Quiz 3: water and salt pt 2 Flashcards
Which of the following compartments
contains the greatest volume of water?
intracellular
The greatest proportion of sodium in an average diet
in US is derived from ________.
sodium salts in processed foods
Which of the following foods exhibits the highest
content of potassium?
vegetables
The electrogenic transport of sodium in the apical
(luminal) membrane of the enterocyte, which is mainly
active in colon, is carried out by ________.
epithelial sodium channel (eNaC)
In normal subjects consuming an average
American diet, what percentage of ingested sodium,
potassium and chloride is absorbed in the intestine?
> 85%
Which of the following are the most abundant ions
found in the extracellular compartment?
Na and Cl
In the mechanism of action potential in
excitable cells, during depolarization ____________.
sodium channels open, potassium closed
All of the following are a functions of chloride (Cl-)
EXCEPT ______.
- main anion in the extracellular fluid
- phagocytosis of pathogens in white cells
- maintenance of gastric acid secretion
- exchange anion for HCO3 (bicarbonate) in red
blood cells
main site of electrolyte regulation
what plays a minor role?
kidney!
intestine plays a minor role
human kidneys are poised to conserve __ and excrete __
human kidneys are poised to conserve sodium and excrete potassium
kidney responds to dietary excess or deficiency of Na, K, Cl by modulating their excretion: (2)
- adjust amount filtered in glomerulus (filtration rate)
- change secretion or reabsorption
for long term regulation, __ rate plays a minor role
for long term regulation, glomerular filtration rate plays a minor role
4 mechanisms of Na, K, Cl balance
- vascular pressure receptors
- natriuretic peptides (ANP and BNP)
- renin-angiotensin-aldosterone (RAAS) system
- arginine vasopressin (ADH)
vascular pressure receptors: __ sense stretch or tension
vascular pressure receptors: baroreceptors sense stretch or tension
vascular low-pressure receptors
- distension of cardiac atria and pulmonary vein
- decreases vagal activity and activates AVP secretion
vascular high-pressure receptors
- distension in aortic arch and carotid sinus
- increased vagal activity
- inhibits AVP secretion
ANP and BNP are released into circulation when heart muscle is __ and and increase in __
ANP and BNP are released into circulation when heart muscle is stretched and and increase in plasma
function of ANP and BNP
- increase glomerular pressure and filtration rate
- reduce renin and aldosterone release
- promote dilation of blood vessels
effect of ANP and BNP
decrease plasma volume and lower blood pressure
Aldosterone _________ the reabsorption of
sodium mainly in the ____________ of the nephron.
Aldosterone increases the reabsorption of
sodium mainly in the distal tubule and collecting ducts of the nephron.
renin-angiotensin-aldosterone system sensors
a) baroreceptors in glomerulus sense changes in perfusion.
b) chemoreceptors in macula densa (distal tubule) sense changes in Na+ load
effect of renin-angiotensin-aldosterone
release of renin by granular cells –> angiotensin production –> aldosterone –> Na+ and water reabsorption in kidney
aldosterone increases the reabsorption of __ and excretion of __ in __ and __
aldosterone increases the reabsorption of Na+ and excretion of K+ in distal tubule and collecting duct
Choose the most correct option. ________, a
hormone produced in the hypothalamus, stimulates the
direct reabsorption of water by mainly activating _______
in the distal tubule and collecting duct of kidney.
Choose the most correct option. Arginine-vasopressin, a
hormone produced in the hypothalamus, stimulates the
direct reabsorption of water by mainly activating aquaporins
in the distal tubule and collecting duct of kidney.
arginine vasopressin stimulates __ of water in the kidneys, which __ urine output and __ ECF volume
arginine vasopressin stimulates reabsorption of water in the kidneys, which reduces urine output and increases ECF volume
Arg-vasopressin stimulates __ which increases fluid consumption and __ ECF volume
Arg-vasopressin stimulates thirst which increases fluid consumption and increases ECF volume
Arg-vasopressin stimulates __ of the arterioles, which __ blood pressure
Arg-vasopressin stimulates vasoconstriction of the arterioles, which increases blood pressure
increasing plasma osmolarity = __ plasma vasopressin
increasing plasma osmolarity = increased plasma vasopressin
vasopressin aka
ADH
vasopressin increases reabsorption of water by activating __ in __ and __
vasopressin increases reabsorption of water by activating aquaporins in distal tubule and collecting duct
blood-pressure responses to salt are
heterogeneous
__% of ppl with hypertension are thought to have salt-sensitive blood pressure
30-50% of ppl with hypertension are thought to have salt-sensitive blood pressure
low __ and __ can increase salt sensitivity
low potassium and calcium can increase salt sensitivity
salt-sensitive blood pressure is assocaited with these people
low-renin hypertension
old age
metabolic syndrome
Almost all 12- to 24-month-old toddlers
have salt intake that is higher than their “adequate levels.”
TRUE
reducing sodium intake reduces
systolic blood pressure
Increasing evidence suggests that a high salt intake
directly (i.e., beyond the effect of salt intake on blood
pressure) promote all the following alterations EXCEPT
________.
ALL
- endothelial fibrosis
- cardiac hypertrophy
- diastolic and systolic dysfunction
high salt intake promotes damage of what organs
- heart
- kidney
- blood vessels
- increases arterial pressure
high salt on kidney
glomerular injury
renal failure
high salt on heart
cardiac hypertrophy
diastolic dysfunction
systolic dysfunction
high salt on blood vessels
oxidative stress
endothelial dysfunction
fibrosis
decreased vascular elasticity
In response to a decrease in salt intake, the
reduction in blood pressure levels is generally more
pronounced in hypertensive subjects that normotensive
subjects.
TRUE
effective diet interventions
DASH + salt restriction
effective diet interventions
DASH + salt restriction
low K+ associated with increased risk of
hypertension
high ratio of __ to __ is more potent than either alone
high ratio of Na to K is more potent than either alone
dietary K+ supplementation improves
__ function
__ and __ structure and functional parameters
dietary K+ supplementation improves
endothelial function
vascular and cardiovascular structure and functional parameters
industrial diets are high in __ and low in __
industrial diets are high in Na and low in K
