[4] Histology of the Urinary System

Question 1

How does excess uric acid manifest in man?

Answer 1

Gout Stones

Question 2

Define: Nephrin

Answer 2

Proteins anchored in the podocyte cytoskeleton that permit passage of water, glucose, AAs, and metabolic products but exclude plasma proteins

Question 3

Development of the Visceral Layer of the Bowman’s Capsule

Answer 3

Invaginated Epithelium of the developing glomerulus

Question 4

Development of the Parietal Layer of the Bowman’s Capsule

Answer 4

Tubule lining cells of the primitive renal tubule

Question 5

Function: Proximal Convoluted Tubule

Answer 5

• Reabsorption of 85% of water and salt in the glomerular filtrate
• Absorbs glucose and AAs
• Excretes creatine

Question 6

[Proximal Convoluted Tubule]
Describe:

Epithelium
Nucleus
Cytoplasm

Answer 6

E: Cuboidal/Low Columnar
N: Spherical Nucleus
C: Eosinophilic Cytoplasm (Highly active mitochondria)

Question 7

Function: Loop of Henle

Answer 7

Thin limb of the loop pumps out Na and Cl ions out of the lumen

Reabsorbs 5% of the glomerular filtrate’s water

Question 8

Location: Vasa Recta

Answer 8

Medulla

Question 9

Differentiate: Thin Limb of the Loop of Henle vs. Vasa Recta

Answer 9

Presence of RBCs

Question 10

Function: Distal Convoluted Tubule

Answer 10

• Reabsorbs sodium
• Secretes potassium
• Absorbs about 8% of the water of the filtrate

Question 11

What controls the Distal Convoluted Tubule?

Answer 11

Aldosterone

Question 12

[Distal Convoluted Tubule]

Epithelium of the Ascending Thick Limb

Answer 12

Cuboidal

Question 13

[Distal Convoluted Tubule]

With or without brush border?
Microvilli?

Answer 13

Lacks a brush border

May have microvilli

Question 14

[Collecting Tubules and Ducts]

Two types of cells

Answer 14

Principal Cells

Intercalated Cells

Question 15

[Collecting Tubules and Ducts]

What controls it?

Answer 15

Antidiuretic Hormone

Aldosterone (partly)

Question 16

Characteristics that can distinguish Collecting Tubules from rest of the tubular elements

Answer 16

• Low cuboidal epithelium
• Clear cellular boundaries
• Homogenous but paler cytoplasm

Question 17

How does the collecting tubule become permeable to Urea?

Answer 17

Antidiuretic Hormone

Question 18

Importance of Urea

Answer 18

Adds to the hyperosmolarity of the interstitium of the pyramids, without which the countercurrent mechanism is nearly impossible

Question 19

What is the Macula Densa?

Answer 19

Specialized cell in the distal tubule

Dark-staining parts of the wall

Question 20

Function: Macula Densa

Answer 20

Osmoreceptor that detects the Cl content and regulates the filtration rate and blood pressure (Activates RAAS)

Question 21

Describe: Juxtaglomerular Cells

Answer 21

Modified smooth muscle cells in the media of the afferent arteriole

Question 22

Function: Juxtaglomerular Cells

Answer 22

Baroreceptor that detects pressure levels

Question 23

Function: Cerebroside

Answer 23

Special protein that coats the transitional epithelium to prevent urine from seeping through the epithelium

Question 24

Barriers in the Urinary Bladder

Answer 24

Juxtalumenal Tight Junction
Desmosomes
Thick Luminal Membrane

Question 25

How many ml of filtrate produced every minute?

Answer 25

125mL but only 1mL of urine is formed and the rest is reabsorbed