Histo Lecture 12

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What are the three areas of reabsorption in the nephron?
- Proximal tubule
- Loop of Henle
- Distal tubule
Water follows what in the capillaries?

NaCl
What is the proximal tubule in charge of?

Reabsorbing most nutrients
What is transcellular transport?

Movement through the cytoplasm
What is paracellular transport?

Movement through "tight junctions" between cells
Most humeral control of kidney reabsorption involves what?

Alteration in NaCl reabsorption
What are some some hormones affecting NaCl reabsorption?

Angiotensin II, aldosterone, atrial natriuretic peptide (ANP), brain netriuretic peptide (BNP), catebholeamines
What does Renin do?
- Catalyzes conversion of angiotensin I to angiotensin II
- Occurs in the lungs
Renin is released from kidney cells in response to
- Decreased perfusion pressure in the kidney (decreased BP)
- Decreased filtered load of NaCl (decreased GFR)
- Inreased sympathetic nerve activity
Where does Angiotensin II act?

Stimulates NaCl reabsorption in the proximal tubule
What is aldosterone secreted in response to?

Plasma concentration of angiotensin II
What is epinephrine/norepinephrine released in response to?
- Low ECF
- Stimulates reabsorption of NaCl in all parts of nephron
What stimulates sympathetic input to the kidney?

Low ECF volume or low BP
What is dopamine released in response to?

Increased ECF
What is the function of dopamine on the kidney?

Inhibits NaCl/H2O reabsorption in the proximal tubule
What stimulates secretion of ANP and BNP?

Increase in BP and ECF
What are the functions of ANP and BNP?
- Decrase total peripheral resistance
- Inhibit Nacl/H2O reabsorption in the collecting duct
- Reduce ADH secretion from posterior pituitary
Natriuretic peptides are secreted by what?

By the heart in response to increased ECF or BP
How do ANP and BNP perform their functions?
- Stimulate vasodilation
- Increase H2O/NaCl excretion
- Inhibits secretion of renin, aldosterone and ADH
Where is Urodilatin secreted?

By distal tubule and collecting duct
What stimulates secretion of urodilatin?

Increase in BP and ECF
What does urodilatin inhibit?

NaCl and H2O reabsorption in the collecting duct
What is the definition of dehydration?

Increased plasma osmolarity and more concentrated urine
What is definition of over-hydration?

Decreased plasma osmolarity and more dilute urine
What is the normal range in adults for osmolarity?

280-295mOsm
Where is ADH synthesized?

hypothalamus
Where is ADH stored and secreted from?

posterior pituitary
What is ADH released in response to?

Low BP and high Osmolarity
Where are the baroreceptors that monitor arterial pressre?
- aortic arch
- carotid sinus
Where are the baroreceptors that monitor venous blood pressure?
- Atria
- pulmonary vessles
What is the osmolarity range for urine?

50-1200mOsm
Ascending LOH absorbs what and not what?
- NaCl
- NOT WATER
Decreased filling of pulmonary system/atria results in:
- Increased sympathetic activity to generate BP
- Increase ADH secretion - increases ECF
What is the systemic response to increased ECF?
- Decreased renal sympathetic signaling
- Increased release of ANP/BNP and urodilatin
- Inhibition of ADH secretion and activity
- Decreased renin secretion resulting in decreased angiotensin and aldosterone
What is the systemic response to decreased ECF?
- Incrased renal sympathetic signaling
- Inhibition of ANP/BNP and urodilatin secretion
- Increased ADH secretion
- Increased renin secretion resulting in increased angiotensin and aldosterone

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Card Set

Histo Lecture 12

Description

Renal Control of Fluid

Updated

2011-03-02T15:49:07Z

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