▪ Components ;
a) kidneys - produce urine
b) ureters - deliver urine
c) bladder - temporary store urine
d) urethra - urination
▪ Functions ;
1) eliminate metabolic wastes, excess water and electrolytes
2) maintaining the homeostasis
* control acid-base balance
* control water and electrolytes balance
3) secrete some bioactive factors:
* Renin - important for regulation of blood pressure by cleaving circulating angiotensinogen to angiotensin I
* Erythropoietin - stimulates erythrocyte production in red marrow when the blood O2 level is low
* Prostaglandin
Kidney
Bean-shaped and each kidney has a ;
concave medial border = the hilum—where nerves enter, the ureter exits, and blood and lymph vessels enter and exit
convex lateral surface
Both covered by a thin fibrous capsule.
① Capsule :- DCT
② Cortex :- outer dark stained
a) medullary ray
Renal lobule - renal tissue including one medullary ray and the surrounding cortical tissue
b) cortical labyrinth
c) renal columns
③ Medulla :- slightly stained
a) renal pyramids (8-15)
b) renal papillae
④ Renal pelvis :-
a) Renal pelvis - funnel-shaped expansion of upper end of ureter
b) Renal calyx - branches from renal pelvis
* major calyx (2-3)
* minor calices : each being a drain for the papilla of a pyramid
1
, Renal Parenchyma
Nephron + Interstitium :- Connective Tissue , Blood Vessels , Nerves
(1) Renal corpuscle
(2) Renal tubule
* Proximal tubule Nephron :- ▪ structural and functional unit
* Loop of Henle ▪ the site of blood filtration, consists of renal corpuscle and renal tubule
* Distal tubule a) Superficial nephrons - 80% of the nephrons
(3) Collecting tubule
b) Juxtamedullary nephrons - 20% of the nephrons
Renal Corpuscle
▪ Spherical shaped and 200 μm in diameter , 1-4 million/ each kidney
▪ Two poles :- the vascular pole and the urinary pole
▪ Consists of glomerulus and renal capsule
Glomerulus
▪ afferent arterioles → a tuft of 20-40 loops of fenestrated capillaries → efferent arterioles
▪ capillary network :-
a) endothelial cells - pore (70-90 nm ) and no diaphragm
b) basal lamina (330 nm)
Interglomerular Mesangium
(1) Mesangial cells
▪ LM :- small , irregular, with processes，small dark N
▪ EM :- RER , Golgi , lysosome , phagocytic vesicles , cytoskeleton - MF, MT , IF and secretory granules
▪ Functions :- I. produce ground substance
II. phagocytosis
III. contract
IV. secrete renin and enzymes
(2) Matrix ;
a) type IV collagen
b) glycoprotein :- sulphate chondritin , heparin and dermatan
2
a) kidneys - produce urine
b) ureters - deliver urine
c) bladder - temporary store urine
d) urethra - urination
▪ Functions ;
1) eliminate metabolic wastes, excess water and electrolytes
2) maintaining the homeostasis
* control acid-base balance
* control water and electrolytes balance
3) secrete some bioactive factors:
* Renin - important for regulation of blood pressure by cleaving circulating angiotensinogen to angiotensin I
* Erythropoietin - stimulates erythrocyte production in red marrow when the blood O2 level is low
* Prostaglandin
Kidney
Bean-shaped and each kidney has a ;
concave medial border = the hilum—where nerves enter, the ureter exits, and blood and lymph vessels enter and exit
convex lateral surface
Both covered by a thin fibrous capsule.
① Capsule :- DCT
② Cortex :- outer dark stained
a) medullary ray
Renal lobule - renal tissue including one medullary ray and the surrounding cortical tissue
b) cortical labyrinth
c) renal columns
③ Medulla :- slightly stained
a) renal pyramids (8-15)
b) renal papillae
④ Renal pelvis :-
a) Renal pelvis - funnel-shaped expansion of upper end of ureter
b) Renal calyx - branches from renal pelvis
* major calyx (2-3)
* minor calices : each being a drain for the papilla of a pyramid
1
, Renal Parenchyma
Nephron + Interstitium :- Connective Tissue , Blood Vessels , Nerves
(1) Renal corpuscle
(2) Renal tubule
* Proximal tubule Nephron :- ▪ structural and functional unit
* Loop of Henle ▪ the site of blood filtration, consists of renal corpuscle and renal tubule
* Distal tubule a) Superficial nephrons - 80% of the nephrons
(3) Collecting tubule
b) Juxtamedullary nephrons - 20% of the nephrons
Renal Corpuscle
▪ Spherical shaped and 200 μm in diameter , 1-4 million/ each kidney
▪ Two poles :- the vascular pole and the urinary pole
▪ Consists of glomerulus and renal capsule
Glomerulus
▪ afferent arterioles → a tuft of 20-40 loops of fenestrated capillaries → efferent arterioles
▪ capillary network :-
a) endothelial cells - pore (70-90 nm ) and no diaphragm
b) basal lamina (330 nm)
Interglomerular Mesangium
(1) Mesangial cells
▪ LM :- small , irregular, with processes，small dark N
▪ EM :- RER , Golgi , lysosome , phagocytic vesicles , cytoskeleton - MF, MT , IF and secretory granules
▪ Functions :- I. produce ground substance
II. phagocytosis
III. contract
IV. secrete renin and enzymes
(2) Matrix ;
a) type IV collagen
b) glycoprotein :- sulphate chondritin , heparin and dermatan
2
