S2W5 Renal physiology

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What is the process of nephron function?
1. Filtration occurs at the glomerular capillaries in the renal corpuscle
2. Active removal of ions, glucose and amino acids at the PCT
3. Water reabsorption occurs in the PCT and descending limb of the LOH, this increases filtrate conc.
4. Active transpo
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What is the role of the bowmans capsule?
Holds blood vessels ready for filtration
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What is the role of the glomerulus?
Site where blood is filtered
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What is the role of the proximal tubule?
The first entry for the filtrate
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What is the role of the proximal convoluted tubule?
Where glucose, amino acids and ions are actively absorbed.
Largest site of water reabsorption (60-70%)
Sodium is reabsorbed in exchange for hydrogen ions (NHE)
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What is the role of the loop of henle?
Descnding limb is impermeable to solute but permeable to water
Ascending limb is impermeable to water but permeable to solutes
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What is the role of the NKCC transporter?
One sodium, one potassium and two chlorides are carried by this transporter
This is the site of action of loop diuretics
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What is the role of the distal convoluted tubule?
NaCl is actively reabsorbed here
NCC transporter is here - carrues out one sodium and two chlorides
The site for thiazide diuretics.
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What is the role of the collecting duct?
Epithelial sodium chanels absorb Na
These channels are aldosterone sensitive
Aquaporins absorb water here - sensitive to Vasopressin (ADH)
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What are natriuretic peptides?
A hormone released from cardiomyocytes in response to stretch
They relax smooth muscle causing vasodilation
They also inhibit sodium reabsorption and the activity of ENaC which promotes diuresis and naturesis (supresses sodium reabsorption)
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What is the role of natriuretic peptide receptors?
the receptors when activated cause activation of cGMP, which causes the activation of protein kinase G and in turn causes smooth muscle relaxation.
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What is the RAAS?
Renin-angiotensin-aldosterone system
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What is the renin-angiotensin-aldosterone relationship?
Renin acts on angiotensinogen to form angiotensin I.
ACE is released from the lungs and converts angiotensin I into angiotensin II
Angiotensin II then stimulates the adrenal gland to release Aldosterone
Aldosterone then acts on the kidney to reabsorb salt
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How does angiotensin II cause vasoconstriction?
The angiotensin receptor causes the activation of phospholipase c which breaks down PIP2 into IP3 and DAG.
IP3 cause the release of Ca2+ ions and calcium is a key factor in the contractile mechanism of muscle -causes vasoconstriction in the blood vessels.
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What is angiotensin II role in the kidneys?
Increases sodium reabsorption in the kidney by the NHE. This increases water reabsorption and stroke volume
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What is aldosterone's role in the kidney?
Acts via the mineralcorticoid receptors (nuclear) and increase the expression of ENaC.
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What is the role of Vasopressin?
Increase aquaporin expression (water reabsorption)
Constricts blood vessels
Stimulates thirst sensation
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Other cards in this set

Card 2

Front

What is the role of the bowmans capsule?

Back

Holds blood vessels ready for filtration

Card 3

Front

What is the role of the glomerulus?

Back

Preview of the front of card 3

Card 4

Front

What is the role of the proximal tubule?

Back

Preview of the front of card 4

Card 5

Front

What is the role of the proximal convoluted tubule?

Back

Preview of the front of card 5
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