What is the urinary system composed of ?
Short summary of how the urinary system works
Urine produced in the kidneys is conducted by the ureters to the bladder where it is stored until voided via the urethra
What is the Hilum?
The hilum (in the kidney): site of entry and exit of the renal blood vessels and ureter.
What is a nephron?
A nephron is the functional unit of the kidney; consists of renal corpuscle and renal tubule
Renal corpuscle – plasma filtration. consists of 2 structures:
Bowman’s capsule; distended, blind end
of the renal tubule
Glomerulus; packed capillaries that
invaginate Bowman’s capsule derive
from the afferent arteriole
Renal tubule – reabsorption.
extends from Bowman’s capsule to the
collecting duct. Convoluted in shape,
four histological-physiological zones
a: proximal convoluted tubule (PCT)
b: loop of Henle
c: distal convoluted tubule (DCT)
d: collecting tubule
Plasma filtrate from the glomerular capillaries passes through 3 layers before entering the renal tubule, which ?
Capillary endothelium – fenestrated
Glomerular basement membrane – thick (~ 300 nm) as formed by 2 basal laminae of podosomes & endothelia. Otherwise normal composition (collagen IV, laminin, proteoglycan rich in heparin sulphate)
Podocytes – interdigitating pedicels (primary and secondary processes). The secondary pedicels attach directly to the glomerular basement membrane.
Gaps between pedicels are filtration slits.
What is the ureter?
A muscular tube that conduct urine from the kidney to the bladder
What is the ureter formed of ?
Two layers of smooth muscle: Longitudinal (L); inner layer and really an elongated spiral. Circular (C); outer layer and also a (tight) spiral.
Lumen of ureter is lined by transitional epithelium, with deep lamina propria rich in collagen (LP).
An adventitia surrounds ureter: note the arteries (A) and veins (V).
What are the 3 layers of the bladder ?
Wall of bladder consists of 3 smooth muscle layers (as does lower section of ureter) and abundant elastic fibres.
IL: inner longitudinal
OC: outer circular
OL: outermost longitudinal
The adeventitia (A) contains arteries, veins and lymphatics
Cut edge of capsule
Cut edge of pelvis