Chapter 14 Flashcards
(132 cards)
1
Q
job of the kidney
A
filtration, reabsorption, and secretion
2
Q
what would kill you first if there were no kidneys?
A
the lack of potassium secretion causing an increase in ECF which would cause convulsions and make the gradients less steep so AP are easier to fire
3
Q
renal blood supply is what percentage of cardiac output
A
20-22%
4
Q
cortex of the kidney is seen where?
A
outside
5
Q
medulla of the kidney is located where?
A
inside
6
Q
what is the functional unit of the kidney
A
nephron
7
Q
two types of the nephron
A
cortical (80%) and juxtamedullary (20%)
8
Q
cortical region of the nephron loop of henle
A
hairpin loop
9
Q
juxtamedullary region of the nephron contains
A
the vasa recta
10
Q
where is the juxtamedullary region found
A
deep in the medulla
11
Q
what does the juxtamedullary region do
A
establish concentration gradient and affects concentrations of urine
12
Q
what would happen if you did not have a juxtamedullary region?
A
you would pee to death
13
Q
vascular component of the nephron
A
- afferent arteriole
- glomerulus
- efferent arteriole
14
Q
what is the glomerulus
A
group of capillaries that filters into bowman’s capsule
15
Q
efferent arteriole
A
unfiltered blood leaving the glomerulus
16
Q
parts of the efferent arteriole
A
peritubular capillaries and vasa recta
17
Q
peritubular capillaries
A
supply renal tissues with blood and exchanges between tubular system and blood during conversion of filtrate to urine
18
Q
bowman’s capsule
A
collects glomerular filtrate
19
Q
proximal tubule
A
uncontrolled reabsorption and secretion of selected substances occur here
20
Q
loop of henle of nephron
A
establish osmotic gradient in the renal medulla that is important in the kidney’s ability to produce urine of varying concentration
21
Q
distal tubule and collecting duct (distal nephron)
A
variable, controlled reabsorption of sodium and water and secretion of potassium and hydrogen occur here; fluid leaving the collecting duct is urine which enters the renal pelvis
22
Q
juxtaglomerular apparatus
A
produces substances involved in the control of kidney function
23
Q
descending loop of henle
A
thin portion- squamous epithelium
24
Q
ascending loop of henle
A
thick portion- cuboidal epithelium
25
what is the only controlled portion of the nephron
distal tubule and collecting duct
26
t/f: juxtamedullary nephron is long-looped and is important for establishing the osmotic gradient
true
27
what is the most abundant type of nephron
cortical nephron
28
glomerular filtration anatomy
- huge fenestrated endothelium
- basement membrane
- podocytes with filtration slits
- 100x more permeable
29
t/f: capillaries don't have pores
false
30
what are the filtration slits in podocytes similar to (IRL example)
interlocking fingers and still have gaps for things to squeeze between
31
where is filtrate found
in the nephron
32
what is secretion
actively putting something into the nephron (skip filtration via glomerulus)
33
t/f: plasma proteins and RBC are filtered by the glomerular capillary
false
34
what substances can fit in the pores between the glomerular capillary and bowman's capsule
glucose and ions
35
albumin
smallest plasma protein that can fit through pores but is repelled by the negatively charged glycoproteins
36
lupus
protein in urine
37
glomerular capillary blood pressure
55 mmHg
38
how much of plasma that enters the glomerulus is filtered
20%
39
Glomerular filtration rate
125 mL/min
40
how often do the kidneys filer plasma volume?
65 times per day
41
blood capillary blood pressure
37 mmHg
42
hypertensive affect on glomerular filtration
increase hydrostatic pressure which causes you to filter more than you should
43
inward pressures of glomerular filtration
plasma colloid osmotic pressure and Bowman's capsule hydrostatic pressure
44
outward pressure of glomerular filtration
glomerular capillary blood pressure
45
net filtration
outward pressures - inward pressures
46
how much urine is produced per minute
1 mL/min
47
GFR equation
Kf * NFP
48
importance of glomerulus
filtration and reabsorption
49
what happens to GFR when MAP increases and why
increases; increased MAP causing increased glomerular capillary blood pressure (outward) which increase net filtration pressure(NFP) which increases GFR
50
what does vasoconstriction do to GFR and why
decrease GFR; less blood flow to glomerulus
51
what does vasodilation do to GFR
increase GFR; more blood flow to glomerulus
52
autoregulation mechanisms of GFR
myogenic mechanism and tubuloglomerular feedback mechanism
53
tubuloglomerular feedback mechanism
macula densa
- release vasodilator if flow is too slow
- release vasoconstrictor if flow is too fast
54
what is adenosine?
vasoconstrictor
55
t/f: adenosine is potentially potent
true
56
sympathetic stimulation of kidneys affects GFR how
constricts arterioles
57
mesangial cells
hold glomerular capillary in position and control the size of the filtration pore
58
transepithelial transport
places substances back into the peritubular capillaries
59
barriers of tubular reabsorption
- membrane of tubular cells
- cytosol of tubular cell
- membrane at lateral space
- interstitial fluid
- capillary wall
60
active tubular reabsorption
at least one step requires energy - goes against electrochemical gradient
61
passive tubular reabsorption
no steps require energy - with/down concentration gradient
62
t/f: majority of the filtrate is reabsorbed per day
true
63
how much glucose is reabsorbed (%)
100%
64
how much water is reabsorbed? (%)
99%- almost all
65
how much sodium is reabsorbed? (%)
99.5%- not all of the salt from the diet is reabsorbed
66
how much energy does sodium require?
80% of all energy used by kidneys
67
how much sodium is reabsorbed in the proximal tubule?
67%
68
the proximal tubule plays a pivotal role in reabsorbing what substances?
glucose, amino acids, water, chloride, and urea
69
how much sodium is reabsorbed in the loop of henle?
25%
70
what does the sodium reabsorption in the loop of henle create?
osmotic gradient
71
what does the loop of henle affect?
chloride reabsorption, water conservation, urine variations in concentration and volume
72
how much sodium is reabsorbed in the distal and collecting tubules?
8%
73
what does the distal and collecting ducts affect?
regulate ECF volume linked to potassium secretion
74
how is the distal nephron controlled?
hormones
75
How is sodium brought from the lumen into the tubular cell?
with glucose through the SGLT2 carrier
76
t/f: sodium potassium pumps are required to exchange sodium and potassium from the ISF and tubular cell
true
77
hormonal influences on distal nephron
- RAAS
- decrease in salt and BP cause granular cells to release renin
- renin converts angiotensin to angiotensin 1
- ACE converts angiotensin 1 to angiotensin 2 (LUNGS)
78
What does the RAAS system respond to
decrease in NaCl, ECF volume, and arterial BP
79
macula densa
contains sensor for sodium to release renin when too much sodium is passing by
80
how does arterial BP increase renin secretion?
baroreceptors activate sympathetic activity which stimulates the granular cells to secrete more renin (juxtamedullary apparatus cells)
81
what does an increase in arterial BP do to plasma volume
increase
82
how is plasma volume restored
osmotically inducing water retention
83
where is ACE found
high in the pulmonary capillaries- high in lungs because 100% of cardiac output goes through the lungs and is the easiest way to disperse
84
treatments for hypertension and congestive heart failure
ACE inhibitors and aldosterone receptor blockers
85
Angiotensin 2
Arteriolar constriction
- stimulate thirst
- release ADH
- release aldosterone from adrenal cortex
86
aldosterone
increase sodium reabsorption at distal tubules via PRINCIPAL CELLS
- increase sodium leaky channels in luminal membrane and increase Na+K+ pumps in the basolateral membranes
87
what happens when sodium load, ECF and plasma volume, and arterial pressure are above normal?
- renin is inhibited
- no aldosterone
- sodium excreted in urine (large loss of sodium after multiple days)
88
natriuretic peptide (ANP)
inhibits sodium reabsorption (excrete more sodium)
| inhibits RAAS
89
when is ANP released?
when heart muscle cells are mechanically stretched by an expansion of circulating plasma volume when ECF volume increases which is caused by sodium and water retention that increases BP
90
inhibiting RAAS does what to sodium reabsorption
inhibit sodium reabsorption and increase excretion (along with H2O)
91
t/f: inhibiting RAAS will inhibit actions of vasopressin (ADH)
true
92
what is the problem with using natriuretic peptide? how is the problem solved?
more sodium is passing the macula densa (more sodium being excreted) along with water which decreases blood volume
- ACE inhibitor used to combat this
93
transport maximum of glucose
375 mg/min
94
t/f: kidneys don't regulate chloride
true
95
GLUT transporter
facilitate glucose and amino acids across basolateral membrane
96
t/f: phosphate and calcium reabsorption can be regulated by parathyroid hormones
true
97
what does ADH do for water reabsorption?
increase aquaporin channels (AQP2) to increase water reabsorption
98
how much urea is excreted? how much is reabsorbed?
50%, 50%
99
t/f: tubular secretion is controlled by systemic pH
true
100
What does aldosterone do to K+ secretion?
reabsorb more K+ than we secrete
101
what do secretion of drugs, metabolites, and pollutants do to the excretion of them?
increase elimination
102
what ions are secreted?
hydrogen and potassium
103
aldosterone up-regulate mechanisms
1. add more Na+K+ pump
2. add more K+ carriers (K+ back into lumen)
3. add more sodium channels (Na+ into distal nephron)
104
short term regulation of secretion
insulin- push K+ into the cell, keep ECF levels regulated
105
t/f: reabsorption is controlled in the proximal tubule
false
106
plasma clearance
volume of plasma cleared of specific substance per minute
107
t/f: plasma clearance depends on the concentrations that are cleared out
false
108
plasma clearance formula
PC = (Xurine * UFR)/ (Xplasma)
109
What does it mean when PC= GFR?
Excretion ONLY-- no reabsorption or secretion
| - measures arteriolar and glomerular health
110
two substances that have a PC=GFR
inulin and creatine
111
What does it mean when PC < GFR?
REABSORPTION-- not secreted
112
substance that has a lower PC than GFR
urea
113
What does it mean when PC > GFR?
secreted but not reabsorbed
| - determine health of nephron
114
substances that have PC greater than GFR?
Hydrogen and PAH
115
isotonic urine: _______ BP
normal
116
hypotonic urine: _______ BP/BV
decrease (hypertensive)
117
hypertonic urine: _______ BP/BV
increase in response to hypotension
118
t/f: hypotonic urine releases more water
false
119
t/f: hypertonic urine releases more water
true
120
Descending loop of henle: iso, hypo, or hyper tonic
hypertonic
121
Ascending loop of henle: iso, hypo, or hyper tonic
hypotonic
122
ISF: iso, hypo, or hyper tonic
isotonic
123
ADH
produced by hypothalamus
acts at basolateral membrane in distal nephron
- opens AQP2
- concentrates the urine
124
What kind of urine is produced without ADH
hypotonic
125
What kind of urine is produced with low levels of ADH
isotonic
126
t/f: ADH os water soluble
true
127
how do arterioles balance osmolarity
pick up salt and lose water at first, then before leaving to the veins, pick up water and lose salt
128
micturition
spinal reflex
129
Parasympathetic activity of micturition
initiates contraction of smooth muscle- detrussor muscle
| initiates relaxation of smooth muscke- Internal urethral sphincter
130
Somatic control of micturition
relaxation of urethral sphincter (skeletal muscle)
131
t/f: somatic control of micturition can override the parasympathetic contraction by the detrussor muscle
true
132
t/f: in micturition, parasympathetic will always win
true
