KIDNEY – HISTOLOGY :
Two bean shaped organs located in the back part of abdominal cavity.
Each kidney is covered by a thin but tough capsule of dense irregular
connective tissue consisting of collagen fibers, fibroblast and myofibroblasts.
HILUM; a depression on the medial side of kidney.
RENAL PELVIS; upper expanded part of ureter, has large and cup like
extensions called major and minor calyces.
ZONES OF KIDNEY:
The substance of kidney is divided into two zones
CORTEX; outer reddish brown (as it contains 90% of blood flowing
through the kidney) , granular ( as it contains renal corpuscle and
convulated parts of renal tubules) zone.
MEDULLA; inner striated (as it lodges longitudinally arranged blood
vessels and straight parts of tubules) zone of lighter color, contains
10% of blood.
RENAL PYRAMIDS; Medulla also shows 8 – 10 conical masses called
renal pyramids. The base of renal pyramid lies adjacent to the
cortex, whereas the apex, known as papilla, projects into the
minor calyx.
LOBE OF KIDNEY; Each renal pyramid with its associated cortex.
RENAL COLUMNS; Extensions of cortical tissue into the medulla,
separates renal pyramid from each other
MEDULLARY RAYS; Longitudinal striations radiating into the cortex
from the base of pyramids , and represent the extensions of
medullary tissue into the cortex.
PARENCHYMA OF KIDNEY:
Parenchyma consists of 1 – 4 million tubular structures called nephrons (the
chief structural and functional units of kidney).
Nephrons drain into collecting ducts.
, The scanty space between nephrons and collecting ducts is occupied by
peritubular capillaries and interstitial connective tissue.
THE NEPHRON:
A long epithelium lined tube that begins blindly and ends by joining the
collecting tubule.
It consists of 5 major segments:
1. Renal corpuscle
2. Proximal tubule
3. Loop of henle
4. Distal tubule
5. Cortical collecting tubule
URINEFEROUS TUBULE; nephron + collecting tubules
1. Renal corpuscle:
Bowman’s capsule + glomerulus.
Each corpuscle has a urinary pole (where PCT begins) and a vascular pole
(where the afferent arteriole enters).
BOWMAN’S CAPSULE:
Aka glomerular capsule.
Double walled cup like structure.
Consists of an outer parietal wall and an inner visceral wall.
Space between both the layers or wall is referred to as the urinary space or
capsular space.
PARIETAL LAYER; simple squamous epithelium, at the urinary pole the
simple squamous epithelium becomes continuous with the simple cuboidal
epithelium of PCT.
Two bean shaped organs located in the back part of abdominal cavity.
Each kidney is covered by a thin but tough capsule of dense irregular
connective tissue consisting of collagen fibers, fibroblast and myofibroblasts.
HILUM; a depression on the medial side of kidney.
RENAL PELVIS; upper expanded part of ureter, has large and cup like
extensions called major and minor calyces.
ZONES OF KIDNEY:
The substance of kidney is divided into two zones
CORTEX; outer reddish brown (as it contains 90% of blood flowing
through the kidney) , granular ( as it contains renal corpuscle and
convulated parts of renal tubules) zone.
MEDULLA; inner striated (as it lodges longitudinally arranged blood
vessels and straight parts of tubules) zone of lighter color, contains
10% of blood.
RENAL PYRAMIDS; Medulla also shows 8 – 10 conical masses called
renal pyramids. The base of renal pyramid lies adjacent to the
cortex, whereas the apex, known as papilla, projects into the
minor calyx.
LOBE OF KIDNEY; Each renal pyramid with its associated cortex.
RENAL COLUMNS; Extensions of cortical tissue into the medulla,
separates renal pyramid from each other
MEDULLARY RAYS; Longitudinal striations radiating into the cortex
from the base of pyramids , and represent the extensions of
medullary tissue into the cortex.
PARENCHYMA OF KIDNEY:
Parenchyma consists of 1 – 4 million tubular structures called nephrons (the
chief structural and functional units of kidney).
Nephrons drain into collecting ducts.
, The scanty space between nephrons and collecting ducts is occupied by
peritubular capillaries and interstitial connective tissue.
THE NEPHRON:
A long epithelium lined tube that begins blindly and ends by joining the
collecting tubule.
It consists of 5 major segments:
1. Renal corpuscle
2. Proximal tubule
3. Loop of henle
4. Distal tubule
5. Cortical collecting tubule
URINEFEROUS TUBULE; nephron + collecting tubules
1. Renal corpuscle:
Bowman’s capsule + glomerulus.
Each corpuscle has a urinary pole (where PCT begins) and a vascular pole
(where the afferent arteriole enters).
BOWMAN’S CAPSULE:
Aka glomerular capsule.
Double walled cup like structure.
Consists of an outer parietal wall and an inner visceral wall.
Space between both the layers or wall is referred to as the urinary space or
capsular space.
PARIETAL LAYER; simple squamous epithelium, at the urinary pole the
simple squamous epithelium becomes continuous with the simple cuboidal
epithelium of PCT.
