comparative anatomy

1. PRESENTED BY:FATIMA KHARBE

2. URINOGENITALSYSTEM
o 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

3. BASIC STRUCTURE OF EMBRYONIC KIDNEY
Pair of compact organs lying on
either side of dorsal aorta.
Each kidney is composed of large
no of units called as
URINIFEROUS TUBULES OR
NEPHRONS.
Kidney tubules arise in the embryo
in a linear series from mesoderm.
Each uriniferous tubule is
differentiated into 3 parts.
1.PERITONEAL FUNNEL
2.MALPIGHIAN BODY
3.TUBULE

4. Urinary System - Kidneys
Kidneys are pair of compact
organs lying on either
Side of dorsal aorta.
Evolution of kidney takes place
as:
ARCHINEPHROS
PRONEPHROS
MESONEPHROS
METANEPHROS

5. ARCHINEPHROS
Excretory organ of ancestral vertebrates.
Also called as HOLONEPHROS 0r
complete kidney as it runs throughout
the entire length of coelom.
Composed of pair of archinephric ducts.
Each duct has a pair of tubules to a
segment.
Each tubule is opened by a nephrostome in
coelom.
Near each nephrostome there is an external
glomerulus.
All tubules are drained into duct
Which opens in cloaca.

6. Archinephros
 Larvae of caecilians and
Hagfish have this type of
excretory system.
Tissue fluid discharge from
glomerulus<<coelom<<
Nephrostome<<tubules<<
Archinepric ducts<<cloaca.

7. PRONEPHROS 1 Embryonictubuleto appearhencecalledas pronephros.
 Alsocalledashead kidney.
 Composedof pronephricducts.
 Consistof 3to 15 tubulessegmentallyarranged,
 Eachtubulesopenintocoelomby nephrostome.
 Alsoprojectingintocoelomthereisanexternal glomerulus.
 Insomecasesglomeruliuniteto formglomus.

8. PRONEPHROS
 All tubules of pronephros open into the pronephric duct.
 Which opens into cloaca..
 Pronephros is functional only in embryonic or larval stage,and
it is soon replaced by mesonephros.
 Pronephros is retained throughout life in adult cyclostomes
and teleost fishes.
 Filtrate of blood through
glomerulus<<coelom<<nephrost
ome<<
 Tubule<<pronephric
duct<<cloaca.

9. MESONEPHROS
 Develops from middle part of
intermediate mesoderm.
 Form soon after degradation of
pronephros.
 Mesonephros is functionally
better than pronephros
 bcoz mesonephric tubules
are numerous in number.
 They develop internal
glomeruli.

10. MESONEPHROS
 They are also termed as
wolffian body.
 Mesonephros is functional
only in embryos in amniotes.
 In sharks n caecilians tubules
extend posteriorly
 Throughout coelom such
kidney is called as
OPISTHONEPHROS.

11. Mesonephros
 Soon 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.

12. METANEPHROS
 Arise posterior to the mesonephros.
 It’s the functional kidney of higher
vertebrates or amniotes.
 it is formed from the posterior end of the
nephrogenic mesoderm.
 When 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.

13. METANEPHROS
Renal Cortex:
Renal corpuscle
Convoluted tubules
Renal Medulla:
Collecting ducts
Loop of Henle
Each Minor calyx drains a tree
of collecting ducts
within a renal pyramid
Pyramids are separated by
columns of cortical tissues
called renal columns
The Renal pyramids

14. Nephron
 The tubules differentiates into the
 1) Bowman’s capsule
 2) Proximal convoluted tubule
 3) Loop of Henle
 4) Distal convoluted tubule
 The distal convuluted tubule fuses with the
collecting duct Renal corpuscle = Bowman’s
capsule/glomerulus. 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 – sequence of differentiation
 renal corpuscle 􀃆 proximal tubule 􀃆 distal
tubule
 Loop of Henle elongates into the medulla

16. URINARY BLADDER

17. Urinary bladder
Most vertebrates have urinary bladder to store urine
before it is discharged.
FISHES: enlargement of mesonephric ducts called
TUBAL BLADDER.
AMPHIBIANS: termed as CLOACAL BLADDER.
AMNIOTES: ATLONTOC BLADDER
Mammals lack cloaca hence the kidney ducts or ureter
lead directly into the urinary bladder which opens into
URETHRA

18. GENITAL SYSTEM
 Vertebrates exhibit sexual reproduction.
 Sexes are separate with exception of few hagfishes and
few bony fishes.
 Male gonads…..Testes ….. produces sperms
 Female gonads …..Ovaries ….produces ova
 Gonads originate as a pair of genital ridges.
 Generally 1 pair of gonad are present but some
vertebrates have single gonad.

19. TESTES AND MALE GENITAL
DUCTS.
 TESTES: Seminiferous
tubules: sperm factory
 Produces sperm
 Mature spermatozoa will
move to rete testis
 Then to efferent
dutules<<epididymis<<vas
deferens<<urethra.
 Testes also act as an endocrine
gland produces teststerone.

21. OVARIES
Ovaries 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.

24. In the absence of testosterone:
The mesonephric duct degenerates
The Mullerian duct develops uninhibited
Mullerian duct - cranial funnel-shaped opening to
the
coelom forms the fimbriare of the infundibulum
The cranial Mullerian duct forms the uterine tubes
The caudal end of the Mullerian ducts fuse to form
the
uterovaginal canal that later forms the uterus and
the superior vagina

25. nt organs:
 useful when fertilization is internal; introduce sperm
into female reproductive tract
 found in some fish, some birds, reptiles, & mammals
 cartilaginous fish - appendages of pelvic fins
called claspers direct sperm into female
reproductive tract
 snakes & lizards - have pair of HEMIPENES
 turtles, crocodilians, a few birds, & 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 &
ending in a glans penis (sensory endings that
reflexly stimulate ejaculation)

26. GOT BORE??