2

to 5 hours.

• In males, the urethra is about 7.87

inches in length.

• In female, the urethra is shorter,

about 1.18–1.57 inches in length.

• Over 60 percent of an adult’s

weight is water.

SphinctersSphincters are the circular muscles in urinary bladder that prevent the urine from leaking.

Urine Discharge Organ The urethra is a special urinary organ that finally discharges urine from the body.

Urinary System

The urinary system of the body consists of two kidneys, two ureters, one bladder, two sphincter

muscles, and one urethra. The main job of the urinary system is to filter out the excess fluid and other substances from the blood. The urinary system reabsorbs some of the

fluids and substances that it filters. The rest is excreted from the body in

the form of urine. Some other body parts such as lungs, skin, and intestine also excrete waste.

Female urinarysystem

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Kidneys are organs of the urinary system. They are bean-shaped

organs located on the backside of the abdomen. They are found on each side of the spine. A normal kidney is about 3.93 inches long and 1.96 inches thick. The kidneys weigh around 10.5 oz, which is about 0.5 percent of the total body weight. They receive huge amounts of blood —around 20 percent of the blood pumped by the heart—to carry out their normal functions.

One Kidney Can Function WellIf the body loses one kidney, the other kidney enlarges and does the work of two.

Kidney

• Each kidney contains one to two

million nephrons.

• Some of the most common

kidney diseases and conditions

are polycystic kidney disease,

nephrosis, lupus nephritis, diabetic

nephropathy, rhabdomyolysis,

kidney stones, and renal tubular

acidosis.

• Diabetes is the most common cause

of kidney failure.

• The kidneys excrete a variety

of waste products produced

by metabolism, including the

nitrogenous wastes: urea and uric

acid.

As Endocrine GlandKidneys also function as endocrine glands and secrete an enzyme known as renin.

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The digestive system consists of organs that break down and absorb food. The system includes the mouth, esophagus, stomach, small

intestine, large intestine, rectum, and anus. The process of digestion begins in the mouth and ends as the solid waste that gets stored in the rectum. There are some other organs, which help in digestion, but are

not part of the digestive tract. They are the tongue, salivary glands, pancreas, liver, and gallbladder.

• For the average person it takes

eight seconds for food to travel

down the esophagus, 3–5 hours in

the small intestine, and 3–4 days in

the large intestine.

• The stomach produces a new lining

every three days in order to avoid

digesting itself in the acid that it

produces.

• When you eat, the body digests

the food so that cells can use it to

make energy.

• Acids and enzymes eat away at the

surface of food to break it down.

• The human stomach contains

about 35 million small digestive

glands.

• The large intestine takes

undigested food paste and turns

it into solid waste by removing the

water.

Digestion PeriodIt takes the body six hours to digest a high-fat meal versus two hours for a carbohydrate meal.

Glands in StomachThe human stomach contains about 35 million small digestive glands.

Digestive System

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The esophagus is a muscular tube that connects the mouth to the stomach. The

stomach is a hollow, muscular organ. It lies between the esophagus

and the first part of the small intestine. The food passes from the mouth to the stomach through the

esophagus.

Diseases of Stomach Common disorders of the stomach include: stomach ulcer, gastritis, and stomach cancer.

Esophagus and Stomach

• The connection between the

stomach and the esophagus is

called the cardiac sphincter.

• The human stomach can be

distended up to four liters, which is

more than one gallon.

• As food is liquefied in the stomach,

it is slowly released into the small

intestine for further processing.

• Food in the stomach that is partly

digested and mixed with stomach

acids is called chyme.

• The interior of the stomach is able

to secrete about 2.1–3.1 quarts of

gastric fluid everyday.

Extension of EsophagusThe esophagus is about 9.8 inches long and it extends through the neck and chest into the abdomen.

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There are two sections of the intestines: small and large

intestines. The intestines extend from the stomach to the anus. They absorb the digested food.

• The large intestine is about 4.9 feet long,

which is about one-fifth of the whole

length of the intestinal canal.

• The most obvious difference between the

small intestine and the large intestine is

that the large intestine is wider.

• The cecum is a sac with a closed end. It

is the very first part of the large intestine.

• The lining of the small intestine secretes

a hormone called secretin, which

stimulates the pancreas to produce

digestive enzymes.

• Disorders of intestine include Crohn’s

disease, constipation, Irritable Bowel

Syndrome, or infections caused by

worms.

• Food products are absorbed in the small

intestine whereas the large intestine is

responsible for the absorption of water

and excretion of solid waste material.

• The large intestine hosts several kinds

of bacteria that deal with molecules the

human body is not able to breakdown

itself.

Absorption ProcessThe large intestine is responsible for the absorption of water and excretion of solid waste material. Food products are absorbed by the small intestine.

Small and Large Intestine

Length of Small IntestineThe small intestine with a 19.6 feet length, is the longest section of digestive tube.

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The liver is the largest internal organ of the body. It lies on the right of the stomach and

plays a major role in metabolism. The liver is mostly made up of hepatic cells.

These are specialized cells that perform

chemical processes.

Filtration PowerThe liver filters over a quart of blood each minute.

Capacity to RegenerateThe liver is the only organ which has the capacity to regenerate even after being removed almost completely.

• Insulin controls the amount of sugar in

the blood by moving it into the cells,

where it can be used by the body for

energy.

• The liver is the largest and heaviest

internal organ of the body and weighs

about 3.5 pounds.

• The liver affects nearly every

physiological process of the body and

performs over 500 different chemical

functions.

• Hepatitis is the inflammation of the

liver.

• The liver is mostly made up of hepatic

cells.

• Liver cells take several years to replace

themselves.

• A healthy liver processes 190 gallons of

blood per day.

• The liver detoxifies poisonous

Liver

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The pancreas is an organ of the digestive and endocrine systems.

It is pistol-shaped and located behind the stomach and above the intestines. The gall bladder is an organ of the digestive system. It

is a pear-shaped muscular sac located near the duodenum.

• The gall bladder stores and

concentrates bile produced in the liver.

• The pancreas produces two hormones:

insulin and glucagon.

• The pancreas releases enzymes that

help in digestion of food.

• Cholecystectomy is a surgery to remove

the gall bladder.

• Length of human pancreas is

5.9–9.8 inches.

• Pancreatitis is a condition that affects

the pancreas.

Gall StonesGall stones are one of the major and common causes of gall bladder diseases.

Herophilus (335–280 BCE)Herophilus, a Greek anatomist and surgeon, discovered the pancreas.

Pancreas and Gall Bladder

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Nutrients from the digested food are mostly absorbed by the small intestine.

Undigested materials are converted into feces and excreted out of the body. The small intestine also absorbs water and electrolytes, while the colon absorbs leftover nutrients and water from the undigested food.

Absorption and Excretion

Waste MaterialThe human body has CO2, nitrogen compounds, and salts as most important waste products.

• The liver acts as a filter for the

blood. It cleans out toxic waste

and acid in the blood.

• Water vapor and carbon dioxide

is driven out by the lungs.

• The small intestine is covered

with tiny finger like projections

known as villi.

• Digested food is absorbed by

the body through four processes:

active transport, passive

diffusion, facilitated diffusion,

and endocytosis.

• Nutrients enter the blood

through the microvilli.

Role of SkinSkin performs an important role in excretion by removing excess water, salts, and waste such as urea.

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Reproduction is essential to keep a species alive. It is the biological process by which

one organism creates another. Reproduction in humans requires two kinds of sex cells or gametes. The male gamete is the sperm and the female gamete is the egg or the ovum. The male reproductive organs are located both inside and outside the pelvis. The organs include: testicles, epididymis, and vas deferens, the seminal vesicles, prostate gland, and penis.

• About 500 million sperm mature

everyday in a normal male adult.

• The average life span of a sperm

is about 36 hours.

• The male organs produce and

transfer sperm to the female for

fertilization.

• Testicles produce and store

millions of sperm cells.

• Testosterone is the hormone that

causes males to develop deeper

voices, bigger muscles, and body

and facial hair, and it stimulates

the production of sperm.

Hormone for Sperm ProductionFSH (Follicle Stimulating Hormone) is responsible for stimulating and maintaining sperm production.

Accessory GlandsSeminal vesicles and the prostate glands are known as accessory glands that provide fluids which lubricate the duct system and nourish the sperm.

Male Reproductive System

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The female reproductive system is a group of organs that are necessary for reproduction. It includes ovaries, fallopian tubes, uterus, and vagina. The

female reproductive system enables a woman to give birth to a child. It produces eggs, and protects and nourishes the fertilized egg until it is fully developed.

Female Reproductive System

Capability of Giving BirthThe female human body is capable of giving birth to 35 children in one lifetime.

Largest CellThe largest cell in the female human body is the ovum or egg present in the ovaries.

• In the womb, the baby’s body is

covered by a thin layer of hair,

but as soon as the baby is born, it

disappears.

• In preparation for fertilization, the

egg will be moved through the

fallopian tube in order to meet the

man’s sperm.

• Conception, the fertilization of an

egg by a sperm, normally occurs in

the fallopian tubes.

• The female has a reproductive

system located entirely in the pelvis.

• The vagina is about 3.14–

4.7 inches long in a matured

woman.

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Humans undergo sexual reproduction. The male

and female reproductive cells unite and form a single cell, which ultimately forms the baby. The female goes through a gestation period of about 40

weeks. During this period, the zygote

develops within the womb into a full-grown baby.

Premature and Post MatureBabies born before the 37-week mark are premature, and those born after the 43-week mark are considered post-mature babies.

FetusThe baby is refered to as a fetus while in the developmental stage inside the mother's womb.

• The baby lives inside a transparent

membrane called the amniotic sac.

• The arms begin to form at about

3 weeks.

• Fingernails are present at 7 months.

• The eyelids remain closed until the

7th month to protect the eyes.

• An ultrasound in the beginning of

pregnancy can find out the age of

pregnancy correctly.

Pregnancy and Birth

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Genetics

Genetics is the study of genes and heredity. It tells us about the

transfer of traits from parents to their offspring. Genetics is the scientific study of how particular traits and characteristics are transmitted from one generation to the other. In the 1850s Gregor Mendel was the first to conduct experiments on heredity. He is regarded as the father of genetics.

Genetic DiseasesSome of the common genetic diseases are sickle cell anemia, down syndrome, cystic fibrosis, hemophilia, muscular dystrophy, and color blindness.

BatesonBateson first used the term “genetics” publicly in 1906 in an international conference on genetics (London, England).

• In 1903 chromosomes were

discovered to be hereditary

units.

• The science, which grew out of

the union of biochemistry and

genetics, is widely known as

molecular biology.

• Genetic diseases are caused by

a defect in the person’s genes.

• Genetic engineering deals with

the modification of the genetic

structure of a living being.

• Genes are made up of

deoxyribonucleic acid or DNA.

• Genes carry traits, diseases,

and all other hereditary

information.

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DNA or deoxyribonucleic acid is the basis of life.

Although most of the DNAs are found in the nucleus of the cell, some of them are also found in the mitochondria. DNA has a double-helix structure, and it is made of four chemical bases: adenine (A), guanine (G), cytosine (C), and thymine (T). These chemical bases are known as nucleotides. Each DNA contains millions of these chemical bases attached in a particular way: ‘A’ combines with ‘T’, and ‘C’ joins with ‘G’.

DNA

Flexibility of DNADNA is a flexible molecule that can bend, twist, and kink.

• DNA encodes all genetic

information.

• DNA is found directly in the

cytoplasm.

• “Base pair” is a name given to

two nucleotides paired together.

• “Junk DNA” represents sequences

that do not appear to contain

genes or to have a function.

• The largest human gene is on the

X chromosome—the dystrophin

gene.

DNA DiscoveryAmerican biochemist James D. Watson and British biophysicist Francis Crick published the first description of the structure of DNA in 1953.

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DNA testing is also known as DNA fingerprinting.

It is mostly used in criminal investigations. DNA testing is believed to be more reliable, as DNA cannot be altered. DNA testing is even more reliable because apart from identical twins, no two individuals can have same set of DNA.

DNA Testing

Mode Methods of DNA testing are RFLP analysis, AmpFlp analysis, STR analysis, Y-chromosomes analysis, and mitochondrial analysis.

InventionSir Alec Jeffreys at the University of Leicester announced the invention of DNA testing in 1985.

• The most popular ancestry tests are

Y-chromosome (Y-DNA) testing and

mitochondrial DNA (mtDNA) testing.

• Mitochondrial DNA is a DNA in the

human passed down to the child by

the mother without any change.

• A person’s maternal ancestry can be

traced using his or her mitochondrial

DNA.

• DNA testing is often used in

situations involving child custody

and/or support, adoption,

inheritance, and immigration.

• DNA paternity and maternity testing

is the most accurate method of

confirming biological relationships

between alleged parents and

children.

• The DNA in each of our cells not

only dictates the color of our eyes,

but also contains the footprints of

our ancestors.

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Enzymes

Enzymes are molecules that help to speed up various chemical

reactions taking place inside the cell. Enzymes have a unique shape and they are made of amino acids. Their unique shape helps them to carry out specific chemical reactions. Restriction enzymes are enzymes that recognize and cut DNA at a specific target.

• En-zyme means “in yeast”, so

called because that is where these

proteins were first found.

• Every function of the body is

dependent upon enzymes,

including breathing, seeing,

hearing, and thinking.

• Enzymes are proteins, and the

shape of proteins determines their

function.

• Enzymes are known to catalyze

about 4,000 biochemical

reactions.

• Enzymes work very fast as they

carry out their task thousands of

times per second.

• Humans have two large categories

of enzymes: digestive enzymes and

systemic enzymes.

• The level of enzymes in the human

body decrease with age.

Categories of EnzymesEnzymes in the human body are categorized into digestive enzymes and systemic enzymes.

Wilhelm KühneWilhelm Kühne (1837–1900), a German physiologist coined the term enzyme in 1878.

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Ovaries

Hormones

Hormones are chemicals secreted

by the endocrine glands. They control growth, differentiation, and metabolism in the body. Hormones are of two types: amino acid hormones and steroid hormones. The secretion of hormones is regulated by the chemicals in the body, other hormones, and the nervous system.

HypothalamusThe hypothalamus secretes chemicals that stimulate or suppress hormone secretions from the pituitary gland.

Sex HormonesTestosterone, secreted by testes, is the male sex hormone. Estrogen and progesterone are female sex hormones secreted by ovaries.

• Prolactin hormone secreted by the

pituitary gland activates milk production in

women.

• Thyrotropin hormone secreted by the

pituitary gland stimulates the thyroid

gland to produce thyroid hormones.

• Thyroxine hormone secreted by the thyroid

gland controls the rate at which cells burn

fuels from food to produce energy.

• Insulin secreted by the pancreas helps

to maintain a steady level of glucose or

sugar in the blood.

• Catecholamines hormone secreted by the

adrenal glands increases blood pressure

and heart rate when the body experiences

stress.

• Melatonin hormone secreted by the pineal

gland regulates the wake-sleep cycle.

Steriod hormone

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Genome

Genome refers to the complete genetic

instructions for an organism. They are also like a library of instructions. A gene is a sequence

of adenine, thymine, guanine, and cytosine. These nucleotides combine together to provide the instructions.

The normal human genome consists of 3 billion base pairs of DNA in each set of 23 chromosomes from one parent.

• In 1920 Hans Winkler, Professor of

Botany at the University of Hamburg

coined the term “genome.”

• In 1976 Walter Fiers was the first to

establish the complete nucleotide

sequence of a viral RNA.

• Phage-X174 was the DNA-genome

project to be completed by Fred

Sanger in 1977.

• In 1995 the first bacterial genome

of Haemophilus influenzae was

completed.

• The Human Genome Project was

organized to map and to sequence

the human genome.

• Currently, there are two human

genome projects: the first is

being produced by a group of

international government bodies and

organizations, and the second by a

private company—Celera Genomics.

• Shotgun sequencing is the technique

used in breaking the DNA into

millions of pieces.

Genome DegradationGenome degradation is the process by which a genome shrinks relative to its ancestor.

Genome SizeGenome size refers to the total amount of DNA contained within one copy of a genome.

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RNA

RNA or ribonucleic acid is similar to DNA

except that it has a single strand. RNA is made of four chemical bases, similar to DNA, except for thymine. Uracil takes the place of thymine in RNA. The process of protein synthesis is carried out with the help of RNA.

• RNA is found in animal and plant cells.

• Messenger RNA is RNA that carries

information from DNA.

• RNA is usually a single-stranded molecule

and has a much shorter chain of

nucleotides.

• Synthesis of RNA is usually catalyzed by an

enzyme.

• RNA also serves as the hereditary material

in some of the viruses.

• The discovery of ribozymes added to the

evidence that RNA, not DNA, was the

earliest genetic material.

• In 1981 American biochemist, Thomas

Cech, discovered that certain RNA

molecules act as enzymes.

Ribonuclease-PThe enzyme, ribonuclease-P, is in all organisms. It is the part of RNA that has enzymatic activity.

In Laboratory SynthesisRNA was produced in a laboratory for the first time in 1955.

T-RNA

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Cloning

• Therapeutic cloning, also called

“embryo cloning,” is the production

of human embryos for use in

research.

• Cloning is asexual reproduction.

• Cloning of any DNA sequence

involves the following four steps:

amplification, ligation, transfection,

and screening/selection.

• The first mammal to be cloned was a

sheep called Dolly. She was born on

July 5, 1996, at the Roslin Institute,

Edinburgh, Scotland.

• Biomedical scientists use stem cells

to generate all the other specialized

types of cells in the human body.

Bone marrow is a rich source of stem

cells.

Technologies of CloningDNA cloning, reproductive cloning, and therapeutic cloning are different technologies of cloning.

Cloning refers to the creation of an identical copy of an original organism. A clone is

genetically identical to the original organism. Cloning started in 1970s, when scientists experimented with frogs and toads. The possibilities of cloning a human became a reality when a sheep named Dolly was cloned.

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The endocrine system is a system of ductless glands in the human body. These glands are called endocrine glands. The

endocrine glands produce and secrete hormones into the blood or lymph systems. The endocrine glands are pituitary, thyroid, parathyroid, adrenal, Islets of Langerhans in the pancreas, and

the gonads (testes and ovaries).

Hormones in the Human BodyThe human body contains 30 amazing hormones, which regulate activities like sleep, body temperature, hunger, and managing stress in times of crisis and so on.

PubertyPuberty for girls usually begins between ages 9 to 13, and for boys the age is 10 to 15.

• The pituitary gland is known as

master gland because it makes

hormones to control several other

endocrine glands.

• Diabetes mellitus is a disease in

which glucose is not sufficiently

metabolized. It results from

deficiency of insulin.

• Acromegaly is a disease in which

the growth hormone is produced

throughout a person’s lifetime.

• The pituitary gland regulates the

growth of bone and tissue.

• The thyroid gland regulates the rate

of growth and metabolism.

• The gonads are the main source of

sex hormones.

• The pancreas produces two

important hormones—insulin and

glucagon.

Endocrine System

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Blood Transfusion

A blood transfusion is the transferring of blood or blood-based products. Blood transfusions take place from one person into the circulatory system of another.

It happens in many situations, such as massive blood loss and severe anemia. In 1818 Dr. James Blundell performed the first successful blood transfusion to treat hemorrhage.

• Every three seconds someone needs

blood. Blood and blood products

are used to treat accident and burn

victims, cancer patients, and other

patients undergoing surgeries and

medical treatments.

• One unit of blood is roughly the

equivalent of one pint. On average,

an adult has approximately seven to

nine units of blood.

• Each year approximately 8 million

volunteer donors give about

14 million blood donations.

• About 12 million units of red blood

cells and whole blood, 8 million

platelet units, and 3 million plasma

units are transfused annually.

• More than 90 percent of transfusion

complications have been attributed

to the presence of leukocytes in

allogeneic blood.

Universal Blood DonorsPersons belonging to the O blood

group are called universal blood donors.

First Effort for Blood Transfusion 15th century chronicle, Stefano Infessura, described the first historical attempt at a blood transfusion.

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Kidney Dialysis

Kidney dialysis is used to remove impurities from the blood.

Blood is pumped out of the body and cleaned inside a machine called a dialyser, which acts as an artificial kidney. Dialysis is of two types: hemodialysis and peritoneal dialysis. Most patients with damaged kidneys receive hemodialysis.

• Dialysis works on the principle of

the diffusion of solutes across a

semipermeable membrane.

• In 1913 John J. Abel “dialyzed”

animals by directing their blood

outside the body and through tubes

with semipermeable membranes.

• In 1924 German doctor Georg

Haas performed the first dialysis

treatment involving humans.

• Willem Kolff is acknowledged as the

father of the modern kidney dialysis.

• In 1943 Willem Kolff invented a

crude kidney dialyzer.

• The next generation of Kolff’s

dialyzer was a stainless steel Kolff-

Brigham kidney, which paved the

way for the first kidney transplant in

1954.

• In 1962 Dr. Belding Scribner started

the world’s first outpatient dialysis

facility.

Parallel Plate DialyzerThe Parallel Plate Dialyzer was a kidney dialyzer that worked by directing the flow of dialysis solution and blood through alternating layers of membranous

Father of DialysisScottish chemist, Thomas Graham, was known as the “Father of Dialysis.”

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Yellow Fever

Yellow fever is a viral disease. Aedes aegypti mosquitoes transmit the

yellow fever virus. This disease mainly affects the liver. Symptoms of yellow fever include jaundice, muscle pain, high fever, bleeding, and sometimes death.

Tropical FeverYellow fever is a tropical disease caused by infected mosquitoes, and found only in Africa and South America.

Vaccination for Life A single dose of yellow fever vaccine provides protection for 10 years and probably for an entire life.

• Yellow fever is preventable by

immunization.

• There are two kinds of yellow

fever: jungle and urban yellow

fever.

• The “yellow” in the name is

explained by the jaundice that

affects some patients, causing

yellow eyes and yellow skin.

• Yellow fever results in epidemics

that can affect 20% of the

population.

• Yellow fever is caused by the

yellow fever virus, which belongs

to the flavivirus group.

• Fever, headache, and muscle

ache may occur 5 to 14 days after

vaccination. In rare instances,

encephalitis (inflammation of

the brain) has developed in very

young infants.

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Mumps

Mumps is a viral infection that is highly contagious.

Mumps primarily affects children under nine years of age. This disease causes the swelling of the parotid gland. Symptoms of mumps include high fever, headache, loss of appetite, and bumps on the cheek.

Transmission of MumpsMumps is a viral disease spread through direct contact with saliva, secretions from the respiratory tract, and urine of an infected person.

Prevention of MumpsThe mumps vaccine is known as MMR, which is given in one injection with the measles and rubella vaccines.

• Mumps is caused by the myxo virus.

• Mumps infections are uncommon in

children younger than 1-year-old.

• Mumps can lead to inflammation and

swelling of the brain and other organs,

though this is not common.

• About 1/3 of people have no symptoms.

• The virus may cause a miscarriage if a

woman becomes infected during the first

three months of pregnancy.

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Gout

Gout is a form of arthritis that occurs mostly in men.

It is caused by excess uric acid crystal deposits in the blood and joints. It is an extremely painful disease, which usually affects the big toe. Symptoms of gout

include red, swollen joints, and acute pain.

Obesity Increases the RiskExcessive weight can increase the risk of developing hyperuricemia and gout due to availability of tissues for breakdown that leads to excess uric acid production.

Attack of GoutGout usually affects a single joint and may begin anytime but often at night.

• The leading risk factor for gout

is a buildup of uric acid in the

bloodstream—a condition known

as hyperuricemia.

• About 90% of people with gout

have reported at least one flare-

up in their big toe. But they can

also experience symptoms in

other joints, including the hands,

elbows, and knees.

• Men are at least four times

more likely to develop gout than

women.

• Men who develop gout usually do

so between the ages of 30 and

50. Women are more likely to

develop gout after the age of 60.

• Events such as strokes, heart

attacks, or surgery may also cause

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Chickenpox

Chickenpox is an infectious, viral disease

caused by the varicella virus. It is an acute, communicable disease that usually occurs in young children. A person suffering from chickenpox is covered with red spots all over the body. Symptoms of chickenpox include fever, headache, tummy ache, loss of appetite, and classic pox rash on the skin.

Viral DiseaseChickenpox is a contagious viral disease spread from person to person directly from broken chickenpox blisters.

Chickenpox ComplicationsAlthough chickenpox is a mild disease, it can cause problems for pregnant women, newborn babies, and people having certain immune system problems.

• Chickenpox is spread by direct contact

or breathing in from nose and throat

secretions.

• Incubation period lasts 10–21 days

before symptoms appear.

• A chickenpox (varicella) vaccine,

approved in 1995, is recommended

for all children ages 1–13 who haven’t

already had chickenpox.

• Chickenpox has a superficial

resemblance to smallpox. It is completely

different and less severe.

• The number of pox is different for

everyone. Some people get just a few

bumps; others are covered from head to

toe.

• Chickenpox is infectious from about 2

days before the rash appears, and lasts

until all the blisters are crusted over.

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Allergy

An allergy is an abnormal response of the body's

immune system. It occurs because of the body’s high sensitivity to certain substances such as oil, fungi, molds, pollen, animals, plants, etc. Symptoms of allergies include runny nose, watery and itchy eyes, sneezing, asthma, and allergic shiners (dark circles under the eyes) in children.

Antibody Immunoglobulin EAllergic people make a special antibody called immunoglobulin E that react with environmental substances in a harmful way.

Symptoms of AllergiesSneezing, runny nose, itchy throat, red or swollen eyes.

• Anaphylactic shock is a severe

allergy which affects many organs

at the same time causing a rapid

decrease in blood pressure, fainting,

and, occasionally, death.

• People with allergies have an

antibody called IgE (immunoglobulin

E).

• Feathers, wool, dyes, cosmetics, and

perfumes may act as allergens.

• The most common allergens are

animal dander, pollen, house

dust, house dust mites, molds,

some drugs, and many foodstuffs,

especially fish, eggs, milk, and nuts.

• Conjunctivitis is an allergic condition

of the eyes mostly in adults.

• Asthma may begin at any age and

one can suffer from attacks that

obstruct the flow of air to the lungs.

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Acne

Acne is a skin disease that occurs in adolescents. The

over-activity of oil glands at the base of a hair follicle causes acne. Acne can take many forms, such as whiteheads, blackheads, pimples, and cysts.

Inflammatory AcneThe papule is a small, solid, usually inflammatory elevation of the skin that does not contain pus.

Hormonal ChangesAcne is caused due to changes in hormones during the menstrual cycle.

• Acne is more prevalent in women

than men.

• Factors that may contribute to acne in

women include: hormonal fluctuations of

menstrual cycles and use of cosmetics.

• There are two classes of acne, non-

inflammatory (blackheads and

whiteheads), and inflammatory (papules,

pustules, and cysts).

• Acne can cause psychological problems.

• There is no cure for acne. There are

only treatments that prevent and control

breakouts.

• Chocolate and greasy foods do not cause

acne.

• In acne, too much sebum is produced by

the over-stimulated sebaceous glands.

• Hormones are known to be the main

culprit for acne.

• The full cycle of acne generally lasts

about 8 weeks.

• Laser therapy, chemical peels,

dermabrasion, and other treatments have

been suggested for acne scarring.

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Cancer

Cancer is the uncontrolled

growth of cells. Cancerous cells can spread in any tissue of the body. Cancer is a class of diseases that can affect people of all ages. It is one of the main causes of death in many countries.

Treatment of CancerCancer can be treated by surgery, chemotherapy, and radiotheraphy.

Cancer is CurableCancer risk can be reduced by not smoking, eating healthy food, and avoiding contact with carcinogens.

• More than 11 million people across

the world are affected by cancer.

Cancer causes 12.5% deaths every year

worldwide.

• Common types of cancer are leukemia,

breast and ovarian cancer in women,

prostate cancer in men, and cancer of

lungs, colon, rectum, kidney, skin, head,

and neck.

• Infectious diseases and exposure to

chemicals can lead to cancer.

• The disease tends to affect older people –

but can strike at any time.

• Cancer happens when a tiny part of the

cell’s mechanism goes wrong.

• The key symptom of lung cancer is a

persistent cough that gradually gets

worse.

• Leukemias and lymphomas are cancers

which affect the cells that are part of the

fluids circulating around the body.

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HIV

HIV or Human Immuno- deficiency virus is a

retrovirus. HIV causes AIDS or Acquired Immunodeficiency Syndrome. This virus attacks the human immune system. Viruses are nucleic acid wrapped in a layer of protein. They spread from one person to another through coughs, sneezes, vomit, or contact with body fluid of an infected person.

HIV Causes AIDSIn 1984 scientists proved that HIV causes AIDS. The first reported case of AIDS was in the United States in 1981.

Medicine for AIDSAIDS cannot be cured but with the new medications and protease inhibitors available, people can live longer.

• HIV spreads through

unprotected sex, transfusions

of unscreened blood,

contaminated needles, and

from an infected woman to

her child during pregnancy,

childbirth, or breastfeeding.

• A blood test for HIV is the

only way to test for the virus.

• HIV is most frequently

transmitted sexually.

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IndexAntigens 19, 21

Autoimmune 19

Axial 6, 12

Carcinogens 62

Cardiac 12, 25

Cerebrum 15

Coronary 22

Cysts 61

Dendrites 17

Dialyzer 55

Diaphragm 9, 31, 33

Duodenum 40

Endocrine 3, 5, 35, 40, 49, 53

Epithelial 4

Gestation 44

Gregor Mendel 45

Heinrich Wilhelm Gottfried 17

Hepatic 39

Keratin 10

Lumen 24

Lymphatic 5, 19

Mastication 8

Meninges 16

Neurons 4, 14, 17, 18

Nucleotides 46, 50, 51

Parasites 21

Parotid gland 57

Pathogens 19

Pituitary 49, 53

Platelets 23

Restriction enzymes 48

Retina 27

Sperm 42, 43

Thalamus 15

Trachea 29, 32, 33

Uracil 51

Urethra 34

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