The Urinary System I Components Function of the

The Urinary System

I. Components & Function of the U. S. A. Components - two kidneys, two ureters, bladder, & urethra

I. Components & Function of the U. S. B. Uriniferous Tubule 1. basic structural and functional unit of the kidney 2. each tubule is composed of a nephron and a system of collecting ducts

C. Kidney Functions 1. excretion of waste products of metabolism 2. elimination of foreign substances and their breakdown products 3. regulation of total body water 4. maintenance of extracellular fluid volume 5. regulation of various salts to be retained or excreted by the body, renin, is involved 6. control of acid-base balance 7. production of the hormone, erythropoietin (for RBC production)

D. Formation of Urine 1. filtration - ultrafiltrate of plasma, approx. 180 liters filtered/day, 1 -2 liters urine/day 2. secretion - additional substances added to filtrate 3. reabsorption - intratubular filtrate returns across tubular cells back into renal interstitium

II. Macroscopic Anatomy A. B. C. D. E. F. G. Renal Hilus Renal Sinus Renal Pelvis Cortex Medulla Renal Lobe Renal Lobule

C. Renal Pelvis 1. major calyxes 2. minor calyxes

D. renal Cortex 1. corpuscles & tubules 2. renal columns 3. medullary rays

E. Medulla

E. Renal Medulla

F. Renal Lobe

G. Renal Lobule

G. Renal Lobule

III. The Nephron

A. Renal Corpuscle 1. in cortex 2. glomerulus, mesangial cells & Bowman's capsule 3. parietal layer 4. visceral layer 5. Bowman's space 6. vascular pole 7. urinary pole

A. Renal Corpuscle 3. parietal layer 4. visceral layer

A. Renal Corpuscle 1. in cortex 2. glomerulus, mesangial cells & Bowman's capsule 3. parietal layer 4. visceral layer 5. Bowman's space 6. vascular pole 7. urinary pole

B. Glomerulus 1. Podocytes a. b. c. visceral layer processes & pedicles interdigitate d. filtration slits

1. Podocytes

B. Glomerulus 2. Basal lamina a. between podocytes & endothelium b. three zones § § § lamina rara interna lamina rara externa lamina densa 3. Endothelium a. b. fenestrated diaphragms 4. Filtration barrier a. b. c. components water & ions proteins & charge

B. Glomerulus 5. Mesangium a. b. c. interstitial spaces cells & matrix phagocytosis

III. The Nephron

C. Proximal Convoluted Tubule 1. largest & longest tubule 2. simple cuboidal epi 3. abundant mitochondria 4. zonule occludens juncts & lateral interdigitations 5. reduces volume of glomerular filtrate

C. Proximal Convoluted Tubule

C. Proximal Convoluted Tubule

D. Straight Proximal Tubule

E. Thin Limb 1. 2. 3. 4. within the medullary pyramid hairpin loop simple squamous epithelium concentrating urine

E. Thin Limb 1. within the medullary pyramid 2. hairpin loop 3. simple squamous epithelium 4. concentrating urine

F. Straight Distal Tubule 1. in the medullary ray 2. part of loop of Henle 3. simple cuboidal epi 4. microvilli 5. transport ions

G. Distal Convoluted Tubule 1. begins at the macula densa 2. similar to straight portion 3. actively transport sodium

H. Macula Densa 1. in distal tubule 2. part of juxtaglomerular apparatus 3. “dense spot” 4. cells monitor fluid

H. Macula Densa

I. Juxtaglomerular Apparatus 1. at the vascular pole 2. modified smooth muscle cells, the macula densa, & mesangial cells 3. decrease in extracellular fluid volume

Renin-Angiotensin-Aldosterone System

IV. Intrarenal Collecting Ducts A. Collecting Ducts 1. in cortex & medullary ray 2. simple cuboidal epi 3. respond to ADH

B. Papillary Ducts (of Bellini) 1. 2. 3. 4. 5. 6. medullary pyramid simple columnar epi empty into minor calyxes area cribrosa respond to ADH concentrated urine

B. Papillary Ducts (of Bellini)

4. Area Cribosa

V. Blood Supply of Kidney A. Renal Artery B. Interlobar Arteries C. Interlobular Arteries D. Efferent Arterioles E. Vasa Rectae

V. Blood Supply of Kidney A. Renal Artery B. Interlobar Arteries C. Interlobular Arteries D. Efferent Arterioles E. Vasa Rectae

V. Blood Supply of Kidney C. Interlobular Arteries D. Efferent Arterioles

E. Vasa Rectae

VI. Extrarenal Passages A. Renal Pelvis B. Ureter C. Urinary Bladder

A. Renal Pelvis

A. Renal Pelvis

VI. Extrarenal Passages B. Ureter 1. between renal pelvis & bladder 2. transitional epi 3. smooth muscle 4. peristaltic waves

VI. Extrarenal Passages B. Ureter 1. between renal pelvis & bladder 2. transitional epi 3. smooth muscle 4. peristaltic waves

VI. Extrarenal Passages C. Urinary Bladder 1. thick transitional epithelium 2. epi can change its morphology 3. thin basement membrane & loose FECT 4. thick smooth muscle & layered

C. Urinary Bladder

C. Urinary Bladder