<meta http-equiv="refresh" content="1; url=/nojavascript/"> Organization of the Human Body | CK-12 Foundation
You are reading an older version of this FlexBook® textbook: CK-12 Biology Workbook Go to the latest version.

# 21.1: Organization of the Human Body

Created by: CK-12

## Lesson 21.1: True or False

Name___________________ Class______________ Date________

Write true if the statement is true or false if the statement is false.

_____ 1. Cells are the basic units of structure and function in the human body.

_____ 2. The human body consists of four tissue types.

_____ 3. Bone is an example of epithelial tissue.

_____ 4. Epithelial tissue is made up of cells that only line outer body surfaces.

_____ 5. Muscles attached to bones enable the body to move.

______6. Neurons carry electrical messages.

_____ 7. After tissues, organs are the next level of organization of the human body.

_____ 8. An organ is a structure that consists of only two types of tissues that work together to do the same job.

_____ 9. The digestive system breaks down food and absorbs its nutrients.

_____ 10. The endocrine system removes excess fluid from tissues and transports substances.

_____ 11. All of the organs and organ systems of the human body work together like a well-oiled machine.

_____ 12. The nervous system controls virtually all body activities.

_____ 13. Keeping a stable internal environment does not require constant adjustments.

_____ 14. A low concentration of carbon dioxide in the blood triggers faster breathing.

_____ 15. A low level of water in the blood triggers retention of water by the kidneys.

Name___________________ Class______________ Date________

Read these passages from the text and answer the questions that follow.

Maintaining Homeostasis

The process in which organ systems work to maintain a stable internal environment is called homeostasis. Keeping a stable internal environment requires constant adjustments. Here are just three of the many ways that human organ systems help the body maintain homeostasis:

• Respiratory system: A high concentration of carbon dioxide in the blood triggers faster breathing. The lungs exhale more frequently, which removes carbon dioxide from the body more quickly.
• Excretory system: A low level of water in the blood triggers retention of water by the kidneys. The kidneys produce more concentrated urine, so less water is lost from the body.
• Endocrine system: A high concentration of sugar in the blood triggers secretion of insulin by an endocrine gland called the pancreas. Insulin is a hormone that helps cells absorb sugar from the blood.

Failure of Homeostasis

Many homeostatic mechanisms such as these work continuously to maintain stable conditions in the human body. Sometimes, however, the mechanisms fail. When they do, cells may not get everything they need, or toxic wastes may accumulate in the body. If homeostasis is not restored, the imbalance may lead to disease or even death.

Questions

1. What is homeostasis?

$\\\\\\\\\\$

2. What is the result of the lungs exhaling more frequently?

$\\\\\\\\\\$

3. What is the result of a more concentrated urine?

$\\\\\\\\\\$

4. What is the function of insulin?

$\\\\\\\\\\$

5. If there is a failure of homeostasis and homeostasis is not restored, what may happen?

$\\\\\\\\\\$

## Lesson 21.1: Multiple Choice

Name___________________ Class______________ Date________

Circle the letter of the correct choice.

1. Approximately how many cells does the average person reaching adulthood have?
1. 100 thousand
2. 100 million
3. 100 billion
4. 100 trillion
2. Cartilage is an example of which of the following tissues?
1. connective tissue
2. epithelial tissue
3. muscle tissue
4. none of the above
3. The lymphatic system removes which of the following from tissues?
1. excess gases
2. excess fluids
3. excess solids
4. none of the above
4. All of the organs and organ systems of the human body work well together because they are closely regulated by which of the following systems?
1. lymphatic and nervous
2. endocrine and muscular
3. nervous and endocrine
4. circulatory and lymphatic
5. Which of the following systems secretes hormones?
1. nervous
2. endocrine
3. circulatory
4. respiratory
6. Which of the following systems produces gametes?
1. reproductive
2. endocrine
3. circulatory
4. nervous
7. Insulin is secreted by an endocrine gland called the
1. thyroid.
2. pineal body.
3. pancreas.
8. The correct order of levels of organization is
1. cell → organ → tissue → organism.
2. cell → tissue → organ → organ system.
3. organelle → cell → organ → organ system.
4. atom → cell → organ → tissue.
9. Which of the following statements is true concerning maintaining homeostasis? (1) Homeostasis is maintained through the interactions of a number of organ systems. (2) Not maintaining homeostasis can lead to death. (3) A high concentration of carbon dioxide in the blood triggers faster breathing to remove the oxygen. (4) A high level of water in the blood triggers retention of water by the kidneys.
1. 1 only
2. 1 and 2
3. 3 and 4
4. All four statements are correct.

## Lesson 21.1: Vocabulary I

Name___________________ Class______________ Date________

Match the vocabulary word with the proper definition.

Definitions

_____ 1. a structure that consists of two or more types of tissues that work together to do the same job

_____ 2. made up of neurons, or nerve cells, that carry electrical messages

_____ 3. made up of cells that form the body’s structure

_____ 4. a group of connected cells that have a similar function

_____ 5. takes in oxygen and releases waste gases

_____ 6. made up of cells that line body surfaces

_____ 7. secretes hormones that regulate other organs and organ systems

_____ 8. basic units of structure and function in the human body

_____ 9. a hormone that helps cells absorb sugar from the blood

_____ 10. process in which organ systems work to maintain a stable internal environment

_____ 11. made up of cells that have the unique ability to contract, or become shorter

_____ 12. a group of organs that work together to carry out a complex overall function

Terms

a. cells

b. connective tissue

c. endocrine system

d. epithelial tissue

e. homeostasis

f. insulin

g. muscle tissue

h. nervous tissue

i. organ

j. organ system

k. respiratory system

l. tissue

## Lesson 21.1: Vocabulary II

Name___________________ Class______________ Date________

Fill in the blank with the appropriate term.

1. The human machine is organized at different levels, starting with the cell and ending with the entire _______________.

2. At each higher level of organization, there is a greater degree of _______________.

3. Many human cells are specialized in form and _________________.

4. Muscle cells have many __________________ that provide the energy they need to move the body.

5. After the cell, the ________________ is the next level of organization in the human body.

6. _________________ tissue protects the body and its internal organs.

7. Epithelial tissue secretes substances such as ________________.

8. Nervous tissue makes up the brain and the _______________ that connect the brain to all parts of the body.

9. Human organs are organized into organ _________________.

10. The __________________ system takes in oxygen and releases waste gases.

11. The skeletal system provides ___________________ to the body and protects internal organs.

12. Functioning together, the organ systems keep _______________, pH, and other conditions at just the right levels to support life processes.

## Lesson 21.1: Critical Writing

Name___________________ Class______________ Date________

Thoroughly answer the question below. Use appropriate academic vocabulary and clear and complete sentences.

Describe the four types of tissues and give an example of each.

Feb 23, 2012

Jun 06, 2014