Dr. ANAND SRINIVASAN

At the end of the lecture students shall be able to :

Identify the key features and slides of kidney, ureter, urinary bladder and urethra.

Composed of Kidneys Ureters Urinary bladder Urethra

Know the following macroscopic features : Renal sinus Renal cortex & medulla Renal pyramid Renal papillae Ducts of Bellini Medullary rays Renal column of Bertin

With your knowledge in gross anatomy, identify the labels

1 – 11.

Composed many renal (uriniferous) tubules made of Nephron Collecting tubule

NEPHRON Structural and functional unit 1 – 4 million in each kidney Cortical nephrons & Juxtamedullary nephrons Made of▪ Renal corpuscle▪ Proximal & Distal convoluted tubule▪ Loop of Henle

Made of 2 components Bowman’s capsule Glomerulus

BOWMAN’s CAPSULE Blind end of the nephron Parietal layer – simple squamous epithelium

continuous with PCT at urinary pole. Visceral layer – specialized epithelium

(Podocytes) continuous with parietal layer at vascular pole

Bowman’s space – between parietal & visceral layers

GLOMERULUS Afferent arteriole more diameter than efferent Glomerular capillaries lined by fenestrated

endothelium Supported by mesangial cells

PODOCYTES Primary and secondary (pedicels)foot processes

GLOMERULAR FILTER Fenestrated endothelium of capillaries Glomerular basement membrane Filtration slits between pedicels of podocytes

PROXIMAL CONVOLUTED TUBULE Simple cuboidal epithelium with microvilli

LOOP OF HENLE Thick segment – simple cuboidal epithelium Thin segment – simple squamous epithelium

DISTAL CONVOLUTED TUBULE Simple cuboidal epithelium (no brush border)

COLLECTING TUBULES Simple cuboidal epithelium with pale cytoplasm

COLLECTING DUCT Simple columnar epithelium with pale cytoplasm

JUXTAGLOMERULAR (JG) CELLS Modified smooth cells of tunica media of

afferent arteriole at the point of contact with DCT

Sensitive to blood pressure in afferent arteriole. Secretes – Renin

MACULA DENSA Specialized region in DCT sensitive to Na+

LACIS / POLKISSEN CELLS Extraglomerular mesangial cells; ?

Erythropoietin

MUCOSA Transitional epithelium Lamina propria rich in elastic fibers Mucosa thrown into star shaped lumen

MUSCLE COAT 2 layers in the upper 2/3 and 3 in the lower

1/3 Inner longitudinal, outer (middle) circular

ADVENTITIA Outermost coat made of loose connective

tissue

MUCOSA Transitional epithelium with lamina propria Superficial cells flattened when bladder is full

MUSCLE COAT Inner longitudinal, middle circular and outer

longitudinal

ADVENTITIA / SEROSA Fibroelastic connective tissue ± Peritoneum

Divided into Prostatic – transitional epithelium

Membranous – (Pseudo)stratified columnar

Penile – (Pseudo)stratified columnar

Fossa navicularis – stratified squamous

4 cms

Lined by stratified squamous epithelium except near the bladder where it is lined by transitional epithelium

Urethral (Skene’s) glands open into urethra

Inner longitudinal and outer circular muscle layers

Cell biology & Histology – BRS Review

Microanatomy workbook – RAKMHSU

Di Fiore’s Histology

http://quizlet.com/7937689/urinary-system-flash-cards/

http://imueos.wordpress.com/2010/05/08/anatomy-histology-of-the-urinary-tract/