Physio B Midterm 2

what is the primary function of the kidneys?

filter plasma

what two outcomes occur to the plasma once filtered?

excreted through urine or reabsorbed into blood

what are four other functions of the kidneys?

regulate blood pressure, regulate pH of body, regulate water volume, maintain blood glucose level

what is gluconeogenesis?

the production of new glucose

besides the kidneys, what other organ participates in gluconeogensis?

the liver

what is the functional unit of the kidney?

the nephron

what is are the two types of nephrons and their percentages?

juxtamedullary (20%) and cortical (80%)

what is the job of the juxtamedullary nephrons?

to dilute and concentrate urine

what is used to push filtrate into the Bowman’s capsule?

hydrostatic pressure

what are the three layers that the filtrate must cross through before getting into the Bowman’s capsule?

endothelium, basement membrane, podocytes

how do smaller molecules get into the Bowman’s capsule?

through the presence of small pores/slits

in other words, what type of pressure is needed to create pressure for filtration?

blood pressure

what is the Glomerular Filtration Rate (GFR)?

the rate at which blood can be pushed into the Bowman’s capsule

which type of arteriole has more effect on the GFR?

afferent arteriole

how will vasoconstriction of the afferent arteriole affect GFR?

the GFR will decrease

how will vasodilation of the afferent arteriole affect GFR?

the GFR will increase

how will vasoconstriction of the efferent arteriole affect GFR?

the GFR will increase

how will vasodilation of the afferent arteriole affect GFR?

the GFR will increase

what is the myogenic response?

an autoregulation response that adjusts blood pressure through contraction/relaxation of smooth muscle on the arterioles to maintain a constant GFR

what is the tubuloglomerular feedback?

when the macula densa sense NaCl flowing past; if the NaCl is too high, this means that the GFR is too high and the afferent arteriole will constrict; if the NaCl is too low, the afferent arteriole will vasodilate to increase GFR

which cells control vasoconstriction/dilation?

mesangial cells (smooth muscle)

what happens when you eat lots of salt in reference to the tubuloglomerular feedback?

the presence of lots of salt in the blood leads to vasoconstriction, causing GFR to decrease and lead to water retention; higher blood volume due to increase in water = higher stroke volume = higher blood pressure

what is the role of the proximal tubule?

to reabsorb glucose and amino acids

what fraction of solutes in the filtrate are reabsorbed in the proximal tubule/thick descending limb?

2/3 of solutes

which solutes are pretty much all reabsorbed?

glucose and amino acids

which solutes are still present in the filtrate after passing the proximal tubule/thick descending limb?

sodium chloride, water, calcium

what is a symptom of diabetes that can be seen in the urine?

the presence of glucose in the urine indicates diabetes, since this points to a very high blood glucose to the point where it cannot be completely reabsorbed

what is transcellular?

the reabsorption across the cell

what is paracellular?

the reabsorption between the cells

which molecules are reabsorbed through transcellular means?

sodium, glucose, amino acids

which molecules are reabsorbed through paracellular means?

chloride ion, water, calcium

what is secondary active transport?

the act of transporting using an existing gradient (2 in 1 transport)

which molecules participate in secondary active transport in the proximal tubule?

sodium gradient facilitates reabsorption of glucose (sodium wants to come into the cell)

what side of the epithelial cells is the sodium-potassium pump located?

the lumen side