Histology

Question 1

describe arterial blood flow through the kidney, starting with the renal artery and ending with the peritubular capillaries of the cortex and medulla

Answer 1

1. renal artery
2. interlobar arteries
3. arcuate arteries (along corticomedullary junction)
4. interlobular arteries
5. afferent arterioles, feed
6. capillary tufts in glomerulus
7. efferent arterioles, which give rise to
8. peritubular caillaries

Question 2

idifferentiate between the cortical labryinth and medullary rays and list the basic tubular components located within each region

Answer 2

labryinth: convoluted tubules (proximal and straight), arched cortical collecting ducts, renal corpuscles
rays: straight tubules (proximal and distal) and straight cortical collecting ducts

Question 3

describe the boundaries of kidney lobule

Answer 3

between two interlobular vessels with a medullary ray in the middle

Question 4

differentiate between the vascular and urinary poles in the renal corpuscle

Answer 4

vascular: afferent and efferent arterioles
urinary: proximal convoluted tubule

Question 5

differentiate between the parietal and visceral layers of the glomerular/Bowman’s capsule and identify the urinary space

Answer 5

parietal: outer endothelial layer/simple squamous
visceral: inner endothelial; podocytes
urinary space is between these two layers

Question 6

differentiate between the intraglomerular and extraglomerular mesangium

Answer 6

intraglomerular: flll unoccupied space inside glomerulus/tuft
extraglomerular: around the outside of the glomerulus that is not a podocyte; part of juxtaglomerular apparatus

Question 7

describe the glomerular filtration barrier (3)

Answer 7

1. fenestrated endothelium of the glomerular capillary tuft
2. fused basal laminae of the endothelial cells and podocytes (glomerular basement membrane)
3. filtration slits and slit diaphragms of podocytes (visceral epithelium)

Question 8

differentiate between the proximal and distal convoluted tubules and arched collecting ducts of the cortical labrynth

Answer 8

proximal is more acidophilic and has striations (active mitochondria) and a brush border;

distal is less acidophilic with fewer active mitochondria and no brush border with nuclei that float at apical surface;

collecting ducts: connect between the distal convoluted tubules of the labryinth and the cortical collecting ducts; located in cortical labryinth

Question 9

differentiate between the proximal and distal straight tubules and cortical collecting ducts of the medullary rays

Answer 9

proximal straight tubules: similar to proximal convoluted but more cuboidal

distal straight tubules: cuboidal epithelium without a brush border

cortical straight collecting ducts: pass down medullary rays through corticomedullary junction; low cuboidal epithelium (lower than proximal straight)

Question 10

differentiate between the macula densa of the distal tubule, the arterioles, and the extraglomerular mesangium of the juxtaglomerular apparatus

Answer 10

1. macula densa: within a region of the distal tubule that comes in close contact with the afferent arteriole and its JG cells; tubular epithelial cells are tall and narrow
2. extraglomerular mesangium: exterglomerular mesangial cells that provide support to the JG apparatus
3. juxtaglomerular cells: modified smooth muscle cells within the tunica media of the afferent arteriole

Question 11

differentiate between the outer and inner medulla

Answer 11

outer medulla is darker staining and inner medulla is lighter staining

Question 12

differentiate between the collecting ducts and distal straight tubules of the outer medulla

Answer 12

collecting ducts are the only tubules lined with a simple cuboidal epithelium in the inner medulla!

Question 13

differentiate between thin tubules and straight vessels based on presence or absence of RBCs in the lumen of the outer medulla

Question 14

differentiate between collecting ducts and papillary ducts of the inner medulla

Answer 14

become papillary ducts at level of medullary papilla; are medullary ducts up until then in outer and inner medulla

Question 15

differentiate between the renal pelvis and the ureter

Question 16

identify equine mucus-secreting mucosal glands at the renal pelvis and proximal ureter (urothelium) and recognize this normal species difference

Answer 16

tubuloalveolar that sometimes appear to have branching adenomeres; open directly into the ureter lumen without a need for a duct

Question 17

identify transitional epithelium of lamina epithelialis and smooth muscle of the tunica muscularis of the ureters

Answer 17

lamina eptihelialis is a transitional epithelium

tunica muscularis is smooth muscle

Question 18

identify transitional epithelium of lamina epithelialis and smooth muscle of tunica muscularis in the bladder

Answer 18

lamina epithelialis is transitional epithelium;

tunica muscularis is thick and well developed, called the detrusor muscle

Question 19

know what the detrusor muscle is and understand the basic innervation of micturition

Answer 19

the thick tunica muscularis of the urinary bladder; smooth muscle innervated by the hypogastric nerve (beta sympathetic) for filling and pelvic nerve (parasympathetic) for emptying

Question 20

list all the tubules and ducts of the kidneys and give location within the kidney (9)

Answer 20

1. proximal convoluted tubules: cortical labryinth
2. proximal straight tubules/descending thick limb: medullary rays to outer stripe of outer medulla
3. thin limbs (desc and asc): inner medulla
4. distal straight tubules: junction between inner and outer medulla, head back to vascular pole of corpuscle in cortical labryinth to vascular pole to form macula dense of JGA
5. distal convoluted tubules: cortical labyrinth
   1-5 as part of the nephron
6. cortical arched collecting tubules/ducts: cortical labryinth
7. cortical straight collecting ducts medullary ray
8. medullary collecting ducts: continuation of cortical straight once reach corticomedullary junction, descend through outer and inner medulla, at medullary papilla converge to form papillary ducts
9. papillary ducts: empty urinary filtrate into renal pelvis