W26 Renal Biology (MH)

Question 1

What are the functions of the kidneys? (7)

Answer 1

Regulate blood volume and electrolytes
Removal of urea from bloodstream
Conserving nutrients
Regulate acid-base balance
Regulate BP
Calcium homeostasis
Production of erythropoietin and renin

Question 2

What are examples of Kidney damage/disorders? (5)

Answer 2

AKI
CKD
Polycystic Kidneys
Kidney infection
Kidney stones

Question 3

Anatomy of the kidneys:

Answer 3

1% body mass
1/4 cardiac output
1200ml of blood passes through glomeruli each minute
650mls is plasma
120-125 ml is forced into the renal tubules
* Filtrate- Everything plasma contains except proteins
* Urine- Remnants of filtrate percolated into the collecting ducts (therefore loss of water, nutrients, and some ions)

Question 4

What is the pathway of urine?

Answer 4

Glomerulus, Bowman’s capsule, Proximal CT, Loop of Henle, Distal CT, Collecting tubule, Collecting ducts, Calyces, Renal pelvis, Ureter, Urinary bladder, Urethra

Question 5

What are the 3 major renal processes?

Answer 5

1. Filtration
2. Tubular Reabsorption (passive and active process returning material to the blood from filtrate)
3. Tubular secretion (removing material from the blood into the filtrate)

Question 6

Juxtaglomerular complex (JGC) of a nephron:

Answer 6

• Macula Densa Cells- chemoreceptors that measure NaCl of filtrate going into DCT
• (JG) Granular Cells: Mechanoreceptors detect BP, secrete renin accordingly
• Mesangial Cells- contraction, actin

Question 7

What is GFR?
Normal range?
It is directly proportional to..?
GFR affects systemic BP

Answer 7

• Volume of filtrate formed per minute by both kidneys (normal =120-125 ml/min)
• Net filtration pressure (NFP)
• Total SA available for filtration
• Filtration membrane permeability

Constant GFR is important- allows kidneys to make filtrate and maintain extracellular homeostasis

Myogenic mechanism and Tubuloglomerular feedback mechanism