topic 11 powerpoint 11.2 Flashcards
Kidney function controls
-osmolarity
-total fluid volume
-ph
Water absorption in the kidney is regulated by what hormone?
ADH- antidiuretic hormone
1)osmoreceptors in hypothalamus detect an increase in osmolarity
2) The pituitary gland releases angiotensin(peptide hormone) which stimulates ADH secretion
3) ADH makes distal convoluted tube more permeable to water, less urinary output but reabsorbed and retained
Result: increase water absorption and stimulate thirst
ADH involves what type of feed back mechanism
negative- output which is ADH opposes input
Parasympathetic activation vs sympathetic activation in relation to heart
Parasympathetic activation- decreased contractility of heart results in decrease CO/Bp/HR
Sympathetic: increased contractility of the heart results in increased CO/Bp/HR
What detects increase/decreased contractility of the heart?
Baroreceptors in aorta and carotids detect “stretch”, send signals to medulla oblongata (brainstem).
If you want to decrease blood pressure, what would you do the parasympathetic and sympathetic system?
activation of the parasympathetic nervous system and inhibition of the sympathetic nervous system
T/F Kidney is involved with blood pressure
true
-Juxtaglomerular cells aka intra-renal baroreceptors in the kidney release renin which increases bp
-Atria releases ANP(atrial natriuretic factor), a protein hormone that inhibits rene, lowering bp
Explain the mechanism that ANP lowers bp
1)natriuresis, process of excretion of
sodium in the urine via the action of the kidneys. ANP increases renal dilation, increase blood flow and glomerular filtration rate, more filtrate is processed.
2)Na+ cleaves, water follows it
Loss of fluid volume, decreases bp
What is released in response to high stretch?
ANP, because stretch indicates high blood volume
Explain autoregulation in the kidney
Juxtaglomerular apparatus: located in the region where distal convoluted tubule contacts the afferent arteriole. Signals from juxtaglomerular apparatus constrict or dilate afferent arterioles to keep filtration rate constant during variations in bp
Hyponatremia
low levels of sodium in the blood.
result: reduces osmolarity, less water absorbed by kidneys, bp drops
eating salty foods can
increase bp
Overview: Renin-Angiotensin-Aldosterone
System (RAAS)
RAAS aims to raise bp
1)renin triggers angiotensin I to II
-stimulates arteriole constriction
-stimulate ADH(water reabsorption)
-stimulate aldosterone increases Na+ aborption and thus H20
JGA
Juxtaglomerular apparatus
the site of blood pressure regulation via the renin- angiotensin-aldosterone system (RAAS) in the kidney
Where can we find the JGA and its formed by what conjunction of cells?
-located on side of glomerulus
-formed by macula densa (distal tubule), juxtaglomerular (JG) cells of the
afferent arteriole, and others extraglomerular mesangial cells
macula densa (distal tubule)
Low Na+, macula densa cells signal JG cells to make renin
Juxtaglomerular cells (JG)
specialized smooth muscle
cells in the wall of the afferent arteriole which synthesize
and secrete renin
RAAS
low blood volume or low Na+
kidneys secrete renin
renin stimulates the production
antiogensisn 1
AngiotensinI Angiotensin II causes
blood vessels to constrict
increased blood pressure
Angiotensin II stimulates the secretion of
aldosterone from the adrenal
cortex.
Aldosterone
increase the reabsorption of sodium and water in kidney
*increases the volume of fluid in the body
blood pressure is low, what is produced
Recall that renin, angiotensin, aldosterone, are all produced
ANP is inhibits
reabsorption of Na+ directly (on the nephron).
It inhibits the release of aldosterone
