Histology of the Renal/Urinary Excretory System

Question 1

Artery that arises from the abdominal aorta at a right angle, immediately inferior to the SMA, dividing into 5 segmental arteries into the kidney

Answer 1

Renal artery

Question 2

5 arteries that branch from the renal artery and feed into the interlobar arteries of the kidney

Answer 2

Segmental arteries

Question 3

Arteries the feed from the segmental arteroes onto the renal pyramids to the border of the renal cortex and medulla

Answer 3

Interlobar arteries

Question 4

The arteries that feed from the interlobular arteries to pass along the cortical-medullary border, parralel to the lateral convex border of the kidney, further dividing into the interlobular arteries; also give branches to the vasa recta or straight capillaries of the medullary kidney

Answer 4

Arcuate arteries

Question 5

Arteries the run into the cortex from the arcuate arteries to form the afferent artery of the glomeruli

Answer 5

Interlobular arteries

Question 6

Artery that SUPPLY the glomerulus

Answer 6

Afferent artery

Question 7

Blood leaves the glomerulus through this artery, which forms with the vasa recta of the medullary microcirculation

Answer 7

Efferent artery

Question 8

This capillary makes up the medullary microcirculation, forming directly from the arcuate arteries and from the efferent arteries from the cortex, runs parallel to the tubules of the medulla from the cortex-medulla border to the papilla and back; results in a countercurrent vascular architecture, which enables the high osmotic gradient in the medulla

Answer 8

Vas rectus (pl. vasa recta)

Question 9

Vein that drains the vasa recta into the arcuate veins

Answer 9

Vena rectus (pl. venae recta)

Question 10

Drains the venae recta into the interlobular vein

Answer 10

Arcuate vein

Question 11

Drains the arcuate vein into the renal vein

Answer 11

Interlobular vein

Question 12

Function unit of the kidney

Answer 12

Nephron

Question 13

5 subsections of the nephron

Answer 13

1. Renal corpuscle (glomerulus)
2. Proximal tubule (PT)
   - Proximal convoluted tubule (PCT) or pars convoluta
   - Proximal straight tubule (PST) or pars recta
3. Loop of Henle (LH)
   - Descending thin limb (DTL)
   - Ascending thin limb (ATL)
   - Thick ascending limb (TAL)
4. Distal tubule (DT)
   - Thick ascending limb (TAL)
   - Macula densa
   - Distal convoluted tubule (DCT)
5. Collecting duct (CD)

Question 14

Cup-like sack at the beginning of the tubular component of a nephron in the kidney that performs the first step in the filtration of blood to form urine, enclosing a glomerulus

Answer 14

Bowman capsule (or glomerular capsule, or capsula glomeruli)

Question 15

Type of cell that lines the PARIETAL layer of the Bowman capsule - does NOT function in filtration

Answer 15

Simple squamous epithelial cell

Question 16

Type of cell that lines the VISCERAL layer of the Bowman capsule with its foot-like appendages called PEDICELS, just above the glomerular basement membrane and the underlying fenestrated glomerular capillaries (with filtration slits)

Answer 16

Podocytes

Question 17

Tissue that consists of matrix and cells that can be intraglomerular or extraglomerular; insert with microfilaments to the glomerular basement membrane

Answer 17

Mesangium (mesangial cells)

Question 18

Specialized, granular smooth muscle cells that synthesize, store, and secrete the enzyme RENIN in response to pressure drops detected by stretch receptors in the nearby vascular walls or when stimulated by macula densa cells; located near the glomerulus

Answer 18

Juxtaglomerular cells (or JG cells, or granular cells)

Question 19

Closely-packed cells lining the wall of thick ascending limb of the LH to the DCT (mainly DCT); sensitive to NaCl concentration changes where:

A decrease in NaCl concentration initiates:

• decrease in resistance to blood flow in the afferent arterioles (increases glomerular hydrostatic pressure and helps GFR return to normal)
• increases renin release from hte JG cells of the afferent and efferent arterioles for rening storage

An increase in NaCl concentration initiates:

• afferent arteriole vasoconstriction
• reduced paracrine strimulation of JG cells

Answer 19

Macula densa cells

Question 20

Renal tubule with the following characteristic:

• lining of simple cuboidal epithelium with WIDE BRUSH BORDER
• strong basolateral folds
• rich mitochondria (for Na-L-ATPase activity)

Answer 20

Proximal tubule

• PCT first segment to get primary urine from the glomerulus
• PST leads the urine to the first part (DTL) of the loop of Henle

Question 21

Mesangial cells that are specialized pericytes or contractile cells that control/enable high glomerular filtration pressures (35-50mmHg) by maintaining contractility; also known to secrete erythropoietin and some renin

Answer 21

Lacis cells, or:

• Polkissen cells
• extraglomerular mesangial cells
• Goormaghtigh cells

Question 22

Mesangial cells that are specialized smooth muscle myocytes or monocytes reponsible for extra structural support, filtration, and phagocytosis; they are also known to monitor glucose levels via processes sent into the capillary lumen

Answer 22

Intraglomerular mesangial cells

Question 23

Renal tubule with the following characteristic:

• divided into 3 segments - DTL, ATL, TAL
• DTL and ATL lined by a single layer of squamous epithelium, highly permeable to water and ions via solvent drag through weakly tight junctions (zonula occludens)
• TAL lined by low cuboidal cells without brush border (impenetrable by water)

Answer 23

Loop of Henle

Question 24

Renal tubule with the following characteristic:

• divided into 3 segments - TAL, macula densa, DCT
• lined by low cuboidal cells without brush border

Answer 24

Distal tubule

Question 25

Renal tubule with the following characteristic:

• lined with simple cuboidal epithelium with 2 types of cells (principal cells and intercalated cells)
• without brush border

Answer 25

Collecting ducts

Question 26

Cells of the collecting duct that are scattered in the CD epithelium and participate in acid-base homeostasis specifically via PROTON SECRETION

Answer 26

Type A intercalated cells

Note: defect in type A intercalated cells leads to distal renal tubular acidosis

Question 27

Cells of the collecting duct that are scattered in the CD epithelium and participate in acid-base homeostasis specifically via BICARBONATE SECRETION

Answer 27

Type B intercalated cells

Question 28

The MAJORITY of cells of the collecting duct which regulate Na and K concentrations under control of aldosterone and ADH

Answer 28

Principal cells

Question 29

Muscular layers of the urinary bladder (tunica muscularis)

Answer 29

DETRUSOR MUSCLE

• Spiral/oblique
• Inner longitudinal
• Outer circular

(as opposed to the GIT:

• Inner circular
• Outer longitudinal)

(Note: stomach

• Inner oblique
• Middle circular
• Outer longitudinal

Question 30

Adrenal gland region and secretion

Answer 30

• zona GLOMERULOSA: ALDOSTERONE
• zona FASCICULATA: CORTISOL > testoserone
• zona RETICULARIS: TESTOSTERONE > cortisol
• adrenal MEDULLA: NOREPINEPHRINE & EPINEPHRINE

Question 31

Lining epithelium of the prostatic urethra

Answer 31

Uroepithelium (or urothelium, or transitional epithelium)

Question 32

Lining epithelium of the membranous urethra

Answer 32

Stratified OR pseudostratified columnar epithelium

Question 33

Lining epithelium of the spongy urethra

Answer 33

Stratified OR pseudostratified columnar epithelium (EXCEPT AT THE FOSSA NAVICULARIS)

Question 34

Lining epithelium at the fossa navicularis

Answer 34

Stratified squamous non-keratinized epithelium