Unit 8 - 1 Histology

Front 1

hilium

Back 1

location on kidney where ureters, blood vessels, nerves and lymphatics pass

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Back 2

ARTERIAL PORTAL SYSTEM - KIDNEY

VENOUS PORTAL SYSTEM – LIVER & PITUITARY

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Back 3

A coronal view (left) shows the major blood vessels of the kidney. The microvascular components extending into the cortex and medulla from the interlobular vessels are shown on the right. Pink boxes indicate vessels with arterial blood and blue indicate the venous return. The intervening lavender boxes and vessels are intermediate sites where most reabsorbed material re-enters the blood.

Front 4

efferent arterioles of cortical nephrons

Back 4

give rise to plexus of peritubular capillaries

Front 5

efferent arterioles of juxtamedullary nephrons give rise to

Back 5

vasa rectae spuria projecting radially
toward hilum.

Front 6

afferent vs efferent tubular size

Back 6

efferent arteriole is smaller than afferent; creates pressure to drive filtration process; regulated by arteriole smooth muscle cells

Front 7

function of endothelial fenestrations

Back 7

permeable to H20, Na, urea, glucose and small proteins (<60 kD); endothelial cells negatiely charged (heparan sulfate -> slows passage of anionic proteins)

Front 8

mutation in nephrin gene

Back 8

Podocyte pedicels sit on GBM and form filtration slits. Filtration slit
diaphragm is composed of nephrin. Mutation in nephrin gene is cause of
congenital nephrotic syndrome (massive proteinuria).

Front 9

mesangial cell

Back 9

provide phagocytosis, structural support, and secret IL-1 and PDGF in response to glomerular injury

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Goodpasture syndrome

Back 10

autoimmune disorder
progressive glomerulonephritis and pulmonary hemorrhage due to
anti-collagen a3(IV) antibodies binding to and disrupting glomerular and
alveolar basal laminae.

GBM is produced by both endothelial cells and podocytes: Type IV collagen, laminin, fibronectrin an dproteoglycans (enrinched in GAGS via heparan sulfate)

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Proximal convoluted tubule

Back 11

receives ultrafilate from urinary space of Bowmans capsule

is the initial and MAJOR site of absorption

note brush border

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Back 12

loop of henle

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Back 13

distal convoluated tubule

Front 14

macula densa cells

Back 14

chemoreceptors

feedback system

low Na+ => ATP, ACe in endothelial cells

system bp = renin - angiotensin - aldosterone

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ADH

Back 15

regulates water permeability in collecting ducts

CDs also secrete H+ and bicarb -> important for blood pH balance

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principal cells in collecting tubules

Back 16

reabsorb Na and H20

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intercalated cells

Back 17

secrete H+/HC03

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Back 18

Diagram of the induction of permeability to water in a collecting tubule. When
antidiuretic hormone (ADH) binds to basal receptors of collecting tubule cells, it
triggers the movement of cytoplasmic vesicles to the cell surface. These vesicles,
containing aquaporin-2 water transporters, allow the entry of water, which then
exits the cell at its basolateral surface via aquaporin-3 and -4 channels.

Front 19

EPO

Back 19

EPO is produced mainly by peritubular fibroblasts in the cortex)

Front 20

Renin

Back 20

(Renin is produced by juxtaglomerular cells in afferent arteriole)

Front 21

atrial natriuretic peptide

Back 21

intercalated cells of collecting ducts;
production much lower than in atrial cardiomyocytes)

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Back 22

renin angiotensin system

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Back 23

renal papilla

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Back 24

Each ureter carries urine from the renal pelvis of the kidney to the urinary bladder for storage prior to voiding via the urethra.
(a): Diagram of a ureter in cross section shows a characteristic pattern of longitudinally folded mucosa, surrounded by a thick muscularis that moves urine by regular waves of peristalsis. The lamina propria is lined by a unique stratified epithelium called transitional epithelium or urothelium resistant to the potentially deleterious effects of contact with hypertonic urine.
(b:) Histologically the muscularis is much thicker than the mucosa and an adventitia is also present. [H&E].

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Back 25

The urethra is a fibromuscular tube that carries urine from the bladder to the exterior of the body.
(a): A transverse section shows that the mucosa has large longitudinal folds around the lumen (L) [H&E].
(b): A higher magnification of the urethral epithelium is shown in this micrograph. The thick epithelial lining is stratified columnar in some areas and pseudostratified columnar elsewhere, but becomes stratified squamous at the distal end of the urethra [H&E].

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Back 26

general anatomic and histologic organization of the kidney

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Back 27

compound tubular gland covered with thin capsule of dense connective tissue & fat
parenchyma: outer dark red cortex, striated medulla, funnel-shaped pelvis
medulla composed of 12 -15 renal pyramids with apex of papilla extending into calyx
hilum on medial surface: ureters, blood vessels, nerves, lymphatics pass