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HUMANBODY HUMAN
BODYTITLES IN THIS SERIES
Animal WorldEarth
Human BodyMachines & Inventions
PlantsUniverse
HU
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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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