1. Twelve things to know about… HUMAN ORGAN SYSTEMS
12T2K!
Twelve things to know about…
HUMAN ORGAN SYSTEMS

2. Thing 1: Systems are made of organs
Every system in our body is made up of some number of organs.
Each organ in a system is made up of some number of tissues.
Tissues  Organs System
Some organs belong to more than one system.

3. Thing 2: Integumentary system
Covers and protects the body.
Skin is the main organ of the integumentary system.
Skin has several functions:
Regulates body temperature
Produces vitamin D
Protects our body
Helps us sense our surroundings

4. Thing 3: Skeletal system
There are 206 bones in a normal adult.
Functions of the skeletal system include:
Support of body shape
Protection
Skull protects brain
Ribs protect heart and lungs
Vertebrae protect spinal cord
Bone marrow makes blood cells and stores fat
Mineral storage (calcium)

5. Thing 4: Muscular system
There are three types of muscle
Smooth muscle lines inside of hollow organs (stomach, blood vessels, bladder) and is involuntary.
Cardiac muscle is in the heart and is involuntary.
Skeletal muscle are attached to bones by tendons. These are voluntary muscles.

6. Thing 5: Nervous system
The central nervous system is made up of the brain and spinal cord. The CNS has many functions, including:
Sending messages
Processing information
Storing information
Analyzing responses

7. The peripheral nervous system has two kinds of neurons (nerve cells).
Sensory neurons send information about the environment to the CNS.
Motor neurons send signals from the CNS to other body parts (muscles, etc.)

8. Thing 6: Circulatory system
The body’s transport system.
Delivers oxygen and nutrients to cells
Removes waste products
Main parts:
Blood
Blood vessels
Heart

9. Two types of large blood vessels:
Arteries carry blood away from the heart.
Veins carry blood to the heart.

10. Thing 7: Respiratory system
Allows for gas exchange (O2, CO2).
Lungs are the main organs.
Breathing is the movement of air in and out of lungs.
Respiration is the exchange of gases.

11. Thing 8: Excretory system
Remove wastes from blood.
Kidneys are the main organs.
Skin and lungs are part of excretory system, too.

12. Thing 9: Digestive system
Three main functions:
Take in food
Break down food
Gets rid of undigested material
Many organs involved, including:
Stomach
Liver
Intestines (large and small)
Pancreas
Gall bladder
Esophagus

13. Thing 10: Endocrine system
Endocrine organs produce hormones, chemical messengers that act on target cells and tissues.
Organs (glands) include:
Pituitary gland
Thyroid gland
Adrenal gland
Many others

14. Thing 11: Reproductive system
Main organs in males:
Penis
Testicles
Main organs in females:
Ovary
Uterus
Vagina

15. Thing 12: Immune system Protects against infection
Skin, tears, and mucus membranes help prevent infectious particles from entering our body.
White blood cells called B cells and T cells fight infection inside our body.
B cells make antibodies. Anything that an antibody binds to is called an antigen.