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.

Types of uterus:

(i)Duplex:-

These are the simplest type of uteri.In both the uteri are completely separated and open independently into the vagina through two separate openings e.g.,Rat.

(ii)Biparite:

In these uteri,the lower part of the two uteri are fused and there is a septa in between the two,e.g.,Carnivore mammals.

(iii)Bicornuate:

The lower parts of the 2 uteri are fused with each other but the partition wall is absent,e.g.,Rabbit.

(iv)Simplex:

When both the uteri are completely fused with each-other to form only one structure,these are the most developed uteri e.g.,Man.

Function of uterus:

The uterus plays multiple role.The uterus is site of menstruations,implantation of a fertilized ovum,development of foetus and labour.

4.Vagina:-

It is tubular female copulatory organ,passageway for menstrual flow as well as birth canal of about 10cm length between external opening(vaginal orifice) in vestibule and cervix with depression or fornix around cervix,two longitudinal ridges and numerous transverse folds or vaginal rugae.Vaginal wall is made of an internal mucosa,muscular layer and an outer adventitia.Its mucus membrane is nonkeratinised stratified squamous epithelum.Glands are absent.However, cervical glands do pass on some mucus into it during ovulation.The epithelial cells contain glycogen(from puberty to menopause) which shows cyclic changes which due to decomposition produce organic acid.Certain bacteria (species of Lactobacillus and Lactoneustroc,also called Doderlein's Bacillus) bring about fermentation and produce acid which inhibits growth of other microorganism.In virgins the vaginal orifice is partially covered by an annular centrally perforated membrane called hymen.

5.External genitalia/vulva:

It is tubular female copulatory organ,passageway for menstrual flow as well as
birth canal of about 10cm length between external opening(vaginal orifice)

There is a depression,the vestibule,in front of the uterus.It is flanked by two pairs of fleshy folds of skin.the inner small,thin,moist labia minora and outer larger,hair-covered labia majora.All the labial folds have numerous sebaceous and sweat glands on both sides.A small erectile organ,the clitoris,lies at the anterior junction of the labia minora.It is homologous to the penis in the male but is very small and solid,having no passage through it.It consists of a short-shaft with erectile tissue.It ends in a rounded glans clitoridis.The latter is covered by a small hook of skin,the prepuce.Rubbing of clitoris during intercourse produces a pleasurable sensation.This seems to be its only function.A membranous fold,called fourchette,connects the posterior ends of the labia minora.The area between the fourchette and the anus is termed perineum.Urethra and vagina open by separate aperatures,the upper urethral and lower vaginal orifices,into the vestibule.The vaginal orifice is normally covered in the virgin by a membrane,the hymen.A slit in the hymen allows menstrual flow to pass out.The hymen is ruptured during first copulation,or due to some other reason.The hymen presumably has a protective role,but is absent in many women. A fleshy elevation above the labia majora is known as mons veneris or mons pubis. It bears pubic hair,made up of adipose tissue.

6.Bartholins or vestibular glands:

They are a pair of small glands which open in the vestibule lateral to vaginal orifice.The secretion is thick,viscid and alkaline for lubrication and counteracting urinary acidity(similar to Cowper's gland in males).

Breasts/Mammary glands