Final Essay

Question 1

Angiotensin system

Answer 1

• BP falls -> liver secrete angiotensin into blood
• negative feed back loop to bring BP up
• sensed by stretched receptor by the afferent arterial (in the kidney) on the way to glumerulus
• trigger kidney to release enzyme called renin
• Renin goes into blood and cleaves angiotensin into angiotensin I
• Angiotensin 1 travels in the blood to the lungs
• in the lungs theres different enzyme angiotensin converting enzyme ACE that cleaves angiotensin 1 to 2
• Angiotensin 2 is active
• Simultaneously Angiotensin 2 cause:
  
  • go to hypothalamus to make us feel thirsty
  • cause vasoconstriction
  • go to adrenal cortex to release aldosterone
• aldosterone goes to kidney and tell kidney reabsorb Na+ and H2O and excrete K+ into urine
• Blood pressure goes up

Question 2

Briefly describe reabsorption of salt and water

Answer 2

• 65% of H2O and salt are reabsorbed
• PCT: Na+ Gradient Active transport out of filtrate, CL- follows charge gradient passivel, H2O follows by osmosis
• 20 % Reabsorbed at the descending loop of Henle
• Last 15% are reabsorbed variably depending on need of body by aldosterone at DCT and ADH acting at collecting duct