11.4 production of gametes

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11.4 Production of Gametes

Topic 11 Human Health & Physiology

Spermatogenesis 11.4.1 Annotate a light micrograph of testis tissue to show

the location and function of interstitial cells (Leydig cells), germinal epithelium cells, developing spermatozoa and Sertoli cells.

11.4.2 Outline the processes involved in spermatogenesis within the testis, including mitosis, cell growth, the two divisions of meiosis and cell differentiation.

(The names of the intermediate stages in spermatogenesis are not required.)

11.4.3 State the role of LH, testosterone and FSH in spermatogenesis.

Oogenesis 11.4.4 Annotate a diagram of the ovary to show the

location and function of germinal epithelium, primary follicles, mature follicle and secondary oocyte.

11.4.5 Outline the processes involved in oogenesis within the ovary, including mitosis, cell growth, the two divisions of meiosis, the unequal division of cytoplasm and the degeneration of polar body.

(The terms oogonia and primary oocyte are not required.)

Gametogenesis 11.4.6 Draw and label a diagram of a mature sperm and

11.4.7 Outline the role of the epididymis, seminal vesicle and prostate gland in the production of semen.

11.4.8 Compare the processes of spermatogenesis and oogenesis, including the number of gametes and the timing of the formation and release of gametes.

Structure of the Testis

Ref: Biology for the IB Diploma, Allott

Spermatogenesis

Summary of Spermatogenesis

Hormonal control of Spermatogenesis Three hormones are involved in the production of sperm. FSH (Follicle Stimulating Hormone).

Produced in the pituitary gland (brain). Stimulated primary spermatocytes to undergo the first meiotic

division to form secondary spermatocytes. Testosterone.

Produced in the interstitial cells in the testies Stimulates the development of secondary spermatocytes into

mature sperm. LH (Lutenising Hormone) - (ICSH will not be used)

Produced in the pituitary gland (brain). Stimulates the secretion of testosterone by the testis

Production of Semen Three structures help to produce semen:

The epididymis. Sperm arrive here unable to swim. The sperm mature while they are stored in the epididymis and learn

to swim. Seminal vesicles.

Produces fluid which contains nutrients for the sperm (fructose). Also contains mucus which protects the sperm in the vagina.

Prostate gland. Produces a fluid which contains mineral ions. The fluid is also alkaline to protect the sperm in the acidic

conditions of the vagina.

Structure of Mature SpermRef: Biology for the IB Diploma, Allott

Ref: Yr11 Biology, Biozone

Structure of the Ovaries

Oogenesis

Summary of Oogenesis

Structure of a Mature Egg

Spermatogenesis and Oogenesis Compared

Spermatogenesis Millions produced daily Released during ejaculation.

Sperm formation starts during puberty in boys.

Sperm production continues throughout the adult life of men.

Four sperm produced per meiosis.

Oogenesis One matures every 28 days Released on about day 14 of

menstrual cycle by ovulation. The early stages of egg

production happen during fetal development in females.

Egg production becomes irregular and then stops at menopause in women.

Only one egg is produced per meiosis.

IBO guide: 11.4.1 Annotate a light micrograph of testis tissue to show