Homeostasis and Control Systems

1
Homeostasis and Control Systems
2
Homeostasis

• Body works best at a certain set point
• However the environment is constantly changing
  and your body must respond
• Body Temp 37
• pH 7.35
• Blood glucose 0.1
• Homeostasis is the bodies ability to maintain
  balancewhen it gets out of balance that is when
  things go wrong

3
3 Functional Components

• All control systems have functional components to
  make sure everything stays in balance
• 1. A monitor
• 2. Coordinating centre
• 3. Regulator
• Homeostasis is often referred to as Dynamic
  equilibrium - stays stable even with fluctuations
  bodys limits are fluctuating

4
Homeostasis and Feedback

• When the body gets out of balance there needs to
  be a system that helps bring it back
• Negative feedback - restores bodys settings back
  to set point
• Works like a thermostat
• Positive feedback - increases change, pushes it
  past set point
• Where might this be necessary?

5
Thermoregulation

• Temperature range control
• Ectotherms bodys temp depends on the
  environment to help maintain
• Endotherm bodys temp is regulated regardless of
  the external environment
• Hypothalmus regulates bodys temperature,
  natural thermostat
• Everyones is different

6
Bodys response to temp stress

• Heat
• Exercise or high environmental temperatures
• Nerve impulse to hypothalmus, signals sweat
  glands to start secreting sweat
• Evaporation cools body down
• Nerve also sends signal to blood vessels causing
  them to dilate causing more blood flow to the skin

7

• Cold
• Initiated the same way as with heat
• Signal is sent to hypothalmus
• Hypothalmus signals muscles to contract/constrict
  which will limit blood flow
• Hair stands on end, traps warm air
• Shivering muscle contractions 10 - 20 times per
  minute
• Prolonged exposure to cold temps will increase
  metabolism - heat is generated
• Table 1 pg 341 copy in notes

8
HWK

• Read pgs 335 - 341
• 1 -7 pg 341

9
(No Transcript)