Anatomy and Histology of the Kidney

Question 1

organization of the kidney

Answer 1

surrounded by a dense, fibrous CT capsule

distinct cortex and medulla

blood vessels, nerves, and lymphatics enter and leave at the hilus

blood vessels, nerves, and lymphatics enter and leave at the hilus

urine leaves via the ureter

Question 2

capsule

Answer 2

connective tissue covering kidney surface

Question 3

hilus

Answer 3

entry point for renal blood vessels, nerves, lymphatics, and ureter

Question 4

pelvis, major and minor calyces

Answer 4

collection area for urine

Question 5

components of the cortex

Answer 5

outer region containing:

cortical labrynth including glomeruli and convoluted tubules

straight tubules called medullary rays (not part of medula)

the renal columns are cortical regions that extend between the pyramides of the medulla

Question 6

medulla

Answer 6

inner region organized into pyramids containing straight tubules, collecting ducts, and capillaries

Question 7

lobe

Answer 7

medullary pyramid + asspcoated cprtex

Question 8

Describe the system of arteries supplying the kidneys.

Answer 8

renal artery

interlobar artery

arcuate artery

afferent arteriole

glomerular capillaries

efferent arteriole

peritubular capillaries or vasa recta

Question 9

What does the renal artery divide into?

Answer 9

interlobar arteries - separates the kidney into lobes

Question 10

arcuate artery

Answer 10

enters a lobe at the cortico-medullary border

Question 11

interlobular arteries

Answer 11

arteries that ascend within the centers of the cortical labyrinths

Question 12

afferent arterioles

Answer 12

branch off from the interlobular arteries, giving rise to glomerular capillaries

Question 13

efferent arterioles

Answer 13

vessels that exit the glomeruli becoming either peritubular capillaries or descending vasa recta

Question 14

What is the difference between peritubular capillariies and the descending vasa recta?

Answer 14

the peritubular capillaries supply the superficial glomeruli, whereas the descending vasa recta feeds into the juxtamedullary glomeruli

Question 15

Describe the benous return for the kidney

Answer 15

beings with the interlobular vein and ascending vasa recta

starting at the arcuate vein, outflow parallels inflow

Question 16

What is the ratio of cortical to medullary blood supply

Answer 16

7:1 - most of this to glomeruli

Question 17

two types of regions in the renal cortex

Answer 17

maze-like regions consisting of tubules (cortical labyrinth)

regions with straight tubules that can be though of as extensions of the medulla (medullary rays)

Question 18

components of a nephrone

Answer 18

renal corpuscle and renal tubule

Question 19

renal corpuscle

Answer 19

beginning of the nephrone that consists of:

Bowman’s capsule

endothelial cells of glomerular capillaries

glomerular basement membrane (GBM)

specialized phagocytic cells

Question 20

Bowman’s Capsule

Answer 20

consists of an encircling layer of parietal epithelium (squamous), an open space (Bowman’s space, and a layer of visceral epithelium, the podocytes, which envelop the glomerular capillaries

Question 21

visceral epithelium (podocytes)

Answer 21

highly arborized cell that envelops the glomerular capillaries with many first, ssecond, and third degree pedicels (food processes)

Question 22

endothelial cells of glomerular capillaries

Answer 22

cells with open fenestrations, each about 70-90 nm in diameter

Question 23

glomerular basement membrane (GBM)

Answer 23

the fused basal laminae of the glomerular endothelium and podocytes

Question 24

specialized phagocytic cells of the renal corpuscle

Answer 24

intraglomerular mesangial cells

extragomerular mesangial cells (Lacis cells)

Question 25

glomerular filter

Answer 25

composed of:

the glomerular capillary endothelium (70-90 nm fenestrations)

GBM (main barrier)

complex interdigitated pedicels and slit diaphragms (~25 nm) of the podocytes

intraglomerular cells keep the filter clean

Question 26

J-G apparatus (JGA)

Answer 26

place where the renal tubule of the nephrone returns to contact the renal corpuscle at the vascular pole

comprised of the macula densa and the juxtaaglomerular cells

Question 27

macula densa

Answer 27

specialized cuboidal epithelia

in the region closest to the vascular pole, the cuboidal cells of hte Thick Ascending Limb have a very different morphology than the rest of the TAL cells

they are taller, thinner, and have a darker staining cytoplasm

Question 28

juxtaglomerular cells

Answer 28

modified smooth muscle cells of afferent and efferent arterioles (more on afferent side)

these cells synthesize and secrete renin

Question 29

divisions of the renal tubule

Answer 29

proximal tubule (PT)

loop of Henle

distal tubule (DCT)

collecting system

Question 30

components of the proximal tubule

Answer 30

convoluted segment (PCT)

straight segment (PST)

Question 31

divisions of the loop of Henle

Answer 31

a very thin walled segment in the shape of a hairpin

a straight thick ascending limb (TAL)

Question 32

collecting system

Answer 32

connecting the collecting tubules of the cortex

inner and outer medullary collecting ducts

Question 33

collecting duct

Answer 33

receive input from many individual tubules

in the medulla, many medullary collecting tubules merge into larger caliber ducts (ducts of Bellini) which empty into a minor calyx

Question 34

What distinguishes PCT from DCT?

Answer 34

stellate lumen

lumen wiht “fuzz”

larger diameter

more numerous