Chapter 20. Chapter 20: Introduction to Animal Physiology

Review & Rehearse

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You must read each slide, and complete any questions on the slide, in sequence.

Instructions

Review the visual summaries and answer the essay questions below.

Make sure to enter a brief response that completely answers each question and explains your reasoning. When you click "Submit," you will be provided instant feedback, allowing you to check if your response is correct.

(This activity contains 12 total essay questions. Each new question will be revealed once you complete the preceding question.)

1.

1. What is the major benefit to organisms of multicellularity?

A chief benefit of multicellularity is that it makes possible a division of labor and specialization at the cellular level.

2.

2. Why is connective tissue sometimes referred to as “cellular glue”?

Connective tissue is like a “cellular glue” because it holds cells together in a matrix and gives shape, support, and structure to other tissues and organs throughout the body.

3.

3. Describe one way that epithelium functions in the secretion of molecules.

Epithelial tissue can form exocrine glands, which, depending on the type, produce and secrete saliva, sweat, or mucus.

4.

4. Describe the three types of muscle tissue in vertebrates and their similarities and differences.

(a) Skeletal muscles attach to bones and generate movement; most are under conscious control (some, such as those that control breathing, are not). (b) Cardiac muscle is located only in the heart and is not under conscious control. (c) Smooth muscle is found in the bladder and stomach and in many other organs. It generates slow rhythmic contractions and is not under conscious control. All three types of muscle are similar in that they consist of cells that can contract.

5.

5. What is a possible consequence of damage to your glial cells?

Glial cells support, nourish, and protect nerve cells (neurons). Damage to the glial cells could cause overall dysfunction of the nervous system, including impairment of signal propagation, of nervous system development, and of the repair of nervous system injury.

6.

6. Which organ system regulates the rate at which the heart pumps blood?

The circulatory system regulates the pumping of blood around the body.

7.

7. What is hyperthermia? How does it reflect a failure of the body to maintain homeostasis?

Hyperthermia is a dangerously elevated body temperature. It is caused by a failure of the body to maintain homeostasis—a consistent internal environment, including a consistent body temperature, that is necessary for the normal functioning of cells, tissues, and organ systems.

8.

8. Multicellularity and large body size typically lead to the increased importance of the internal (relative to the external) environment in influencing cell functioning. Why?

In large multicellular organisms, the vast majority of cells are not in direct contact with the external environment, and thus the internal environment takes on greater importance than the external environment in influencing cell functioning. Internal variables such as pH, blood gas concentrations, and temperature are kept within a relatively constant range.

9.

9. In organisms, why are negative feedback systems more common than positive feedback systems?

Negative feedback systems are more common in organisms because they oppose or reduce change in the internal environment. Positive feedback systems, in contrast, oppose homeostasis in response to a change, pushing the body away from normal conditions.

10.

10. An organism’s temperature is a function of the heat produced by its body in conjunction with the heat transferred from the environment to its body or from its body to the environment. Describe two ways in which heat exchange occurs.

(a) Evaporation is the loss of heat that occurs as a liquid turns to gas (the evaporation of sweat is an example). (b) Radiation is the transfer of heat, without direct contact, from a warmer object to a colder object (the heat from a fireplace is an example).

11.

11. Does an invertebrate osmoconformer living in salt water have a set point with respect to the solute concentrations in its body fluids? Why or why not?

An invertebrate osmoconformer living in salt water does not have a set point for solute concentration in its body fluids. The solute concentrations of its body fluids reflect those of the external environment.

12.

12. Describe the factors that influence the amount of urine produced by a human in one day.

The amount of urine excreted each day depends on fluid intake and water loss due to perspiration or exhalation.

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