comparative anatomy - reproductive system

REPRODUCTIVE SYSTEM

Briones, Abigail LorenCelajes, Chrizz ShainneMontuya, Robert AngeloOkamoto, Eigi

INTRODUCTION

FUNCTION OF GENERAL

STRUCTURES

Function of General Structures• Female Reproductive System• The female external reproductive structures include the clitoris

and two sets of labia• The internal organs are a pair of gonads and a system of ducts

and chambers that carry gametes and house the embryo and fetus

• Ovary• Follicle • Mesovarium

Cont.• Female Reproductive System• Oviducts and Uterus• Oviduct or Fallopian tube• Cervix • Vagina and Vulva

OOGENESIS

Cont.• Male Reproductive System• The male external reproductive structures in most mammals

include the scrotum and the penis.• The internal organs consists of gonads, which produces

sperm and hormones, and accessory glands.

• Testes• The male gonads, or testes, consist of highly coiled tubes

surrounded by connective tissue.• Seminiferous tubules.• Production of normal sperm cannot occur at the body

temperatures of most mammals

Cont.• Male Reproductive System

• Ducts• seminiferous tubules • Epididymis • Vas deferens• Urethra.

• Glands• Seminal vesicle, • Prostate• Bulbourethral (Cowper’s) gland• Seminal fluid, or semen.

COMPARATIVE ANATOMY OF

DIFFERENT CLASSES OF VERTEBRATES

Female Reproductive SystemOvary

• Development

-Germinal epithelium thickens and covers the indifferent gonad (consists of cortex and medulla)

-♀ , migrating germ cells cortex – primary sex cords = secondary sex cords-follicle ripening egg cells theca-blastema becomes stroma or matrix

Kardong, K. V. 2000. Fig. 14.19 & 14.16. Embryonic Formation of the Gonad & Female reproductive system (humans).

Female Reproductive SystemOvary

• Structure

Crocodilians, Turtles, Birds, and Mammals-solid and compact with much stroma

Cyclostomes, Cartilaginous Fishes, Dipnoans, and some Primitive Ray-Finned Fishes

-solid but less compact Amphibians

-stroma is absent-soft and pleated

Teleosts-hollow ovaries

Female Reproductive SystemFemale Ducts

• Opistonephric Ducts and Ureters

-convey only urine in females

Sharks and Urodeles-drains with accessory ducts

Amniotes (Reptiles, Birds, and Mammals)-leaves vestiges

Shark Salamander

Kardong, K. V. 2000. Fig. 14.24 & 14.27. Oviducts of female fishes & Urogenital anatomy of tetrapod females

Amniotes

Kardong, K. V. 2000. Fig.14.27. Urogenital anatomy of tetrapod females

Female Reproductive SystemFemale Ducts

• Oviducts-anterior end funnels w/ openings-ciliated columnar epithelium-peristaltic contraction

Teleostei-ovaries encloses pockets of coelom

Chondrichthyes-fuse in the midline-some are oviparous (shell glands)• Mermaid purse

Amphibians-glandular and coiled oviducts-posterior portion coat of jelly

Kardong, K. V. 2000. Fig. 14.24. Oviducts of female fishes.

Lauder, Bermis, et. al. Fig. 21.15. Reproductive tracts of female anamniotes

Teleostei

Chondrichthyes

Lauder, Bermis, et. al. Fig. 21.15. Reproductive tracts of female fishes.

Wyatt, M. 2007.

Female Reproductive SystemFemale Ducts

• Oviducts Reptiles, Birds, and Monotremata

-large eggs and genital tracts vary widely-large and pleated ovarian funnels-glandular anterior portion albumen-enlarges near the cloaca shell gland and ovisac

Reptilesright side is larger

Birdsright side is vestigial

Female Reproductive SystemFemale Ducts

• Oviducts Therian Mammals

Oviducts-ciliated epithelium-straight and slender; w/o albumen or shells

Uterus-Endometrium-Myometrium-Cervixo Types of Mammalian Uterus

• Duplex (Monotremes, Marsupials, Elephants and many Rodents)

• Bipartite (most Ungulates and most Carnivores)• Bicornuate• Simplex (most Primates and some Edentates

Marieb. Figure 27.14a.

Kardong, K. V. 2000. Figure 14.52. Reproductive organs of female eutherian mammals.

Female Reproductive SystemFemale Ducts

• Oviducts Therian Mammals

Vagina-stratified epithelium-receives penis during copulation-serves as birth canal-soft and distensible; glandular or cornified

Female Reproductive SystemFemale Ducts

• Oviducts Marsupials

-terminal part of the tract fuses single urogenital canal-two embryonic uteri and vaginae-third pseudovagina grows

Kardong, K. V. 2000. Figure 14.51. Reproductive organs of female marsupials.

Development and Structure of Testes

• Indifferent gonad - early developmental stage is similar in both sexes which includes cortex and medulla.

• Germinal epithelium forms only the peritoneal covering of adult testes.

• Primary sex cords do NOT degenerate and secondary sex cords are NOT formed.

• Testes are paired except in CYCLOSTOMES.

• Each testis is suspended from the dorsal wall of a coelom by a mesentery called the mesorchium.

• Testes are paired but may be partially fused as in ELASMOBRANCHS, or completely fused as in ADULT CYCLOSTOMES.

• Testes are elongated in CYCLOSTOMES, MOST FISHES, CAECILIANS, and URODELES.

• Testes are compact and ovoid in some CARTILAGINOUS FISHES, ANURANS, and AMNIOTES.

Kardong, K.V. 2000. Figure 14.19

Kardong K.V. 2000. Figure 14.32

Hagfish Elasmobranch Lungfish Teleost

Cont.

• Testes are elongated in CYCLOSTOMES, MOST FISHES, CAECILIANS, and URODELES.

• Testes are compact and ovoid in some CARTILAGINOUS FISHES, ANURANS, and AMNIOTES.

• BIRDS- abdominal air sacs; MAMMALS (PRIMATES – MOST CARNIVORES, and MOST UNGULATES) – scrotum; MAMMALS (MONOTREMES, WHALES, ELEPHANTS) – testes are abdominal or pelvic in position if body temperature is relatively low.

Male Ducts

•Except in CYCLOSTOMES, sperms are released in a closed system of ducts.

•Deferent ducts carries either the sperm or both sperm and urine.

•CHONDRICHTHYANS have paired deferent ducts that convey ONLY SPERM.

•Several PRIMITIVE RAYFINNED FISHES and SOME DIPNOANS pass sperm into the anterior end of deferent duct which convey both sperm and urine.

•All AMPHIBIANS have deferent ducts, some species convey ONLY SPERM and in others BOTH sperm and urine.

•Deferent ducts of AMNIOTES carry ONLY SPERM.

Copulatory (Intromittent) Organs and Fertilization

• CYCLOSTOMES and MOST BONY FISHES lack copulatory organs.

• SOME TELEOST retained their eggs during development or bear live young.o Gonopodium- margin of the anal fin as copulatory organ in males.

• CARTILAGINOUS FISHES also have INTERNAL fertilization.o Claspers- pelvic fins as copulatory organ in males.

• ANURANS have EXTERNAL fertilization. Hence, they don’t have copulatory organs.

• URODELES have INTERNAL fertilization but LACK copulatory organs. o Cloacal kiss ( male and female press their cloacas together to transfer sperm)

Cont.

• TURTLES and CROCODILES have evolved a grooved penis. (it is located internally on the floor of the cloaca.o Small clitoris are present in female turtles and crocodiles.

• BIRDS copulate by pressing the cloacas together for the transfer of sperm.o Primitive birds (OSTRICHES, DUCKS and GEESE) have a small penis.

• THERIAN MAMMALS have a penis formed from the genital tubercle located anterior to the cloacal opening.

• Glans is variously shaped and is forked in MONOTREMES and MARSUPIALS.

Cloaca and Derivatives• Development

-Nephric and Paramesonephric ducts extends posteriorly to the hindgut

-common passageway for urinary, digestive, and reproductive systems (primitive condition)-L. word “cloaca” = “sewer”-3 fuctions: defecation, urination, and copulation-3 compartments:

Coprodeum- most proximal; empties intestine Urodeum- receives products from the urinary and

genital ducts Proctodeum- copulation; in many amniotes develops

a penis

Kardong, K.V. 2000. Figure 14.47. Diagrams of sagittal sections of tetrapod cloacae.

Cloaca and Derivatives• Development

-Hans Gadow- clocal compartments separated by folds Rectocoprodeal Fold- between intestine and

coprodeum Coprourodeal Fold- between coprodeum and

urodeum Uroproctodeal Fold- between urodeum and

proctodeum

Kardong, K.V. 2000. Figure 14.49. Bird cloacae.

Cloaca and Derivatives Adult Hagfishes, Elasmobranchs, Dipnoans, Amphibians,

Reptiles, and Birds-retains primitive condition

Kardong, K.V. 2000. Figure 14.46, 14.48, 14.49. Cloacal and anal regions of fishes, Cloaca of the lizard Coleonyx,Bird cloacae.

Cloaca and Derivatives Adult Lampreys, Chimaeras, and Bony Fishes

-Rectum no longer joined by the urogenital ducts-Nephric and genital ducts independently/ fuse to exit at

a common papilla anus

Kardong, K.V. 2000. Figure 14.46. Cloacal and anal regions of fishes.

Cloaca and Derivatives Monotremes

-cloaca is partly divided by a septum resulting into three structures:

Dorsal Coprodeum Ventral Urodeum- joined by ureters and

paramesonephric duct Common posterior Proctodeum

Kardong, K.V. 2000. Figure 14.47. Diagrams of sagittal sections of tetrapod cloacae..

Cloaca and Derivatives Therian Mammals

-embryonic septum continues to push back dorsal rectum is completely separated

Kardong, K.V. 2000. Figure 14.50. Embryonic derivatives of the urogenital sinus in some eutherian mammals..

Cloaca and Derivatives Therian Mammals

Males-urine and sperm release through common urethra

Females• Most Mammals

-urinary and genital tracts exit by a common urogenital sinus

• Primates and some Rodents-Fetal eversion anterior urethral opening and posterior urethral opening

Kardong, K.V. 2000. Figure 14.50. Embryonic derivatives of the urogenital sinus in some eutherian mammals..

COMPARISON AND CONTRAST OF ORGANS PRESENT ON DIFFERENT

CLASSES

Lauder, Bermis, et al. Fig. 21.28

END….. Thank you