Homeostasis

• Vasoconstriction means less heat is lost in radiation, convection and conduction, therefore there is less sweat
• Low water in the blood (hot day / sweating)

  1. Hypothalamus
  2. Detects change in osmolarity, low water in blood (water & salt ratio)
  3. Pituitary gland
  4. Secretes more ADH
  5. Sent to distal and collecting duct
  6. Makes tubules more permeable
  7. More water reabsorbed returns to the norm and a small amount of urine is produced

  
• High water in blood (osmoregulation):

  1. Hypothalamus
  2. Detects change in osmolarity, high water in blood (water & salt ratio)
  3. Pituitary gland
  4. Secretes less ADH
  5. Sent to distal and collecting duct
  6. Makes tubules less permeable
  7. Less water reabsorbed returns to the norm and a larger amount of urine is produced

  
• vasodilation:

  1. Receptors in the skin
  2. Stimulus sent to hypothalamus
  3. Dermal arterioles
  4. Circular muscles relax
  5. More blood flow to surface
  6. Shunt vessels contract
  7. Less blood is diverted to subcutaneous layer

  
• More Sodium is reabsorbed = more water will be reabsorbed into blood.
• Carbon dioxide (PH Decreases)

  1. CO2 levels increase
  2. Chemoreceptors in wall of aorta & carotid are stimulated by LOW pH of blood
  3. Impulse sent to medulla oblongata
  4. Stimulates heart & breathing muscles
  5. Heart beats faster & breathing muscles contract more
  6. More CO2 is exhaled
  7. pH of blood increases and returns to the norm

  
• High Glucose (eating):

  1. Increased blood glucose levels
  2. Blood passes through pancreas
  3. Beta cells detect glucose increase
  4. Secrets insulin
  5. Liver and muscles absorb more glucose. Liver converts glucose to glycogen
  6. blood glucose levels drop
  7. Negative feedback causes insulin levels to drop

  
• Low Glucose (starving):

  1. Decrease blood glucose levels
  2. Blood passes through pancreas
  3. Alpha cells detect glucose decrease
  4. Secrets glucagon
  5. Liver converts glycogen to glucose
  6. blood glucose levels increase
  7. Negative feedback causes glucagon levels to drop

  
• Low thyroxin (metabolism slowing):

  1. Thyroxin levels drop
  2. Pituitary gland registers drop
  3. Secretes TSH
  4. Sent to the Thyroid gland
  5. Thyroid now secretes thyroxin
  6. TSH then reduces
  7. Cellular respiration increases
• The hypothalamus is responsible for thermoregulation.
• On a cold day your circular muscles in the dermal arterioles will contract
• On a cold day your shunt vessels in the dermal arterioles will relax.
• On a hot day your shunt vessels in the dermal arterioles will contract
• On a hot day your circular muscles in the dermal arterioles will relax.
• Name the receptor for osmoregulation

  Hypothalamus
• Which gland secretes ADH?

  Pituitary
• What affect does ADH have on the renal tubules? Makes them more permeable to water
• On a hot day, sweating a lot you will produce more ADH
• On a cold day, sweating less you will produce less ADH
• What stimulus triggers the hypothalamus to secrete more or less ADH?


  Osmolarity
• Which gland produces aldosterone?


  Adrenal
• Name the receptor that is responsible for monitoring the salt in the blood.

  Afferent arterioles
• What hormone does the afferent arterioles secrete?

  Renin
• What hormone is secreted due to Renin?

  Angiotensin
• When the blood salt levels are low more aldosterone is secreted.
• Cellular respiration increasing when insulin is produced.
• Only glucose is taken from the liver when blood sugar levels are low.
• The receptor that is stimulated by low thyroxin is?

  Pituitary gland
• Which gland secretes TSH?

  Pituitary gland