Lecture 0.2

Question 1

What does organization mean in relation to the human body?

Answer 1

Parts of the body interact to perform specific functions

Question 2

Define metabolism

Answer 2

Ability to use energy to perform essential functions

Question 3

What are the forms of metabolism?

Answer 3

Anabolism and catabolism

Question 4

Define anabolism

Answer 4

synthesis/production

Question 5

Define catabolism

Answer 5

breakdown

Question 6

What is responsiveness in relation to the human body?

Answer 6

the ability of an organism to sense changes in the environment and make adjustments to maintain life

Question 7

Why aren’t viruses considered living organisms?

Answer 7

they lack metabolism and responsiveness

Question 8

What is homeostasis?

Answer 8

the existence and maintenance of a relatively constant environment within the body despite fluctuations in either the external or internal environments

Question 9

How is homeostasis regulated?

Answer 9

By negative an positive feedback mechanisms

Question 10

What initiate a homeostatic mechanism?

Answer 10

a stimulus, such as changes in temp, pressure, humidity, oxygen or CO2 levels, blood electrolyte levels or injuries to tissue

Question 11

Name the three components of a homeostatic mechanism.

Answer 11

receptor, control center and effector

Question 12

What is negative feedback?

Answer 12

Deviation from set point is made smaller or is resisted. The variation is kept within a narrow range

Question 13

what is an example of negative feedback?

Answer 13

restoring BP to a homeostatic set point. the stimulus such as change in plasma levels or arterial wall stretching is sent to a receptor that may increase or decrease stretch (create AP) this is then sent to the control center (brain) to tell the effector muscle to do something (in this case release episode to increase HR or release acetylcholine to decrease HR)

Question 14

How are disease and negative feedback systems related?

Answer 14

Many disease states are the result of failures in the negative feedback mechanisms. Medical therapy can help overcome illness through aiding these mechanisms.

Question 15

Define positive feedback.

Answer 15

Deviation from set point becomes greater; variation is allowed to deviate beyond the normal range; eventually self limiting

Question 16

What is an example of positive feedback?

Answer 16

uterine contractions, hemostasis; action potentials

Question 17

Which homeostatic feedback mechanisms are more common in humans? and why.

Answer 17

Negative feedback is more common. Positive feedback mechanisms have the risk of going out of control and becoming unstable and so greater complexity is required to manage them. They are also self limiting which allows for eventual return to a normal set point.