Sexual and AsexualReproduction Sexual reproduction occurs when a new individualis formed through the union of two sex cells(gametes). produce zygote Haploid gametes formed by meiosis in sex organs(gonads). Asexual reproduction occurs when geneticallyidentical cells are produced from a single parentcell by mitosis. fission or budding
Gametogenesis Gamete production By meiosis The chromosomal number in gamete is half ofchromosomal number in parent cell Gamete will carry different genetic constitution
-Testis is located in scrotum, outside the body to maintain the lowtemperature [suitable for gamete production]-Inside the testes, seminiferous tubule is densely coiled, connected toepididymis that connected to vas deferans that connected to semenalvesicle.
Male Reproductive SystemMale accessory sex organs epididymis vas deferens seminal vesicles prostate gland urethra
1. Prostate gland - large gland behindurinary bladder and producesseminal fluid.2. Seminal vesicles - paired glands atbases of vas deferentia and produceseminal fluid.Seminal fluid serves as a lubricant,pH buffer, and nutrient (high insugars) seminalvesicleprostate
Male Reproductive SystemHormonal control of male reproductionFSH stimulates the Sertoli to facilitate spermdevelopment.LH stimulates Leydig cells to secretetestosterone.Principle negative feedback inhibition appliesto FSH and LH secretion.
OogenesisOvum production processOccurs in ovaryOocyte develop simultaneously withthe development of follicle.
Female Reproductive SystemMenstrual and estrous cycles At birth, a female’s ovaries containapproximately 2 million follicles.Some follicles are stimulated todevelop each cycle.Human menstrual cycle lastsapproximately one month, and iscommonly divided into a follicularphase and a luteal phase.
Hormone involvePituitary secretes: FSH [Follicle Stimulating Hormone] stimulate thedevelopment of follicle in the ovary LH [Luteinizing – stimulate ovulationFrom ovary: Follicle cells produce Estrogen- – stimulate the endometrial wall (uterine lining) aftermenstrual Corpus luteum produces Progestrone- – stimulate and maintain the thickness of endometrial.
Identical twin Produce after fertilization of an ovum by a sperm Membentuk satu zigot Diperingkat morula berlaku pemisahan tisu kepada dua – dua fetusberkembang serentak Berkongsi plasenta Ciri-ciri: Jantina sama Rupa paras sama
Infertility has been defined as theinability of a couple to conceiveafter one year of regular intercoursewithout the use of contraceptives.The definition has also cometo include couples who are able toconceive but, due to repeated miscarriages,are unable to carry a pregnancy to term.
causes of infertility>>>In men, these include environmentaland hormonal factors that affect the production ofhealthy, motile sperm and normal semen, as well asblockages that affect the delivery of sperm>>>In women, the causes are more varied since she plays agreater role in reproduction. First, one of the organs involvedin reproduction may be absent, mal-formed or non-functional.Second, the organs may be normal, but the complexhormonal feedback system that is necessary tosupport follicular development, ovulation and implantationof the fertilized egg may be disrupted
If there are enough sperms ?>>less than 20 million sperm per ml,this is considered to be a lowsperm count.>>Less than 10 million is very low.
# Whether the sperms aremoving well or notGrade a ( fast progressive) sperms are thosewhich swim forward fast in a straight lineGrade b ( slow progressive) sperms swim forward,but either in a curved or crooked line,Grade c ( nonprogressive) sperms move their tails,but do not move forward ( local motility only).Grade d ( immotile ) sperms do not move at all
Whether the sperms arenormally shaped or not>> a good sperm should have a regularoval head, with a connecting mid-pieceand a long straight tail.>> abnormal* round heads;* pin heads;* very large heads;* double heads;* absent tails