Lect 5 - Block 3 - Concentration & Dilution

Question 1

During micturition, ________ fires, causing _____ to contract
______ stops firing, causing ________ to relax

Answer 1

Parasympathetic neurons fire, causing smooth muscle to contract, passively pulling open int. sphincter

Motor neurons stop firing, causing external sphincter to relax

Question 2

Bladder volume ___ to ____
Adults void ____ to ____ times per day
Daily urine output _____ to ______

Answer 2

Bladder volume 300 to 500 mL
Adults void 5 to 6 times per day
Daily urine output 800 to 1800 mL

Question 3

Abnormal daily urine volume
Anuria ____
Oliguria _____
Polyuria ______

Answer 3

Anuria less than 100mL
Oliguria 100-400mL
Polyuria 1800+mL

Question 4

______ and _____ are associated with acute or chronic renal failure secondary to systemic events! renal injury, or post renal obstruction

(Anuria, oliguria, Polyuria)

Answer 4

Anuria, oliguria

Question 5

______ may be associated with diabetes mellitus, diabetes insipidus, adrenal insufficiency, or diuretic medication

Answer 5

Oliguria

Question 6

Increased urinary frequency is defined as ________

May be caused by large urine vol., decreased bladder capacity, increased post void residual vol. (bladder outlet obstruction), inflammation of bladder mucosa, or psychological disorders

Answer 6

Less than 2 hours between voids

Question 7

Nocturia is defined as ______

Dependent edema,
May be caused by large urine vol., decreased bladder capacity, increased post void residual vol. (bladder outlet obstruction), inflammation of bladder mucosa, or psychological disorders

Answer 7

More than 2 per night

Question 8

ADH increases permeability of the ______ and _____ to _____ and ______

Answer 8

Distal tubule and collecting duct to water and urea

Question 9

The continuous loss of NaCl into the renal medulla (thick ascending limb) is called ___________

Answer 9

Countercurrent multiplication

Question 10

The vasa recta has a very low blood flow to prevent washout of the gradient created by ________ in the thick ascending limb

Answer 10

NaK2Cl transport protein

Question 11

Countercurrent exchange has to do with what

Answer 11

Descending limb has high osm so water out and Na and urea in
When back up, lower osmolarity outside, and water can’t move so you can dilute it further

Question 12

4 things ADH does in the kidney

Answer 12

1. Increase perm of entire collecting duct to water
2. Increase perm of medullary CD to urea
3. Decrease Vasa recta blood flow (prevents washout of gradient)
4. Increases expression of NaK2Cl transporter in the TAL

Question 13

Fluid in the thick ascending limb has an osmolarity of _____

Answer 13

100mOsm

Question 14

What proportion of water is reabsorbed in the proximal tubule?

Answer 14

2/3 (66%)

Question 15

Without ADH, ____mL/min of water is the flow rate and ____ mOsm
With ADH, ____mL/min of water is the flow rate and ____ mOsm

Answer 15

20mL/min without ADH at 100mOsm

Less than 0.4mL/min with ADH at 1200-1400mOsm

Question 16

The biggest effect on urea concentration is due to ______ movement

Answer 16

Water

Question 17

Water intake is controlled by 4 things

Answer 17

1. Increased osmolarity
2. Decreased arterial pressure
3. Decreased blood volume (cardiopulmonary stretch receptors)
4. Angiotensin II (other side do blood-brain barrier)

Question 18

Stimuli for water output (7 things)

(Most stimulate secretion if ADH)

Answer 18

1. Increased osmolarity
2. Decreased arterial pressure
3. Decreased blood volume
4. Angiotensin II?
5. Trauma
6. Surgery
7. Drugs (opiates and anesthetics)

Question 19

Ethanol ______ ADH release

Answer 19

Inhibits

Question 20

Central diabetes insipidus is cause by _____

Answer 20

Impaired hypothalamic ADH synthesis/release
Kidneys still respond to exogenous ADH (desmopressin)

Question 21

Nephrogenic diabetes insipidus is caused by ______

Answer 21

Impaired renal ADH receptors
High circulating ADH
No effect of exogenous ADH (desmopressin)

Question 22

Water deprivation test consists of no water intake and measuring urine osmolarity. Once osmolarity plateaus, or the patient is dehydrated (lose 3% body weight), the patient is given _______, followed by further urine specimens

Answer 22

Desmopressin (exogenous ADH)

Question 23

Complete central diabetes insipidus is characterized by what in a water deprivation test.

Partial central diabetes insipidus

Nephrogenic diabetes insipidus

Psychogenic polydipsia

Answer 23

Urine osm remains lower then plasma osm,
With greater than 50% increase in osm after desmopressin

Partial - urine is 10-50% increased in osm following desmopressin

Nephro- urine osm less than 2x plasma osm with less than 9% increase after desmopressin

Psychogenic- patient usually hypo-osmolar and hyponatraemic

Question 24

Micturition reflex involves what muscles

Answer 24

Renal pelvis
Ureters (peristalsis)
Bladder detrusor muscles (PNS) (int. and ext. sphincters)
Urethra