Exam 2 Flashcards
0
Q
What four things contribute to net filtration pressure?
A
Bowman’s capsule colloid osmotic pressure – 0mmHg
Bowman’s capsule hydrostatic pressure – 18mmHg
Glomerular hydrostatic pressure – 60 mmHg
Glomerular capillary colloid osmotic pressure – 32mmHg
1
Q
What is the net filtration pressure?
A
10mmHg
2
Q
If kf is 12.5 what is the GFR?
A
125mL/min
3
Q
What if we decrease the amount of functional glomerular capillaries?
A
It decreases surface area for filtration = decrease in kf
4
Q
What if we increase the thickness of the capillary membrane(hypertension or diabetes mellitus)?
A
Decreases the permeability of the capillary membrane=decreasein Kf
5
Q
What is the end result from a decrease in kj?
A
a decrease in GFR
6
Q
What is the most common way that the body regulates GFR?
A
Increase in glomerular hydrostatic pressure
7
Q
What effect does Norepinephrine & epinephrine have on GFR?
A
decrease
8
Q
What effect does Endothelin have on the GFR?
A
Decrease
9
Q
What effect does Angiotension II have on GFR?
A
prevents a decrease
10
Q
What effect does Endothelial-derived nitric oxide have on GFR?
A
increase
11
Q
What effect does Prostoglandins have on the GFR?
A
increase
12
Q
What three factors determine the urinary excretion rate?
A
Glomarular filtration (+)
Reabsorption of substances from the renal tubules
into the blood (-)
Secretion of substances from the blood to the renaltubules (+)
13
Q
What are the four ways that the kidney handles substances?
A
Freely filtered by the glomerulus & not reabsorbedor secreted
Freely filtered & partially reabsorbed
Freely filtered & totally reabsorbed
Freely filtered & not reabsorbed and additional
amounts of the substance are secreted
14
Q
What are the substances that freely filtered & not reabsorbed or secreted?
What is the urinary excretion rate compared to the glomerular filtration rate?
A
Creatinine, urea, uric acid and other by productsof metabolism are handled this way
Urinary excretion rate = glomerular filtration rate
15
Q
Substances that are freely filtered & partially reabsorbed what does the excretion rate equal to?
excretion rate is less than or more than filtration rate
what substances are handled this way?
A
Excretion rate=filtration rate-reabsorption rate
less then
Many electrolytes (sodium, bicarbonate ions &chloride ions)
16
Q
What are the three parts of the Loop of Henle?
A
Thin descending segment
thin ascending segment
thick ascending segment
17
Q
What is the first portion of the distal tubule called?
It is part of what complex?
A
macula densa
Juxtaglomerular complex
18
Q
The proximal tubule before the loop of Henle is _______ active and __________ reabsorbtion.
a. high; active
b. high; passive
c. low; active
d. low; passive
A
b
19
Q
Excess water in the body=urine with osmolarity as low as _______mOsm/L
A
50
20
Q
Deficit of water in the body=urine with anosmolarity as high as ________mOsm/L
A
1400
21
Q
The concentration of the urine is ____________ solute concentration
a. dependent on
b. independent of
A
b
22
Q
What is the result of an increase in osmolarity of the body?
A
Increased release of ADH Increase in water permeability of the distal tubule and collecting ducts Large reabsorption of water Concentration of urine No marked change in excretion of solutes
23
Q
What determines whether the kidneys excrete dilute or concentrated urine?
A
Concentration of ADH
24
Osmolarity of filtrate at the beginning of proximal tubule=
300mOsm/L
25
Osmolarity of filtrate a the end of the proximal tubule=
300mOsm/L
26
Osmolarity of plasma=
300mOsm/L
27
The proximal tubule is _________.
a. hypertonic
b. hypotonic
c. isotonic
c
28
How so we create a hyperosmotic renal medullary interstitial fluid?
Countercurrent mechanism
Juxtamedullary nephrons
Vasa recta
Collecting ducts (that travel through thehyperosmotic renal medulla)
29
Interstitial fluid is around __________ in most ofthe body
300mOsm/L
30
For the countercurrent mechanism the to work we need a?
high osmolarity in the renal medulla
31
At the papilla of the renal pyramids the osmolaritycan be as high as ________
1200mOsm/L
32
What are the four ways that fluid are regulated in the body?
Respiration
GI tract
Through the skin
Obligatory urine volume loss
33
How much plasma volume is there?
How much is the GFR/day?
How many times a day does the blood plasma get filtered?
3L
180 L/day
60 times a day
34
Large amounts of fluid are filtered from the
| glomerular capillaries to what area?
Bowman's capsule
35
Glomerular filtrate does not contain what two substances?
No proteins, no cellular elements
36
Glomerular filtrate substances (salts & organicmolecules) = what?
plasma
37
GFR is determined by what two substances?
hydrostatic pressure and colloid osmotic pressure
38
the capillary filtration coefficient is determined by what?
Permeability of the capillary
| Surface area of the capillary
39
The GFR in a normal non-pathologic adult has a high or low glomerular hydrostatic pressure?
Large or small filtration surface area?
High or low permeability of the glomerular capillary
high
Large
High
40
What is the filtration fraction?
amount of renal plasma that is filtered = 20%
41
How are the glomerular capillary membrane different than others in the body?
made of three layers rather than two
42
What are the three layers of the glomerular capillary membrane?
(1) endothelium
(2) basement membrane
(3) epithelial cell layer (podocytes)
43
What layer of the Glomerular capillary membrane contain fenestrae?
What is the size of the fenestrae?
endothelium
8 nanometers
44
What keeps albumin from passing through the Glomerular capillary membrane?
The negative charge of the capillary prevents the passage of plasma proteins
45
What layer of the Glomerular capillary membrane contains a meshwork of proteoglycan fibrillae & collagen
basement membrane?
46
The glomerular capillary membrane contains a meshwork of proteoglycan fibrillae & collagen what is the function?
Allows for the flow of a lot of water and smallsolutes to pass
47
What is the proteoglycan charge in the basement membrane?
negative charge
48
T/F the epithelium is a continuous layer
false
49
What lines the outer surface of the glomerulus in the epithelium?
Podocytes
50
Long footlike projections that encircle the capillaries
What are filtered through the gaps between the footlike projections?
What are they called?
podocytes
water and solutes
slit pores
51
epithelium is __________ charged?
negatively
52
Filtration barrier is highly dependent on a molecules size and _____________
electrical size
53
What are the three things freely filtered through the Glomerular capillary membrane
Water, sodium, glucose
54
What is more likely to be filtered a negative, neutral, or positively charged particle?
neutral, or positively
55
What happens if the basement membrane loses it’s electrical charge?
albumin is filtered and the urine is frothy
56
What is the Glomerular hydrostatic pressure
60mmHg
57
What is the Bowman’s capsule colloid osmotic pressure?
0mmHg
58
What is the Bowman’s capsule hydrostatic pressure?
18mmHg
59
What is the Glomerular cap. colloid osmotic pressure?
32mmHg
60
What is the net filtration rate?
10mmHg
61
What determines GFR?
Kf x net filtration rate
Kf = 4.2mL/min/mmHg
62
What are the three things that determine Glomerular capillary hydrostatic pressure?
Arterial pressure
Afferent arteriolar resistance
Efferent arteriolar resistance
63
What if we change Glomerular capillary hydrostatic pressure?
very little increase due to arterial pressure
64
What happens if there is a 3 fold increase in efferent arteriole constriction?
Colloid osmotic pressure of the arteriole will exceedhydrostatic pressure = decreased GFR
65
Renal Blood Flow is ________ of the cardiac output?
22%
66
T/F the kidney receives 2x the blood flow of the brain
true
67
Why does the kidney absorb 2x the oxygen than the brain?
because of the high rate of sodium reabsorption in the tubules
68
The kidney receives _____x the oxygen than the brain
7
69
What does the blood supply to the kidney do?
supplies nutrients and removes waste from the blood
| supplies plasma to the kidney for a high rate of GFR
70
difference between renal artery pressureand renal vein pressure divided by total renal vascular resistance.
Renal Blood flow
71
Renal arterial pressure
systemic arterial pressure
72
Kidneys maintains fairly constant blood flow & GFR of what?
80-170mmHg
73
What is the renal vein pressure?
3-4mmHg
74
What location does renal vascular resistance take place?
Interlobular arteries, Afferent arterioles, Efferent arterioles
75
Renal vascular resistance is controlled by what?
sympathetic nervous system, hormones, internal renal control mechanism
76
The renal medulla accounts for what percentage of renal blood flow?
1-2%
77
The renal medulla is supplied by what?
the vasa recta
78
The vasa recta that descends into the renal medulla accompanies what?
the loop of Henle of the juxtamedullary nephron
79
The vasa recta plays a role in what?
urine concentration
80
what part of the kidney receives the most blood flow
renal cortex
81
What does a mild to moderate sympathetic activation have on blood flow and GFR?
little or none
82
What does a strong sympathetic stimulation do to GFR?
decreases GFR
83
What would be some reasons for strong sympathetic signal to the kidney?
Defense reaction
Brain Ischemia
Severe Hemorrage
84
What is the physiological effect of Epinephrine and Norepinephrine on GFR and blood flow?
What occurs when it is paired with sympathetic activity?
Constrict afferent and efferent arterioles
will only decrease GFR in extreme cases such as hemorrhages
85
What hormone is typically released from damaged vascular endothelial cells of the kidney?
What is the end result?
endothelin
vasoconstriction to decrease blood loss
86
Endothelin release is seen in what disease states?
What is the end result?
toxemia of pregnancy, acuterenal failure & uremia
renal constriction and reduce GFR
87
Angiotension is a powerful vaso__________
constrictor
88
What determines the release of Angiotensin II?
decreased arterial pressure or decreased blood volumn
89
Which is more receptive to Angiotensin II?
a. afferent arterioles
b. efferent arterioles
b
90
What is the purpose of Angiotensin II?
maintain GFR
91
What hormone decreases flow through the peritubular capillaries=increase reabsorption of sodium and water in renal tubules
Angiotensin II
92
What hormone maintain vasodilation of the kidney?
Endothelial derived nitric oxide
93
What hormone allows for normal secretion of water and sodium?
Endothelial derived nitric oxide
94
A patient with atherosclerosis and damage to the endothelium of the kidney might have decreased production of what hormone?
What will happen to vasoconstriction?
What will happen to blood pressure?
decreased nitric oxide production
increases
increases
95
Prostaglandins and Bradykinin are vasodilators or vasoconstrictors?
What do they counteract?
Vasodilators
Vasoconstriction of the afferent tubules
96
After surgery a patient is given a nonsteroidal drug like asperine, what is the purpose of this?
decreases the productions of prostoglandins and bradykinins which cause vasodilation
97
```
What is the effect of the follow on GFR?
Norepinephrine & epinephrine
Endothelin
Angiotension II
Endothelial-derived nitric oxide
Prostoglandins
```
```
decrease
decrease
prevents decrease
increase
increase
```
98
What is an intrinsic mechanism of the kidneys that keeps blood flow andGFR relatively constant?
Autoregulatoin
99
Arterial pressure can range from 75mmHg to 160mmHg with only about _______% change in GFR
10
100
Without autoregulation an increase in blood pressure would quickly deplete what?
blood volume
101
What feedback mechanism links sodium concentration at the macula densa with renal arteriole resistance?
This type of feedback does what?
Tubuloglomerular feedback
ensures a constant delivery of sodium to the distal tubules
102
What does Tubuloglomerular feedback depend on?
juxtaglomerular complex (macula densa cells)
103
What do macula densa cells do?
sense a decrease in sodium concentration
104
In the Tubuloglomerular feedback mechanism, macula densa cells initiate a process that does what 2 major things?
Decreases resistance to blood flow in the afferent arterioles
Renin is released from juxtaglomerular cells
105
How does the macula densa cells decrease resistance to blood flow in the afferent arterioles?
increases GFR
| raises glomerular hydrostatic pressure
106
What does renin do that is released from the juxtamedullar cells increase the formation of?
angiotension I
107
angiotension I from the renin is converted into what?
What does this do to efferent arterioles?
angiotension II
Constriction
108
The ability of the individual blood vessels in the body to resist stretching during increased arterial pressure
Myogenic mechanism
109
What mechanism is thought to protect the kidney from an increase in blood pressure?
Myogenic Mechanism
110
What mechanism of auto-regulation is thought not to have a direct effect on GFR and renal blood flow regulation?
Myogenic Mechanism
111
Urinary excretion is equal to what?
Glomerular filtration - Tubular reabsorption + Tubular secretion
112
Which is more vital?
a. tubular secretion
b. tubular reabsorbtion
b
113
What play a role potassium and hydrogen ion excretion in the urine?
a. tubular secretion
b. tubular reabsorbtion
a
114
What is the formula for secretion?
Glomerular filtration rate x Plasma concentration
Only works with substances that are freely filtered
115
What is the glucose concentration of:
1. plasma concentration
2. Glucose filtered per day
3. filtration
1. 1g/L
2. 180L/day
3. 180g/day
116
Glomerular filtration & tubular reabsorption of substancesare large compared to what?
excretion
117
Tubular reabsorption is...
a. highly selective
b. nonselective
a
118
Glomerular secretion is...
a. highly selective
b. nonselective
b
119
Tubular secretion is...
a. active
b. passive
c. both
c
120
What is the process for tubular reabsorption?
tubular epithelial membrane -> interstitial fluid -> Peritubular capillary membrane -> blood
121
What are the two routs through the tubular epithelium?
trans cellular rout
| paracellular rout
122
Which rout goes through the tubular epithelium that goes through the cell membrane?
transcellular rout
123
Which route through the tubular epithelium goes through the tight junctions of the cells?
paracellular rout
124
What are two forms of active transport?
primary and secondary
125
primary active transport is couple with what?
What is an example of this?
hydrolysis of ATP
sodium-potassium ATPase pump
126
What kind of tubular reabsorption is coupled indirectly to the energy source (ie) ion gradiant?
What is an example of this?
secondary active transport
reabsorption of glucose through the renal tubules
127
Water is primarily absorbed through by what mechanism?
passive
128
The movement of sodium from the interstitial fluid to the Peritubular capillary is what kind of process?
passive
129
Travel through the peritubular capillary walls into the blood is done by?
ultrafiltratioin
130
What is required for secondary active transport?
what are their names?
a carrier molecule
Sodium Glucose co-transporters (SGLT2 &SGLT1)
131
Where are the Sodium Glucose co-transporters (SGLT2 &SGLT1) typically located?
brush border
132
What is the purpose of Sodium Glucose co-transporters (SGLT2 &SGLT1)?
transport glucose against a concentration gradient
133
Where are the SGLT2 located?
early part of the proximal tubule
134
Which carrier protein transports 90% of filtered glucose for reabsorption?
SGLT2
135
Which carrier protein in located in the last part of the proximal tubule?
SGRT1
