Homeostasis

Question 1

What are the types of signalling molecules?

Answer 1

Endogenous

Exogenous

• type 1
• type 2

Question 2

What are endogenous signalling molecules?

Answer 2

Signalling molecules from within the body

Question 3

What are exogenous type 1 signalling molcules?

Answer 3

Signalling molecules that are external to the body, but natural e.g. plant-based

Question 4

What are exogenous type 2 signalling molecules?

Answer 4

Signalling molecules that are man-made

Question 5

What is homeostasis?

Answer 5

Keeping the extracellular environment stable

Question 6

What are some examples of conditions in the extracellular environment that are kept stable?

Answer 6

Temperature

Water

Oxygen, carbon dioxide

Ions

pH

Glucose

Question 7

What are the components of a homeostatic control system?

Answer 7

Sensor

Controller

Effector

Question 8

What is the set point?

Answer 8

Normal levels of condition

Question 9

What is a stimulus?

Answer 9

Change in levels of a condition to being too low or too high

Question 10

What are the functions of a sensor?

Answer 10

Detects levels of condition under control

In response to stimulus, produces signals that run to controller

Question 11

What are the functions of a controller?

Answer 11

Produces signals that run to effectors

Question 12

What determines the size of the signal sent to the controllers, effectors etc.?

Answer 12

The difference between the set point and what the sensors detect

Question 13

What are the functions of an effector?

Answer 13

Bring about the change in condition back to normal

Question 14

What is negative feedback?

Answer 14

Change away from set point results in mechanism that reverses the direction of change and brings levels back to set point

Question 15

What are the different ways by which different control feedback loops can interact with each other?

Answer 15

Synergistically - work together to produce same effect

Antagonistically - oppose the effects of one another

Question 16

Are synergistic or antagonistic feedback loops more physiologically useful? Why?

Answer 16

Antagonistic feedback loops

give more precise control of condition levels

Question 17

What is the normal body temperature range?

Answer 17

36-38C

Question 18

Why is normal body temperature range 36-38C?

Answer 18

Proteins function optimally at this temperature

Reduces rate of denaturation of proteins

Question 19

Where are the sensors of core body temperature located?

Answer 19

Hypothalamaus

Question 20

Where are the sensors of peripheral body temperature located?

Answer 20

Skin

Question 21

What are the mechanisms to increase body temperature?

Answer 21

Peripheral blood vessels constrict, reducing heat loss from skin surface

Skeletal muscle shivers, generating heat

Question 22

What are the mechanisms to decrease body temperature?

Answer 22

Peripheral blood vessels dilate, fill with warm blood, heat radiates from skin surface

Sweat glands are activated, heat lost by evaporation

Question 23

What is the dynamic range of a condition?

Answer 23

Levels outside of the normal range

but system itself and the control system can still function in this range

Question 24

What happens if the levels of a condition go outside of the dynamic range?

Answer 24

Control system function is affected

system itself is affected