Week 6: Kidney Histo

Question 1

What are the largest collecting ducts in the kidney called?

Answer 1

Papillary ducts

Question 2

Minor calyx epithelium type

Answer 2

Transitional

Question 3

Where is transitional epithelium found?

Answer 3

Unique to urinary system. Found in minor and major calyx, ureter, bladder, (+prostatic urethra in males)

Question 4

What are the “basketball-like) structures in the lobules?

Answer 4

Renal corpuscles

Question 5

Where in the kidney are arcuate vessels found?

Answer 5

Between the cortex and medulla

Question 6

What are the components of a nephron?

Answer 6

Renal corpuscle/glomerulus + proximal convoluted tubule + Loop of Henle + distal convoluted tubule

Question 7

What structures make up medullary rays?

Answer 7

Ascending and descending Loops of Henle + collecting tubule

Question 8

What is the vasa recta?

Answer 8

A loop of capillaries that lies parallel to the Loop of Henle

Question 9

What makes up the glomerulus?

Answer 9

Entirely arterial vascular apparatus with afferent and efferent arterioles

Question 10

What are podocytes?

Answer 10

Cells that make up the visceral layer of Bowman’s capsule. They have primary and secondary processes that interdigitate to form slit pores.

Question 11

What composes the glomerular basement membrane?

Answer 11

Fusion of secondary processes of podocyte with endothelial cells.

Question 12

How can the macula densa be recognized?

Answer 12

Closely packed cells in distal tubule with Golgi apparatuses are on the opposite side of the cell, away from the lumen.

Question 13

What does the macula densa do?

Answer 13

Senses NaCl concentration. When low -> release of renin by juxtaglomerular cells + vasodilation of afferent glomerular arterioles which increases GFR

Question 14

What regulates the flow of particles across the GBM?

Answer 14

Size of capillary pore + heparan sulfate’s highly negative charge.

Question 15

Which collagen type makes up the lamina densa of the GBM?

Answer 15

4

Question 16

Mesangial cell function

Answer 16

GBM constantly getting plugged up. Mesangial cells clean out and turn over the GBM (and support it)

Question 17

What makes up the bulk of the cortex?

Answer 17

Proximal tubules

Question 18

How can proximal tubules be identified histologically?

Answer 18

Fuzzy/brush luminal border. Most eosinophilic tubule type, interdigitation via lateral membrane folding, mitochondria in cytoplasmic folds -> striated appearance

Question 19

What is the role of apical canaliculi? Where are they?

Answer 19

Proximal tubules. Resorption of proteins from the initial filtrate.

Question 20

Proximal convoluted tubule and thick segment of descending limb epithelium type

Answer 20

Cuboidal

Question 21

Thin segment (distal portion of desc LoH) epithelium type

Answer 21

Simple squamous

Question 22

Vasa recta descending and ascending component names

Answer 22

Arterioli recti and veni recti respectively

Question 23

Distal straight tubule epithelium type

Answer 23

Simple cuboidal

Question 24

How are distal straight tubules recognizable histologically?

Answer 24

Less eosinophilic and larger lumen than prox tub. Cleaner apical and lateral borders. More nuclei around circ of tubules. Basal memb folds & mitochondria.

Question 25

Which component of the kidney is sensitive to ADH?

Answer 25

Distal convoluted tubules

Question 26

Collecting tubule epithelium type

Answer 26

Cuboidal to low columnar

Question 27

What are the two cell types for collecting tubules, and what do they do?

Answer 27

Light (CD): respond to ADH. Dark (IC/intercalated): adjust pH (alpha -> H+ prod and release to urine, beta -> bicarbonate)

Question 28

Where are juxtaglomerular cells found?

Answer 28

Wall of afferent (and occasionally efferent) arterioles at vascular pole

Question 29

Juxtaglomerular cell function

Answer 29

Release renin, maintenance of normal blood pressure

Question 30

Angiotensin II activity

Answer 30

Constriction of arterioles and stimulates release of aldosterone from adrenal cortex

Question 31

What does aldosterone do? Where is its site of action?

Answer 31

Acts on distal tubules to increase Na and water reabsorption -> inc BP

Question 32

Inferior capillary network via vasa recta - what do the midcortical and supra regions have?

Answer 32

Much shorter loops that for the peritubular network

Question 33

Nerve supply of kidney

Answer 33

Sympathetic -> contraction of vasc smooth muscle.

Question 34

Result of sympathetic activity in kidney

Answer 34

Contraction. In afferent arteriole -> dec filtration rate. Opposite in efferent.

Question 35

Effect of loss of kidney nerve supply

Answer 35

Increased urinary output. Innervation is not functionally necessary.

Question 36

What layers make up the ureter?

Answer 36

Mucosa (submucosa indistinguishable) - muscular coat - adventitia.

Question 37

Ureter epithelium

Answer 37

transitional

Question 38

Stellate cross-section suggestive of…

Answer 38

Ureter cross section

Question 39

Smooth muscular pattern in ureter

Answer 39

inner longitudinal, outer circular

Question 40

Layers of urinary bladder and how they compare to the ureter

Answer 40

Same layers but has 3 muscular layers that go spiral - longitudinal - circular.