Hormonal Mechanisms

Question 0

Hypervolemia

Answer 0

Increased ECF volume
Can be with or without high perfusion pressure
Causes: nephrotic syndrome, advanced renal failure
Symptoms: nocturia, pruritis, edema, nausea, vomiting, appetite loss tiredness, protienuria, hypoalbuminemia

Question 1

Hypovolemia

Answer 1

Decreased ECF volume
Loss of total body Na+
Causes:haemorrhage, d and v, poor fluid intake, polyuria
Symptoms: dry mucous membranes, fainting, tachy cardia, arthostatic hypertension
N

Question 2

Effector mechanisms on renal Na+ transport: Sympathetic stimulation

Answer 2

Increase Na+ reabsorption
Noradrenaline influences proximal Na+ reabsorption
Activates RAA
Decreases GFR-> less Na+ filtered

Question 3

Atrial naturetic peptides

Answer 3

Increase GFR by vasodilation
Decrease proximal Na+ reabsorption
Inhibit aldosterone and renin release

Question 4

Natriuretic factors

Answer 4

Decrease tubule reabsorption
Inhibit renin release
Prostanoids-> decrease GFR

Question 5

Factors effecting renin release

Answer 5

Macula densa-> decreased salt delivery to distal tubule-> decreased salt to macula densa co transporter-> increased renin release
Renal Baroreceptor-> decreased renal perfusion pressure detected-> increased renin release
Catecholamines-> decreased ECF/BP->increased sympathetic activity-> bets adrenoceptors-> increased renin release

Question 6

RAA

Answer 6

Renin, inhibited by ANP and ADH
Angiotensinogen
Angiotensin 1
Angiotensin 2-> vasoconstriction, proximal Na+ uptake, increased CO
Aldosterone release by adrenal cortex-> distal Na+ uptake

Question 7

Osmoregulation sensors and effectors

Answer 7

Sensed: plasma osmolality
Sensors: hypothalamic osmoreceptors
Effectors: ADH, thirst
What’s affected? Urine osmolality, water uptake

Question 8

Volume regulation, sensors and effectors

Answer 8

Sensed: effective tissue perfusion
Sensors: macula densa, renal baroreceptors, atria and carotid sinuses
Effectors: RAA,SNS,ANP, naturetic factors, ADH
Effected: urinary sodium, thirst

Question 9

Ingestion of hypertonic saline

Answer 9

Increased osmolality and increased volume
Osmolality-> increased ADH and thirst
Volume-> decreased RAA (high salt delivery to distal tubule and high ECF), increase ANP to inhibit ADH (reduce water reabsorption)
Produce concentrated urine

Question 10

Eating salt without drinking water

Answer 10

Increased osmolality with out volume increase
ADH release by post pit. neurohypophysis
Thirst

Question 11

Ingestion of isotonic salt

Answer 11

Increase volume but osmolality stays the same
Baroreceptors decrease RAA
SNS decreased stimulation
Increased ANP to inhibit ADH
Decreased water reabsorption-> increased urine volume, hypo osmotic

Question 12

Drinking large amounts of water

Answer 12

Decreased osmolality and increased volume
Decreased ADH by osmoreceptors
Decreased RAA by baroreceptors
Increased ANP
Excrete dilute urine, excreting the water returns osmolality to normal

Question 13

Factors effecting K+ secretion

Answer 13

Aldosterone:
Increase Na reabsorption leads to increased electro negativity of lumen, increase Na/K activity, increased luminal permeability to K 
Increased plasma K conc: 
Increased luminal permeability, increased Na/K activity, aldostone secretion
Distal flow rate: 
K washout means less in lumen
Na reabsorption without Cl-:
Decreased luminal charge
Acid base balance: 
Decreased Na pump
Decreased apical permeability to K
Increase H/K