Kidney - structure and function

Question 1

What is the functional unit of the kidney

Answer 1

Nephron

Question 2

What are the 2 main parts of the nephron

Answer 2

Renal corpuscle (glomerulus and Bowman's capsule)
Renal tubules (prox convoluted tubule, loop of Henle, distal convol. tubule)

Question 3

What is inflammation of the glomerulus called

Answer 3

Glomerulonephritis

Question 4

Glomerular Filtration Barrier

Answer 4

Filtration slits are formed b/w podocyte pedicles and fenestrated endothelial cells with shared basal lamina

Question 5

Glomerular Filtration Barrier selectively filters based on (3)

Answer 5

Size
Electrical Charge (cations are permeable)
Capillary Pressure

Question 6

What are Podocytes

Answer 6

visceral epithelial cells that participate in glomerular filtration

Question 7

The amount of connective tissue in the interstitium increases with

Answer 7

Age and Ischemic damage

Question 8

Funcional nephrons of the kidney can be replaced by ______; this is often increased with inflammation

Answer 8

scar tissue

Question 9

What is the main blood supply to the kidney

Answer 9

renal artery

Question 10

What is the vasculature of the kidney

Answer 10

Renal Atrery –> Interlobar Artery –> Arcuate Artery –> Interlobular Artery –> Aff. Glomerular Arterioles –> Glomerular Capillaries –> Eff. Glomerular Arterioles –> Peritubular Capillary Network

Question 11

Interlobular Arteries - What is there lumen diameter

Answer 11

Small lumen diameter

Question 12

What are Interlobular Arteries susceptible to and why

Answer 12

Susceptible to Infarction

B/c terminal end arteries that do not contain anastomoses

Question 13

Interlobular Arteries branch from ______ and extend to _____

Answer 13

branch from arcuate arteries

extend to cortex of kidney

Question 14

Describe the appearance of a renal infarction (5)

Answer 14

Wedge-shaped
Well demarcated
Dark red or white
Acutely swollen
Chronic contraction (fibrosis)

Question 15

Five basic functions of the kidney

Answer 15

1. Formation of urine to eliminate metabolic waste
2. Acid-base regulation thru reclamation of bicarbonate from the glomerular filtrate
3. Conservation of water (up to 99% of water in glomerular filtrate)
4. Maintenance of normal extracellular potassium ion concentration
5. Control of endocrine function

Question 16

How is maintenance of normal extracell. Potassium ion conc. achieved

Answer 16

1. passive reabsorption in proximal tubules

2. active secretion in the distal tubules under influence of aldosterone (K+ excretion)

Question 17

What leads to Sodium retention

Answer 17

Renin-angiotensin-aldosterone system regulates blood pressure and fluid balance

Question 18

Basic functions of the glomerulus of the kidney (4)

Answer 18

• *1. Plasma filtration**
• *2. Regulation of blood pressure (renin-angiotension-aldosterone)**
  3. Regulation of tubular metabolism
  4. Removal of macromolecules from circulation

Question 19

Function of the Proximal Tubules

Answer 19

1. Reabsorption of:

Na+, Cl-, K+, Alb, Glc, Water, Bicarb

Question 20

Function of the Loop of Henle

Answer 20

1. Countercurrent mechanism and Na+/K+-ATPase pumps absorb even more Na+ and Cl- ions from filtrate
2. Produces a hypotonic filtrate that flows into the distal tubule

Question 21

Function of the Distal Tubules

Answer 21

1. Solute concentration gradient promotes water reabsorption (hypotonic filtrate)
2. Aldosterone influences increase Na+ and water reabsorption and K+ excretion

Question 22

Function of the Collecting Ducts

Answer 22

1. Urea gradient promotes water reabsorption

2. Water and Na- reabsorption by Na-/K+-ATPase pumps, also under the influence of ADH

Question 23

Very basic functions of the interstitium of the kidney (3)

Answer 23

1. Provides structural support
2. Produce Erythropoietin (EPO)
3. Interstitial cells/fibroblasts responsible for production of Prostaglandins and immune mediators