Renal 5 Flashcards
Fluid and electrolyte balance involves
Respiratory, Cardiovascular, Renal Systems as well as behavioural responses
Cardiovascualr and Respiratory systems are under
Neural Control
Renal responses
Endocrine control
Water intake must match
Excretion
What creates concentrated urine
Renal medulla
Diuresis
Removal of excess urine (During high blood pressure)
Where does the kidney control urine concentration
Distal nephron (Distal tubule and collecting duct)
How does distal nephron produce concentrated urine
Must reabsorb water and little solute
Uses aquaporins
How dpes the distal tubule and collecting duct alter their permeability to water
By adding or removing water pores in the apical membrane under the direction of the posterior pituitary hormone vasopressin (AVP)
What senses the changes in blood volume and blood pressure
Volume receptors in atria and cartoid and aortic baroreceptors
Decrease in blood volume and blood pressure
Cardiovasuclar System: Cardiac output up by vasoconstriction
Behaviour: Thirst causes water intake; ECF AND ICF up
Kindneys: Conserve salt and water to minimize water loss
Increase blood volume and increased blood pressure
Cardiovascular system: Cardiac output down (Vasodialation)
Kidneys: Excrete salts and h2o in urine: ECF and ICF goes down
Water intake must match
Excretion
Sources of water intake
Food and drink
Metabolism
Sources of water output
Skin
Lungs
URINE
Feces
Volume gain will be offset with
Increase loss
Diuresis
Removal of excess urine (No solute just fluid)
Steps of Renal medulla creating concentrated urine
- Isosmotic fluid leaving the proximal tubule and becomes more progressively more concentrated in the descending limb (Only water reabsorbtion occurs here)
- Removal of solute in thick ascending limb creates hyposmotic fluid
how do the distal tubule and collecting duct alter their permeability to water?
By adding or removing water pores in the apical membrane under the direction of posterior hormone vasopressin (AVP) Aka antidiretic harmone
Without Vasopressin (AVP)
Water cannot be reabsorbed
Steps of AVP induced AQP2 insertion
- Vasopressin binds to membrane receptor
- Receptor activate cAMP adenyl cyclase pathway.
- Cell inserts AQP2 water pores into the apical membrane (fluid comes in)
- Water is reabsorbed
What stimuli control vasopressin secretion
Decrease Blood volume, Decrease Blood pressure and Increased Osmolarity
which neurons synthesize vasopressin
Hypothalamic Neurons
AVP secretion also shows a
Circadian Rhythm (At night)
AVP Production and secretion
- AVP is made and packaged in cell body neuron
- Vesicles are transported down the cell
- Vesicles containing AVP are stored in posterior pituitary
4, AVP is released into blood
