Renal Phys Flashcards
(112 cards)
1
Q
what are the main functions of kidneys
A
excretion of waste, regulate blood volume, electrolyte compostion, and pH, production of hormones and active agents, and gluconeogenesis
2
Q
what is excreted in the waste
A
AA breakdown products such as urea and NH3, creatinine-creatinine phosphate, and drugs
3
Q
how much protein and glucose should be in the urine
A
0 grams
4
Q
where does the renal artery enter the kidney
A
thru the hilum
5
Q
what does the renal artery progressively form in the kidney
A
interlobar arteries, arcuate arteries, interlobular arteries, afferent arterioles, and glomerular capillaries
6
Q
where are the large amounts of fluid and solutes filtered for urination
A
the glomerular capillaries
7
Q
what does the distal end of the capillaries of each golmerulus coalesce form
A
the efferent arteriole which leads to a second capillary network (peritubular capillaries) that surrounds the renal tubules
8
Q
what do the arterioles help regulate
A
the hydrostatic pressure
9
Q
what does high hydrostatic pressure in the glomerular capillaries cause
A
rapid fluid filtration
10
Q
what does a low hydrostatic pressure in the peritubular capillaries cause
A
rapid fluid reabsorption
11
Q
what is the function of antidiuretic hormone arginine vasopressin (AVP)
A
it regulates the amount of glomerular filtration rate of the two kidneys the pro urine is around 90% reabsorbed in the proximal tubule and descending limb of Henle’s loop the remaining fluid is then reabsorbed in the collecting duct
12
Q
what is the ureter
A
a muscular tube composed of an inner longitudinal layer and an outer circular layer of smooth muscle that connects the kidney and the bladder
13
Q
what is the lumen of the ureter covered by
A
the transitional epithelium
14
Q
what is another name for the transitional epithelium
A
urothelium
15
Q
what is detrusor muscle
A
irregular crisscrossing bands of smooth muscle that comprise the bladder
16
Q
what is the interior surface of the bladder made of
A
transitional cellular epithelium that is structurally suited for the large volume fluctuations of the bladder
17
Q
does the strengh of contraction of the detrusor muscle deminsih over time
A
yes
18
Q
what do voluntary contractions of abdominal skeletal muscles increase to promote a more forceful bladder
A
intra abdominal pressure
19
Q
what are other moments where the intra abdominal pressure increases
A
during forceful defecation or childbirth
20
Q
what is the renal fat pad
A
a shock absorbing layer of adipose tissue that covers the fibrous capsule
21
Q
what is the fibrous capsule
A
irregular connective tissure that holds the shape of the kidney vascule and protects it
22
Q
what is the renal fat pad covered with
A
tough renal fasica
23
Q
what holds the kidneys in their postion in the abdominal cavity
A
the fasica and the overlying peritoneum
24
Q
what does the afferent arterioles branch from
A
the cortical arteries
25
what do the afferent arterioles form
the glomerulus of the nephron
26
what is the nephron
the functional filtration unit of the kidney
27
what are juxtaglomerular cells or granular cells
cells in the kidney that synthesize, store, and secrete the enzyme renin that are specialized SM cells that are mainly in the walls of the afferent arterioles and some in the efferent arterioles that deliver blood to the glomerulus
28
what does synthesizing renin play a critical role in
the renin angiotensin system and the autoregulation of the kidney
29
what causes the juxtaglomerular cells secrete renin
due to a drop in pressure detected by stretch receptors in the vascular wall or when stimulated by macula densa cells
30
where are the macula densa cells located
in the distal convoluted tubule
31
what do the macula densa cells stimulate in juxtaglomerular cells
the release of renin when they detect a drop in sodium concentration in tubular fluid
32
what is the juxtaglomerular apparatus
juxtaglomerular cells, extraglomerular mesangial cells and macula densa cells
33
what do beta 1 adrenergic receptors in juxtaglomerular cells do when stimulated by epinephrine or norepinephrine
they induce the secretion of renin and decrease systemic blood pressure
34
what is the connecting vessel between the glomerulus and the peritubular capillaries and vasa recta
the efferent arteriole
35
what are the four principal functions of urine formation
filtration, reabsorption, secretion, and osmoconcentration
36
what are podocytes
specialized epithelial cells that cover the network of capillaries in the glomerulus
37
what are podocyte foot processes connected by
nephrin
38
what is the filtration co efficient the product of
a biological membrane's permeability to water and the surface area of the membrane
39
formula for KP
surface area * permeability
40
formula for GFR
NFP * KP
41
what is filtration regulated by
fenestrations in capillary endothelial cells, podocytes w/ filtration slits, membrane charge (negatively charged), and the basement membrane between capillary cells
42
what is the glomerular basement membrane
a layer of connective tissue that surrounds glomerular filtration
43
what is the creation of glomerulus filtration
a filtrate that does not contain cells or large proteins and has a slight predominance of positively charged substances
44
what is filtration further optimized by
regulation of blood flow
45
t/f: less substances move across the membranes of the PCT than any other portion of the nephron
false, more substances move across the PCT
46
what are secondary mechanisms where substances are moved from one side of the PCT membrane to the other
antiport active transport, diffusion, and facilitated diffusion
47
what are the substances that are transported w/ Na+ on the apical side of the membrane
Cl-, Ca++, AA, glucose, (PO4)3-
48
what is Na exchanged w/ on the basal membrane
K+
49
about what percentage of water, Na+, and K+ is reabsorbed in the PCT
67%
50
t/f: 100% of glucose, AA, and other organic substances such as vitamins are recovered in the PCT
true
51
what would cause glucose to be present in urine
if glucose levels are so high that all the transporters in the PCT are saturated
52
what does glycosuria typically points to
type 1 or type 2 diabetes
53
what binds simultaneously to the same symport protein on the the apical surface of the cell to be transported toward the interstital space
glucose and Na+
54
describe how Na+ and glucose move together
Na moves down its electrochemical and concentration gradient into the cell and takes glucose w/ it Na+ which then actively pumps out of the cell at the basal surface of the cell into the interstitial space
55
how does glucose leaves the cell to enter the interstitial space
facilitated diffusion
56
what is a vital to the maintenance of acid base balance
recovery of bicarbonate
57
what does CO2 in the transportation of RBC's of the stomach and pancreas produce
hydrochloric acid and HCO3
58
what happens w/ HCO3- ions in lumen of the PCT
it combines w/ hydrogen ions to form carbonic acid which catalyzed into CO2 and water which diffuses across the apical membrane into the cell water then moves osmotically across the lipid bilayer due to the presence of aquaporin water channels
59
what does the reverse reaction in the cell produce
bicarbonate ions
60
what does the Na+/H+ antiporter do
excretes H+ and recovers Na+
61
what does PCT stand for
proximal convoluted tubule
62
what is the function of aquaporins
to allow movement of water across the lipid rich hyrophobic cell membrane
63
what happens when the collecting ducts are stimulated by ADH
aquaporin channel proteins are inserted which allows water to bass into the interstitial space to be recovered by the vasa recta
64
what does the process of ADH stimulating the collection ducts allow
for water to be recovered from filtrate and put back into the blood
65
what does simple diffusion remove from the PCT
Cl-
66
what is the loop of Henle
the middle section of the nephron that has permanent aquaporin channel proteins and is where most reabsorption happens
67
what does the permant aquaporin channel proteins allow
unrestricted movement of water
68
what does increased interstitial osmolarity result in
reabsorption of up to 15% of the water filtrate allowing for small amounts of urea, Na+, and other ions to be recovered
69
characteristics of the descending part of the loop of Henle
the thin segment is highly permeable to water and moderately permeable to most solutes, but has few mitochondria and little to no active reabsorption
70
characteristics of the ascending part of the loop of Henle
the thick segment reabsorbs about 25% of the filtered Na, Cl, and K as well as large amounts of Ca, bicarb, and Mg and secretes H+ into the tubular lumen
71
what does removal of Na+ in the ascending loop of Henle lead to
a hypo-osmotic filtrate by the time it reaches the distal tubule
72
what does pumping Na+ into the interstitial space contribute to
the hyperosmotic environment of the kidney medulla
73
what does the structure of the loop of Henle and its capillary network create
a countercurrent multiplier system
74
what is the baroreceptor flex trigger
an increase in sympathetic activity when systemic BP drops stimulates renin
75
what two things leads to an enzyme reaction in the blood that produces angiotensin 1
when the macula densa senses low fluid flow or low Na+ concentration signalling the juxtaglomerular cells to secrete renin and when the liver releases angiotensinogen
76
what causes a secondary enzyme reaction in the blood turning angiotensin 1 into angiotensin 2
when the lungs release angiotensin-converting enzyme (ACE) into the blood
77
what does angiotensin 2 stimulate
widespread vasoconstriction
78
what does widespread vasoconstriction cause the adrenal cortex to secrete
aldosterone
79
what does aldosterone stimulate
an increase in the amount of Na+/K+ ATPase in the basal membrane of the DCT and the collecting ducts
80
what is DCT
distal convoluted tubule
81
about how much filtered water will be recovered in the DCT in addition to the 80% already recovered
10-15%
82
what does increasing the amount of Na+/K+ ATPase in the basal membrane of the DCT and collectng duct do
the movement of Na+ out of the lumen of the collecting duct creates a negative charge that promotes the movement of Cl- out of the lumen into the interstitial space by a paracellular rout across tight junctions
83
what do peritubular capillaries do with the solutes and water it recieves from the DCT and collecting ducts
it returns them to the circulation
84
what all does angiotensin 2 in the blood trigger
increase in sympathetic activity, increase in tubular Na+ and Cl- reabsorption, K+ excretion, water retention, aldosterone secretion, arteriolar vasoconstriction, increase in BP, and ADH secretion
85
what does NFP stand for
Net filtration pressure
86
what is atrial natrueretic peptide produced b
the stretch of the atria stimulates the production of ANP
87
what is the typical pH of blood
7.4
88
what is a huge part of maintaining blood pH
bicarbonate and CO2
89
what does it mean when there is more CO2 present in the blood
more H+ end up being present in the blood making it more acidic (higher number)
90
what are the steps to returning the pH balance when the pH is too high
alkalosis, stimulating the brain and arterial receptors, decreasing resp rate, increasing blood CO2, and increasing blood H2CO3
91
what are the steps to returning the pH balance when pH is too low
acidosis, stimulating the brain and arterial receptors, increasing resp rate, decreasing blood CO2, and decreasing blood H2CO3
92
what are the steps to supplying bicarbonate ions to the bicarbonate buffer system
Na+ are reabsorbed from the filtrate in exchange for H+ by an antiport mechansim in the apical membranes of cells lining the renal tubule, the cells produce bicarb ions that can be shunted to peritubular capillaries, when CO2 is available, the reaction is driven to the formation of carbonic acid which dissociates to form a bicarb ion and a H+, finally the bicarb ion passes into the pertubular capillaries and returns to the blood the H+ is secreted into the filtrate where it can become part of new water molecules and be reabsorbed as such or removed in urine
93
what is the renal papilla
where the renal pyramids in teh medulla empty urine into the minor calyx
94
what is the renal papilla histologically marked by
the medullary collecting ducts converging to form a papillary duct to channel the fluid
95
what is the renal cortex
the outer region of the kidney
96
what is the medulla
the inner region of the kidney
97
what are the renal columns
the connective tissue extensions that radiate downward from the cortex thru the medulla to separate the renal pyramids and renal papillae
98
what are papillae
bundles of collecting ducts that transport urine made by nephrons to the calyces of the kidney for excretion
99
what is order of the renal vascular system starting w/ the renal artery
segmental artery, interlobar artery, arcuate artery, interlobular artery, afferent arteriole, glomerulus, efferent arteriole, peritubular capaillaries, vasa recta, interlobular vein, arcuate vein, interlobar vein, and renin vein
100
what are the three funtions of nephron
ultrafiltration, selective resborption, and osmoregulation
101
what is ultrafiltration
blood is filtered out of the glomerulus at the bowman's capsule to form filtrate
102
what is selective reabsorption
unsable materials are reabsorbed in convoluted tubules (both proximal and distal)
103
what is osmoregulation
the loop of henle establishes a salt gradient, which draws water out of the collecting duct
104
t/f: the tubules in a nephron dont have a distinct macro- and micro- anatomical organization
false they do have a distinct macro and micro section
105
what is active transport
the movement of materials against a concentration gradient and requires an expenditure of energy
106
what is primary active transport
the direct use of hydrolysis of ATP in active transport
107
what is secondary active transport
the use of coupling transport of another molecule moving along its electrochemical gradient
108
what is co transport
coupled transport of two distinct molecules in unisyn
109
what is a symport
two molecules that are transported in the same direction
110
what is a antiport
two molecules that are transported in the opposite direction
111
what does primary active transport of Na+ on the basolateral surface create
Na+ gradient
112
t/f: more substances move across the membrane of the PCT than any other portion of the nephron
true
