regulating blood pressure urinary system

juxtaglomerular cells

The cells of the afferent artery at the juxtaglomerular apparatus. They are baroreceptors that sense pressure change

macula densa cells

Specialized cells in the ascending limb which monitor the NaCl content of the filtrate entering the DCT. When it senses that there isn't enough NaCl it inhibits nitric oxide (nitric oxide causes vasodilation)

high blood pressure

smooth muscles in the walls of the arterioles stretch (increase GFR, decreasing reabsorption- it's moving too fast)

myogenic mechanism

Smooth muscle cells in afferent arterioles contract in response to elevated blood pressure ( reaction of muscles to contract when stretched)

juxtaglomerular apparatus

in the nephron, the complex of cells from the distal tubule and the afferent arteriole which helps regulate blood pressure by secreting renin in response to blood pressure changes in the kidney; located near the glomerulus

acute stress

1) the myogenic mechanism is triggered which stretches the arterioles

2)the little amount of NaCl in the DCT (from not enough filtration) is sensed by the macula densa cells which inhibits nitric oxide (a vasodilator) from the juxtaglomuler apparatus which causes vasoconstriction

chronic hypertenstion leads to:

-can cause damage to renal vessels (prolonged stretching)

-nephrons don't recieve enough oxygen

-less blood is filtered

-fluid is retained

-blood pressure rises (positive feedback)

low blood pressure

the juxtaglomerular cells don't stretch, meaning blood flow is slow and too much reabsorption. The cells release renin in response which is a catalyst for angiotensin 1 which interacts with ACE in the lungs to turn into angiotensin 2, a powerful vasoconstrictor. brain releases antidiuretic to reclaim water and adrenal gland releases aldosterone to reabsorb sodium and reclaim more water to increase blood pressure

angiotensin 2

potent vasoconstrictor

aldosterone

Hormone that stimulates the kidney to retain sodium ions and water released by the adrenal gland

antidiuretic hormone

hormone secreted by the posterior pituitary gland to prevent the kidneys from expelling too much water (helps retain water)