Regulation of Na Balance

Question 1

Quantity of sodium excreted is exactly adujusted by kidney to match ___

Answer 1

salt intake

Question 2

__ is the most important determinant of ECF volume

ICF sodium concentration = ___

ECF sodium concentration = ___

Answer 2

sodium

10 mEq/L

145 mEq/L

Question 3

Water movement between compartment rules

1) ___ must separate two compartments with diff concentrations of impermeable solutes
2) water moves into compartment with the ___ solute concentraiton
3) freely permeable solutes (like ___) do/do not affect this movement of water
4) the ___ determines the magnitude of water movement
5) movement of water occurs until ___

Answer 3

1) water-permeable membrane
2) higher
3) urea; do not
4) magnitude of concentration gradient
5) eithe concentration gradient dissipates or resulting incr in hydrostatic pressure balances osmotic pressure

Question 4

what portion of the body fluid compartments is affected with CPR?

Answer 4

1/4 of intravascular compartment (3.5L)

affects LV filling and MAP

Question 5

___ is the most abundant solute in ECF

Sodium is most important determinant of __

disorders of sodium balance = disorders of ___

maintenance of ECF volume determines __ and ___

Answer 5

1) sodium
2) ECF volume
3) disorders of ECF volume
4) mean arterial pressure and LV filling volume

Question 6

Homeostatic response Objective = ___

Define effective arterial blood volume

Answer 6

1) maintain ECF volume

EABV = amount of arterila blood volume to adequately fill capcity of arterial circulation

Question 7

Integrated homeostatic response to volume change

in response to volume contraction and expansion

Answer 7

1) normal extracellular volume
2) volume contracted
3) activ of volume sensors (AFFERENT)
4) renal effector –> anti-natriuresis to retain Na and water

________

1) normal extracellular volume
2) volume expansion
3) activ of volume sensors
4) renal effector –> natriuretic –> pee out water and Na+

Question 8

Components of homeostatic response

Afferent Limb = volume sensors (4)

Answer 8

1) low pressure baroreceptors
2) high pressure barorreceptors
3) intrarrenal sensors
4) hepatic and CNS sensors

Question 9

1) Describe low-pressure baroreceptors includes (3)
2) located on the ___ side of the circulation
3) protects body against …

Answer 9

1) cardiac atria receptors + LV recepotrs + pulmonary vascular bed receptors
2) venous
3) ECF volume expansion and contraction

Question 10

Renal response to volume expansion

Answer 10

1) volume expansion
2) incr venous return –> too much filling of arterial blood volume
3) decr sympathetic nervous system in brain
4) kidney decr sodium/water reabsorption–> pee out more to decr volume expansion

Question 11

1) high pressure barorecpetors include (2)
2) located on the ___ side of the circulation

3) assess the ___ of the circulation and work to maintain the __
4) goal of high pressure baroreceptors

Answer 11

1) carotid sinus body at carotid bifurcation

aortic body in aortic arch

2) arterial side
3) pressure of arterial circulation

maintain mean arterial pressure

4) normalize ECF volume in response to volume expansion or contraction

Question 12

1) intrarenal sensors

JGA brings into close apposition the __ and __ arterioles with specialized regulation of the thick ascending limb (___)

macula densa expresses the ___ transporter and secrete ___

Answer 12

afferent and efferent arterioles

macula densa; renin

Na+/K+/2Cl-

Question 13

what causes increased renin secretion

what causes decreased renin secretion

Answer 13

1) more angiotensin II and aldosterone –> decr arterial pressure, decr Na delivery, beta adrenergic, PGEI 1/2, nitric oxide

decr arterial pressure –> stretch receptor –> incr intracellular calcium –> incr renin secretion –> incr Na+ reabsorption

2) incr arterial pressure, incr Na delivery, angiotensin II, ANP

Question 14

Efferent limb: efferent elements

what is most important control?

1) sodium excreted in urine depends on ___
2) fluctuation in GFR will influence the ___
3) equation for SNGFR

Answer 14

glomerular filtration

1) how much sodium is filtered
2) renal handling of sodium
3) Kf x [(Pgc - Pt) - (Pigc - PiT)

Question 15

Describe renal autoregulation

Answer 15

keeping RBF and GFR constant by contraction of vascular smooth muscle

if patient volume depleted, kidney needs to correct by decr effective arterial blood volume-

Question 16

Describe tubuloglomerular feedback

Answer 16

incr distal delivery of NaCl to macula densa incr afferent arteriolar tone and returns RBF and GFR back to normal

Question 17

Describe glomerulo-tublar balance

Answer 17

changes in GFR induce proportional change in rate of prox tubular sodium reabsorption

incr reabsorption of Na+ if volume depleted state

Question 18

efferent effectors

physical factors at level fo proximal tubule influence ___

Answer 18

renal reabsorption of sodium between proximal tubule and renal interstitium and between

renal interstitium with efferent arteriole

Question 19

Humoral effector mechanism

1) incr sodium reabsorption (antinatriuresis) - when effective blood volume low
2) decr sodium reabosrption (natriuresis - to incr salt excretion and water excretion

Answer 19

1) angiotensin II, aldosterone, catechoalmines, vasopressin
2) natriuretic peptides, prostaglandins, bradykinin, dopamine

Question 20

renal sympathetic nerves

1) sympathetic nerve innerv the ___ of glomerulus
2) activation of renal symp nerve has a ___ effet
3) nerve stim enhances release of ___

Answer 20

1) afferent and efferent arterioles
2) anti-natriuretic effect
3) renin from JGA

Question 21

How does nephron reabsorb sodium

Question 22

Proximal tubule reabsorbs ___

sodium reabsoprtion occurs down ___

graident for sodium reabsorption maintained by ___

active mechanism of sodium transport is through ___

Answer 22

1) 60% of filtrate including Na
2) electrochem gradient of sodium

3) Na/K atpase at basolateral
4) Na/H antiporter

Question 24

Loop of henle

1) 30% of filtered sodium reabsorbed in ___
2) impermeable to __ but highly permeable to ___
3) tubular fluid =
4) reabsorption of Na at apical membrane occurs by ___

Answer 24

1) TALH
2) water; sodium
3) dilute with low NaCl concentration
4) Na/K/2Cl cotransporter (active) –> if block, then block reabs of Na, K, Cl –> diuresis

Question 29

Renal losses of sodium and water

Failure of effectors mechanism can lead to …

Answer 29

1) solute diuresis, gluocsuria
2) diuretic agents
3) adrenal insufficency (lack of aldosterone)
4) selective aldosterone deficiency
5) mutations in sodium transporters (Bartter’s = mutation in loop of henle transporter similar to furosemide and Gitelman’s syndrome = mutation in Na/Cl cotransporter similar to giving DCT diuretic)

Question 30

Intrinsic renal diseases causing renal loss of sodium and water

Answer 30

1) non-oliguric ARF
2) As ARF recovering, diuretic phase of ARF
3) post obstructive diuresis
4) salt wasting nephropathy- not responding to CNS command
5) tubulointerstitial disease

Question 31

sources of extra-renal losses

Answer 31

1) Gastrointestinal (GI) tract fluid losses (vomiting/diarrhea)
2) Dermal fluid losses (burn)
3) Fluid losses into a “third space” - nephrotic syndrome - fluid in intravascular space now in interstitium

Question 32

cardiovascular response to decr ECF volume

Answer 32

1) incr HR, incr cardiac inotropy (cold, clammy)
2) incr SVR, incr angiotensin II
3) incr AVP (to reabsorb water), incr endothelin (vasoconstrictor)

Question 33

renal response to decr ECF volume

Answer 33

1) decr GFR –> decr load of sodium
2) activ of renal symp nerve
3) decr hydrostatic pressure, incr oncotic pressure in peritubular
4) stim RAAS = more renin released
5) incr AVP release
6) incfr ANP release

afferent alarm and efferent system –> to restore volume

Question 34

Clinical manifestations of decr ECF volume

Answer 34

1) Thirst, postural dizziness
2) Weakness, palpitation
3) Decrease urinary output, confusion
4) Weight changes
5) Orthostatic blood pressure, tachycardia, hypotension
6) Decreased elasticity or turgor of the skin
7) Dry mucous membranes

Question 35

each of these means what?

} Increased BUN: plasma creatinine ratio

} Metabolic alkalosis during upper GI loss of fluid

} Metabolic acidosis during lower GI loss of fluid

} Increased hematocrit and serum albumin because of hemoconcentration

Answer 35

Signs of severe volume contraction

1) -
2) vomiting
3) diarrhea- lose lots of bicarbonate
4) elderly patient resolved after hydration

Question 36

if urinary sodium > 20 mEq/L =

if urinary sodium < 20 mEq/L =

if FENa <<< 1% means

if urinary sodium gravity > 1.010

if urine osmolality > 300 mOsm/kg

Answer 36

of volume contraction

1) renal losses (problem with kidney)
2) extra renal losses (kidney working fine) = diarrhea and vomiting
3) low urine Na
4) body has reabsorbed lots of water

Question 37

How to treat decr ECF volume

Answer 37

1) replacement fluid simil to lost fluid
2) blood, albumin, dextran help expand intravascular volume
3) isotonic normal salne (0.9% NaCl) expands ECF volume MUST USE TO RESUSCITATE UNLESS PATIENT IS HEMORRHAGING

Question 38

if you resuscitate patient with blood, dextrain

if you resuscitate patient with saline

if you resuscitate patient with 1L water or D5W

Answer 38

1)
1L of plasma goes to intravascular space
most interested in resuscitating

2) not as good as plasma
but not bad
good to resusc BP and HR

3) intravascular only incr from
3.5 to 3.59 because no
salt in solution so
nothing stays in intravascular
space —> goes to
interstitium

Question 39

1) Causes of disturbed starling forces
2) causes of excess primary hormones
3) causes of primary renal Na retention

Answer 39

1) CHF, nephrotic syndrome, cirrhosis
2) primary hyperaldosterone, cushing’s, SIADH
3) acute glomerulonephritis

Question 40

what allows for persistence of edema?

Answer 40

1) alteration in starling forces
2) arterial underfilling –> decr effective arterial circulating volume
3) excess renal Na and water retention

Question 41

Initiation of renal sodium and water retention in heart failure

Answer 41

1) heart failure = decr Cardiac output
2) activ of afferent system
3) incr activ of AVP, SNS, RAAS = vasoconstriction, water/Na retention
4) if heart failure not fixed, edema because fluid goes to wrong space –> orthopnea, basilar pulm rales, water weight,

Question 42

if specific gravity low what does that mean

Answer 42

dilute urine

low urine osmallity

Question 43

what happens in nephrotic syndrome

Answer 43

1) loss albumin in urine
2) decr capillary oncotic pressure
3) fluids from vascular space into interstitium and decr effective arterial blood volume

Question 44

Mechanism for initiation of renal sodium and water retention in cirrhosis

Answer 44

1) peripheral arterial vasodilation = too large of blood volume
2) decr effective arterial blodo volume
3) activ of arterial baroreceptors
4) AVP, SNS, RAAS activ
5) water retntion, incr peripheral arterial resistance, sodium retnetion
6) incr cardiac output, maintain integrity

Question 45

Mechanism of loop diuretic

Mechanism of thiazide

Answer 45

1) inhibit Na/2Cl/K co transporter across apical membrane in ascending loop of Henle
2) inhib Na/Cl transport, incr Ca reabsorption, decr urinary Ca2+

Question 46

Mechanism of triamterene and amiloride

Mechanism of spironolactone

Answer 46

K+ sparing diuretics

1) sodium channel blocker
2) competitive inhib of aldosterone

Question 47

Mechanism of carbonic anhydrase diuretic

when to use?

dangers of excess use

Answer 47

to mobilize edema- nonspecific effect on decr Na reabsorption

improve cardiac and resp fxn

worsen kidney function

Question 48

when to use loop diuretic

Answer 48

Metabolic alkalosis, hypokalemia, hypocalcemia, and hypomagnesemia