urinary system: ii

URINARY SYSTEM: II(cont.)

TO IDENTIFY THE COMPONENTS OF THE URINARY SYSTEM

TO IDENTIFY THE COMPONENTS OF THE URINARY SYSTEM

TO EXAMINE THE HISTOLOGICAL STRUCTURE OF THE NEPHRON AND THE COLLECTING DUCTS

TO EXAMINE THE HISTOLOGICAL STRUCTURE OF THE NEPHRON AND THE COLLECTING DUCTS

TO CORRELATE STRUCTURE OF VARIOUS COMPONENTS WITH FUNCTION

TO CORRELATE STRUCTURE OF VARIOUS COMPONENTS WITH FUNCTION

URINARY SYSTEM: IIURINARY SYSTEM: II

TO CHARACTERIZE THE GENERAL ORGANIZATION OF THE KIDNEY

TO CHARACTERIZE THE GENERAL ORGANIZATION OF THE KIDNEY

URINARY SYSTEM

KIDNEY (ORGANIZATION)

CORTEXCORTEX

MEDULLAMEDULLA

- region immediately beneath renal capsule

- composed of two distinct regions:

(1) CORTICAL LABYRINTH

(2) MEDULLARY RAY

- 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

RCRC

PP

PPPP

PP

PP

PPPP

URINARY SYSTEM

KIDNEY (ORGANIZATION)

PP

PPPP

PP

PP

PPPP

RENAL LOBE

- a single pyramid with its associated overlying cortex

RENAL LOBULE

- defined within cortex and involves a single medullary ray (central axis of lobule) with adjacent adjacent cortical labyrinth

- defined as a functional unit that consists of a collecting duct and all the nephrons that it drains

Cortical Labyrinth with interdigitating Medullary Rays

URINARY SYSTEM

THE NEPHRON & COLLECTING DUCTS

1) THE NEPHRON1) THE NEPHRON

2) COLLECTING DUCTS2) COLLECTING DUCTS

a) RENAL CORPUSCLE

- distributed throughout cortex and various zones of medulla

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

URINARY SYSTEM


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

CORTEX:

URINARY SYSTEM


OUTER ZONE

INNER ZONE

MEDULLA:



4- COLLECTING DUCTS

3- THIN SEGMENTS OF LOOP OF HENLE (DESCENDING & ASCENDING)

2- COLLECTING DUCTS


URINARY SYSTEM


1) THE NEPHRON1) THE NEPHRON

2) COLLECTING DUCTS2) COLLECTING DUCTS

a) RENAL CORPUSCLE

- distributed throughout cortex and various zones of medulla


b) PROXIMAL TUBULE

CONVOLUTED AND STRAIGHT PORTIONS

c) HENLE’S LOOP

THICK AND THIN PORTIONS

d) DISTAL TUBULE

STRAIGHT AND CONVOLUTED PORTIONS

HISTOLOGICAL STRUCTURE AND FUNCTIONHISTOLOGICAL STRUCTURE AND FUNCTION

URINARY SYSTEM

RENAL CORPUSCLE


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

FILTRATION APPARATUS OF KIDNEY

URINARY SYSTEM

RENAL CORPUSCLEBOWMAN’S CAPSULE + GLOMERULUSFILTRATION 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&EKIDNEY H&Eca

psul

eca

psul

e

CO

RTE

XC

OR

TEX

MED

ULL

AM

EDU

LLA

MRMR

CLCL

MRMR

CLCL

MRMR

AVAV

KIDNEY H&EKIDNEY H&E

GLOMERULUSGLOMERULUS

GLOMERULUSGLOMERULUS

MEDULLARY RAYMEDULLARY RAY MEDULLARY RAYMEDULLARY RAYCORTICAL LABYRINTHCORTICAL LABYRINTH


MEDULLARY RAY

MEDULLARY RAY

MEDULLARY RAY

MEDULLARY RAY

CORTICAL LABYRINTHCORTICAL LABYRINTHMEDULLARY

RAYMEDULLARY

RAY

MEDULLARY RAY

MEDULLARY RAY

RCRC

RCRC

RCRC

RCRC

RCRC

RCRC

RCRC

RCRC

URINARY SYSTEM

CORTICAL LABYRINTHCORTICAL LABYRINTH

1- RENAL CORPUSCLES1- RENAL CORPUSCLES

2- PROXIMAL CONVOLUTED TUBULES2- PROXIMAL CONVOLUTED TUBULES

3- DISTAL CONVOLUTED TUBULES3- DISTAL CONVOLUTED TUBULES

CORTEX:CORTEX:

- longer than DCT and thus more numerous- longer than DCT and thus more numerous

- stain slightly darker and have a larger diameter than DCT- 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

- cells are larger and have an irregular luminal surface due to the presence of a “brush border” and glycocalyx

- shorter than PCT and thus less prevalent- shorter than PCT and thus less prevalent

- stain slightly lighter and have a smaller diameter than PCT- 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- 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- luminal surface is more uniform since it lacks a brush border






CORTEX:CORTEX:

RENAL CORPUSCLERENAL CORPUSCLE

glomerulusglomerulus

Bowman’s capsuleBowman’s capsule

PCTPCT

DCTDCT

URINARY SYSTEM





CORTEX:CORTEX:

- 80-90% of H2O and NaCl in glomerular filtrate is reabsorbed in addition to most organic materials: (glucose, proteins, amino acids, etc.)

- 80-90% of H2O and NaCl in glomerular filtrate is reabsorbed in addition to most organic materials: (glucose, proteins, amino acids, etc.)

- further resorption of H2O in presence of ADH- further resorption of H2O in presence of ADH

- sodium resorption in response to aldosterone- sodium resorption in response to aldosterone

- calcium resorption in response to PTH- calcium resorption in response to PTH

KIDNEY SILVER METHENAMINEKIDNEY SILVER METHENAMINE

URINARY POLE

URINARY POLE


VASCULAR POLE

VASCULAR POLE

DCTDCT

PCTPCT


DCTDCT

PCTPCT

DCTDCT


DCTDCT

PCTPCT

PCTPCT

PCTPCTPCTPCT

DCTDCT

PCTPCT


DCTDCT

PCTPCT

PCTPCT

PCTPCT

PCTPCT

DCTDCT

PCTPCT

DCTDCT



DCTDCT

PCTPCTPCTPCT

DCTDCT

DCTDCT


AAAA

EAEA

peritubular capillary plexus

peritubular capillary plexus


MEDULLARY RAYMEDULLARY RAY

1- S

TRAIG

HT PO

RTIONS

OF PR

OXIMAL

TUBULE

(THIC

K DES

CENDIN

G)

2- S

TRAIG

HT PO

RTIONS

OF DIS

TAL

TUBULE

(THIC

K ASC

ENDIN

G)

3- C

OLLEC

TING D

UCTS

URINARY SYSTEM

MEDULLARY RAY



3- COLLECTING DUCTS

CORTEX:

- cells are cuboidal in cortex and become progressively more columnar in the medulla and papilla

- cells are cuboidal in cortex and become progressively more columnar in the medulla and papilla

- cells stain very lightly with well-defined boundaries

- cells stain very lightly with well-defined boundaries

- transport urine from nephron to excretory ducts and aids in further H2O resorption in the presence of ADH

- transport urine from nephron to excretory ducts and aids in further H2O resorption in the presence of ADH


CDCD

CDCDTDTD


COLUMNAR COLLECTING DUCTS NEAR RENAL PAPILLACOLUMNAR COLLECTING DUCTS NEAR RENAL PAPILLA

URINARY SYSTEM


OUTER ZONE

INNER ZONE

MEDULLA:



4- COLLECTING DUCTS


2- COLLECTING DUCTS



TDTD

CDCD

CDCDTATA

TLTL

OUTER MEDULLAOUTER MEDULLA


TLTLTLTL

TATA

TATA

OUTER MEDULLAOUTER MEDULLA

VASA RECTAVASA

RECTA


INNER MEDULLAINNER MEDULLA

CDCD

TLTL

CDCD

CDCD

CDCD

TLTL

TLTL

URINARY SYSTEM

JUXTAGLOMERULAR APPARATUSMACULA DENSA + JUXTAGLOMERULAR (JG) CELLSREGULATE BLOOD FLOW THROUGH GLOMERULUS

MACULA DENSA

JG CELLS

- cells located in the DCT in close contact with the glomerulus and the afferent and efferent arterioles

- specialized smooth muscle cells in the wall of the afferent arteriole which contain and secrete RENIN to regulate blood flow through the glomerulus

ANGIOTENSINGOGEN (PLASMA PROTEIN) ANGIOTENSIN I ANGIOTENSIN II

ALDOSTERONE SECRETION

VASOCONSTR

RENIN

URINARY SYSTEM


BARORECEPTOR THEORY

MACULA DENSA THEORY

- assumes JG cells function as stretch receptors (high blood pressure would inhibit release of renin)



VASOCONSTR

RENIN

- 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)

URINARY SYSTEM




VASOCONSTR

RENIN


MACULA DENSA

MACULA DENSA


JG CELLSJG CELLS

AAAA

RENIN GRANULES

URINARY SYSTEM

KIDNEY

CALYCES/ URETER

BLADDER

URETHRA

1- mucosa lined with transitional epithelium2- usually lacking submucosa

3- muscularis best developed in ureters (2-3 layers) and bladder (3 layers)

URETER H&EURETER H&E

MUCOSAMUCOSA LAMINA PROPRIALAMINA PROPRIA MUSCULARISMUSCULARIS

1: IL1: IL 2: OC2: OC

ADVADV

URINARY SYSTEM

URETER

URINARY SYSTEM

BLADDER

URINARY SYSTEM

BLADDER

transitional epithelium

urinary system: ii

Documents

renal capsule

renal cortex

function urinary system

collecting ducts

ductsa renal corpuscle

pyramids renal columns

cortical tissue

glomerulus capillaries