FINAL EXAM Flashcards
The kidney’s functions are to…
Filter blood by removing wastes via urine.
Remove metabolic wastes and foreign substances.
Regulate plasma’s volume/MAP, ion composition, osmoloarity, and pH.
Blood enters the _________ and branches into arterioles which feed individual __________. Residual blood exits the ________.
renal artery
nephrons
renal vein
Any tubular filtrate not reabsorbed back into the bloodstream is sent to the ________ via the _______.
bladder
ureter
Basic renal exchange process involves what 4 processes?
Glomerular filtration
Reabsorption
Secretion
Excretion
Filtration involves what units of the kidney?
Glomerulus and Bowman’s capsule.
Reabsorption involves what units of the kidney?
Kidney tubules and peritubular capillaries (back into blood).
Secretion involves what units of the kidney?
Peritubular capillaries and nephron tubules.
Excretion involves what units of the kidney?
Nephron tubules (to the body).
What do afferent arterioles bring to the kidney?
Bring in blood to be filtered.
Smooth muscle in the afferent/efferent arterioles vasoconstrict to help regulate what two processes?
Blood flood and glomerular filtration rate.
Fenestrations in the glomerulus allow for…
Water, ions, and glucose to easily pas through.
Efferent arteriole vasoconstriction can back up blood which leads to _____ glomerular capillary hydrostatic pressure and _____ glomerular filtration rate.
high
high
Afferent arteriole vasoconstriction ______ blood flow through the glomerulus and consequently ______ glomerular filtration rate.
lowers
lowers
Glomerular hydrostatic pressure = what kind of force?
Large pro-filter force.
Glomerular oncotic pressure = what kind of force?
Medium anti-filter force, which is mediated by trapped proteins.
Bowman’s capsule oncotic pressure = what kind of force?
Small pro-filter force.
Boman’s capsule hydrostatic pressure = what kind of force?
Small anti-filter force.
During transient modest disruptions of MAP, like during exercise, ________ maintain a normal glomerular filtration rate.
intrinsic controls
What are the parts of the nephron?
Glomerulus/Bowman’s capsule
Proximal tubule
Loop of Henle
Distal tubule/collecting duct
Molecular movement from tubules back into peritubular capillaries (which are returned to blood) is defined as what?
Reabsorption
Diffusion rate is dictated by what two mechanisms?
Membrane permeability; size and charge. Differential concentration (high to low).
Pumping ATP at either the apical or basolateral membranse can allow…
passive transport to occur at the other membrane.
Normal plasma concentrations of glucose can be fully reabsorbed back into capillaries via…
basolateral glucose transport protein located on the promixal tubule.
What happens in people with diabetes mellitus, when extra high glucose concentrations occur and the transporter is saturated?
Glucose doesnt ger reabsorbed so it is excreted in the urine.
Used to do “taste tests”
If a solute is pumped out, what happens to water?
Water follows the solute.
True or False: water actively flows across kidney membranes.
False: it passively moves.
Where does unregulated reabsorption occur?
Proximal tubule (the mass reabsorber).
Where does regulated reabsorption occur?
Distal tubule.
Water and sodium are often reabsorbed.
What are some of the important characteristics of proximal tubule epthelium?
Leaky tight junctions.
Brush border for larger surface area.
Mitochondria.
H+ secreted into it (from peritubular capillaries).
True or false: more glucose is reabsorbed in the proximal tubule than sodium.
True
70% Na+
100% Glucose
The loop of henle produces ___________________ to allow fine control of urine volume in subsequent collecting duct.
medullary osmotic gradient
What are the differences between the descending loop of henle vs. the ascending loop of henle?
Descending is permeable to water, and does not transport ions.
Ascending is impermeable to water, and has a Na+/K+/Cl- cotransporter.
What are some of the important characteristics of the distal tubule and collecting duct epithelium?
Tight junctions.
Hormones regulate reabsorption like ADH and Aldosterone.
Secreation of K+ and H+ occurs in the distal tubule.
H2O reabsorption in the collectein duct is regulated via what hormone?
ADH
What is the difference between diabetes mellitus and diabetes insupidus?
Diabetes insipidus = no AHD to conserve water.
Diabetes mellitus = uncontrollable insulin production.
When blood volume is low (blood osmolarity high) ADH is released from the brain causing what?
Aquaporin insertion into the collecting duct membrane.
What is the function of aquaporins in the kidney?
To allow water to leave the tubular fluid down its concentration gradient back into the blood stream.
Conserves water.
Control of urinary water excretion in the distal tubule is instrumental in regulating what two mechanisms?
Plasma volume/MAP and osmolarity.
How is Na+ reabsorbed in the distal tubule?
Na+ is actively pumped across the basolateral membrane via Na+/K+ ATPase.
Na+ moves across apical membrane by channels or cotransport.
What happens when aldosterone is released from the adrenal cortex?
Aldosterone crosses the plasma membrane and binds to the cytosolic receptor, which increases the number of Na+/K+ pumps on the basolateral membrane and Na+ and K+ channels on the apical membrane.
What is aldosterone secretion regulated by?
Renin/angiotensin system.
Juxtamedullary apparatus contains specialized kidney cells that help regulate what two mechanisms?
Blood volume and MAP.
What do juxtamedullary granular cells secrete?
Protease renin.
Involved in Na+ reabsorption and MAP regulation.
When MAP declines, ________________ system can kick in to increase MAP back to set point level.
Renin/angiotensin
Fluid remaining in the collecting duct drains to the….
minor/majoy calyx cavities and onto the ureter.
What is micturition (urination) mediated by?
spinal cord reflex.
In the spinal cord reflex that mediates micturition, what happens when the parasympathetic system is activated?
Causes contraction of detrusor muscle.
In the spinal cord reflex that mediates micturition, what happens when the sympathetic system is inhibited?
Relaxes the internal sphincter, causes urine to escape.
Blood/body pH regulation occurs via what three mechanisms?
Buffering of hydrogen ions
Respiratory compensation
Renal compensation
What is acidosis?
Depression of the nervous system.
Confusion, coma, and death.
Too many H+ ions.
What is alkalosis?
Hyper-excitability of neruons.
Too many OH- ions.
Which of the three mechanisms is the quickest defense against changes in pH?
Buffering
True or false: Buffering completely gets rids of H+ ions.
False; it only sequesters, can’t completely get rid of it.