Week 6 - Urinary System Flashcards
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)
How do the KD regulate blood volume?
conserve / eliminate water
How do the KD regulate blood pressure?
secrete renin
adjust renal resistance
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
Describe the path of urine drainage in the KD
Papillary duct in renal pyramid minor calyx major calyx renal pelvis ureter
The KD receives ___% of resting cardiac output via renal arteries
25%
Sympathetic vasomotor nerves regulate blood flow and ______ by altering _______
renal resistance
arterioles
In the KD nephron, __________are formed between the afferent & efferent arterioles. Efferent arterioles give rise to _______ and ______
glomerular capillaries
peritubular capillaries
vasa recta
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
KD has over ______ nephrons composed of a _______ and ______
1 million
corpuscle
tubule
80-85% of nephrons are _____ nephrons. The remaining 15-20% are _______ nephrons.
cortical
juxtamedullary
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
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
T/F - the number of nephrons remains constant from birth
T
Dysfunction of KD nephrons is not evident until function declines by ________
25% of normal
Nephrons and collecting ducts perform 3 basic processes. List them
glomerular filtration
tubular reabsorption
tubular secretion
Rate of excretion in renal physiology is defined as ________
rate of filtration + rate of secretion - rate of reabsorption
Glomerular filtrate is produced by _________
Filtering capacity is enhanced by _________
blood pressure
thinness of membrane, large surface area of glomerular capillaries, glomerular BP
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
