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
Nervous
c. Removes waste
Respiratory
d. Controls communication in 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. Muscular system

10. 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

11. Endocrine system

12. Define the following terms:
Gland:
An organ that secretes a hormone
Hormone:
A chemical secreted by the body to stimulate a type of action
Negative Feedback Loop
A reaction that occurs in the body that is meant to counteract another reaction (work in the opposite way)

13. What are three functions of the endocrine system?
Maintaining homeostasis
Growth
Development

14. Excretory system

15. Aorta
Renal vein
Kidney
Ureter
Bladder
Urethra

16. Skeletal system

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