C15 - Homeostasis

Question 1

What is homeostasis

Answer 1

Maintenance of a stable equilibrium in the conditions inside the body

Question 2

What are receptors?

Answer 2

Extrinsic glycoproteins that bind to chemical signals triggering a response by the cell

Question 3

What are effectors?

Answer 3

Muscle/gland which carries out body’s response to a stimulus

Question 4

What is a negative feedback system?

Answer 4

Change detected by sensory receptors
Effectors work to reverse change to return to normal levels

eg. in water balance

Question 5

What is a positive feedback system?

Answer 5

Change detected by sensory receptors
Effectors work to exacerbate change to return to normal levels

eg. in child birth (head of baby presses against cervix, stim production of oxytocin, oxytocin stim uterus to contract, pushing baby head even harder against cervix)

Question 6

What is thermoregulation?

Answer 6

Maintenance of a relatively constant internal temperature

Question 7

Why is thermoregulation important?

Answer 7

Enzymes control rate of reactions in body
They have optimum temp

-If temp is too high, they denature
-If temp too low, they don’t work fast enough

Question 8

What physical processes impact thermoregulation in all animals?

Answer 8

Exothermic chemical reactions

Latent heat of evaporation - cools as water evaporates from surface

Radiation - transmission of EM waves to/from air, water, ground

Convection - heating + cooling of by currents of air/water (warm air/water rises in organism)

Conduction - heating as result of collision of molecules

Question 9

What is an ectotherm?

Answer 9

Animals that use their surroundings to warm their bodies so their core body temp is heavily dependent on the environment