BCMB 230 Lecture Notes - Lecture 22: Distal Convoluted Tubule, Juxtaglomerular Apparatus, Posterior Pituitary
16 Dec 2016
School
Course
Professor
OVERALL PHYSIOLOGY
1. Blood Pressure
a. Increasing contractility increases BP.
b. Flo euatio does’t hae lood olue e assue it’s ostat.
i. Blood volume can change:
ii. dehydration
iii. A cut vessel
iv. We a’t easue lood olue- so we have to look at the factors
indicating lower blood volume.
1. Low NaCl, Low pressure
2. Juxtaglomerular apparatus of kidney detects pressure
3. Renin→ Angiotensinogen is coverted to Angiotensin I then to
Angiotensin II via ACE. Angiotensin II acts on the adrenal cortex to
release aldosterone which causes sodium reabsorption→ Water is
reabsorbed. Water is not increased, but we ARE stopping loss
v. Angiotensin II stimulates the hypothalamus → posterior pituitary→
ADH/vasopressin release→ distal convoluted tubule and collecting
tubules of the kidney are more permeable to water (More aquaporins).
vi. Vasopressin refers to the vasoconstrictor aspect
c. Aldosterone
i. Turns on a 1:1 Na+/K+ ATPase in distal convoluted tubule
ii. Acts to aid in sodium reabsorption
iii. Secretion of K+
iv. Low Na, High K+= more aldosterone
v. H+ also regulated by secretion
vi. Calcium and Na regulated by reabsorption
vii. Low Na+ and Low K+= Conflicting signals need aldosterone;
noaldosterone?
viii. Which is more important?
ix. Which is more subject to loss by the kidney?
1. Sodium is because it is extracellular
2. So we will secrete aldosterone.
x. This helps with low BP. What about high?
1. Evolutionarily low BP was the problem. High BP is recent. Caused
mainly by stress and diet.
2. We do have Atrial Natriuretic Factor/hormone/peptide to act on
the kidney. Decreases Na+ absorption. Release caused by stress.
Not a very strong response. Exists in the heart
xi. Low BP tells the hypothalamus to make you thirsty to bring up pressure
via drinking.
xii. Animals bleeding out near water, because they are thirsty.
xiii. Problems with BP may come from: Kidney, endocrine, heart. The point is
we must consider multiple factors.
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Angiotensin ii acts on the adrenal cortex to release aldosterone which causes sodium reabsorption water is reabsorbed. Water is not increased, but we are stopping loss: angiotensin ii stimulates the hypothalamus posterior pituitary . Which is more subject to loss by the kidney: sodium is because it is extracellular, so we will secrete aldosterone, this helps with low bp. What about high: evolutionarily low bp was the problem. Caused mainly by stress and diet: we do have atrial natriuretic factor/hormone/peptide to act on the kidney. Low bp tells the hypothalamus to make you thirsty to bring up pressure via drinking. xii. Animals bleeding out near water, because they are thirsty. xiii. Problems with bp may come from: kidney, endocrine, heart. Bicarbonate may be lost in urine: chronic diarrhea= more hydrogen ions, h+ may be lost in co2, urine, vomit, hyperventilation- breathing fast to get rid of more co2, ph involves digestive, respiratory, and urinary system.
