Week 6 - Urinary System Flashcards by Darren L

List functions of Kidneys

Excrete waste in urine
Regulate blood volume
Regulate blood composition
Regulate blood pH, osmolarity & glucose 
Regulate blood pressure
Release erythropoietin
Participate in Vitamin D synthesis (calcitriol)

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How do the KD regulate blood volume?

conserve / eliminate water

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How do the KD regulate blood pressure?

secrete renin

adjust renal resistance

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The KD is located __________ and is protected by ______ ribs and by layers of ______ and ________

above the waist between peritoneum & posterior wall of abdomen
11th & 12th
adipose tissue
fascia

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Describe the path of urine drainage in the KD

Papillary duct in renal pyramid
minor calyx
major calyx
renal pelvis
ureter

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The KD receives ___% of resting cardiac output via renal arteries

25%

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Sympathetic vasomotor nerves regulate blood flow and ______ by altering _______

renal resistance

arterioles

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In the KD nephron, __________are formed between the afferent & efferent arterioles. Efferent arterioles give rise to _______ and ______

glomerular capillaries
peritubular capillaries
vasa recta

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Glomerular filtration is where ________ occurs
Peritubular capillaries function to ________
Vasa recta supplies _________

filtration of blood
carry away reabsorbed susbtances from filtrate
nutrients to renal medulla w/o disrupting its osmolarity

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KD has over ______ nephrons composed of a _______ and ______

1 million
corpuscle
tubule

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80-85% of nephrons are _____ nephrons. The remaining 15-20% are _______ nephrons.

cortical

juxtamedullary

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In Juxtamedullary nephrons, the renal corpuscles are located ________ and long loops of Henle extend into ________ enabling _________ of dilute or concentrated urine.

close to medulla
deepest medulla
excretion

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The Juxtamedullary nephron is the structure where ______ makes contact w/ ________ of loop of Henle. The ______ is the thickest part of the ascending limb. Juxtaglomerular cells are modified _______ in arteriole.

afferent arteriole
ascending limb
macula densa
muscle cells

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T/F - the number of nephrons remains constant from birth

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Dysfunction of KD nephrons is not evident until function declines by ________

25% of normal

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Nephrons and collecting ducts perform 3 basic processes. List them

glomerular filtration
tubular reabsorption
tubular secretion

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Rate of excretion in renal physiology is defined as ________

rate of filtration + rate of secretion - rate of reabsorption

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Glomerular filtrate is produced by _________

Filtering capacity is enhanced by _________

blood pressure

thinness of membrane, large surface area of glomerular capillaries, glomerular BP

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Glomerular blood pressure is high due to ______

small size of efferent arteriole

List the layers of the filtration membrane in the glomerular capillaries and what each layer filters

endothelial cells - cells and platelets
basal lamina - large plasma proteins
slit membrane - medium-sized proteins

In glomerular filtration the net filtration pressure is defined as _________

Glomerular blood hydrostatic pressure - capsular hydrostatic pressure - blood colloid osmotic pressure

The average adult male forms glomerular filtrate at a rate of ________

125mL/min

Glomerular filtration functions normally with mean arterial pressures of _______

80-180mmHg

What mechanisms autoregulate glomerular filtration rate?

myogenic mechanism - smooth muscle adjusts diameter of afferent arteriole
tubuloglomerular feedback - macula densa releases vasoconstrictor from juxtaglomerular apparatus to constrict afferent arteriole

How is glomerular filtration rate regulated hormonally?

ANP - atrial natriuretic peptide relaxes glomerular mesangial cells increasing capillary surface area and increasing GFR Angiotensin II reduces GFR - vasoconstricts afferent and efferent arterioles

With respect to neural regulation of glomerular filtration rate, blood vessels of the KD are supplied by _______ nerve fibers that cause _____ of _____ arterioles

sympathetic vasoconstriction afferent

At rest, renal blood vessels are maximally dilated because ______ activity is minimal and renal ________ prevails

sympathetic | autoregulation

How does extreme sympathetic stimulation change GFR?

vasoconstriction of afferent arterioles lowers urine output and permits blood flow to other tissues

KD nephron must reabsorb ____ of glomerular filtrate. Most tubular reabsorption occurs mostly in _______

99% | proximal convoluted tubules

Describe the routes of tubular reabsorption in KD nephrons

paracellular reabsorption - diffusion | transcellular reabsorption - move through membranes of tubule cell via active transport

What materials are reabsorbed in the first half of the proximal convoluted tubule via Na+ symporters?

glucose, amino-acids, lactic acid, water soluble vitamins

How is bicarbonate ion reabsorbed into blood?

Na+ antiporters reabsorbs Na+ and secrete H+ into tubular fluid. For each H+ secreted one filtered bicarbonate ion returns to blood via facilitated diffusion

Electrochemical gradients produced by ______ and ______ causes passive reabsorption of solutes such as ________

symporters antiporters Cl-, K+, Ca2+, Mg2+

Thick limb of the loop of Henle has _____ symporters that reabsorb these ions

Na+, K+, Cl-

Distal convoluted tubule is major site where ______ hormone stimulates reabsorption of ____. It is also where _____ are reabsorbed via symporters

parathyroid Ca2+ Na+, Cl-

By end of distal convoluted tubule, ___ of solutes and water have been reabsorbed and returned to bloodstream

95%

In the principal cells in late distal tubule and collecting duct: _____ is reabsorbed into blood and _____ is secreted into urine

water, Na+, urea K+

Tubular fluid leaving the collecting duct is dilute when ADH level is _____ and concentrated with ADH level is _____

low high

Aldosterone increases _______ reabsorption and _____ secretion by principal cells by stimulating _________

Na+, water K+ the synthesis of new pumps and channels

Intercalated cells reabsorb ____ and secrete _____

K+, bicarbonate ions H+

Atrial natriuretic peptide suppresses secretion of ______ and increases secretion of _____ which increases ____ and decreases blood volume.

aldosterone, ADH Na+ urine output

ADH stimulates the insertion of _______ into membrane of principal cells which increases ______

aquaporin-2 channels | water permeability

Urea recycling causes a buildup of urea in ______

the renal medulla

Caffeine inhibits ____ reabsorption | Alcohol inhibits secretion of _____

Na+ | ADH

Which stage of urine formation involves 99% of the filtrate moving back into the blood?

Reabsorption

Excess H+ ions are deposited into the urine during which stage of urine formation?

Secretion

List the actions of Antidiuretic hormone

- decrease urine output - decrease perspiration - raise blood pressure by vasoconstriction