URINOGENITAL SYSTEM

PRESENTED BYFATIMA KHARBE

URINOGENITAL SYSTEMo URINARY SYSTEM OF VERTEBRATES INCLUDE KIDNEYS

AND THEIR DUCTS

o REPRODUCTIVE SYSTEM INCLUDES MALE AND FEMALE GONADS AND THEIR DUCTS

o THE 2 SYSTEMS ARE INTIMATELY RELATED MORPHOLOGICALLY IN VERTEBRATES HENCE THE TWO SYSTEM ARE AS DESCRIBED AS UROGENITAL OR URINOGENITAL SYSTEM

BASIC STRUCTURE OF EMBRYONIC KIDNEY

Pair of compact organs lying on either side of dorsal aortaEach kidney is composed of large no of units called as URINIFEROUS TUBULES OR NEPHRONSKidney tubules arise in the embryo in a linear series from mesodermEach uriniferous tubule is differentiated into 3 parts1PERITONEAL FUNNEL2MALPIGHIAN BODY3TUBULE

Urinary System - Kidneys

Kidneys are pair of compact organs lying on eitherSide of dorsal aortaEvolution of kidney takes place asARCHINEPHROSPRONEPHROSMESONEPHROSMETANEPHROS

ARCHINEPHROSExcretory organ of ancestral vertebratesAlso called as HOLONEPHROS 0r

complete kidney as it runs throughout the entire length of coelom

Composed of pair of archinephric ductsEach duct has a pair of tubules to a

segmentEach tubule is opened by a nephrostome

in coelomNear each nephrostome there is an

external glomerulusAll tubules are drained into duct Which opens in cloaca

ArchinephrosLarvae of caecilians and

Hagfish have this type of excretory system

Tissue fluid discharge from glomerulusltltcoelomltlt

Nephrostomeltlttubulesltlt

Archinepric ductsltltcloaca

PRONEPHROS1 Embryonic tubule to appear

hence called as pronephrosAlso called as head kidneyComposed of pronephric ductsConsist of 3 to 15 tubules

segmentally arrangedEach tubules open into coelom

by nephrostomeAlso projecting into coelom

there is an external glomerulus In some cases glomeruli unite

to form glomus

PRONEPHROS All tubules of pronephros open into the

pronephric duct Which opens into cloaca Pronephros is functional only in

embryonic or larval stageand it is soon replaced by mesonephros

Pronephros is retained throughout life in adult cyclostomes and teleost fishes

Filtrate of blood through glomerulusltltcoelomltltnephrostomeltlt

Tubuleltltpronephric ductltltcloaca

MESONEPHROSDevelops from middle part

of intermediate mesodermForm soon after

degradation of pronephrosMesonephros is functionally

better than pronephros bcoz mesonephric tubules

are numerous in numberThey develop internal

glomeruli

MESONEPHROSThey are also termed as

wolffian bodyMesonephros is

functional only in embryos in amniotes

In sharks n caecilians tubules extend posteriorly

Throughout coelom such kidney is called as OPISTHONEPHROS

MesonephrosSoon with the degradation of

pronephros the pronephric duct forms the wolfian or mesonephric duct

In amniotes mesonephros is functional only in the embryos and replaced by metanephros in adults

Nephrpstomes are generally lacking in embryonic amniotes

METANEPHROSArise posterior to the mesonephros Itrsquos the functional kidney of higher

vertebrates or amniotes it is formed from the posterior end

of the nephrogenic mesodermWhen all metanephric tubules

develop all mesonephric ducts disappear except those

Associated with testis in male forming vasa efferentia

It shows greater multiplication and concentration of nephrons

It s functional unit is nephron

METANEPHROSRenal CortexRenal corpuscleConvoluted tubulesRenal MedullaCollecting ductsLoop of HenleEach Minor calyx drains a tree of collecting ductswithin a renal pyramidPyramids are separated by columns of cortical tissuescalled renal columnsThe Renal pyramids

Nephron The tubules differentiates into the 1) Bowmanrsquos capsule 2) Proximal convoluted tubule 3) Loop of Henle 4) Distal convoluted tubule The distal convuluted tubule fuses with the

collecting duct Renal corpuscle = Bowmanrsquos capsuleglomerulus The nephron is

the metanephric excretory unit The origin of the Renal corpuscle and tubules

is distinct from the collecting duct (Metanephric duct) Duct systems merge Renal duct ndash sequence of differentiation renal corpuscle 1048774 proximal tubule 1048774 distal

tubule Loop of Henle elongates into the medulla

URINARY BLADDER

Urinary bladderMost vertebrates have urinary bladder to store

urine before it is dischargedFISHES enlargement of mesonephric ducts

calledTUBAL BLADDERAMPHIBIANS termed as CLOACAL BLADDERAMNIOTES ATLONTOC BLADDERMammals lack cloaca hence the kidney ducts

or ureter lead directly into the urinary bladder which opens into URETHRA

GENITAL SYSTEMVertebrates exhibit sexual reproductionSexes are separate with exception of few

hagfishes and few bony fishesMale gonadshellipTestes hellip produces spermsFemale gonads hellipOvaries hellipproduces ova Gonads originate as a pair of genital ridgesGenerally 1 pair of gonad are present but

some vertebrates have single gonad

TESTES AND MALE GENITAL DUCTS

TESTES Seminiferous tubules sperm factory

Produces sperm Mature spermatozoa will

move to rete testisThen to efferent

dutulesltltepididymisltltvas deferensltlturethra

Testes also act as an endocrine gland produces teststerone

OVARIESOvaries are found in pairs

except in some cyclostomes and teleosts

Ovary shows layer of germinal epithelium showing ova in various stages of development

Mature eggs are releasesd in the oviduct

This process is termed as OVULATION

In the absence of testosteroneThe mesonephric duct degeneratesThe Mullerian duct develops uninhibitedMullerian duct - cranial funnel-shaped opening to thecoelom forms the fimbriare of the infundibulumThe cranial Mullerian duct forms the uterine tubesThe caudal end of the Mullerian ducts fuse to form theuterovaginal canal that later forms the uterus andthe superior vagina

Intromittant organs

useful when fertilization is internal introduce sperm into female reproductive tract

found in some fish some birds reptiles amp mammals

cartilaginous fish - appendages of pelvic fins called claspers direct sperm into female reproductive tract

snakes amp lizards - have pair of HEMIPENES

turtles crocodilians a few birds amp mammals - exhibit an unpaired erectile penis penis - usually a thickening of floor of

cloaca consisting of spongy erectile tissue (corpus spongiosum) with grooves to direct sperm amp ending in a glans penis (sensory endings that reflexly stimulate ejaculation)

GOT BORE