Histo Lecture 12

What are the three areas of reabsorption in the nephron?

Proximal tubuleLoop of HenleDistal tubule

Water follows what in the capillaries?


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 IIOccurs 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 ECFStimulates 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 resistanceInhibit Nacl/H2O reabsorption in the collecting ductReduce 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 vasodilationIncrease H2O/NaCl excretionInhibits 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?


Where is ADH synthesized?


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 archcarotid sinus

Where are the baroreceptors that monitor venous blood pressure?

Atriapulmonary vessles

What is the osmolarity range for urine?


Ascending LOH absorbs what and not what?


Decreased filling of pulmonary system/atria results in:

Increased sympathetic activity to generate BPIncrease ADH secretion - increases ECF

What is the systemic response to increased ECF?

Decreased renal sympathetic signalingIncreased release of ANP/BNP and urodilatinInhibition of ADH secretion and activityDecreased renin secretion resulting in decreased angiotensin and aldosterone

What is the systemic response to decreased ECF?

Incrased renal sympathetic signalingInhibition of ANP/BNP and urodilatin secretionIncreased ADH secretionIncreased renin secretion resulting in increased angiotensin and aldosterone