close

the human lifestyle cycle

 the human existence cycle Dissertation

п»ї

Spermatogenesis

Spermatogenesis is a production with the male gametes (reproductive or sex cell) otherwise referred to as sperm. The production of semen takes place in the seminiferous tubules within the testes and are shaped from skin cells by a form of cell section called mitosis and then meiosis. This process starts at growing up.

Spermatogonia cells are made simply by mitotic division of the determinant germ cell. Mitotic cellular division makes diploid cellular material that are the same to the Parent or guardian cell with 46 chromosomes.

The Spermatogonia increases in size and mass and turns into a spermatocyte which then divides simply by meiosis. Meiotic cell division results in several haploid skin cells each with 23 homologous chromosome pairs.

Secondary spermatocytes are created by the first meiotic division.

The second meiotic division generates two spermatids from each secondary spermatocyte.

The spermatids now grow a cytoskeletal structure plus the flagellum begins to grow. The flagellum abounds with mitochondria which will provide energy for motility.

The spermatids DNA is highly condensed plus the nucleus turns into surrounded by the Golgi human body. The acrosome develops which is full of digestive enzymes that will allow the ejaculate to enter the oocyte.

Mature spermatozoon is created under the influence of testosterone from the leydig cells in the testes. This kind of hormone as well removes unneeded cytoplasm and organelles. The excess cytoplasm is now consumed simply by endocytosis through the surrounding sertoli cells in the testes.

The mature spermatozoon is now suspended in the lumen, it will after that break away and float over the tube on the epididymis to get storage.

Oogenesis

Oogenesis is definitely the production from the female gametes otherwise known as the Ova or Egg. This process begins inside the ovaries before birth. Prior to Birth

Oogonia are made by mitotic division of the esencial germ cell.

As a result of mitosis from your germinal epithelium the oogonia becomes between follicle cellular material forming a structure known as the primary hair follicle. Theses major follicles then migrate to the centre of the ovary.

When the oogonia begin the initial meiotic split they are called Primary Oocytes which are diploid. Primary oocytes stay in meiosis phase you until the girl reaches puberty. They develop size although don't fully divide.

At Birth

At birth you will find around 4 hundred, 000 principal follicles inside the human female ovaries.

In puberty and menopause

By puberty meiosis phase 1 is finish. The release of hormones cause the oocyte inside the hair follicle to divided by meiosis just before after. A secondary oocyte is formed together with a small cell called a polar body. The polar human body will after degenerate and stay absorbed into the body.

The follicle that contain the extra oocyte continually mature till a surge inside the hormones FSH and LH initiates after. This produces the secondary oocyte within a process known as meiosis period 2 which will cannot be completed until fertilisation occurs.

During and After Sexual activity

The extra oocyte goes in the oviduct where fertilisation can take place. Meiosis phase 2 is completed when a sole sperm gets into the cytoplasm of the second oocyte

The cytoplasm divides unequally producing a second extremely body and mature ovum. The fusion of the haploid ova cell and the haploid sperm cell creates a diploid zygote.

Cellular Division

Mitosis Meiosis Prophase

Prophase 1

Metaphase

Metaphase 1

Anaphase and telophase

Anaphase 1

Telophase you

Meiosis a couple of

The difference between spermatogenesis and oogenesis

Spermatogenesis

Oogenesis

Takes place in the...

Sources: Human Biology, Seventh Edition, Sylvia T. Mader

www.nhs.uk/livewell/contraception

http://www.xtremepapers.com/revision/gcse/biology/characteristics_of_living_organisms.php

School Notes

Category Power Factors

 Research Newspaper

Research Newspaper

Interracial Going out with: The Effects of Competition for Starting a Romantic Relationship Tina Meters. Harris Department of Presentation Communication School of Atlanta Athens, Atlanta, USA…...

Read
 Creative Play Essay

Creative Play Essay

Creative Play Creative development is definitely provided within just settings through role perform, music, dance and messy activities. Imagination can stem to a array of other things to, such…...

Read