More lecture 10qs Flashcards
The renal artery gives rise to how many segmental arteries?
5
Where does water in urine come from?
Plasma
How do the kidneys protect acid base balance?
By conserving or excreting H+ ions
What do the kidneys activate?
Vitamin D
How are kidneys involved with blood cell regulation?
Produce EPO
What is made of striated triangles called renal pyramids?
Renal medulla
One of what supplies each nephron and delivers blood to each glomerulus?
Small afferent arterioles
Only place in the body where capillaries drain into arterioles rather than veins is where?
Glomerular capillaries
What is the juxtaglomerular apparatus?
Specialized region made of vascular and tubular cells
All nephrons originate where?
Cortex
What type makes up 80% of nephrons?
Cortical
The glomerulus lies in inner cortex of what nephrons?
Juxtamedullary
Peritubular capillaries of ____________________ nephrons form vasa recta
juxtamedullary
How much filtrate is formed each day?
180L
______% of the plasma that enters glomerular capillaries is filtered into the Bowman’s capsule
20%
Of the 180L of filtered plasma, 178.5L is ________________
reabsorbed
What do the 3 layers fluid passes to enter Bowman’s capsule retain? What do they let pass?
Retain blood cells and plasma proteins, pass H2O and smaller molecules
True or false: the fenestrations in the glomerular capillaries do not let RBCs out
True
Where are glycoproteins found?
In the basement membrane (b/t glomerulus and bowman’s capsule)
1% of proteins that slip through are degraded into amino acids in __________________ and reabsorbed, thus normal urine is protein free
proximal tubule
Podocytes are found where?
Inner layer of Bowman’s capsule
True or false: No local energy is used to move fluid across the membrane into Bowman’s capsule
True
What 2 things does glomerular capillary blood pressure depend on?
1) Heart contraction
2) Resistance in afferent and efferent arterioles
True or false: glomerular capillary blood pressure only depends on afferent arteriole pressure
False; both afferent and efferent
Glomerular capillary pressure is _____________ than other capillaries
higher
What concentration gradient establishes tendency of water to move from Bowman’s capsule into glomerulus?
Plasma proteins
What does increased arterial blood pressure do?
Increase blood flow into glomerular capillaries
What pressure tends to push fluid out of capsule (opposing filtration)?
Bowman’s capsule hydrostatic pressure
GFR depends on what 3 things?
1) NFP
2) Glomerular surface area
3) Glomerular permeability
What is a measure of how much blood passes through glomeruli each minute?
GFR
Can burns increase or decrease GFR?
Increase
Can dehydration increase or decrease GFR?
Decrease
Urinary tract obstruction (kidney stone, enlarged prostate) can increase what pressure?
Bowman’s capsule hydrostatic pressure
MAP and afferent arteriole resistance largely determine what?
Glomerular capillary blood pressure
The body regulates GFR by adjusting what pressure?
Glomerular capillary blood pressure
Two control mechanisms regulate GFR by regulating ______________________ of ________________ arterioles
radius (resistance); afferent
What is extrinsic control of GFR also called?
Sympathetic control
What prevents momentary changes in BP from changing GFR?
Autoregulation (intrinsic)
Extrinsic controls do what to autoregulatory responses?
Override them
Are baroreceptors or chemoreceptors involved in GFR control?
Baroreceptors
Baroreceptor reflex response achieves what?
Sympathetic control of GFR
1) When baroreceptors detect a fall in BP, what does the brainstem then do?
2) What two things does this then increase?
1) Initiates sympathetic stimulation of heart and vessels
2) Cardiac output and peripheral resistance (incl. of afferent arteriole)
Which arterioles are more sympathetically innervated?
Afferent
What happens when the baroreceptors detect low BP?
Sympathetic vasoconstriction is reduced
Substances being returned from tubular lumen into peritubular capillaries is called what?
Tubular reabsorption
To leave tubular fluid, a substance must cross what?
Luminal membrane [of tubular cell]
What is within tubular cells?
Cytosol
What part of tubular cells must be crossed to enter IF?
Basolateral membrane
How do substances enter plasma?
Diffusing through IF, then penetrating capillary wall
List 3 things that require active transport during reabsorption
Glucose, amino acids, electrolytes
80% of the energy spent by kidneys is used for ______ transport
Na+
True or false: all segments of the tubules transport the same amounts of Na+
False; different segments of the tubules transport differing amounts of Na+
Where is the Na-K ATPase pump?
Basolateral membrane of tubular cells
How is Na+ reabsorbed?
Na-K pump transports Na+ out of tubular cell into lateral space where it builds up
Once it’s pumped out for reabsorption, sodium diffuses _[up/down]___concentration gradient into interstitial fluid and then peritubular capillary
down
Na+ and Cl- account for _____% of ECF osmotic activity
90%