Osmolality And Volume Flashcards
BP falls when standing which will have what affect on the afferent arteriole ?
The afferent arteriole will relax and allow more blood flow to the glomerulus to support hydrostatic pressure in the glomerulus and maintain filtration.
What does a decrease in sodium chloride concentration cause when detected by the macula dense cells ?
Decreases resistance to blood flow in the afferent arterioles to increase hydrostatic pressure of glomerular capillaries to increase GFR.
It also increases renin release from the juxtaglomerular cells.
This causes vasodilation of the afferent arteriole to increase blood flow
What is a common cause of hypertension ?
Excess sodium in diet
What effect does an increased filtration fraction of sodium and chloride ions arriving at the DCT have on the macula dense cells ?
There is a decreased release of renin by the macula densa cells from the juxtaglomerular apparatus
Granular cells of the juxtaglomerular apparatus secret renin in response to what stimuli?
A decrease in arterial blood pressure detected by baroreceptors
A decrease in sodium chloride in the ultrafiltrate
Sympathetic stimulation acting through beta 1 adrenergic receptors
What happens when the body is submerged in water in relation to the compression of the peripheries ?
Increased external pressure on the peripheries can trick the baroreceptors into thinking the BP is higher than it actually is so the body decreases RAAS and less ADH is released to excrete more urine in repsonse to the feeling of hypervolaemia.
What type of hormone is aldosterone ?
Steroid
What effect can ADH have on V1 receptors ?
They can activate V1 receptors on vascular smooth muscle to cause vasoconstriction triggering the thirst response in the hypothalamus
What is seen in a diagnosis of central - neurogenic - diabetes insipidus ?
An increase in serum sodium after an overnight water restriction
What causes dipsogenic diabetes insipidus ?
A defect or damage to the hypothalamus causing malfunction to the thirst mechanism.
What occurs in dispogenic diabetes insipidus ?
The person feels thirsty excessively regardless of their fluid status. The person consumes large volumes of fluid which suppresses the release of ADH so urine output increases
What causes neurogenic diabetes insipidus ?
Anything that affects the pituitary and production of ADH
