Welcome to Zoology World

balindrakumar033@gmail.com   25/11/2017,Saturday

WELCOME TO ZOOLOGY WORLD

The science or study of animal life. Together with botany, the study of plant life, it forms the science of biology. Zoology is such a vast subject that most zoologists specialize or focus on the study of particular organisms or taxonomic groups. tion of animals.

Female reproductive system:

The female reproductive system consists of a pair of ovaries,a pair of fallopian tubes,uterus,vagina,external genitalia or vulva and breasts.

Reproductive system:

1.Ovaries:-

Ovaries are the primary sex organs of female.The ovaries are almond shaped bodies,about 3cm long,1.5cm wide and 1cm thick.The ovaries, like the testes,have both an exocrine function(production of ova) and an endocrine role(secretion of female sex hormone:oestrogen and progesterone). After menopause,the ovaries become small and lose follicles.

Each ovary is located close to the lateral walls of the pelvic cavity,being suspended from the dorsal body wall just behind the kidney,by a section of peritoneum,the mesovarium.

Ovaries are the primary sex organs of female.The ovaries are almond
shaped bodies,about 3cm long,1.5cm wide and 1cm thick. Each ovary is a compact or solid organ,consisting of an outer cortex and inner medulla. The stroma of the cortical region is composed of spindle shaped fibroblasts. A poorly delineated dense connective tissue layer,the tunica albuginea,covers the cortex.It imparts the whitish colour to the ovary.Located outside the tunica albuginea,the germinal epithelium,formed of simple squamous or cuboidal epithelial cells,covers the surface of the body.

Ovaries are the primary sex organs of female.The ovaries are almond
shaped bodies,about 3cm long,1.5cm wide and 1cm thick.

2.Fallopian tube/Uterine tubes/ Oviducts:-

Each ovary is located in front of a funnel shaped opening of the uterus, the oviduct.The oviduct is a muscular tube,measuring about 12cm in length.Its lumen is lined by ciliated epithelium.Oviduct develop from the mullerian duct of the embryo.It conveys the egg from the ovary to the uterus,and provides the appropriate environment for its fertilization.It is supported by a double fold of peritoneum called mesosalpinx.The wall of oviduct is made of three layers:-

(i)Serosa:->

It is the outermost layer of visceral-peritoneum.

(ii)Muscle-layer:->

The middle layer of the oviduct is made up of unstriped-muslce.

(iii)Mucus membrane:->

It is the innermost layer.This layer is made up of ciliated columnar epithelium and the connective tissue.

The oviduct shows 4 regions:

(a)Infundibulum:-

It is the broad,funnel-shaped part.Its margin bears motile,finger-shaped
processes called fimbriae.It opens into the body cavity by an aperture called ostium.
The latter lies close to the ovary to receive the egg released from the ovary.

It is the broad,funnel-shaped part.Its margin bears motile,finger-shaped processes called fimbriae.It opens into the body cavity by an aperture called ostium. The latter lies close to the ovary to receive the egg released from the ovary.The fimbriae bear cilia which beat toward the ostium to direct the egg into the infundibulum.

(b)Ampulla:-

It is the long,wide,thin-walled,tortuous major part of the fallopian tube next to the infundibulum.Ampulla is site for fertilization.

(c)Isthmus:-

It is very short,narrow,thick-walled,straight part that follows the ampulla.

(d):Uterine part:-

It is also narrow and passes through the uterine wall,and communicates with the uterine cavity.

3.Uterus:-

It is pyriform,hollow muscular thick-walled but distensible median structure located above and behind urinary bladder that is meant for nourishing and development of foetus.For this uterus is capable ofo tremendous enlargement.The empty uterus is 7.5cm long and 5cm broad and 2.5cm thick.Lining layer of uterus,called endometrium(mucus membrane),consists of an epithelium and lamina propria of connective tissue.Epithelium is a mixture of ciliated and secretory columnar cells.Lamina propria contains tubular glands,fibroblasts and blood vessels.

Histologically,uterus consist of 3 layers of tissue perimetrium,myometrium and endometrium.Perimetrium composed of ciliated columnar epithelia. The normal position of the uterus is antiflexed,that is,it is bent forward on itself at the level of the internal os so as to lie almost horizontally over the bladder. The cervix is composed largely of the biggest and the most powerful sphincter muscle in the body.It is strong enough to hold about 7kg.of foetus and fluid in the uterus against the pull of gravity during pregnancy. The cavity of the uterus can expand 500 times during pregnancy,from 10cm3 to 5,000cm3

Types of uterus