Structure and Function Flashcards
1
Q
What is the function of the kidney
A
- Regulation - control concentrations of key substances in extracellular fluid
- Excretion - excretes waste products
- Endocrine - synthesis or renin, erythropoietin, prostaglandins
- Metabolism - active form of vitamin D, catabolism of insulin, PTH, calcitonin
2
Q
Define osmolality and how it is measured in patients
A
- Osmolarity - number of osmoles of solute per litre
- Osmole - measure of solutions ability to create osmotic pressure and thus affect movement of water
- Proportional to the number of osmotic particles formed in solution
- To measure patients extracellular osmolality - take concentration of sodium and double it
- Normal osmolality - 280-310 mOsm/kg
3
Q
State the location of the kidney
A
- At T11/T12 and extend down to L2/L3
- Right kidney usually situated slightly lower than the left due to liver
4
Q
Explain the general structure of the kidney
A
- Outer layer of cortex and inner layer of medulla
- Organised into triangular sections called pyramid containing long lines (papillae) which act as collecting ducts
- Empty into calyx which enters renal pelvis and ureter
- Organised into triangular sections called pyramid containing long lines (papillae) which act as collecting ducts
5
Q
Explain the blood supply of the kidneys
A
- Renal artery comes from abdominal aorta
- Renal vein drains into inferior vena cava
6
Q
List the normal volume of each fluid compartment in adults
A
- 70kg man has ~42L of water
0 Intracellular fluid - 28L, extracellular fluid - 14L- Extracellular fluid contains 11L interstitial fluid and 3L intravascular plasma
7
Q
State the electrolyte compositions intracellular and extracellularly
A
- Sodium higher extracellular
- Potassium higher intracellular
- Chlorine higher extracellular
- Calcium higher extracellular
8
Q
What does Na/K pump transport
A
3 Na out and 2 K in
9
Q
Explain reabsorption and secretion in the kidney
A
- Reabsorption is when molecules leave the nephron lumen into the epithelial cells and capillaries
- Secretion is when molecules exit the epithelium and enter the lumen
- Paracellular reabsorption and secretion occurs through tight junctions
- Most absorption done transcellular
10
Q
Outline how glucose reuptake occurs
A
- Occurs in proximal tubule
- SGLT2 co-transports sodium and glucose on apical membrane
- Na/K pump drives sodium out on basolateral membrane
- GLUT2 transports allow glucose diffusion into the interstitial space
11
Q
Outline how amino acid reuptake occurs
A
- Occurs in proximal tubule
- Same process as glucose where sodium dependent cotransporter on apical membrane and amino acid transports on basolateral
12
Q
Outline how urea uptake occurs
A
- Occurs in proximal tubule
- Same process as glucose and amino acids
13
Q
Outline how vitamin reuptake occurs
A
- Receptor mediated endocytosis on apical membrane of proximal tubule
- Lysosome release vitamin into the tubular cells which diffuse into the blood
