4.1 - Intro to Homeostasis & Regulation

Question 1

What is homeostasis?

Answer 1

It describes a state of having a stable interal environment.
In animals, this was achived through natural selection and evolution.

Question 2

What are some factors that need to be regulated in order to maintain homestasis?

Hint: 4 main factors

Answer 2

• Temperature balance
• water balance: osmoregualtion, dissovled nutirents, pH, etc…
• gas balance: O2, CO2, etc…
• nutrient balance

Question 3

What is the endocrine system?

[endo-cr-in]

Answer 3

A system of chemical signals and hormones

Question 4

What are feedback loops?

Answer 4

• the system that connects stimuli and the other responses that send signals when homeostasis is disturbed

Question 5

What is a negative feedback loop?

Answer 5

• when one response decreses the effect of the stimulus
• negative feedback counter acts the inital change, which is needed for controlling homeostasis

Question 6

What is a positive feedback loop?

Answer 6

• when one response increased the effect on the stimulus
• positive feedback examples-> 1: release of oxytocin increases uterine contractions for child birth. 2: Blood clotting. Injury stimulates the release of platelettes which causes more platelettes to activate until the wound is closed.

Question 7

What is a stimulus?

Answer 7

It is a change in environment.

Question 8

What is a receptor?

Answer 8

It’s the part that detects the stimulus/change.

Question 9

What is the integrator?

Answer 9

It’s part that decides that to do with the stimulus/change.

Question 10

What is the effector?

Answer 10

It’s the part that generates the response decided by the integrator.

Question 11

How does the receptor send info to the integrater?

Answer 11

Through an afferent pathway.

Question 12

How does the integrater send intructions?

Answer 12

Through the efferent pathway.

Question 13

What is the order of feedback loops?

Answer 13

• stimulus
• receptor/sensor
• integrator (intergrating center)
• effector
• response (then back to the receptor)

Question 14

What is thermoregulation?

Answer 14

The process of maintaining body temperature

Question 15

What are endotherms?

Answer 15

• organisms that speed up or slow down their metabolism to adjust the amount of body heat generated internally
• advantage: helps when living in cold environments
• disadantage: comsumes a lot of energy
• when too cold, endotherms go into a state of torpor. Extended torpor is called hibernation

Question 16

What is torpor?

Answer 16

When an endotherm saves energy by slowing down their metabolism, which causes less heat to be produced

Question 17

What are ectotherms?

Answer 17

• organisms that generate body heat but cannot change the amoun they produce
• they must manipulate their surroundings. Ex) lizzards sunbathe when cold and stay in shade when hot