Lecture 22: Renal histology

Question 1

Cortical nephrons

Answer 1

Glomeruli empty into peritubular capillary networks

Short loops of Henle-do not extend deep into medulla

Question 2

Juxtamedullary nephrons

Answer 2

Glomeruli empty into vasa recta

Long loops of Henle extend deep into medulla

Question 3

Sequence of branches of the renal artery

Answer 3

Interlobar arteries
Arcuate arteries
Interlobular arteries
Afferent arterioles
Gomeruli
Efferent arterioles
Vasa recta or peritubular capillaries
Interlobular veins
Arcuate veins
Interlobar veins
Renal vein

Question 4

Glomerulus is a

Answer 4

Capillary bed inserted between two arterioles

Afferent and efferent arterioles

Question 5

Efferent arteriole of glomerulus feeds into either

Answer 5

A capillary loop- the vasa recta

A capillary network- the peritubular capillaries

Question 6

Renal corpuscle glomerulus includes

Answer 6

Afferent arteriole w/juxtaglomerular cells (secrete renin)

Efferent arteriole

Question 7

Renal corpuscle Bowmans capsule structure

Answer 7

Parietal layer- outer layer- simple squamous continuous with epithelium of proximal convoluted tubule
Visceral layer- inner layer of podocytes in contact with endothelium of glomerular capillaries

Question 8

Bowmans space

Answer 8

Located between parietal and visceral layers and is continuous with the lumen of the proximal convoluted tubule

Question 9

Renal corpuscle is involved in

Answer 9

Producing a filtrate of blood

Question 10

Intraglomerular mesangial cells

Answer 10

Located between nearby capillaries in the glomerulus and cover endothelium not covered by podocytes

Question 11

Extraglomerular mesangial cells

Answer 11

Located between the afferent and efferent arterioles at the vascular pole and are associated with the juxtaglomerular apparatus

Question 12

Mesangium characteristics

Answer 12

Contractile- utilize cytoskeletal contractile proteins to modify blood flow through glomerular capillaries
Phagocytic- take up worn out glomerular basal lamina for recycling and phagocytize immunoglobulins
Proliferative

Question 13

Mesangium functions

Answer 13

Synthesize matrix and collagen
Secrete prostaglandins and endothelins
Respond to angiotensin II
Provide mechanical support and regulate blood flow

Question 14

Macula dens

Answer 14

Found at the thick ascending limb-distal convoluted tubule junction
Cells of macula densa are in contact with extraglomerular mesangial cells
Signals renin release from juxtaglomerular cells
Involved in fluid-electrolyte balance and BP regulation

Question 15

Juxtaglomerular apparatus components

Answer 15

Macula dnesa
Extraglomerular mesangial cells
Juxtaglomerular cells

Question 16

Juxtaglomerular cells

Answer 16

Associated with macula densa and afferent arteriole
Secrete renin into blood when stimulated by macula densa
Innervated by sympathetic nerve endings which cause increased renin release

Question 17

Components or renal tubule, in order

Answer 17

Proximal convoluted tubule (First part)
Descending limb of Henle (w/thick and thin portions)
Loop of Henle
Ascending limb of Henle (w/thick and thin portions)
Distal convoluted tubule (continuous w/collecting duct)

Question 18

Renal filtration barrier components

Answer 18

Fenestrated endothelium of capillaries
Basal lamina
Filtration slits created by adjacent pedicels of podocytes

Question 19

Selectivity of renal filtration barrier

Answer 19

Water, glucose and most ions pass through
Proteins are typically excluded
Molecules with a large negative charge are excluded

Question 20

Characteristics of proximal convoluted tube

Answer 20

Simple cuboidal epithelium
Apical tight junctions and brush border
Basolateral infoldings
Basal striations w/abundant mitochrondira
Eosinophilic cytoplasm
Large, pale staining nuclei

Question 21

Functions of proximal convoluted tubule

Answer 21

Reabsorb most of filtrate, including water
Remove essentially all glucose and amino acids from filtrate
Reabsorb most sodium and chloride ions
Contains transporters, cotransporters, channels, exchangers

Question 22

Thick segment of loop of Henle epithelium

Answer 22

Simple low cuboidal

Question 23

Thin segment of loop of Henle epithelium

Answer 23

Simple squamous

Question 24

Ascending limb of Henle is _____ to water

Answer 24

Ascending limb is IMPERMEABLE to water

Question 25

Function of loop of Henle

Answer 25

Descending thin limb is permeable to water, Na+, Cl-
Ascending thin limb is impermeable to water and actively pumps Cl- out, allowing Na+ to follow
Major function is to establish counter-current exchange system which creates osmotic forces necessary to pull water out of distal convoluted tubule and collecting duct in presence of ADH

Question 26

Distal convoluted tubule characteristics

Answer 26

Smaller cells than proximal convoluted tubule
Larger lumen than PCT and no brush border
Cytoplasm is less eosinophilic than the PCT
Impermeable to water except in presence of ADH

Question 27

Principal cells

Answer 27

Found in collecting duct

Reabsorb sodium ions and water and secrete potassium via ATPase pump

Question 28

Intercalated cells

Answer 28

Found in collecting duct

Secrete either hydrogen ion or bicarbonate ion

Question 29

Prostatic urethra

Answer 29

Passes through prostate
Transitional epithelium
Highly vascularized with veins and abundant elastic tissue

Question 30

Membranous urethra

Answer 30

Pseudostratified columnar

Forms external sphincter of bladder

Question 31

Cavernous urethra

Answer 31

Pseudostratified epithelium w/patches of stratified squamous