64: Urinary System I (Histo)

Question 1

What parts make up Urinary System?

Answer 1

Bladder
Kidneys
Urethra
Ureters

Question 2

Functions of the Urinary System

Answer 2

Important excretory system

Formation of urine

Monitoring of blood pressure

Question 3

Functions of Kidneys

Answer 3

Regulation of acid base balance

Maintain composition and volume of extracellular fluid

Excretion of metabolic waste & drugs

Regulation of blood pressure

Question 4

Endocrine functions of Kidneys

Answer 4

hydroxylation of 25-OH vitamin D3 to active 1,25- (OH)2 vitamin D3

erythropoietin ( EPO) : acts on bone marrow to regulate RBC formation in low blood oxygen concentration

secretion of renin- enzyme involved in blood pressure regulation

Question 5

Paired bean shaped, retroperitoneal organs derived from intermediate mesoderm

Answer 5

Kidneys

Question 6

the point of entry of

neurovascular supply and origin of ureter (renal pelvis)

Answer 6

Hilum of kidneys

Question 7

space around the hilar

structures, filled with loose connective tissue

Answer 7

Renal sinus

Question 8

granular in appearance

consists most of the components of the nephron

extends between medullary pyramids as renal columns
(Columns of Bertin)

Answer 8

Cortex

Question 9

striated appearance

arranged as discrete pyramids

apical portion of pyramid
(renal papilla) projects into
minor calyx

consists mainly straight
portion of uriniferous tubules and straight blood vessels

Answer 9

Medulla

Question 10

composed of renal corpuscle and

associated tubular structures

Answer 10

Renal cortex

Question 11

Regions of Renal Cortex

Answer 11

Medullary rays: straight
tubules of the nephron and
collecting ducts

Cortical labyrinth: convoluted tubules of the nephron

Question 12

medulla and

associated cortex

Answer 12

Renal lobe

Question 13

medullary rays and
adjacent cortical tissue

consists of a collecting duct and the nephrons
it drains

Answer 13

Renal lobule

Question 14

predominantly consists rounded structures –> renal

corpuscles, PCT, DCT, peritubular capillaries

Answer 14

Pars convoluta

Question 15

predominantly consists straight structures ->

loop of Henlé, collecting ducts

Answer 15

Pars recta (medullary rays)

Question 16

Consists predominantly straight tubules:

proximal straight tubule
thin loop of Henlé
distal straight tubule
collecting ducts
vasa recta (blood vessels)

Answer 16

Medulla

Question 17

Kidney blood supply

Answer 17

Renal artery (main)
Interlobar artery
Arcuate artery
Interlobular artery

Question 18

arise from interlobular

arteries to form glomerular capillary tuft

Answer 18

Afferent arterioles

Question 19

Capillary tuft leaves the corpuscle as?

Answer 19

Efferent arterioles

Question 20

in corticcal nephrons, efferent arterioles

give rise to?

Answer 20

peritubular capillary

network

Question 21

In Juxtamedullary nephrons: efferent arterioles descend into medulla to become?

Answer 21

Vasa Recta

Question 22

( arteriolae and venulae
rectae) are involved in the countercurrent exchange of ions in the medulla, run
parallel to loops of Henlé

Answer 22

Vasa Recta

Question 23

functional unit of the

kidney

Answer 23

Nephron

Question 24

Glomerulus and

Bowman’s capsule

Answer 24

Renal corpuscle

Question 25

Tubules

Answer 25

Proximal convoluted tubule ``` Loop of Henlé: • proximal straight tubule • Thin descending limb • Thin ascending limb • Distal straight tubule ``` Distal convoluted tubule

Question 26

Nephron + connecting tubule

Answer 26

Uriniferous tubule

Question 27

Three types of Nephrons

Answer 27

Cortical: short loops of Henle (hairpin turn by distal straight) Intermediate (mid cortical) Juxtamedullary: long loops of Henle, these are crucial for concentrating urine

Question 28

Renal corpuscle components

Answer 28

Glomerulus : blood enters via afferent arteriole and leaves as efferent arteriole : both are found at the vascular pole of renal corpuscle Bowman’s capsule surrounds glomerulus Mesangium: mesangial cells (intra-glomerular)

Question 29

Ultra-filtrate

Answer 29

collects in urinary space and is directed to the PCT | at the urinary pole

Question 30

Visceral layer (glomerular) of Bowman's Capsule

Answer 30

podocytes (modified squamous cells) which invests glomerular | capillaries

Question 31

Parietal layer (capsular) of Bowman's Capsule

Answer 31

outer layer of simple squamous epithelium which is continuous with the proximal convoluted tubule

Question 32

Urinary space (Bowman’s space or capsular space)

Answer 32

lies between the | two layers where the ultra-filtrate collects and is channeled to the proximal convoluted tubule (PCT)

Question 33

Consists of mesangial cells (contain actin | filaments) and the matrix they produce

Answer 33

Mesangium

Question 34

Phagocytosis of residue along the GBM Structural support-> secretes ECM Secretion of inflammatory substances: IL-1, prostaglandin E2, PDGF Contractile cells: may regulate glomerular distension in high blood pressure (in response to angiotensin II & ANF (atrial natriuretic factor))

Answer 34

Mesangium functions

Question 35

Numerous fenestrations No diaphragms Produces nitric oxide and prostaglandins (PGE2) Abundant aquaporin-1 receptors

Answer 35

Endothelium of glomerular capillaries

Question 36

Thick 300-370 nm Fused basal lamina of endothelial cells and podocytes Type IV collagen Predominantly contains heparan sulphate

Answer 36

Glomerular basement membrane (GBM)

Question 37

Structural arrangement of GBM

Answer 37

I. Lamina rara interna: (of the capillary) II. Lamina densa: Type IV collagen – physical barrier III. Lamina rara externa: (of thepodocyte) rich in heparan sulphate to repel [-} charged molecules

Question 38

Modified epithelial cells, called podocytes with primary/secondary processes, and pedicels Filtration slits b/n pedicels covered by slit diaphragm (zipper like sheet w/ nephrin transmembrane protein, anchored to filaments w/in pedicels of podocytes)

Answer 38

Visceral layer of Bowman's Capsule

Question 39

Factors affecting filtration

Answer 39

charge: [-} charged repelled size: upper limit of 70 KiloDaltons shape: upper limit of 3.6 nm

Question 40

Filtrates

Answer 40

water, glucose, small amino acids, ions, urea, hormones, Vit. B & C, ketones

Question 41

most abundant tubular profiles in the cortex receive ultrafiltrate from urinary space and reabsorbs 65% of it including 100% of glucose, 98% amino acids, small polypeptides

Answer 41

Proximal convoluted tubules

Question 42

What type of cells are in the proximal convoluted tubules?

Answer 42

Simple cuboidal epithelium specialized for absorption Large cells result in large spaces b/n adjacent cellular nuclei

Question 43

Structure of proximal convoluted tubules

Answer 43

Apical surface : long microvilli forming brush border •Lateral: – Tight junctions and zonula adherens – Plicae: folds which interdigitate w/ adjacent cellular processes Basal interdigitations Basal striations associated w/ elongated mitochondria

Question 44

Which part of nephron has Na +/ K+ pumps on lateral folds that create osmotic gradient for water reabsorption?

Answer 44

Proximal convoluted tubules

Question 45

Which processes are actively involved in protein absorption and recycling in the proximal convoluted tubules?

Answer 45

Endocytic complex (vesicles, endosomes, lysosome)

Question 46

contains enzymes for | absorption of glucose, peptides & stained with PAS

Answer 46

Glycocalyx