Human Body Systems

Levels of OrganizationCells

TissuesOrgans

Organ Systems

Levels of Organization

Level of Organization

Examples

Cells Nerve cell, red blood cell

Tissues Epithelial, connective, nervous, and muscle tissue

Organs Stomach, eye, liver, heart

Organ System Digestive, cardiovascular

Nervous System•Structures: brain, spinal cord, peripheral nerves, neurons•Functions:

• Sensory/Motor• Controls and regulates body’s functions• Communication system (relays info)

Integumentary System Skeletal System Muscular System Circulatory SystemNervous System

FUN FACT!

How many neurons in the brain?Human brain= 86 billionElephant = 23 billionChimpanzee = 7 billionCat = 1 billionMouse = 75 millionCockroach = 1 million

Integumentary System•Structures: skin, hair, nails, sweat & oil glands•Functions:

• Barrier from injury and infection

• Largest organ• Sensory neurons:

Integumentary System Skeletal System Muscular System Circulatory SystemNervous System

FUN FACT!The skin on your mouth is 200 times more sensitive than your fingertips.

Skeletal System•Structures: bones, cartilage, ligaments, tendons

•Functions:• Support• Protection• Movement

Integumentary System Skeletal System Muscular System Circulatory SystemNervous System

FUN FACT!

The area of our body with the most bones is

the hand, fingers and wrist where there are

54 bones.

• Structures: Skeletal muscle, smooth muscle, cardiac muscle

Integumentary System Skeletal System Muscular System Circulatory SystemNervous System

• Functions: • Voluntary

movement >Skeletal system

• Involuntary movement >Circulates blood >Moves food

Muscular System

FUN FACT!

• There are about 60 muscles in the face.

• Smiling is easier than frowning!

• It takes 20 muscles to smile and over 40 muscles to frown.

Circulatory System•Structures: heart, blood vessels, blood

•Functions:• Oxygen and nutrients• Fights infection• Removes cell waste

Integumentary System Skeletal System Muscular System Circulatory SystemNervous System

FUN FACT!

“Broken heart syndrome” (stress cardiomyopathy)•Feels like heart attack:

– chest pain– shortness of breath – arm aches.

•Emotionally stressful event

Respiratory System•Structures: nose, pharynx, larynx, trachea, bronchi, bronchioles, lungs•Functions:

• Provides O2 • Remove CO2 • Works with circulatory system

Digestive System Endocrine SystemExcretory System Reproductive SystemRespiratory System

Digestive System•Structures: Mouth, pharynx, esophagus,

stomach, small and large intestines, rectum

•Functions:• Take in, break down, absorb food• Food simpler molecules • Eliminates wastes

Digestive System Endocrine SystemExcretory System Reproductive SystemRespiratory System

FUN FACT!

The stomach secretes:a) hydrochloric acid

2 liters/dayb) mucus

new coat/2 weeks

Excretory System•Structures: Skin, lungs,

kidneys, ureters, urinary bladder, urethra•Functions:

• Eliminate waste• Homeostasis

Digestive System Endocrine SystemExcretory System Reproductive SystemRespiratory System

FUN FACT!Kidney Stones

•Painful crystals•0.12in = block•Largest= 2.48 lbs (coconut)

Endocrine System•Structures: Hypothalamus, pituitary, thyroid, parathyroids, adrenals, pancreas, ovaries, testes•Functions:

• Uses chemicals (hormones)• Growth and development• Metabolism• Homeostasis• Internal & external stimuli

Digestive System Endocrine SystemExcretory System Reproductive SystemRespiratory System

Reproductive System•Structures: -Ovaries, Fallopian tubes, uterus, vagina -Testes, epididymis, vas

deferens, urethra, penis•Functions:

• Reproductive/sex cells (sperm and egg)

• Male/female sex characteristics• Nurtures and protects embryo

Digestive System Endocrine SystemExcretory System Reproductive SystemRespiratory System

Lymphatic/Immune System

•Structures: white blood cells, thymus, spleen, lymph nodes, lymph vessels•Functions:

• Protects from disease• Fluid collection• B cells and T cells • Immune/Inflammatory

response• Antibody production

Lymphatic / Immune System

B cells – Bone marrow, make antibodiesT cells – Thymus, killer or helper T cells

Homeostasis• “Keeping things in balance”

• Internal conditions = constant external conditions = changing

Room temperature increases

Thermostat senses temperature change and switches on heating system

Thermostat senses temperature change and switches off heating system

Room temperature decreases

Examples of Feedback Inhibition

Can Olaf maintain homeostasis using feedback inhibition?

Reference A