Renal 1 & 2 Flashcards
ADH and oxytocin is produced in the ____. and released in the ____.
- hypothalamus = production
- posterior pituitary = released
What is the role of ADH?
- conserve water in the body
- released into the blood stream to increase water reabsorbtion in kidneys
- water is retained by the kidneys
- released back into the blood and not lost to urine
Plasma osmolality
- affected by water content changes
- measure of [blood substances] like sodium, chloride, potassium, urea, glucose…
- amount of water vs salt in the blood
Flow chart of ADH and osmolality in response to dehydration.
- dehydration = low blood volume (or from salt ingestion)
- therefore increased blood osmolality
- osmoreceptors in hypothalamus
- stimulates posterior pituitary
- increase ADH
- water retention by kidneys
- blood volume increases; blood osmolality decreases
or
-osmoreceptors in hypothalamus tells you you are thirsty and you drink water to increase blood volume and decrease blood osmolality
What happens if you drink too much water?
- blood is far too dilute
- sodium is needed for nerve firing nad heart to pump
- you need a balance of solute and water in the blood
ADH gene mutation - Brattleboro rats
- no ADH
- therefore cannot conserve water in body
- excessive thirst
- excessive dilute urine
- “diabetes insipidis” - kidneys cannot conserve water
ADH and bedwetting
- normal children have AADH secretion that follows circadian rhythm
- ADH increases at night
- reabsorption of water increases
- nocturnal production of concentration of urine is decreased
Water homeostasis maintained by…
water intake = water loss
water intake:
- drinking fluid and water in food
- water produced by metabolism
water loss: urine, feces, sweat, lungs
Distribution of water in the body.
- 2/3 intracellular (i.e. cytoplasm)
- 1/3 extracellular (i.e. interstitial fluid (80% of 1/3), blood plasma volume)
- interstitial fluid acts as a reservoir for water for cytoplasm and blood depending on needs
- water in blood plasma goes to kidneys, lungs, skin
- water to feces comes from GI tract which comes from interstitial fluid
How long can we live without water?
3 days
max 8-10 in special cases
Explain how the Arabian camel regulates water
- lipid is stored in the hump
- lipid metabolism provides significant amount of metabolic water
- dry food has some water
- kidney efficient at water recovery
- thermoregulation
Thermoregulation of the Arabian camel and why does this affect water regulation
- turning off thermoregulation is a water conservation process
- when hydrated: it pants; keeps core bt between 36.5 and 38.5
- when dehydrated: it does not pant but supercools at night and overheats at night (34.5 - 40.5)
Explain how the kangaroo rat can survive without any intake of water.
Adaptations:
- obtain water from dry food and metabolic water
- live in colonies underground ( the moist air reduces respiratory water loss )
- nocturnal to avoid day heat
- very dry feces
What does the urine concentration and urine:blood ratio look like for these adapted species?
Camel, Kangaroo rat and aquatic species all have a very high urine concentration and high urine:blood ratio in comparison to humans
at least double if not more for desert species
Do marine mammals need to regulate their water? Why?
Fresh water is 0.1% salt
Human body 0.9% salt
Seawater 3.5% salt
Sea water is very salty and marine mammals have no access to fresh water
