Urinary System Flashcards
1
Q
what is the function of the kidney?
A
produces urine
2
Q
what is the function of the ureter?
A
transports urine toward the urinary bladder
3
Q
what is the function of the urinary bladder?
A
temporarily stores urine prior to elimination
4
Q
what is the function of the urethra?
A
conducts urine to exterior; in males, transports semen as well
5
Q
what is renal ptosis?
A
kidneys drop
6
Q
where is the left kidney located?
A
just below the spleen
7
Q
where is the right kidney located?
A
just below the liver
8
Q
what is lower, the right or left kidney?
A
right kidney
9
Q
what is the function of connective tissue around the kidney?
A
anchors the kidney and surrounding adipose to abdominal wall
10
Q
what is it called if you are born with 1 kidney?
A
unilateral renal agenesis
11
Q
why do we have two kidneys when we only need 1?
A
serious health problems if get down to only 25% function. kidney disease has no symptoms until just before the kidney fails
12
Q
what are the two most common causes of kidney failure?
A
high BP and diabetes
12
Q
what are the two most common causes of kidney failure?
A
high BP and diabetes
13
Q
order the major parts of the kidney from superficial to deep
A
fibrous capsule, renal cortex, renal medulla, renal pyramid, papillary duct, renal papilla, minor calyx, major calyx, renal pelvis, ureter
13
Q
order the major parts of the kidney from superficial to deep
A
fibrous capsule, renal cortex, renal medulla, renal pyramid, papillary duct, renal papilla, minor calyx, major calyx, renal pelvis, ureter
14
Q
describe the path of blood flow through the renal blood vessels beginning with the aorta?
A
aorta, renal artery, segmental artery, interlobar artery, arcuate artery, cortical radiate artery, afferent arteriole, glomerulus, efferent arteriole, peritubular capillaries/vasa recta, cortical radiate vein, arcuate vein, interlobar vein, renal vein, inferior vena cava
15
Q
what are the two types of nephrons?
A
cortical or juxtamedullary
16
Q
what is the function of the renal corpuscle?
A
filters the blood (filtration); produces filtrate
17
Q
what are the two parts of the renal corpuscle?
A
glomerulus and bowman’s capsule
18
Q
what is the function of the proximal convoluted tubule?
A
returns filtered substances to the blood (reabsorption)
19
Q
what is the function of the loop of henle?
A
helps conserve water and solutes (reabsorption of water)
20
Q
what is the function of the distal convoluted tubule?
A
rids the body of additional wastes (secretion)
21
Q
what is the function of the collecting duct?
A
carries urine from cortex toward renal papilla; water balance, can reabsorb water as needed
22
Q
what is the function of the collecting duct?
A
carries urine from cortex toward renal papilla; water balance, can reabsorb water as needed
23
what is the distinction between cortical and juxtamedullary nephrons?
cortical nephrons have loops of henle that do not extend into the medulla while juxtamedullary nephrones HAVE loops of henle that extend deep into the medulla
24
what is the blood vasculature that surrounds cortical nephrons?
peritubular capillaries
25
what do peritubular capillaries/vasa recta drain into?
venules to cortical radiate veins
26
what is the blood vasculature that surrounds juxtamedullary nephrons?
vasa recta
27
what is the parietal layer of the nephron made of?
simple squamous epithelium
28
what is the visceral layer of the nephron made up of?
podocytes, wrap around glomerular capillaries
29
what is the structural difference between the distal and proximal convoluted tubule?
distal convoluted tubule lack microvilli while proximal convoluted tubule HAS microvilli
30
what is the function of mesangial cells?
supporting cells containing actin filaments. Can contract, respond to AngII, ADH
31
what is the function of the afferent arteriole?
delivers unfiltered blood
32
what is the function of the efferent arteriole?
transports filtered blood away
33
what are the three components of the glomerular filtration membrane?
1. glomerular capillary endothelium with fenestrae
2. basement membrane
3. podocytes
34
true of false, the kidney capillaries are fenestrated?
true
35
what is the glomerular filtration rate?
the volume of filtrate formed by both kidneys per minute
36
what percentage of filtrate is returned to circulation by reabsorption in healthy kidneys?
99%
37
what is the average daily urine output in liters?
1-2 liters
38
what is the function of foot podocytes?
confer size selectivity and filtration surface; slits contain many cell-surface proteins which ensure that large proteins remain in the bloodstream
39
what is the ultrafiltrate?
small molecules (water, glucose, ions) that pass through
40
how do podocytes regulate the glomerular filtration rate?
when podocytes contract, they reduce the size of the filtration slits
41
what can the destruction of the filtration membrane lead to?
proteinuria, excess protein in urine
42
which way does the glomerular hydrostatic pressure push water and solute?
out of the plasma and into the filtrate
43
what is the significance of the efferent arteriole being smaller in diameter than the afferent arteriole?
the GHP is significantly higher than capillary pressures elsewhere in the systemic circuit
44
what does the blood colloid osmotic pressure do?
draws water out of the filtrate and into the plasma, opposing filtration.
45
what does the capsular hydrostatic pressure do?
pushes water and solutes out of the filtrate and into the plasma, opposing GHP
46
what is capsular hydrostatic pressure the result of?
resistance of filtrate already present in the nephron that must be pushed toward the renal pelvis.
47
What is the average pressure of the glomerular hydrostatic pressure?
55 mm Hg
48
What is the average pressure of the blood colloid osmotic pressure?
30 mm Hg
49
What is the average pressure of the capsular hydrostatic pressure?
15 mm Hg
50
what is the net filtration pressure?
10 mm Hg, pushing water and dissolved materials out of glomerular capillaries and into the capsular space
51
what is peritubular fluid?
filtrate that has been reabsorbed into space around peritubular capillaries
51
what is peritubular fluid?
filtrate that has been reabsorbed into space around peritubular capillaries
52
does filtration at the glomerulus require energy?
No, driven by the differences in pressure
53
what is facilitated diffusion?
carrier transport; no ATP; follows concentration gradient
54
what is active transport?
uses ATP; moves against gradient
55
what is co-transport?
carrier protein not linked to ATP hydrolysis; 2 substrates follow gradient. movement follows gradient of at least 1 of the transported substances
56
what is counter transport?
like co-transport but ions move in opposite directions
57
how is glucose reabsorbed in the PCT?
a sodium-glucose co-transported
58
what influences the amount of glucose absorbed?
the number of carriers in the tubules
59
what happens when the carriers are saturated?
excess substance cannot be reabosrbed and is excreted - start spilling into urine = glycosuria
60
what epithelia cell type is found in the PCT and DCT?
cuboidal cells
61
what is citamin D-DBP bound to as it is reabsorbed in PCT?
megalin/cubulin
62
where is most calcium reabsorbed?
PCT
63
what is found in the PCT that synthesizes the active form of vitamin D?
1-alpha hydroxylase
64
what is primarily absorbed in the loop of Henle?
water and salt reabsorption
65
what is primarily absorbed in the descending limb of the loop of Henle?
water
66
what is primarily absorbed in the ascending limb of the loop of Henle?
ions such as sodium
67
what is osmolarity?
number of solute particles in 1 kg of water
68
what is the function of the high osmolarity in the renal medulla?
driving force for water reabsorbtion and urinary concentration
69
why is distinct about the ascending loop of Henle?
impermeable to water; active solute transport of Na+ and Cl-
70
what is the results of the transport of NaCL along the ascending limb?
movement of water from the descending limb
71
what is the exchange of ions at the ascending loop of Henle?
sodium and chloride are reabsorbed in exchange for potassium
72
what substances are reabsorbed at the DCT?
water, sodium ions, and calcium ions (under hormonal control)
73
what is reabsorbed at the collecting duct?
water
74
what is secreted at collecting duct?
sodium, potassium, hydrogen and bicarbonate ions
75
what is the function of the papillary duct?
delivery of urine to minor calyx
76
what are the two cells of the collecting duct?
intercalated cell, principal cell
77
what is the function of the principal cell in the collecting duct?
main sodium reabsorbing cells
78
what is the function of the intercalated cells in the collecting duct?
mediate secrete and bicarbonate reabsorption
79
what cells are found in the papillary duct?
columnar cells
80
where is obligatory water reabsorption occur?
PCT and descending loop of Henle
81
what causes obligatory water reabsorption?
water follows reabsorbed solutes due to osmotic gradients
82
where does facultative water reabsorption take place?
DCT and collecting tubules
83
what is the driving factor behind facultative water reabsorption?
ADH making epithelium water permeable
84
what is key to making concentrated urine and conserving water?
ADH
85
what substance is not reabsorbed at all?
creatinine
86
what are the three types of metabolic waste?
urea, creatinine, uric acid
87
what does urea come from?
breakdown of amino acids
88
what does creatinine come from?
breakdown of creatine phosphate in skeletal muscle
89
what does uric acid come from?
recycling of nitrogenous bases from RNA
90
where is the juxtaglomerular complex located?
found between the afferent arteriole and distal convoluted tubule of the same nephron
91
what are the three cell types of the juxtaglomerular apparatus?
juxtaglomerular cells, macula densa, mesangial cells
92
where are juxtaglomerular cells found?
enlarged, smooth muscle cells in walls of afferent arteriole
93
what is the function of juxtaglomerular cells?
act as mechanoreceptors
94
where are macula densa cells located?
tall, closely packed distal tubule cells that lie adjacent to JG cells
95
what is the function of macula densa cells?
function as chemoreceptors/osmoreceptors
96
what is the function of mesangial cells?
have phagocytic and contractile properties, influence capillary filtration
97
what influences mesangial cell contraction?
vasopressin, angiotensin II
98
what are the three control mechanisms of glomerular filtration rate?
autoregulation, neural regulation, hormonal regulation
99
describe the autoregulation mechanism when homeostasis is disturbed?
1. decreased GFR resulting in decreased filtrate and urine production
2. dilation of afferent arterioles, contraction of mesangial cells, constriction of efferent arterioles
3. increased glomerular blood pressure
4. homeostasis restored = normal GFR
100
what are myogenic mechanisms?
smooth muscle cells strech wall of afferent arteriole
101
what are tubular mechanisms?
macula densa detects solute level in filtrate
102
if there is a decrease in BP what occurs to increase GFR?
dilate afferent artery, relax supporting cells and dilate capillaries, constrict efferent arteriole
103
if there is an increase in BP what occurs to decrease GFR?
constrict afferent, decrease GFR
104
when is neural regulation activated?
under stress or during physical activity; reduces GFR
105
what happens during neural regulation?
sympathetic fibers innervate kidneys, constrict afferent arteriole
106
what else besides fall in BP can stimulate JG cells?
sympathetic innervation
107
what do macula densa cells sense?
low fluid or low NA
108
what do JG cells surrounding afferent arterioles make?
renin
109
what does renin convert angiotensinogen into?
angiotensin I
110
what converts angiotensin I into angiotensin II?
angiotensin-converting enzyme
111
what is the effect of angiotensin II on the PCT?
direct effect to increase Na reabsorption
112
what does angiotensin II do to GFR?
increases GFR by increasing renal perfusion pressure
113
what is the effect of angiotensin II on systemic blood vessels?
widespread vasoconstriction
114
how does angiotensin II regulate water reabsorption?
stimulates the posterior pituitary to make ADH which causes aquaporins to move to the collecting duct which increases water reabsorption
115
how does angiotensin II regulate Na+ uptake?
stimulates the adrenal cortex to secrete aldosterone which stimulates Na+ uptake on the apical cell membrane in the DCT and collecting ducts
116
true of false, angiotensin II stimulates sympathetic activity?
true
117
describe how angiotensin II increases GFR?
blood volume increases, BP goes up, GFR goes up
118
what zone of the adrenal cortex secretes aldosterone?
zona glomerulosa
119
what is aldosterone?
a steroid hormone; mineralocorticoid
120
what is another name for the posterior pituitary?
neurohypophysis
121
what type of tissue is the posterior pituitary?
neural tissue
122
why is the posterior pituitary not a true endocrine gland?
it does not synthesize hormones, it stores/releases neurohormones
123
what are the two hormones released by the posterior pituitary?
oxytocin and antidiuretic hormone (ADH) known as vasopressin
124
what is the role of ADH?
to increase BP by conserving water and constricting vessels?
125
what does ADH do to the collecting duct and DCT?
induces aquaporin translocation
126
how does alcohol affect ADH release?
blocks the voltage gated calcium channels in nerve terminal so ADH not released leading to dehydration when drinking excess alcohol
127
what is synthesized by the JG cells in response to hypoxia?
erythopoietin
128
what does erythropoietin do to RBC production?
increases RBC production in the bone barrow allowing more capacity to transport oxygen
129
what is synthesized by cardiac cells in response to increased blood volume or increased blood pressure?
atrial natriuretic peptide and brain natriuretic peptide
130
what are the two most common health problems that lead to CKD?
hypertension and diabetes
131
why do very few patients with CKD require renal replacement therapy?
they die from cardiovascular disease
132
what is the name of the type of transport that is used to absorb glucose in the nephron and why does glucose appear in the urine?
co-transport with Na, these carrier proteins can become saturated
133
where in the kidney are most substances reabsorbed?
PCT
134
what changes that occur with CKD increase the risk of heart failure?
can't maintain fluid balance- heart must pump larger amount of fluid that the kidneys cannot get rid of. As heart fails there is reduced blood blow to the kidneys so their ability to function decreases
135
why is left ventricular hypertrophy often found in those with hypertension and CKD?
left ventricle pumps blood into the vasculature and CKD patients often have poor blood volume control so the heart pumps blood harder and the left ventricle hypertrophies to accommodate the increased work needed
136
what are some biochemical findings that could be used to provided evidence of alternated renal function in those with CKD?
proteinuria, micro and macroalbuminuria, elevated serum creatinine, reduced glomerular filtration rate, alterations in serum metabolites, elevated cystatin C
137
why is cystatin C blood test a good measure of GFR?
filtered solely by the glomerulus, not secreted by the renal tubules, completely reabsorbed by the tubules then catabolized, generated at a constant rate by all cells in the body
138
what is creatinine clearance used for?
clinical estimation of GFR
139
what are 2 hormones that the body can use to regulate Phosphorus homeostasis?
FGF23 and PTH
140
where is FGF23 made?
osteocyte
141
where is PTH made?
parathyroid hormone
142
how does high P increase risk of cardiac disease?
high P associated with vascular calcification causing narrowing of lumen of the arteries. Vascular smooth muscle cells undergo osteochondrogenic differentiation and calcify
143
what is FGF23 made in response to?
high levels of serum P
144
what is the receptor for FGF 23 and where is it found?
FGFR 1 is found in the kidney
145
what does FGF 23 do in the PCT?
decreases the expression of NaPi transporters needed to reabsorb Pi from tubular filtrate. decrease the expression of 1-a OHase - less 1,25(OH)2D
146
what does FGF 23 do in the DCT?
increases the reabsorption of Ca and Na from the tubular filtrate
147
in healthy kidneys, how does FGF23 work to reduce serum P?
decrease reabsorption by reducing the presence of P transporters in the nephron, less reabsorption, more P in tubule lumen, less P in peritubular fluid, less P in peritubular capillaries, more P in urine = increased renal P excretion
148
what percentage of individuals with CKD is anemia found in?
50%
149
what 2 hormones may explain the anemia that is found in those with CKD and where are those hormones produced?
erythropoietin- made in kidney
hepcidin - made in liver from inflammation caused by CKD
150
how can anemia be treated according to the article issues of iron management in the hemodialysis patient?
intravenous iron, bypass the gut
151
what are some risks associated with use of IV iron?
increases the risk of iron overload
152
what form of Fe would be found in the blood in those with iron overload?
NTBI, taken up by ZIP 14
153
what tissues are most at risk?
pancreas, liver
154
what does CKD lead to chronically?
HIGH serum P
155
what does high serum P cause?
HIGH serum FGF 23
156
what does HIGH FGF 23 cause?
suppresses calcitriol in the kidney
157
what does HIGH P cause specifically in the kidney?
inhibits 1-alpha hydroxylase which suppresses calcitriol in kidney
158
what does suppressed calcitriol levels cause?
LOW serum Ca
159
what does low serum Ca usually do?
normally, high PTH would increase Ca reabsorption and decrease P reabsorption
160
in people with CKD, what do the kidneys fail to do?
do not respond to high PTH and make calcitriol or reduce urinary Ca? Hyperparathyroidism can develop which stimulates bone resorption
