PSIO202 Exam 4 - Urinary Anatomy Flashcards
What are the two primary functions of the kidney?
filter waste from the plasma of the blood, return valuable resources (water and solutes) to the blood
How much blood is filtered per minute and per day by the kidneys? How does that relate to normal blood volume?
125 mL per minute
180 L per day
That is 40 times the total blood volume of an adult
Kidneys regulate…
ionic composition (Na+, K+, Ca2+, Cl-, phosphate)
blood pH and osmolarity
blood glucose
blood volume (water)
blood pressure (renin or renal resistance)
Kidneys release…(2 hormones)
erythropoietin and calcitriol
Kidneys excrete…(two things)
wastes and foreign substances
What are the 4 major physiological functions of the kidney?
filtration, reabsorption, secretion, and excretion
99% of nutrients, electrolytes, etc. filtered from blood plasma…
are returned to the blood through reabsorption
What is a renal threshold?
value for all nutrients and electrolytes that will be returned to the blood, and anything above that threshold will be lost in urine
About how much water, sodium, bicarbonate, and chloride are excreted each day?
less than 1%
water - 1.5 (out of 180)
sodium - 150 (out of 25,000)
bicarbonate - 2 (out of 4,500)
chloride - 150 (out of 18,000)
The kidney has over ——– nephrons, which is (constant/increasing) from birth.
1 million
constant
Increased kidney size indicates…
increase size of individual nephrons
Can injured kidneys or nephrons be repaired/replaced?
No
When does kidney dysfunction become evident? Why?
when it declines to less than 25% of normal
remaining nephrons can handle larger work loads when necessary, and if one kidney is removed the remaining kidney’s nephrons enlarge to handle the additional work)
if one kidney is removed, the other kidney can filter –% of the normal rate of two kidneys.
80%
The two main parts of a nephron are the…
Their functions are to…
corpuscle (plasma filtration) and tubule (reabsorption)
What composes the renal corpuscle? Functions?
glomerulus - knot of capillaries where filtration occurs
glomerular/Bowman’s capsule - double walled epithelial cup that collects filtrate
What composes the renal tubule? Basic functions?
proximal convoluted tubule - reabsorption and secretion
loop of Henle - only reabsorption
distal convoluted tubule - reabsorption and secretion
How many DCTs drain into one collecting duct?
1 or more
What vessels approach and exit the glomerulus?
afferent - approach
efferent - exit
What structures do the efferent arterioles immediately lead into?
peritubular capillaries or vasa recta
Describe blood flow starting at the renal artery, and ending at the afferent arteriole.
renal artery
segmental arteries
interlobar arteries
arcuate arteries
cortical radiate arteries
afferent arteriole
Describe blood flow starting at the efferent arteriole, and ending at the renal vein.
efferent arteriole, peritubular capillaries/vasa recta, cortical radiate veins, arcuate veins, interlobar veins, interlobar veins, renal vein
What materials enter the cortical radiate vein, and from what structures?
vasa recta - reabsorbed/secreted
peritubular capillaries - reabsorbed/secreted
efferent arteriole - not filtered
The glomerular capsule is always located in the…
cortex
The loop of Henle always…
dips down into the medulla
What percent of nephrons are cortical vs juxtamedullary?
80-85% cortical
15-20% juxtamedullary
Describe the different between cortical and juxtamedullary nephrons.
cortical -
renal corpuscle in outer cortex
loops of Henle in cortex with a dip down into the medulla
juxtamedullary -
corpuscles are in the cortex but close to the medulla
loops of Henle are long and extend deep, almost entirely in the medulla
The medulla gets —— as it gets deeper, so a deeper loop of Henle results in more —— reabsorption.
saltier
water reabsorption
The kidney receives about –% of the resting cardiac output.
25%
What is the difference between the functions of glomerular capillaries and peritubular capillaries/vasa recta?
glomerular - filtration
peritubular capillaries/vasa recta - carry away things reabsorbed from filtrate
What regulates the blood flow/renal resistance to the kidney? How?
sympathetic vasomotor nerves alter diameter of arterioles via vasoconstriction and vasodilation
Thin epithelium allows for more ——-, so simple squamous is located in the ———- (opposed to the normal simple cuboidal everywhere else)
diffusion
parietal layer of glomerular capsule, descending and thin ascending limbs of the loop of Henle
Where are microvilli located? Why?
PCT (proximal con. tubule)
intercalated cells of the collecting duct
more surface area for more reabsorption
Where are hormone receptors found, and why?
Distal convoluted tubule cells and principal cells of the collecting duct
regulate BP and filtration rate
