Histology

Question 1

What is the histological Structure of the kidneys :

Answer 1

1) Stroma : Fibrous Capsule and Interstitium
2) Parenchyma : Uriniferous Tubules

Question 2

Describe the anatomy of Uriniferous Tubules :

Answer 2

It consists of two structures :
1) Nephron. 2) Collecting Duct.

Question 3

Nephron consists of :

Answer 3

1) Renal corpuscle = Malpighian Corpuscle
2) Renal tubules
A.Proximal convoluted tubules ( PCT )
B.Loop of Henle
C.Distal convoluted tubules ( DCT )

Question 4

Renal Corpuscle is where ……………………. & Renal tubules where ……………………

Answer 4

Blood plasma is filtered , filtered fluid passes

Question 5

Types of Nephrons :

Answer 5

A) Short nephrons = Cortical nephrons ( MAJORITY )
B) Long nephrons = Juxtamedullary nephrons

Question 6

About Short nephrons OR Cortical Nephrons :

Answer 6

Short = their loop of Henley is short
Cortical = their renal corpuscle in outer portion of cortex

Question 7

About Long nephrons OR Juxtamedullary nephrons :

Answer 7

Long = their loop of Henle is long
Juxtamedullary = Their renal corpuscle lie deep in cortex close to medulla

Question 8

Number of nephrons in the kidneys :

Answer 8

1 million

Question 9

Function of long nephrons :

Answer 9

Excretion of very concentrated urine

Question 10

Each corpuscle has two poles :

Answer 10

A) Vascular Pole
B) Urinary Pole

Question 11

How to differentiate btwn The two poles of Renal corpuscle :

Answer 11

Vascular Pole : where afferent arteriolar enters and efferent arteriole leaves
Urinary Pole : where the proximal convoluted tubule begins

Question 12

Components of renal corpuscle :

Answer 12

A) Glomerulus
B) Bowman’s Capsule

Question 13

Glomerulus is formed of :

Answer 13

1) Glomerular Capillaries
2) Mesangial Cells

Question 14

Glomerular capillaries arise from ……………… and drain into ……………………..

Answer 14

Afferent arteriole , Efferent arteriole

Question 15

Endothelium of Glomerular capillaries :

Answer 15

Fenestrated simple squamous epithelium; these fenestrae are numerous ,large and not closed by diaphragm

Question 16

Define Mesangial Cells :

Answer 16

Contractile connective tissue cells that occupy the spaces between the glomerular capillaries AND help regulate glomerular filtration

Question 17

Define Bowman’s capsule:

Answer 17

Epithelial Capsule that surrounds the glomerulus

Question 18

Layers of Bowman’s Capsule :

Answer 18

Two layers :
Outer layer AND Inner layer
* Outer layer= Parietal layer
Simple squamous epithelium

• Inner layer = Visceral layer ( Envelops the glomerular capillaries )
  Special cells called Podocytes

Between the two layers : Bowman’s Space ; urinary space where the fluid filtered through the capillary wall is recieved

Question 19

Define Podocytes :

Answer 19

Modified simple squamous epithelial cells of visceral layer of Bowman’s capsule

Question 20

Podocytes structure :

Answer 20

Each one has CELL BODY and PRIMARY PROCESSES , these processes give rise to SECONDARY PROCESSES which rises the PEDICLES , these Pedicles are separated by FILTERATION SLITS which are covered by FILTERATION-SLIT DIAPHRAGM…

Question 21

Define blood renal barrier ?

Answer 21

Structures that separate blood in glomerular capillaries from the filterate in Bowman’s space

Question 22

Renal blood barrier function ?

Answer 22

1)PERMITS the passage of water, ions and small molecules from the blood to bowman’s space
2)PREVENTS the passage of large molecules such as Blood cells and proteins

Question 23

What are the structures involved in renal blood barrier ?

Answer 23

1) Fenestrated endothelium of blood capillaries
2) Glomerular basement membrane ( formed from both Podocytes and endothelial basement membrane )
3)Filteration slit

Question 24

Compare btwn PCT and DCT :

Answer 24

Attached in tables app

Question 25

Function of loop of Henle:

Answer 25

1) It connects PCT with DCT 2) it concentrates urine

Question 26

Henle’s loop consists of :

Answer 26

1) Descending limb ( thick part which is similar structurally to PCT and thin part ) 2) Ascending limb ( thick part which is similar structurally to DCT and thin part )

Question 27

The thin segment of Henle loop is lined with …………………….

Answer 27

Squamous epithelial cells

Question 28

Define connecting tubules :

Answer 28

Short segments between DCT and the beginning of cortical collecting ducts

Question 29

Types of Collecting ducts :

Answer 29

Cortical , medullary and papillary ducts

Question 30

Functions of collecting ducts :

Answer 30

1) CONDUCT urine 2) CONCENTRATE urine

Question 31

Common characteristics btwn all Types of collecting ducts :

Answer 31

1) the lumen is relatively wide 2) they are lined with simple cuboidal epithelium 3) the cytoplasm contains few organelles

Question 32

Define Papillary Collecting ducts ?

Answer 32

Ducts formed by the union of several medullary collecting ducts

Question 33

Papillary Collecting ducts open into :

Answer 33

Area cribrosa of renal papilla

Question 34

Define Medullary rays :

Answer 34

Medullary projections that enter the Cortex

Question 35

Medullary rays components :

Answer 35

Single cortical collecting duct and the straight portions of several nephrons that drains into it

Question 36

What is the renal lobe ?

Answer 36

Renal pyramid and the corresponding covering of the cortical tissue

Question 37

What is the renal lobule ?

Answer 37

Group of nephrons that open into branches of the same collecting duct

Question 38

Site of Juxtamedullary complex :

Answer 38

At the vascular Pole of the renal corpuscle , Where the DCT fits btwn afferent and efferent arteriole

Question 39

Define Juxtamedullary complex :

Answer 39

Complex of vascular and tubular components of the nephron

Question 40

Juxtamedullary complex components:

Answer 40

1) Macula dense 2) Juxtaglomerular cells 3) Extra-glomerular mesangial cells

Question 41

Define Macula Densa :

Answer 41

Special type of cells that line of the DCT that facing the glomerulus

Question 42

Histology of Histology of macular densa :

Answer 42

Closely packed columnar cells : A.deeply stained packed nuclei B.Numerous Microvilli C.Thin basement membrane D. They have cell processes, which extend through the lacking basement membrane towards the juxtaglomerular cells.

Question 43

Macula densa is in direct contact with ……………… & ……………….. .

Answer 43

Juxtaglomerular cells , lacis cells

Question 44

define JG cells :

Answer 44

Special modified smooth muscle cells that present in tunica media of afferent arteriole and few in efferent arteriole

Question 45

JG cells function :

Answer 45

Secretion of renin

Question 46

Cytoplasm of JG cells contain :

Answer 46

Large secretory granules ( formed from both renin secretion )

Question 47

Effect of JG cells on the afferent arteriole?

Answer 47

Internal elastic lamina of the afferent arteriole is absent ; then these cells are in close contact with intima and blood in lumen

Question 48

Define EG mesangial cells : Q

Answer 48

Group of cells present in the area between the afferent arteriole , efferent arteriole and macula densa

Question 49

Extra-glomerular mesangial cells communicate with ……………. .

Answer 49

Intra-glomerular mesangial cells

Question 50

Function of EG mesangial cells :

Answer 50

Support and coordination

Question 51

Mention the general arrangement of blood vessels within the kidneys :

Answer 51

Renal artery > Segmental branch > interlobar artery > Arcuate artery > Interlobular artery > afferent arteriole > Glomerulus > efferent arteriole > peritubular network capillaries > Vasa recta > Interlobular veins > Arcuate veins > interlobar veins > single renal vein

Question 52

Interlobar arteries way :

Answer 52

Run in interval , between the two adjacent pyramids toward the cortex

Question 53

Arcuate arteries are located at ……………………………. .

Answer 53

Junction of Cortex and medulla

Question 54

Afferent arterioles arises from :

Answer 54

Interlobular arteries

Question 55

Peritubular network of capillaries surrounds :

Answer 55

Tubular parts of the nephron in the renal cortex