Chapter 1

Question 1

Where do cells live?

Answer 1

Highly protected milieu interior.

Question 2

How do homeostatic mechanisms work?

Answer 2

Through feedback-oriented control.

Question 3

How is the milieu interior maintained?

Answer 3

Homeostatic mechanisms.

Question 4

What exactly is homeostasis?

Answer 4

The control of a parameter that is vital to the body.

Question 5

What are the four elements of a negative/positive feedback mechanism?

Answer 5

1. Ability to sense the vital parameter.
2. Compare the situation to a standardized set point.
3. Ability to amplify the sensed response to create an output response
4. The output signal/response should be able to create an effect that brings the situation back to the “set point”.

Question 6

If there is a common characteristic between two or more feedback loops, what should be taken into account?

Answer 6

1. Competition between the feedback loops.

2. Heirarchy between the feedback loops (which one prevails over the other).

Question 7

How does redundancy relate to feedback mechanisms?

Answer 7

There could be multiple feedback loops that serve a vital parameter. This is why knocking out one component of a feedback loop can sometimes not show deleterious effects.

Question 8

Equilibrium is a state that ____?

Answer 8

…does not require energy consumption.

Question 9

Acclimatization

Answer 9

Occurs after an adaptive homeostatic response to a situation has occurred.

Question 10

Two conditions a physiologist must be prepared to consider when conducting an experiment:

Answer 10

1. Does the gene of interest have the potential to modulate a situation?
2. The mechanism to which the gene acts to modulate a situation.

Question 11

What is the difference between the milieu interior and milieu exterior?

Answer 11

Milieu Interior: the internal environment that interacts with the tissues and cells.

Milieu Exterior: the external environment that surrouds the organism.

Question 12

Give an example of a Milieu Interior:

Answer 12

• Plasma (blood)

- Lymph (extracellular fluid)

Question 13

Give an example of a Milieu Exterior:

Answer 13

• Air (human)

- Water (fish)

Question 14

What is inside of our body but is continuous with the Milieu Exterior? (3)

Answer 14

1. Gastrointestinal tract
2. Sweat ducts
3. Renal tubules

Question 15

Which human body systems work to maintain a constant internal environment?

Answer 15

1. Cardiovascular
2. Respiratory
3. Urinary
4. Gastrointestinal
5. Endocrine

Question 16

What are the 4 properties of a living body?

Answer 16

1. Only living organisms exchange energy and matter with their environments
2. Only living organisms can react accordingly when given environmental stimuli
3. Ability to grow and reproduce
4. Ability to adapt to changing circumstances

Question 17

What are two examples of tightly-controlled parameters in the body?

Answer 17

1. Arterial pressure

2. Blood volume

Question 18

What are some examples of tightly-controlled parameters at the level of the milieu interior, as well as the single cell?

Answer 18

1. Temperature
2. Oxygen levels
3. Glucose levels
4. Potassium (K+) levels
5. Calcium (Ca2+) levels
6. Hydrogen (H+) levels
7. Sodium (Na+) levels