Kidney 3 - Tubular Function

Question 1

What is the glomerular filtration rate?

Answer 1

the rate at which blood is filtered through the glomerulus into the bowman’s capsule

Question 2

How do kidneys regulate blood pressure?

Answer 2

When BP is low, the Na+ filtrate concentration is also low which is detected by macula densa cells, results in RENIN secretion activating renin-angiotensin system causing vasoconstriction -> increased BP

When BP is high, results in increased glomerular hydrostatic pressure -> greater filtration rate & Na+ conc, detected and results in constriction of afferent arteriole bringing kidney function back to norm. Atrial natriuretic peptide then reduces BP

Question 3

How is blood volume restored (when BP is low)

Answer 3

Renin angiotensin-aldosterone system (RAAS)

Angiotensin II results in constriction of arterioles, release of ADH and aldosterone increasing reabsorption of water in kidneys restoring blood volume to norm

Question 4

How does atrial natriuretic peptide counteract RAAS?

Answer 4

ANP reduces BP by reducing extracellular fluid

Question 5

What are the consequences of chronic kidney disease?

Answer 5

• Inadequate removal of fluid and waste products of metabolism
• Inappropriate activation of RAAS, can result in high/low BP leading to cardiovascular disease