Lecture 4

Question 1

Homeostasis

Answer 1

Regulation of the body’s internal environment at a near stable level

Question 2

Set point?

Answer 2

Homeostasis regulates a physiological variable relative to this

Question 3

3 homeostatic mechanisms

Answer 3

Negative feedback
Positive feedback
Feedforward

Question 4

Negative Feedback

Answer 4

Returns variable towards the set point, minimizes the difference between actual level and the set point (body temp regulation)

Question 5

Homeotherms

Answer 5

Maintain a fairly stable body temp. despite swings in the environmental temp. (rabbit)

Question 6

Heterotherms

Answer 6

Have a body temperature similar to that of their surroundings. (iguana)

Question 7

Negative feedback loop

Answer 7

Maintains a balance between heat loss and heat gain

Question 8

Cooling Physiology

Answer 8

Stimulated; heating physiology inhibited, e.g. increased blood flow to skin, sweating, panting

Question 9

Heating Physiology

Answer 9

Stimulated; cooling physiology inhibited, e.g. decreased blood flow to skin, shivering, erect hair or feathers

Question 10

Platyhelminthes

Answer 10

Flatworms

Question 11

Nematoda

Answer 11

Roundworms

Question 12

Temp increase/decrease integrated by ____

Answer 12

Hypothalamus

Question 13

Negative Feedback - Hypothalamus Chart??

Question 14

Negative Feedback - Endocrine slide 12???

Question 15

Positive Feedback

Answer 15

Moves variable away from the set point, amplifies difference between actual level and the set point, used to quickly increase/decrease a process, amplification shut off by negative feedback

Question 16

Positive Feedback - Childbirth slide 16??

Question 17

Oxytocin

Answer 17

Contraction inducing hormone

Question 18

The rising phase of the nerve action potential - slide 17??

Question 19

Feedforward

Answer 19

Future needs are anticipated, physiology is adjusted in advance, often involves learning and complex behaviours, slide 18/19

Question 20

What happens during a fever? (4)

Answer 20

Temporary increase in body temperature usually due to infection
Foreign bodies signal hypothalamus to increase internal temperature set point
Turns on the immune system to help fight infection (symptomatic)
Mild fever ok, high fever can be deadly