BIOL 252 Final UNC Exam Questions
With Fully Explained Answers
What is the filtration membrane - ✔✔✔✔Membrane around glomerulus that material can easily pass
through. Filtration regulated by intrinsic (auto regulation) and extrinsic (hormones, sympathetic nervous
system) sources.
What happens when systemic BP is too low? Hint, it involves hormones. - ✔✔✔✔Sympathetic nervous
system tells adrenal medulla to release norepinephrine and epinephrine. Afferent arterioles are
constricted. Filtration inhibited.
Intrinsic Regulation of glomerular filtration - ✔✔✔✔Autoregulation. When blood pressure is between
90-120. Myogenic stretch receptors detect changes and afferent arteriole contracts or stretches. If
blood pressure decreases, arterioles dilate to let in more blood.
Extrinsic Regulation of glomerular filtration - ✔✔✔✔Hormones, sympathetic nervous system. Occurs
when blood pressure is less than 90mmHg. norepinephrine, epinephrine via adrenal medulla. Leads to
constriction of afferent arteriole and inhibition of filtration.
Osmolality - ✔✔✔✔number of solutes in 1 kg of water.
Osmolality of blood plasma - ✔✔✔✔300 mosm
downward loop of Henle - ✔✔✔✔permeable to H2O
upward loop of henle - ✔✔✔✔permeable to ions.
What diffuses out of the loops of Henle as it goes up the loop? How does it leave? - ✔✔✔✔NaCl. By way
of active transport.
What carries water and NaCl away from loops of henle to bloodstream? - ✔✔✔✔vasa recta
, When blood pressure is high, collecting ducts do what? - ✔✔✔✔Collecting ducts become impermeable
to water. Aquaporins are removed from tubule. Urine becomes more dilute. Water is not needed in
blood vessels.
What happens when osmolality is high? - ✔✔✔✔Osmoreceptors in thirst center make us thirsty.
What also happens when osmolality is high? What hormone is released? - ✔✔✔✔Hypothalamus
releases anti-diuretic-hormone from posterior pituitary.
DCT - ✔✔✔✔Distal convoluted tubule. Between loop of henle and collecting ducts.
Path of filtrate through kidneys - ✔✔✔✔renal corpuscle, proximal tubule, nephron loop, distal
convoluted tubule, collecting duct
How much material do the kidneys filter per day? - ✔✔✔✔180 L. Only 1.5L are excreted.
Sodium is transported from tubule lumen to interstitial fluid via what? - ✔✔✔✔primary active transport
glucose, amino acids, and other nutrients move from lumen to interstitial fluid via what? -
✔✔✔✔cotransport with sodium.
Material is filtered in proximal convoluted tubule. Blood stream is reabsorbing what things at this time?
Does osmolality remain the same at beginning and end of proximal tubule? - ✔✔✔✔NaCl (primary
active transport), water (aquaporins), glucose, amino acids, other nutrients (cotransport). Osmolality
remains the same at 300 mosm.
After proximal convulted tubule, where is material concentrated and filtered even more? - ✔✔✔✔loops
of henle.
With Fully Explained Answers
What is the filtration membrane - ✔✔✔✔Membrane around glomerulus that material can easily pass
through. Filtration regulated by intrinsic (auto regulation) and extrinsic (hormones, sympathetic nervous
system) sources.
What happens when systemic BP is too low? Hint, it involves hormones. - ✔✔✔✔Sympathetic nervous
system tells adrenal medulla to release norepinephrine and epinephrine. Afferent arterioles are
constricted. Filtration inhibited.
Intrinsic Regulation of glomerular filtration - ✔✔✔✔Autoregulation. When blood pressure is between
90-120. Myogenic stretch receptors detect changes and afferent arteriole contracts or stretches. If
blood pressure decreases, arterioles dilate to let in more blood.
Extrinsic Regulation of glomerular filtration - ✔✔✔✔Hormones, sympathetic nervous system. Occurs
when blood pressure is less than 90mmHg. norepinephrine, epinephrine via adrenal medulla. Leads to
constriction of afferent arteriole and inhibition of filtration.
Osmolality - ✔✔✔✔number of solutes in 1 kg of water.
Osmolality of blood plasma - ✔✔✔✔300 mosm
downward loop of Henle - ✔✔✔✔permeable to H2O
upward loop of henle - ✔✔✔✔permeable to ions.
What diffuses out of the loops of Henle as it goes up the loop? How does it leave? - ✔✔✔✔NaCl. By way
of active transport.
What carries water and NaCl away from loops of henle to bloodstream? - ✔✔✔✔vasa recta
, When blood pressure is high, collecting ducts do what? - ✔✔✔✔Collecting ducts become impermeable
to water. Aquaporins are removed from tubule. Urine becomes more dilute. Water is not needed in
blood vessels.
What happens when osmolality is high? - ✔✔✔✔Osmoreceptors in thirst center make us thirsty.
What also happens when osmolality is high? What hormone is released? - ✔✔✔✔Hypothalamus
releases anti-diuretic-hormone from posterior pituitary.
DCT - ✔✔✔✔Distal convoluted tubule. Between loop of henle and collecting ducts.
Path of filtrate through kidneys - ✔✔✔✔renal corpuscle, proximal tubule, nephron loop, distal
convoluted tubule, collecting duct
How much material do the kidneys filter per day? - ✔✔✔✔180 L. Only 1.5L are excreted.
Sodium is transported from tubule lumen to interstitial fluid via what? - ✔✔✔✔primary active transport
glucose, amino acids, and other nutrients move from lumen to interstitial fluid via what? -
✔✔✔✔cotransport with sodium.
Material is filtered in proximal convoluted tubule. Blood stream is reabsorbing what things at this time?
Does osmolality remain the same at beginning and end of proximal tubule? - ✔✔✔✔NaCl (primary
active transport), water (aquaporins), glucose, amino acids, other nutrients (cotransport). Osmolality
remains the same at 300 mosm.
After proximal convulted tubule, where is material concentrated and filtered even more? - ✔✔✔✔loops
of henle.
