URINARY SYSTEM II cont URINARY SYSTEM II TO

URINARY SYSTEM: II (cont. )

URINARY SYSTEM: II TO IDENTIFY THE COMPONENTS OF THE URINARY SYSTEM TO CHARACTERIZE THE GENERAL ORGANIZATION OF THE KIDNEY TO EXAMINE THE HISTOLOGICAL STRUCTURE OF THE NEPHRON AND THE COLLECTING DUCTS TO CORRELATE STRUCTURE OF VARIOUS COMPONENTS WITH FUNCTION

URINARY SYSTEM P KIDNEY (ORGANIZATION) CORTEX P P P - region immediately beneath renal capsule - composed of two distinct regions: P (1) CORTICAL LABYRINTH (2) MEDULLARY RAY P P MEDULL A - located immediately beneath renal cortex - consists of triangular blocks of tissue called the PYRAMIDS - RENAL COLUMNS are strands of cortical tissue that extend down between adjacent pyramids RC

URINARY SYSTEM Cortical Labyrinth with interdigitating Medullary Rays KIDNEY (ORGANIZATION) P RENAL LOBE - a single pyramid with its associated overlying cortex P P P RENAL LOBULE - defined within cortex and involves a single medullary ray (central axis of lobule) with adjacent cortical labyrinth - defined as a functional unit that consists of a collecting duct and all the nephrons that it drains P P P

URINARY SYSTEM THE NEPHRON & COLLECTING DUCTS 1) THE NEPHRON - distributed throughout cortex and various zones of medulla a) RENAL CORPUSCLE BOWMAN’S CAPSULE + GLOMERULUS b) PROXIMAL TUBULE CONVOLUTED AND STRAIGHT PORTIONS c) HENLE’S LOOP THICK AND THIN PORTIONS d) DISTAL TUBULE STRAIGHT AND CONVOLUTED PORTIONS 2) COLLECTING DUCTS

URINARY SYSTEM THE NEPHRON & COLLECTING DUCTS CORTEX: CORTICAL LABYRINTH 1 - RENAL CORPUSCLES 2 - PROXIMAL CONVOLUTED TUBULES 3 - DISTAL CONVOLUTED TUBULES MEDULLARY RAY 1 - STRAIGHT PORTIONS OF PROXIMAL TUBULE (THICK DESCENDING) 2 - STRAIGHT PORTIONS OF DISTAL TUBULE (THICK ASCENDING) 3 - COLLECTING DUCTS

URINARY SYSTEM THE NEPHRON & COLLECTING DUCTS MEDULLA: OUTER ZONE 1 - STRAIGHT PORTIONS OF PROXIMAL TUBULE (THICK DESCENDING) 2 - STRAIGHT PORTIONS OF DISTAL TUBULE (THICK ASCENDING) 3 - THIN SEGMENTS OF LOOP OF HENLE (DESCENDING & 4 -ASCENDING) COLLECTING DUCTS INNER ZONE 1 - THIN SEGMENTS OF LOOP OF HENLE (DESCENDING & 2 -ASCENDING) COLLECTING DUCTS

URINARY SYSTEM THE NEPHRON & COLLECTING DUCTS HISTOLOGICAL STRUCTURE AND FUNCTION 1) THE NEPHRON - distributed throughout cortex and various zones of medulla a) RENAL CORPUSCLE BOWMAN’S CAPSULE + GLOMERULUS b) PROXIMAL TUBULE CONVOLUTED AND STRAIGHT PORTIONS c) HENLE’S LOOP THICK AND THIN PORTIONS d) DISTAL TUBULE STRAIGHT AND CONVOLUTED PORTIONS 2) COLLECTING DUCTS

URINARY SYSTEM RENAL CORPUSCLE BOWMAN’S CAPSULE + GLOMERULUS FILTRATION APPARATUS OF KIDNEY 1. BOWMAN’S CAPSULE: - the beginning of the nephron that consists of a blind sac lined with simple squamous epithelium that is continuous with the PCT - parietal layer & visceral layer (specialized) 2. GLOMERULUS: - specialized tuft of capillaries which housed in the capsular space (10 -20 capillary loops) - blood flowing through glomerulus capillaries undergoes a filtration process to produce the initial urine filtrate

URINARY SYSTEM RENAL BOWMAN’S CAPSULE + CORPUSCLE GLOMERULUS FILTRATION APPARATUS OF KIDNEY VASCULAR POLE URINARY POLE GLOMERULUS (FILTRATION MEMBRANE): 1 - fenestrated capillaries; discontinuous endothelium; fenestrae have a diameter of 500 -1000Å and lack a diaphragm 2 - continuous basal lamina 3 - podocytes of visceral layer; processes contact basal lamina and are separated by slits measuring approximately 250Å

KIDNEY H&E CL MR AV MEDULL A CORTE X capsul e MR

KIDNEY H&E GLOMERUL US MEDULLARY RAY CORTICAL LABYRINTH GLOMERUL US MEDULLARY RAY

KIDNEY H&E MEDULLAR Y RAY RC RC RC MEDULLAR Y RAY RC CORTICAL LABYRINTH RC MEDULLARY RAY

URINARY SYSTEM CORTEX: CORTICAL LABYRINTH 1 - RENAL CORPUSCLES 2 - PROXIMAL CONVOLUTED TUBULES - longer than DCT and thus more numerous - stain slightly darker and have a larger diameter than DCT - cells are larger and have an irregular luminal surface due to the presence of a “brush border” and glycocalyx 3 - DISTAL CONVOLUTED TUBULES - shorter than PCT and thus less prevalent - stain slightly lighter and have a smaller diameter than PCT - cells are smaller and cuboidal, thus more nuclei are apparent in a cross section of a DCT - luminal surface is more uniform since it lacks a brush border

KIDNEY H&E CORTEX: CORTICAL LABYRINTH Bowman’ s capsule 1 - RENAL CORPUSCLES 2 - PROXIMAL CONVOLUTED TUBULES 3 - DISTAL CONVOLUTED TUBULES glomerul us RENAL CORPUSCLE DCT PCT

URINARY SYSTEM CORTEX: CORTICAL LABYRINTH 1 - RENAL CORPUSCLES 2 - PROXIMAL CONVOLUTED TUBULES - 80 -90% of H 2 O and Na. Cl in glomerular filtrate is reabsorbed in addition to most organic materials: (glucose, proteins, amino acids, etc. ) CONVOLUTED 3 - DISTAL TUBULES - further resorption of H 2 O in presence of ADH - sodium resorption in response to aldosterone - calcium resorption in response to PTH

KIDNEY SILVER METHENAMINE DCT VASCUL AR POLE PCT glomerul us URINARY POLE

KIDNEY SILVER METHENAMINE DCT PCT DCT

KIDNEY H&E DCT PCT PCT DCT PCT

KIDNEY H&E PCT DCT glomerul us DCT PCT PCT

KIDNEY H&E DCT EA AA DCT glomerul us peritubular capillary plexus PCT

S TU TRA B IG 2 ST ULE HT TU RA (T PO HI RT BU IG 3 CK IO LE HT CO P D N LL (T HI ORT ESC S O EC C I EN F P TI R NG K A ONS SC O DIN OX DU G) IM EN F CT AL D DI IS S NG T ) AL 1 - KIDNEY SILVER METHENAMINE MEDULLARY RAY

URINARY SYSTEMKIDNEY H&E CORTEX: MEDULLARY RAY 1 - STRAIGHT PORTIONS OF PROXIMAL TUBULE (THICK DESCENDING) 2 - STRAIGHT PORTIONS OF DISTAL TUBULE (THICK ASCENDING) TD C 3 - COLLECTING DUCTS - cells are cuboidal in cortex and become progressively more columnar in the medulla and papilla - cells stain very lightly with well-defined boundaries - transport urine from nephron to excretory ducts and aids in further H 2 O resorption in the presence of ADH D C D

KIDNEY H&E COLUMNAR COLLECTING DUCTS NEAR RENAL PAPILLA

URINARY SYSTEM THE NEPHRON & COLLECTING DUCTS MEDULLA: OUTER ZONE 1 - STRAIGHT PORTIONS OF PROXIMAL TUBULE (THICK DESCENDING) 2 - STRAIGHT PORTIONS OF DISTAL TUBULE (THICK ASCENDING) 3 - THIN SEGMENTS OF LOOP OF HENLE (DESCENDING & 4 -ASCENDING) COLLECTING DUCTS INNER ZONE 1 - THIN SEGMENTS OF LOOP OF HENLE (DESCENDING & 2 -ASCENDING) COLLECTING DUCTS

KIDNEY H&E OUTER MEDULLA C TA D C D TD TL

KIDNEY H&E OUTER MEDULLA VASA RECTA TA TL

KIDNEY H&E INNER MEDULLA TL C D C D TL

URINARY SYSTEM JUXTAGLOMERULAR MACULA DENSA + JUXTAGLOMERULAR (JG) APPARATUS CELLS REGULATE BLOOD FLOW THROUGH GLOMERULUS MACULA DENSA - cells located in the DCT in close contact with the glomerulus and the afferent and efferent arterioles JG CELLS - specialized smooth muscle cells in the wall of the afferent arteriole which contain and secrete RENIN to regulate blood flow through the glomerulus ANGIOTENSINGO GEN (PLASMA PROTEIN) RENIN ANGIOTENSIN II ALDOSTERONE SECRETION VASOCONSTR

URINARY SYSTEM JUXTAGLOMERULAR MACULA DENSA + JUXTAGLOMERULAR (JG) APPARATUS CELLS REGULATE BLOOD FLOW THROUGH GLOMERULUS BARORECEPTOR THEORY - assumes JG cells function as stretch receptors (high blood pressure would inhibit release of renin) MACULA DENSA THEORY - assumes the secretion of renin is regulated by the composition of the fluid in the DCT / afferent arteriole (low sodium would increase the release of renin) ANGIOTENSINGO GEN (PLASMA PROTEIN) RENIN ANGIOTENSIN II ALDOSTERONE SECRETION VASOCONSTR

URINARY SYSTEM JUXTAGLOMERULAR MACULA DENSA + JUXTAGLOMERULAR (JG) APPARATUS CELLS REGULATE BLOOD FLOW THROUGH GLOMERULUS ANGIOTENSINGO GEN (PLASMA PROTEIN) RENIN ANGIOTENSIN II ALDOSTERONE SECRETION VASOCONSTR

KIDNEY H&E MACULA DENSA

KIDNEY H&E RENIN GRANULES JG CELLS AA

URINARY SYSTEM KIDNEY CALYCES/ URETER BLADDER URETHRA 1 - mucosa lined with transitional 2 -epithelium usually lacking submucosa 3 - muscularis best developed in ureters (2 -3 layers) and bladder (3 layers)

URETER H&E 1: 2: OC IL MUCOSA LAMINA PROPRIA MUSCULARIS ADV

URINARY SYSTEM URETER

URINARY SYSTEM URETER

URINARY SYSTEM BLADDER

URINARY SYSTEM BLADDER transitional epithelium