1. Human Body Systems Study Guide
Answer Key

2. Human body organization

3. 1. List the levels of organization in the human body, starting with the smallest unit.
Cells
Tissues
Organs
Organ systems (aka body system)
Organism (aka body)

4. The basic unit of structure and function in a living thing is a(n) .
What is a tissue?
A structure that is made of different types of tissues is a(n) .
Circle the letter of the unit of organization that represents an organ.
cell
A group of cells working together for a common function.
organ
C. Heart

5. 7. Match the organ system with its function.
6. What is an organ system?
An organ system is a group of organs working together for a common function.
7. Match the organ system with its function.
Organ System
Function
Circulatory
a. Takes oxygen into the body
Excretory
b. Supports and protects the body
Integumentary
c. Removes waste
Respiratory
d. Provides coverings for the body
Digestive
e. Takes food into the body and breaks it down
Skeletal
f. Transports materials to and from body cells F C D A E B

6. The process by which an organism’s internal environment is kept stable in spite of changes in the external environment is called
How does your body maintain a constant temperature on a hot day?
homeostasis
The sweat glands in your skin release sweat to help cool the surface of your skin and your blood vessel dilate (get bigger) and move closer to the surface of your skin to release the heat being carried in your blood.

7. Circulatory system

8. Label the diagram of the heart.
Aorta
Superior vena cava
Pulmonary
artery
Right atrium
Left atrium
Inferior vena cava
Left ventricle
Right ventricle

9. Respiratory system

10. Nose
Epiglottis
Trachea
Lung
Bronchus
Alveoli
Diaphragm

11. Nose Trachea Epiglottis Alveoli Lungs Diaphragm Bronchus
8. warms and moistens air; filters dust particles
9. transports air to the lungs
10. prevents food from entering the trachea
11. oxygen passes into the capillaries
12. Organs made up of masses of alveoli
13. A sheet of muscle across the bottom of the chest cavity
14. A division of the trachea
Trachea
Epiglottis
Alveoli
Lungs
Diaphragm
Bronchus

12. Digestive system

13. Mouth: Mechanical digestion of food (chewing)
Esophagus: Carries the food from the mouth to the stomach
Stomach: Chemical digestion of food
Small intestine: Continues last stages of digestion, absorbs nutrients for the rest of the body
Large intestine: Holds the remainder of food (waste); absorbs water from food; eliminates waste

14. Mouth
Esophagus
Liver
Stomach
Pancreas
Gallbladder
Large intestine
Small
intestine
Rectum

15. Nervous system

16. Neuron: brain cells; carries messages from brain throughout the rest of the body
Dendrite: the part of the neuron that receives messages
Axon: the part of the neuron that sends messages
Synapse: The space between the dendrite of one cell and the axon of another cell where information is transferred

17. Neuron
Dendrite
Axon
Synapse

18. Muscular system

19. Thigh Upper Arm Intestine Heart Calf Skeletal Voluntary Skeletal
Think of the type of muscle associated with each of the following body parts. Indicate the type of muscle and whether it is voluntary or involuntary.
Thigh
Upper Arm
Intestine
Heart
Calf
Skeletal
Voluntary
Skeletal
Voluntary
Involuntary
Smooth
Cardiac
Involuntary
Skeletal
Involuntary

20. Excretory system

21. Aorta
Renal vein
Kidney
Ureter
Bladder
Urethra

22. Skeletal system

23. Main Functions Support Movement Protection Production of blood cells
Storage of minerals

24. Integumentary system

25. Main Functions Protection Temperature regulation
Sensation (feeling/physical touch)
Production of vitamin D