Test 4 Vocab Flashcards
1
Q
what are the functions of the kidneys
A
- regulation of water, inorganic ion balance, and acid-base balance (in cooperation with the lungs)
- removal of metabolic waste products form the blood and their excretion in the urine
- removal of foreign chemicals from the blood and their excretion in the urine
- gluconeogenesis
- Production of hormones/enzymes: erythropoietin, renin, conversion of 25-hydroxyvitamin D to 1,25-dihydroxyvitamin D, which influences calcium balance
2
Q
what is the flow of urine
A
kidneys –> ureters –> bladder –> urethra –> environment
3
Q
nephron
A
functional unit of the kidneys (approximately 1 million per kidney)
consists of a renal corpuscle and renal tubule
4
Q
renal corpuscle
A
composed of a capillary tuft (glomerulus) and a Bowman’s capsule, which the tuft protrudes into. Inside the Bowman’s capulse is Bowman’s space, from which fluid flows into the start of the nephron tubule
5
Q
glomerulus
A
supplied with blood by an afferent arteriole and drained by an efferent arteriole
6
Q
Bowmans capsule
A
Blind sack at the beginning of tubular component of kidney nephron
7
Q
what is the fluid flow
A
tubule extends from Bowman’s capsule and is subdivided into the proximal tubule, loop of henle, distal convoluted tubule, collecting ducts. Collecting dicts join and empty into rental pelvis, from which urine flows through the ureters to the bladder
8
Q
proximal tubule
A
First tubular component of nephron after Bowman’s capsule; comprises convoluted and straight segments
9
Q
ascending loop of henle
A
Portion of Henley’s loop of renal tubule leading to distal convoluted tubule
10
Q
descending loop of henle
A
Segment of renal tubule into which proximal tubule drains
11
Q
distal convoluted tubule
A
Portion of kidney tubule between loop of Henle and collecting duct system
12
Q
cortical collecting duct
A
Primary site of sodium ion reabsorption at the distal end of a nephron
13
Q
medullary collecting duct
A
Terminal component of the nephron in which vasopressin-sensitive passive water reabsorption occurs.
14
Q
renal pelvis
A
Cavity abuse of each kidney receives urine from collecting ducts system in empties into ureter
15
Q
ureters
A
16
Q
bladder
A
Thick-walled sack composed of smooth muscle stores urine prior to urination
17
Q
afferent arteriole
A
vessel in kidney that carries blood from artery to renal corpuscle
18
Q
efferent areteriole
A
Renal vessel that conveys blood from glomerulus to pertibular capillaries
19
Q
peritubular capillaries
A
Capillaries closely associated with renal tubule
20
Q
vasa recta
A
long capillary loop that runs next to the loop of henle
21
Q
filtration barrier in renal corpuscle
A
consists of three layers - capilllary endothelium, basement membrane, bowmans capsule epithelium (podocytes); mesagnial cells represent a third cell
22
Q
juxtamedullary
A
renal corpsucle located in cortex just next to the medulla, long loops of henle dive deep into the medulla
23
Q
cortical
A
around 85% of all nephrons
short loops of henle
24
Q
juxtaglomerular apparatus
A
Renal structure consisting of macular densa and juxtaglomular cells; sight of renin secretion and sensors for renin secretion and control of glomerular filtration rate.
25
what does urine filtration begin with
glomerular filtration
26
glomerular filtrate
contains all plasma substances other than proteins (and substances bound to proteins) in virtually the same concentrations as in plasma
27
net glomerular filtration pressure
glomerular filtration is driven by the hydrostatic pressure in the glomerular capillaries and is opposed by both the hydrostatic pressure in Bowman's space and the osmotic force due to the proteins in the glomerular capillary plasma
28
glomerular filtration rate (GFR)
determined by net filtration pressure, the permeability of the corpuscular membranes, and the filtration surface area
29
filtered load
GFR x plasma concentration of filtered substance
30
apical membrane
The surface of an epithelial cell that faces a lumen, such as that of the intestines
31
basolateral membrane
Sides of epithelial cell other than luminal surface.
32
filtrate movement through the tubules
certain substances are reabsorbed either by diffusion of by mediated transport.
- substances that are permeable to tubular epithelium are reabsorbed by diffusion because water reabsorption creates tubule-interstitial-fluid-concentration gradients
- active reabsorption of a substance requires transporters in the apical membrane
-tubular reabsorption rates: high for nutrients, ions, and water; lower for waste products
- tubular secretion: movement of a substance from peritubular capillary plasma into the tubule
33
transport maximum
exhibited by substances moved by mediated transporters. If the filtered load of a substance exceeds to reabsorptive transport maximum, the substance will be excreted in the urine. Ex: poorly controlled diabetes mellitus
34
diabetes mellitus
35
diabetic nephropathy
36
familial renal glucosuria
37
clearance
volume of the plasma completely cleared of a substance per unit time
- calculated by dividing the mass of the substance excreted per unit time by the plasma concentration of the substance
38
GFR measurement
- inulin: infused experimentall; clearance rate equals GFR
- creatine clearance: estimates gfr clinically
39
Inulin
small carbohydrate that is filtered but not reabsorbed or secreted
40
Creatine clearance
estimates GFR clinically becaue it is filtered, not reabsorbed, and secreted only a little
41
renal plasma flow
estimated by the clearance of a substance that is filtered, not reabsorbed, and 100% secreted. ALl that enters the kidneys from the blood is cleared
42
what must be true about a substance whose excretion rate exceeds its filtered load
it must have been secreted in excess of its reabsorption
43
spinal micturition reflex
- involuntary
- bladder distension stimulates stretch receptors that trigger spinal reflexes. These reflexes lead to contraction of the detrusor muscle
- mediated by parasympathetic and sympathetic neurons
- mediated by relaxation of both the internal and the external urethral sphincters
44
detrusor muslce
bladder smooth muscle
45
internal uretheral sphincter
Part of smooth muscle of urinary bladder wall that opens and closes the bladder outlet
46
external urethral sphincter
Ring of skeletal muscle that surrounds the urethra at face of bladder
47
incontinence
involuntary release of urine that occurs most commonly in elderly people
48
water balance
- gain water via ingestion and internal production
- lose water via urine, the gi tract, evaporation from the skin and respiratory tract, and sweat
49
Na+ and Cl- balance
gains by ingestion; losses bia the skin, gi tract, and urine
50
Homeostasis for both water and Na+
renal excretion is the major control point for maintaining stable balance
51
what is a common disorder in which there is excessive loss of Na+, Cl-, and water?
diarrhea when severe can result in losses of ions and water
52
Renal Na+ handling
filtration (glomerulus) and reabsorption (primary active process dependent on Na/K ATPase pumps in the basolateral membranes of the tubular epithelium; Na+ not secreted
- Na+ entry into tubular epithelial cells
- Ascending limb of loop of henle
- Na+ reabsorption
53
Ascending limb of loop of Henle
reabsorption of NaCl (not water) via Na-K-2Cl cotransporters (NKCC)
54
Na+ entry into tubular epithelial cells from the tubular lumen is _____?
passive.
depending on the tubular segment, it is either through ion channels, or by cotransport or countertransport with other substances
55
Na+ reabsorption
creates an osmotic difference across the tubule (drives water reabsorption through aquaporins and where permeable, through the paracellular path)
56
aquaporins
water channels
57
vasopressin
antidiuretic hormone
does not exert major DIRECT effects before the collecting duct system
58
collecting-duct system
vasopressin increases water permeability
- low vasopressin leads to production of larger volume of dilute urine- nonosmotic diuresis)
59
diabetes insipidus
excess loss of dilute urine, due to low vasopressin or renal insensitivity to vasopressin
60
osmotic diuresis
water loss in the urine due to excessive solute excretion
61
countercurrent multiplier systsem
- obligatory water loss
- ascending loop of henle
- vasopressin increases permeability of the cortical collecting ducts
- luminal fluid enters and flows through the medullary collecting ducts
- vasa recta
- urea recycling
62
obligatory water loss
minimal volume of water loss (aroundn 0.44 L/day)
63
what is the role of the ascending loop of henle in the the countercurrent multiplier system
active transport of sodium chloride, which results in increased osmolarity of the interstitial fluid of the medulla but a dilution of the luminal fluid
64
what is the role of vasopressin in the countercurrent multiplier system
increase the permeability of of the cortical collecting ducts to water by increasing the number of AQP2 water channels interested into the apical membrane. Water is reabsorbed by this segment until the luminal fluid is isosmotic to plasma in the cortical pertibulular capillaries.
65
what is the role of the medullary collecting ducts in the countercurrent multiplier system
luminal fluid enters and flows through the medullary collecting ducts
- the concentrated medullary collecting ducts; the concentrated medullary interstitial fluid causes water to move out of these ducts, made highly permeable to water by vasopressin. The result is concentration of the collecting-duct fluid and the urine
66
vasa recta
hairpin-loop blood vessels that prevent the countercurrent gradient (created by long loops of henle) from being washed away
67
urea recycling
helps establish a hypertonic medullary intersitial fluid
68
Na+ excretion
difference between the amount of Na+ filtered and reabsorbed
69
filtered load of Na+
70
Tubular Na+ reabsorption
71
Renin angiotensin system (RAS)
72
what does Renin catalyze
73
Angiostatin converting enzyme (ACE)
74
RAS drugs
75
Atrial natriuretic peptide
76
pressure natriuresis
77
water excretion
78
vasopressin secretion
79
osmoreceptors
80
extraceullular fluid volume
81
what are other stimuli to vasopressin secretion
nausea, hypoxia, pain, and fear
82
what can happen to plasma volume and osmolarity during severe sweating
83
thirst
84
salt appetite
85
potassium balance
86
hyperkalemia
87
hypokalemia
88
how is K+ filtered at the renal corpuscle
89
increase in body K+ results in what
90
what are the two major controllers of aldosterone secretion, and what are this hormones major actions?
91
ionized plasma calcium and phosphate
92
parathyroid hormone
93
how can the PTH effects on the kidney help restore plasma calcium to normal with a low-calcium diet
94
major function and controlling factors of glomerulus/Bowman capsule
95
major function and controlling factors of proximal tubule
96
major function and controlling factors of loop of henle
97
major function and controlling factors of distal tubule and cortical collecting ducts
98
major function and controlling factors of cortical and medullary collecting ducts
99
what is each segment of the nephron responsible for
- proximal tubules:
- loops of henle:
- distal tubules and collecting ducts:
100
how can the kidneys function properly considering that > 80% of nephrons do not have a long loop of henle in the renal medulla?
101
Diuretics
102
what nephron segment do loop diuretics work on
103
what nephron segments do potassium-sparing diuretics work on
104
what segment of the nephron do osmotic diuretics work on
105
why are diuretics used to treat hypertension
diuretics help to mitigate high blood pressure by decreasing total-body sodium and water.
106
Sources of hydrogen gain
107
sources of hydrogen loss
108
acidosis
109
alkalosis
110
interrelationship between CO2 and H+
111
total-body balance of H+
112
considering the relationship between CO2 and H+ what are two potential causes of acidosis
113
Buffers
114
kidneys and the respiratory system
115
metabolic alkalosis
116
metabolic acidosis
117
how do the kidneys maintain a stable plasma H+ concentration
118
Filtered HCO3-
119
filtered phosphate ion (or other nonbicarbonate buffers)
120
ammonium excretion
121
under what circumstances is ammonium excretion is important when responding to metabolic acidosis
122
Renal response to acidosis
123
Renal response to alkalosis
124
acid-base disorders
125
respiratory acid/alkalosis
126
metabolic acid/alkalosis
127
how can exercising at altitude lead to a metabolic acidosis
128
blood flow to and through kidneys
aorta --> renal arteries --> renal circulation --> renal veins
129
functional anatomy of calyx
calyx --> renal pelvis --> ureters
130
renal pelvis
Cavity at base of each kidney receives urine from collecting duct system in empties it into ureter.
131
What is the flow of blood in order in the kidneys
132
what are the three layers in the bowman's space filtration barrie
1. single-celled capillary endothelium
2. a noncellular proteinaceous layer of basement membrane between endothelium and the next layer
3. the single-celled epithelial lining of Bowman's capsule (podocytes)
133
What is it that makes renal circulation unusual
It includes two sets of arterioles and two sets of capillaries
134
What are starling forces
- The hydrostatic pressure differences across the capillary wall that favors filtration
- Protein concentration difference across the wall that creates an osmotic force that opposes filtration
135
What would constriction of the afferent arteriole do to GFR?
decrease
136
What would constriction of the efferent arteriole do to GFR?
increase
137
What would dilation of the efferent arteriole do to GFR?
decrease
138
What would dilation of the afferent arteriole do to GFR?
increase
139
