Urinary-Mace Flashcards
1
Q
Functions of Urinary System:
- Protein metabolism= ___% secreted via urea
- Nucleotide _______
- muscle breakdown–> of _______
A
- 50%
- metabolism
- creatine phosphate
2
Q
Functions of Urinary System (list 5 main fx)
A
- Excretion of Wastes
–BUN – blood urea nitrogen (6-20mg/100ml)
–Reflection of kidney health - Regulates:
a. Blood volume–> alters fluid loss
b. Blood composition –> inorganic ion balance/pH balance - Secretion hormones and enzymes
–Releases EPO in response to low O2
–Calcitriol and renin - Detoxifies free radicals/drugs: Penicillin, histamine, phenobarbital
- Gluconeogenesis (**during starvation)
(ERSDG)
3
Q
Renal corpuscle consists of which 3 things:
A
- Glomerulus
- Visceral capsule layer, the glomerular space
- Parietal capsule layer= bowman’s capsule
4
Q
Describe the Nephron structure
A
afferent arteriole & efferent 6arteriole–> vascular pole–> Glomerulus–> tubular pole–> PCT–> descending limb (of the nephron loop) –> ascending limb (of nephron loop) —> DCT–> collecting duct
5
Q
Which cell types make up the collecting duct?
A
intercalated cells and principal cells**
6
Q
Describe the relationship b/w nephron structures and location (ie in the cortex or medulla)
A
A/E arterioles and renal corpuscle are located in the cortex–>PCT is located in the cortex–> Descending limb and ascending limb are located in the **medulla—> DCT is in the cortex –> collecting duct is in the medulla
7
Q
Describe the flow in the nephron
A
- afferent arteriole–> Glomerulus in renal corpuscle 2. Efferent arteriole 3. peritubular capillaries
Note: blood supply goes in the OPPOSITE direction of the filtrate in the vasa recta (this is a countercurrent= helps concentrate the urine)
8
Q
JG apparatus consists of:
A
- macula densa cells of DCT
- Granular cells of afferent arteriole
9
Q
Describe blood flow in the renal corpuscle VS filtrate flow
A
- afferent arteriole–> Glomerulus in renal corpuscle 2. Efferent arteriole 3. peritubular capillaries
Flow of Filtrate: 1. Vascular pole–> around renal corpuscle (inside the glomerular capsule) —> and out the tubular pole to the PCT
10
Q
List 1 cell type within the Macula densa
A
extraglomerular mesangial cells
11
Q
Renal corpuscle: is the location of _______
A
filtration
12
Q
Renal cortex is made of: (list 3 structures)
A
-glomerulus, PCT, and DCT
13
Q
Describe the blood flow of the Kidney
A
- Renal a
- Segmental a
- interlobar a’s
- Arcuate a
- interlobar a
- afferent arteriole
- glomerulus
- Efferent arteriole
- Peritubular capillaries (assoc. with convoluted tubules) AND the Vasa Recta (assoc. with the nephron loop)
- Interlobar V
- Arcuate V
- Interlobar vein
- Renal vein
14
Q
Describe the structures that transport Filtrate vs Urine
-note: once filtrate enters the PCT it becomes ________
A
- *One filtrate enters the PCT= it becomes TUBULAR fluid
1. Filtrate in the capsular space
2. (becomes Tubular fluid) PCT–>3. Descending limb of nephron loop
4. Ascending limb of nephron loop
5. DCT
6. Collecting tubules
7. Collecting duct
- **becomes urine in the Papillary duct
- minor calyx
- Major calyx
- renal pelvis
- Ureter
- Urinary bladder
- urethra
**once it’s urine IT DOESN’T change! Once you hit the papillary duct it’s urine
15
Q
Glomerular filtration=
A
The movement of substances from the blood within the glomerulus
into the capsular space
(note: only 1 direction of movement)
16
Q
Tubular reabsorption=
A
The movement of substances from the tubular fluid back into the blood
(ie with the PCT, Ascending/descending limbs and DCT and collecting duct there are 2 directions of movement)
17
Q
Tubular secretion=
A
The movement of substances from the blood into the tubular fluid
18
Q
Urine Formation:
-consists of 4 major processes–>
A
- Filtration= Separation of particles and fluid according to size using hydrostatic pressure (BP)-> create a filtrate
- Reabsorption= Substances/particles move from filtrate into Bloodstream
–requires transport proteins in membrane of kidney tubule - Secretion= Substances move from Bloodstream into filtrate
- Water conservation= Water reabsorption, locally and systemically
regulated-> by concentration gradient and aquaporins.
Why? What is accomplished-> trying to make sure osmolarity of blood is correct and BP is correct
19
Q
Filtration membrane contains:
A
- Endothelium of fenestrated capillary
- Basement membrane of capillary
- Filtration slits of visceral layer
20
Q
Capillary lumen is surrounded by the visceral layer of glomerular capillary which contains a _______
A
podocyte–> pedicels located inside podocyte–> pedicel contraction= alters size of holes and alters size of filtration slits to determine how much plasma can go out of the glom capillary into the capsular space
21
Q
Substances Filtered by Filtration Membrane:
- Filtration membrane:
- -Endothelium blocks–>_______
- -Basement membrane blocks–>______
A
- formed elements
- large proteins
22
Q
Substances Filtered by Filtration Membrane:
- Filtration membrane:
- -Filtration slits of visceral layer block _____
A
small proteins
23
Q
Filtrate coming OUT of the glomerulus into capsular space contains:
A
**water, glucose, amino acids,
ions, urea, hormones, vitamins B and C, ketones
(WAGI HUVK)
24
Q
Determining Net Filtration Pressure in the Renal Corpuscle: -Glomerular hydrostatic pressure (HPg )= -Blood colloid osmotic pressure (OPg )= -Capsular hydrostatic pressure (HPc )= -Net filtration pressure (NFP)=
A
- 60mm Hg out
- 32mm Hg in
- 18mm Hg in
NET= 10mm Hg out
25
Net filtration pressure in renal corpuscle: The same as
Capillary exchange,
Except drainage done by?
afferent and efferent arteriole
26
Which of the following correctly describes the process of glomerular filtration?
A. Blood cells and plasma proteins are pushed out of the glomerulus into the glomerular capsule
B. Water, nitrogenous wastes, nutrients and ions are pushed out of the glomerulus into the glomerular capsule
C. Water and dissolved substances move out of the glomerulus by osmosis into the glomerular capsule
D. Water and formed elements are pushed out of the glomerulus into the glomerular capsule.
B. Water, nitrogenous wastes, nutrients and ions are pushed out of the glomerulus into the glomerular capsule
27
Which of the following would reduce the glomerular filtration rate?
A. Vasoconstriction of the efferent arteriole
B. A drop in oncotic pressure
C. Vasodilation of the afferent arteriole
D. Vasoconstriction of the afferent arteriole
E. An increase in osmotic pressure in the glomerular capsule
A. Vasoconstrict the efferent arteriole--> increases GFR
B. Drop in oncotic pressure (oncotic=colloid osmotic pressure)-– this would decrease amount of filtrate going into glomerulus--> actually **increasing GFR
C. Vasodilation of afferent--> Increases GFR
D. True decreases GFR
E. Increase GFR
D. is correct
28
Renal Autoregulation:
| Glomerulus itself has a local autoregulatory mechanism= renal autoregulation due to _____
MAP=b/w 80-180 mmHg--> MAP is considered “normal” in this range. MAP will be maintained by the glomerulus itself
29
MAP BELOW 80 mmHg will lead to..
Insufficient
| urine production
30
MAP above 180 will lead to..
Excessive
| urine production
31
Normal MAP b/w 80-180 mmHg will lead to..
Normal urine production
| maintained by renal autoregulation= GFR remains unchanged
32
Control of GFR via autoregulation:
| Renal autoregulation in response to changes in ________
systemic BP
33
Decrease in systemic BP--> (describe what happens w/ GFR)
-**afferent arteriole vasodilates
-Widened arteriole lumen
-allows more blood into
glomerulus to offset a
decrease in systemic blood pressure
34
INCREASE in systemic BP--> (describe what happens w/ GFR)
- afferent arteriole vasoconstricts
- Narrowed arteriole lumen
- allows less blood into glomerulus to offset increased systemic blood pressure
35
Male GFR=
| Female GFR=
**Male GFR = 120ml/min
| Female GFR = 95ml/min
36
Decrease GFR via sympathetic stimulation:
| -Vasoconstriction of afferent and efferent arterioles results in:
decreased blood flow to glomerulus-->
- Decrease in GFR
- Decrease in urine production
- Retain fluid
- Maintain Blood volume
37
Decrease GFR via sympathetic stimulation:
| -Contraction of Mesangial cells results in:
decreased filtration at the glomerulus (decreased filtration SA) -->
- Decrease in GFR
- Decrease in urine production
- Retain fluid
- Maintain Blood volume
38
Stressor leads to sympathetic stimulation:
| -Directly on arterioles-->
Decreased volume entering, P=constant
39
Stressor leads to sympathetic stimulation:
| -Granular cells--->
**Renin-angiotensinogen-activation
40
Describe the Renin-Angiotensin-Aldosterone-system
1. Stimulus- Low BP and/or SNS activation (1pt)
2. JG apparatus senses stimulus (1pt)
3. JC apparatus releases Renin into blood (1pt)
ALL THE REST OF THE TIME: Liver (1pt) produces and releases Angiotensinogen (1pt) (inactive) (1pt)
4. Renin enzyme transforms Angiotensinogen to ANG I (1pt) (inactive) (1pt)
5. ACE (produced in the lungs and held on the endothelium (1pt)) transforms ANG I to ANG II (1pt) (active) (1pt)
6. ANG II binds to effectors (ang 2 receptors): (located on the following)
At Systemic Blood vessels: vasoconstriction > increased peripheral resistance > increased BP (2pt)
At the Kidneys: decreased GFR > decreased urine output > maintain blood volume > maintain BP (2pt)
At the Hypothalamus: (1pt)
i. Activate thirst center – increased fluid intake > increased blood volume > increased BP(2pt)
ii. Release ADH – decreased urine output > maintain blood volume > maintain BP (2pt)
At the Adrenal Cortex: Release ALDO > increases Na+/H2O reabsorp into blood > maintain blood volume > maintain BP (3pt)
7. Net Effect: BP increases (1pt)
8. Increased blood pressure stops the low BP stimulus – Negative Feedback (2pt)
41
What is the NET effect of Angiotensin 2?
```
Increased BP
(this may turn off the low BP stimulus, BUT it doesn’t turn off the Sympathetic division stimulation (this continues to send the signal to make more renin--> ie more ang 2 is created--> BP still continues to increase)
```
-You must figure out a way to decrease Sympathetic division or use hypertensive drugs (ie hydrochlorothiazide causes you to increase urine output, drop blood volume and decrease bp) , next step is add in ACEI= acts on ACE (inhibits it and competitively binds on this enzyme0 so ang 1 does not get transformed to Ang 2
-one bad thing of being on ACEI (ie lisinopril) 10-15% develop dry cough or resp. problems--> so next drug of choice = ARB (ang receptor blockers) so ARBs like valsartan or losartan= fx is prevent binding of ang 2 to receptors and allows systemic blood vessels to vasodilate and decreases BP and
3 drugs for RAAS= HCTZ, ACEI’s, and ARBS
42
List 3 drug classes for RAAS:
-HCTZ, ACEI’s, and ARBS
43
Describe in detail the pathway for ADH
1. Stimulus: ANG II, low blood volume, increased blood osmolarity (1pt)
2. Hypothalamus senses above stimuli (1pt)
3. Hypothalamus stimulates posterior pituitary to release ADH into blood (2pt)
4. ADH binds to effectors
a. Hypothalamus: thirst center activated – increased fluid intake – increases blood volume – increased blood pressure (4pt)
b. Kidney: increased H2O reabsorption in DCT and Collecting duct – decreases H2O lost in urine – maintained blood volume – decreased blood osmolarity (4pt)
c. Blood Vessels: vasoconstriction – increases TPR – increases blood pressure (3pt)
5. Net Effect:
a. Blood pressure increases (1pt)
b. Blood osmolarity decreases (1pt)
6. The above effects have a negative feedback on the hypothalamus and JG apparatus – turns off ADH release (1pt) – turns off Renin release and thus ANG II production (1pt)
44
Describe the Aldosterone pathway
1. Stimulus: ANG II, decreased Na+ blood plasma levels, increased K+ blood plasma levels (**Hyponatremia or hyperkalemia)
2. Adrenal Cortex receptors sense above stimuli (1pt)
3. Adrenal Cortex releases Aldosterone into the blood (1pt)
4. Aldosterone binds tubules in kidney (1pt)
a. Increases Na+/H2O reabsorption into blood – increases blood volume – increases blood pressure (3pt)
b. Decreases Na+/H2O and increases K+ lost in urine – K+ in blood plasma decreases (2pt)
c. Principle cells in Collecting duct increase K+ secretion - K+ in blood plasma decreases (2pt)
5. Net effect:
a. Na+ blood plasma levels increased(1pt)
b. K+ blood plasma decreased(1pt)
c. Blood volume maintained and Blood pressure at homeostasis (by decreasing urine output)
6. Net effect negatively feeds back - returns K+ and Na+ to homeostatic range thus stopping the stimuli on the adrenal cortex and Aldosterone release is stopped. (4pt)
45
Increase GFR via ____
ANP**
46
How is ANP stimulated to release?
| -describe the 3 main effects of ANP
Atrial wall stretch=>ANP release
- Direct action on afferent arteriole
* *-Inhibition of renin release
* *-Inhibition of aldosterone (antagonist)
Note: ANP release Is related to atrial fibrillation
47
ANP release--> Vasodilation of afferent arteriole--> Result=
increased blood flow at the glomerulus-->
- increase in GFR
- Increase in urine production
- loss of additional fluid
- Decrease in blood volume
48
ANP release-->Relaxation of Mesangial cells-->Result=
(increased filtration SA)= increased filtration at glomerulus-->
- increase in GFR
- Increase in urine production
- loss of additional fluid
- Decrease in blood volume
49
Describe how Atrial Naturetic Peptide (ANP) regulates blood pressure
1. Increased stretch of baroreceptors in atria(1pt)
2. Atria release ANP into blood(1pt)
3. Effectors: ANP binds to effectors to cause-->(1pt)
a. Systemic blood vessels: vasodilation – decreases TPR – decreases blood pressure(4pt)
b. Kidney:
i. Increased GFR – increases urine output – decrease blood volume – decreases blood pressure(4pt)
ii. Increased loss of Na+/H2O in urine – decreases blood volume – decreases blood pressure(3pt)
iii. Decreased release of renin – decreased ANG II release – decreased release of ALDO/ADH(4pt)
4. Net effect: decreased peripheral resistance, decreased blood volume, decreased blood pressure(1pt)
5. Negative Feedback: reduced blood volume and decreased blood pressure reduce the stretch of the atria and thus ANP release is stopped(4pt)
50
An increase in glomerular filtration rate will _________ urine production.
A. Increase
B. Decrease
C. No change in urine
INCREASE
51
Control of Glomerular Filtration Rate:
| -how is GFR maintained?
Renal autoregulation maintains GFR despite
| changes in systemic blood pressure (BP)
52
with a DECREASE in systemic BP, how is GFR maintained?
vs
Increase in systemic BP?
vasodilation of afferent arteriole
-Increased systemic BP=> vasoconstriction of afferent arteriole, using myogenic & tubuloglomerular feedback
53
The sympathetic division decreases GFR by: (list 2 things)
- Afferent arteriole Vasoconstriction
| - Mesangial cells contract, which decreases filtration surface area=>decreases urine production, maintains blood volume
54
Increase in GFR via ____
ANP
55
Atrial natriuretic peptide (ANP) increases GFR by: (2 ways)
1. Afferent arteriole vasodilation
2. Mesangial cell relaxation, which increases filtration surface area=>increases urine production, decreases blood volume
56
In the Peritubular capillary:
- ____ hydrostatic pressure
- _____ colloid pressure
- LOW hydrostatic pressure
| - HIGH colloid pressure
57
Paracellular transport=
movement of substances b/w epithelial cells
58
Transcellular transport=
movement of substances across an epithelial cell
59
Tubular secretion=
substances move from blood into tubule (ie drugs, ammonia, etc)
60
Tubular reabsorption=
: substances move from tubule into blood (from tubular fluid into blood)
61
PCT= ______ reabsorption
**glucose
62
```
PCT: Glucose reabsorption
-Glucose transporter: reabsorbs
______ max. glucose in
blood plasma.
-normal urine glucose=
-normal blood glucose=
```
-Aldosterone/Na+ action”
Stimulates production of ____
230mg/100ml
- urine= 0
- 100mg/100ml (fasting state)
-Na+ channels and Na/K pump
63
What is an antagonist of glucose reabsorption at the PCT?
**ANP (your body will dilute glucose in tubular fluid if this process is antagonized, which increases urine production )
64
PCT: Glucose reabsorption (list 2 steps)
1. In lumen of PCT: glucose is transported up it’s concentration gradient by secondary active transport (high sodium conc. Is helping to drive glucose into tubule cell of PCT (3 Na for 1 glucose)
2. Glucose diffuses down it’s concentration gradient by facilitated diffusion (via glucose uniporter--> glucose moves from tubule cell of PCT into bloodstream ofthe peritubular capillary)
- at the end, 0% glucose remains in tubular fluid
- 100% of glucose reabsorbed into blood
65
Water reabsorption:
| Regulated (facultative) H2O reabsorption in ____ and ___
DCT and CD
66
___% of obligatory
water reabsorption
in PCT
65%
67
__% of water reabsorption in the nephron loop
10%
68
Regulated Water reabsorption in the DCT and CD is controlled via which hormone ?
ADH**
--ADH causes aquaporins to open up and water is reabsorbed (aquaporins on the luminal membrane--> water goes into interstitial fluid---> peritubular capillary
69
Additional water is reabsorbed by _____
**osmosis by Increased aquaporin #
70
Potassium Ion Reabsorption:
| ___% of K+ reabsorption in _____
60-80% in PCT
| --10-20% K+ reabsorption in the nephron loop
71
Potassium Ion Reabsorption:
| -describe which cell types allow K+ reabsorption: Type A vs Principal cells
```
-Regulated K+
reabsorption and secretion
in collecting tubules
-Type A intercalated cells
(of collecting duct)
reabsorb K+ continuously
-Principal cells (of collecting
duct) vary K+ secretion,
depending upon aldosterone
levels
```
72
Calcium Ion and Phosphate Ion Reabsorption:
| - _____ inhibits reabsorption of phosphate in PCT
PTH
Result: increased Phosphate lost in urine (and increased calcium in blood)
73
Calcium Ion and Phosphate Ion Reabsorption:
| -_____ stimulates reabsorption of Ca 2+ in the DCT
PTH
Result: increased Phosphate lost in urine
74
Bicarbonate Ion and Hydrogen Ion Movement:
- ___% of Bicarb reclaimed in PCT
- ___% bicarb reclaimed in nephron loop
- regulated bicarb and H+ reabsorption and secretion in _____
- 80-90%
- 10-20%
- collecting duct
75
```
Glucose and amino acids are reabsorbed from the glomerular filtrate by:
A. The renal corpuscle
B. The proximal convoluted tubule
C. The distal convoluted tubule
D. The glomerular capillaries
E. The collecting duct
```
B. PCT
76
Medullary gradient relies on the _____
nephron loop
77
Nephron loop= countercurrent multplier
| -Describe concentrations (mOsm) throughout the nephron loop
- Start out with 300 mOSm in descending limb of nephron loop--> which is permeable to water and impermeable to salt, water goes out and salt goes in. at the bottom of the loop the tubular fluid is more concentrated (higher salt conc.)= 1200 mOsm
- Ascending loop: permeable to salt and not to water--> at top of loop back to 100 mOsm
Summary: 300 mOsm--> 1200 mOsm--> 100 mOsm
78
Vasa Recta= Countercurrent exchange
| --Describe concentrations (mOsm) throughout the vasa recta
In vasa recta they go the opposite direction
–blood will exchange water and salt as it descends with the ascending loop, it picks up salt, then when it goes back up the descending loop it picks up water.
-Blood vessels help keep this counter exchange in balance
Summary: (from right to left (ie goes backwards))
- 300 mOsm--> 1200 mOsm (blood is more concentrated)--> 300 mOsm
79
Summary of nephron tubule events:
- PCT= site for majority of reabsorption
- -reabsorption=
- -Secretion=
```
Reabsorption: The following substances
move from the tubule into
the blood-->
-100% of nutrients
-majority of water
-ions
-Phosphate reabsorption is inhibited by PTH
```
```
Secretion: The following substances
move from the blood into
the tubule:
-some drugs
-nitrogenous wastes
```
80
Nephron loop and Vasa Recta= site of ____
countercurrent multiplier and
countercurrent exchange
* Continues reabsorption of water and ions that begins in PCT.
* Nephron loops of juxtamedullary nephrons establish interstitial fluid concentration gradient (along with urea recycling)
81
DCT and collecting ducts= sites of ____
regulation
82
DCT and collecting ducts:
-• Na+ reabsorption is regulated by aldosterone and ____
• Water reabsorption is regulated by ______ and _____
-Amount of K+ secreted in the urine at ______ and _______ cells
• Ca2+ reabsorption is increased by _____
- ANP
- aldosterone and ADH.
- intercalated and principal cells
- PTH
83
At the DCT and collecting ducts:
| -pH is regulated by ________ cells
intercalated cells
- -Either secreting acid (H+) and retain base (HCO3-)
- -Or cells secrete base (HCO3–) and retain acid (H+).
84
Average daily urine production=
| -contents of urine=
1-1.5L per day
| --ions, water, nitrogenous wastes and drugs, some hormones, NO formed elements/nutrients
85
What if there is glucose present in urine?
if there is high glucose in the tubular fluid, you tend to reabsorb less water (cuz water stays with glucose ie pee it out)
86
_______ epithelia of the bladder
transitional epithelium**--> it can stretch
87
Urination:
| -describe the storage reflex
A. Sympathetic NS (spinal reflex)
--Contraction of internal urethral sphincter
--Inhibits contraction of detrusor muscle and micturition
B. Somatic NS-> contract external urethral sphincter
storage reflex= about 100 mL in the bladder
88
Urination:
| -describe the Involuntary micturition reflex
A. Mechanoreceptors=> 250 ml in bladder
B. Parasympathetic NS (in pons):
--Efferent pelvic nerve in sacral region, induces inhibition of SNS
--Motor fibers-> contraction of detrusor/relaxation of internal sph.)
--Stimulates micturition
micturition reflex= about 300 mL in bladder
89
Urination:
| Describe Voluntary Control-> via somatic NS (cerebral cortex)
- Prevents urination
- Sensory input-> vision, voluntary
- If inappropriate-> inhibits PNS
90
Micturition reflex: steps
1. Detrusor muscles stretched (250-300 mL in bladder)
2. Micturition center (rostral pons) activated
3. S2/S3/S4--> pelvic splanchnic nerves
4. Detrusor m contracts
5. External urethral sphincter contracted (via pudendal nerve)
- internal urethral sphincter= relaxed
91
Storage reflex: steps
1. urinary bladder has 100mL
2. Detrusor m relaxed
3. Internal and external urethral spinchters contracted
92
Which renal structure is responsible for producing hypertonic urine by reabsorbing water while allowing metabolic wastes and NaCl to pass through?
```
Glomerulus
Proximal convoluted tubule
Distal convoluted tubule
Collecting duct
Nephron loop
```
collecting duct
93
Creatinine has a renal clearance of 140 ml/min due to the fact that
A. It is absorbed by the loop of Henle
B. It is secreted by the glomerulus
C. It is absorbed by the renal tubules
D. It is secreted by the renal tubules
E. It is produced in the pulmonary tissue
D. It is secreted by the renal tubules
```
GFR males: 120 ml/mn
GFR in females= 95 ml/min
b. wrong—glomerulus only filtrates
c. wrong– decreases gfr
d. correct
```
94
```
Because of the great deal of active transport that occurs here, the _________ of all the nephrons collectively account for about 6% of one’s daily resting ATP and caloric consumption.
Proximal convoluted tubules
Distal convoluted tubules
Loops of Henle
Collecting ducts
glomeruli
```
PCT
