Life Sciences tutorial.

Life Sciences tutorial.. For Grade 12..

Introduction. During sexual reproduction in humans, a haploid male gamete with 23 chromosomes fuses with a haploid female gamete also with 23 chromosomes to form a single diploid cell called the zygote with 46 chromosomes/23 pairs of chromosomes. This zygote undergoes mitosis several times to produce an embryo. The cells of the embryo become differentiated to for our various body parts..

Male reproductive system.. Grade 12 IEB Life sciences notes reproductive systems.

Female Reproduction system.. 4. Premium Vector Female reproductive system with labelled.

SPERMATOGENESIS. Diagram Description automatically generated.

OOGENESIS. 6. Oogenesis refers to the process by which ova are produced from the germinal epithelium of the ovaries. It occurs as follows The germinal epithelium in the ovary undergoes mitosis. To form numerous follicles. One cell inside a follicle gets larger and undergoes meiosis. Of the four cells that are formed only one survives to form a mature ovum..

Menstrual cycle Females who reach puberty undergo a reproductive cycle called the menstrual cycle. The menstrual cycle is the change that occur in the ovary and uterus of a female over a period of about 28 days so that fertilization can take place. There are two separate cycles that make up the menstrual cycle: the ovarian cycle and the uterine cycle. The ovarian cycle and ovulation The ovarian cycle describes what occurs inside the ovary as the ovum develops inside the Graafian follicle, which then releases the ovum to become the corpus luteum..

The ovarian cycle and ovulation.. 8. The follicle-stimulating hormone is produced by the hypophysis/pituitary gland. FSH stimulates the development of the Graafian follicle containing a mature ovum. The Graafian follicle produces the hormone estrogen which starts the preparation of the uterus for attachment of the fertilized ovum. The Graafian follicle produces the hormone estrogen which starts the preparation of the uterus for attachment of the fertilized ovum. Approximately every 4 weeks (28 days). The Graafian follicle raptures (breakdown open) to release an ovum. This is called ovulation. The ovum is collected by the funnels of the Fallopian tube. The luteinizing hormone (LH, also produced by the pituitary gland\hypophysis, helps convert the ruptured follicle into a structure called a corpus luteum. The corpus luteum secretes the hormone progesterone which maintains pregnancy. If fertilization does not take place, the corpus luteum degenerates and progesterone production drops. The unfertilized ovum passes down the fallopian tube, into the uterus and leaves the body through a process known as menstruation..

The Uterine Cycle and Menstruation. Diagram Description automatically generated.

The Uterine Cycle and Menstruation. 10. Diagram Description automatically generated.