1.4 Homeostasis

Question 1

Homeo-, ___ ____; -stasis, __ _____

Answer 1

Homeo-, the same; -stasis, to stop

Question 2

Maintenance of a relatively constant internal environment despite fluctuations in the external environment

Answer 2

Homeostasis

Question 3

How to achieve Homeostasis?

Answer 3

The body must actively regulate body conditions that are constantly changing

Question 4

Body conditions that are constantly changing?

Answer 4

Variables

Question 5

Mechanism that maintain normal body conditions

Answer 5

Homeostatic Mechanism

Question 6

Example of a Homeostatic Mechanism

Answer 6

Shivering and sweating to maintain body temp

Question 6

Ideal normal value that homeostatic mechanism aims to achieve

Answer 6

Set Point

Question 7

What systems regulates most homeostatic mechanisms?

Answer 7

Nervous or Endocrine Sytem

Question 8

Increase and decrease slightly around a set point

Answer 8

Normal range of values

Question 9

Average Body Temp

Answer 9

98.6

Question 9

“Negative” feedback Meaning

Answer 9

“Negative” - to decrease

Question 10

Mechanisms that maintain homeostasis

Answer 10

1. Negative Feedback
2. Positive Feedback

Question 11

Three components of Negative Feedback

Answer 11

Receptor, Control Center, Effector

Question 12

___________ signal the _______, which regulates the action of the __________.

Answer 12

Receptors signal the control center, which regulates the action of the effectors.

Question 13

Monitors the value of a variable (ex. Body temp) by detecting stimuli.

Answer 13

Receptor

Question 14

Determines the set point for the variable and receives input from the receptor about the variables and receives input from the receptor about the variable (ex. Part of the brain)

Answer 14

Control Center

Question 15

can adjust the value of the variable when directed by the control center, usually back toward the set point (ex. Sweat glands).

Answer 15

Effector

Question 16

A changed variable because it initiates a homeostatic mechanism.

Answer 16

Stimulus

Question 17

Hallmark of Negative Feedback

Answer 17

Effectors stop their response once the variable has returned to its set point.

Question 18

“Positive” Feedback Meaning

Answer 18

“Positive” - to increase

Question 19

This type of response is required to return to homeostasis.

Answer 19

Positive Feedback

Question 20

Example of Positive Feedback

Answer 20

1. During blood loss, thrombin, a chemical responsible for blood clot formation, stimulates production of even more thrombin.
2. Giving Birth (See Transes Page 5)

Question 21

2 Basic Principles about homeostatic mechanisms

Answer 21

1. Many disease states result from the failure of negative-feedback mechanisms to maintain homeostasis, and
2. Some positive-feedback mechanisms can be detrimental instead of helpful.