Urinary histo

Question 1

Proximal Tubule job (3)

Answer 1

1. ~65% of water and NaCl reabsorbed from tubule
2. Glucose and amino acids reabsorbed
3. Protein absorption

Question 2

Thin segment

Answer 2

1. Abrupt transition to simple squamous epithelium
2. Simple squamous epithelium
3. No brush border
4. Surrounded by capillaries: vasa recta

Question 3

Distal straight tubules

Answer 3

1. Less eosinophilic and larger lumen than proximal tubule
2. ‘cleaner’ apical and lateral borders
3. More nuclei around circumference of tubules
4. Basal membrane folds & mitochondria

Question 4

Distal convoluted tubules

Answer 4

1. Begin at vascular pole of renal corpuscle
2. Appear similar to distal straight tubules
3. Respond to ADH
   
   • Increases tubule permeability to water
   • Helps form concentrated urine
4. Aldosterone: salvages remaining sodium

Question 5

Collecting tubules/ducts

Answer 5

1. Arched and straight portions
2. The terminal portions (papillary ducts) open at area cribrosa into minor calyces
3. Light staining
4. Two cell types
   
   • Light (CD) cells: most numerous & is affected with ADH to increase H2O uptake
   • Dark (IC) cells

Question 6

Collecting tubule functions

Answer 6

1. Water resorption; under influence of ADH
   
   • aquaporin channels
2. Acid-base balance

Question 7

JG apparatus (3)

Answer 7

1. Juxtaglomerular cells
2. Macula densa
3. Extraglomerular mesangial cells

Question 8

JG apparatus function

Answer 8

Function: maintenance of normal blood pressure

Question 9

JG apparatus mechanism of function

Answer 9

Mechanism(s)

• JG cells respond to degree of stretch innervation
• SNS innervation
• Macula densa cells monitor Na+ concentration in the distal tubule
• Low plasma Na stimulates renin release

Question 10

Macula densa

Answer 10

Area where the distal tubule comes really close to the glomerulus- afferent arteriole
- Specialized cells- Golgi on basal side instead of apical side

Question 11

What releases renin?

Answer 11

JG apparatus

Question 12

Angiotensin II

Mechanism & Function

Answer 12

1. Constricts arterioles: blood pressure increases
2. Stimulates zona glomerulosa of adrenal cortex to release aldosterone
3. Aldosterone acts on distal tubules of kidney to increase sodium and water reabsorption: blood pressure increases

Question 13

Mesangial cells

Answer 13

Similar to pericytes
Functions:
  - Cleaning GBM
  - GBM turnover
  - Support

Question 14

Podocytes

Answer 14

1. Visceral layer of Bowman’s capsule
2. have primary and secondary processes
3. Slit pores

Question 15

Blood vessels supplying the lobe

Answer 15

1. Glomerular capillaries
2. Peritubular capillary networks
3. Vasa recta
4. Larger supplying and draining vessels

Question 16

Arteries (1st-glomerulus)

Answer 16

1. Renal artery
2. Interlobar artery
   - Interlobular artery
   
   • Arcuate arteries
3. Afferent arterioles
4. Efferent arterioles
   
   • give rise to the vasa recta

Question 17

Cortical vasculature

Answer 17

Peritubular capillary network

Question 18

Nerve supply to kidney

Answer 18

1. Sympathetic division of autonomic nervous system (extrinsic supply):
   
   • Contraction of vascular smooth muscle
   • Afferent arteriole contraction reduces filtration rate (and urine production)
   • Efferent arteriole contraction increases filtration rate (and urine production)
2. Loss leads to increased urinary output
3. Extrinsic nerve supply not essential

Question 19

Female urethra composition

Answer 19

Female

1. Mucosa
   - Transitional epithelium near bladder; stratified squamous thereafter
   - Lamina propria
2. Muscular wall (mostly smooth)

Question 20

Male urethra composition

Answer 20

1. Mucosa
   - Prostatic: transitional epithelium
   
   • Membranous: stratified columnar
   • Cavernous: stratified or pseudostratified and becoming stratified squamous at end

Question 21

Urinary bladder composition

Answer 21

1. Mucosa
2. Submucosa ??
3. Muscular coat (smooth)
4. Adventitia