Urogenital system of Anamnia

In Anamnia females pronephros is not secreted urine and reduced when mesonephros is appeared. Remain of funnel increased in size and together with ureter of pronephros converted to oviduct. After maturation of ovum in ovary and ovums discharge into body cavity then into funnel and oviduct. Products of dissimilation excreted through primary nephos and it ureter or mesonephros duct, or Wolfov’s duct.

In Anamnia males in embryonic period occurs complete reduce the pronephros, disappear excretory ducts and ureter and arise connection between testis and mesonephros. Mesonephros operates as excretory organ and ureter serves for excretion urine as well as sexual cells (urogenital duct – Wolfov’s duct).

Urogenital system of Amniota Lowest Amniota (Lizard)

Secondary nephros is appeared. Pronephros and mesonephros not secrete urine.

In Amniota females from the rest of a pronephros and its ureter oviduct is develop. Oviduct is differentiated in a number of divisions, for mammals into three parts: fallopian tubes or oviducts, uterus and vagina.

Fallopian tubes are tubes that carry the eggs from the ovary to the uterus. These are not attached to ovaries but have a funnel shaped fimbriated opening to receive the eggs as they mature. Each fallopian tube is lined with cilia to help the egg move towards the uterus. If sperms are present, fertilization takes place in the upper end of the fallopian tubes.

Uterus. The two fallopian tubes open into a thick walled muscular organ the uterus. It is the uterus in which the embryo gets implanted and develops. The inner lining of uterus called endometrium is richly supplied with blood vessels and glands.

Vagina. It is a large muscular tube that runs from the uterus to the outside.

In Amniota males pronephros and its ureter completely reduce. Excretory tubules of mesonephros preserved and transformed to epididymus. From number of small tubules called vasa efferentia emerge that fuse in the head of epididymus. All vasa efferentia open into a single coiled tube called epididymus. And urethra of primary nephros transformed to vas deferens. Epididymus leads into the vas deferens. The sperms formed in the seminiferous tubules pass through vasa efferentia and are stored in the epididymus in each testis. They get concentrated and get matured before they enter the vas deferens which is short straight tube that ascends into the abdominal cavity. Vas deferens loops over the urinary bladder and opens into the common urethra. Urethra passes through the penis which is made up of spongy muscle tissue.

Highest Amniota (Rats)

For highest mammals in males emerge near the bladder a pair of glands called seminal vesicles open into the vas deferens. A little further another gland – prostate and a pair of Cowper’s glands also open into the urethra. So the urethra receives the secretions of the glands, sperms and urine.

Seminal vesicles are present behind the urine bladder and their secretions contain fructosae an energy source for the sperms.

Prostate gland. It adds alkaline secretion to the fluid which is essential to neutralize the acidic secretions present in the vagina.

In females ovaries are paired structures which are present in the abdominal cavity and contains thousands of developing follicles. The inner surface of the ovary is covered with a germinal epithelium which gives rises to the follicles and ova. The inner part is called the stroma which contains the developing follicles with egg in various stages of development. The mature follicle finally ruptures to release the mature egg into the surrounding peritoneal cavity from where it is picked up by the fimbriated opening of the fallopian tube. In uterus the embryo gets implanted and develops for nine month during pregnancy.

The females have separate urinary (urethral) and vaginal openings unlike the males where there is one common duct called urethra for urinary as well as seminal discharge.