Chapter 1- 1.6/7

Question 1

Homeostasis

Answer 1

The ability of an organism to maintain a consistent internal environment or “steady state” in response to changing internal or external conditions

Question 2

Three components of Homeostasis system

Answer 2

Receptor, Control center, and Effector.

Question 3

Receptor

Answer 3

Body structure that detects a stimulus. Made of sensory neurons (nerve cells). Can be found in the skin, Internal organs, or specialized organs like the eye, ear, tongue, or nose.

Question 4

Stimulus

Answer 4

A change in the variable (physical or chemical) For example a change in light, temp. chemicals etc.

Question 5

Control Center

Answer 5

Both interprets input from the receptor and initiates changes through the effector. Normally brain/spinal cord or an organ of the endocrine system. Can also act as a receptor in places like the pancreas.

Question 6

Effector

Answer 6

The structure that brings about change to alter the stimulus. Often muscles and exocrine glands.

Question 7

Negative feedback

Answer 7

In the opposite direction of the stimulus, the variable is maintained within a normal level, aka setpoint.

Question 8

Negative feedback Cold temperature

Answer 8

Blood vessels in the skin constrict, and sweat glands become inactive, skeletal muscles shiver to make heat

Question 9

Negative feedback Hot temperature

Answer 9

Blood vessels in skin dilate, sweat glands secrete sweat, which if evaporated cools the skin’s surface.

Question 10

Positive feedback

Answer 10

Goes in the same direction as the stimulus until a climactic event occurs. End result is to increase activity, not return to the set point.

Question 11

5 characteristics of homeostasis

Answer 11

1. Dynamic
2. Control Center, nervous endocrine system
3. 3 components: Receptor, Control Center and Effector
4. Negative feedback to maintain a normal value/setpoint
5. Failure may threaten survival