28 Electrolytes

Question 1

what is renin release triggered by

Answer 1

low renal perfusion pressure
sympathetic activation (b1)
low NaCl at macula densa

Question 2

what does renin do

Answer 2

converts angiotensinogen to angiotensin I

Question 3

what does ACE do

Answer 3

converts angiotnsin I to angiotensin II

Question 4

where does ACE work

Answer 4

lung vascular endothelium

Question 5

angiotensin II effects

Answer 5

potent vasocontrictor - increase BP
stimulates aldosterone secretion from adrenal cortex
stimulates thirst
stimulates ADH release

Question 6

aldosterone functions

Answer 6

increase Na reabsorption
increase water retention
increase K and H secretion
increases blood volume and pressure

Question 7

where does aldosterone work

Answer 7

distal tubule and collecting duct

Question 8

what is water balance controlled by

Answer 8

plasma Na concnetration and ADH

Question 9

what happens when plasma Na rises

Answer 9

thirst is triggered
ADH release increases from posterior pituitary
kidney collecting ducts become permeable to water via aquaporins
water is reabsorbed and plasma osmolarity decreases

Question 10

what happens when plasma Na falls

Answer 10

ADH is inhibited
dilute urine produced

Question 11

stomach acid secretion ion transport

Answer 11

H/K ATPase pump
H into lumen
K taken into parietal cell

Question 12

stomach acid secretion ion transport requirements

Answer 12

carbonic anhydrase
cl channels
k channels
basolateral na/K pump

Question 13

absorption of amino acids in small intestine

Answer 13

brush border transport - small peptides enter via H coupled transporters
di/tripeptides hydrolysed

amino acid transport into blood
Na dependent active transporters

Question 14

what does transport of amino acids into blood require

Answer 14

Na gradient (created by na/k ATPase pump)
H gradient
facilitated diffusion

Question 15

low sodium (hyponatraemia) clinical features

Answer 15

cellular swelling - espeically brain cells
confusion
seizures
headache
nausea
lethargy

Question 16

water excess clinical features

Answer 16

hypertension
cardiac failure
peripheral oedema
nauesea
muscle weakness

Question 17

high sodium (hypernatraemia) clinical features

Answer 17

cellular dehydration
intense thirst
confusion
irritability
coma

Question 18

water deficiency (dehydration) clinical features

Answer 18

low blood pressure
tachycardia
reduced skin turgor
peripheral vasocontriction
rising plasma protein concentration
(all red flags for urgent care)