Reproduction

• Sexual reproduction is a process involving the fusion of the nuclei of two gametes to form a zygote
• Fertilisation is the fusion Of the sperm and ovum to form a diploid zygote
• Male

  1. Scrotum (keep the testis at lower temperature, optimal for sperm production)
  2. testis ( produced sperms and male sex hormones)
  3. sperm duct (pathway travelled by the sperm from testis to urethra)
  4. Urethra (pathway for urine or semen to travel through the penis to outside of the body)
  5. penis ( organ that deposits semen into vagina during sexual intercourse)
  6. Prostate gland ( releases fluid that contains nutrients and enzymes that helps activate sperms)
• Female

  1. Ovary (produces eggs and female sex hormones such aS oestrogen and progesterone)
  2. Oviduct/fallopian tube (narrow muscular tube where mature eggs are released and bough to uterus. Fertilisation occurs here)
  3. uterus ( where the foetus develops)
  4. uterine lining ( needed for embryo implantation)
  5. cervix ( circular ring of muscle that enlarges to allow delivery)
  6. vagina (where semen deposited during sexual intercourse)
• Puberty; stage of human growth, body becomes capable of reproduction. sex organs mature and sex hormones released
• Menstrual cycle (21-33days, avg28) Menstruation and ovulation. Menstruation is the process where broken down uterine lining and blood discharged from uterus via vagina. Ovulation is the release of egg from ovaries (d14). Fertile period (d11-17) fertilisation more high chance if have sexual intercourse
• before ovulation, oestrogen secreted ( repair and grow uterine lining). After ovulation, progesterone secreted (thickens and maintains uterine lining for implantation of embryo if fertilisation occurs) if no fertilisation, hormone production decrease and cycle repeats
• IMPLANTATION.zygote travels down oviduct, divided and develops into embryo. It reaches uterus and get embedded in uterine lining
• STI; sexually transmitted infections transmitted from infected body fluid or blood

  AIDS; acquired immunodeficiency syndrome Caused by human immunodeficiency virus (HIV). Transmitted by, sharing of needle with infected, blood transfusion, substance exchange at placenta. Can be prevented by, using condom ,not abusing drugs as drug abusers have habit of sharing needles
• What is sexual reproduction?

  It is a process involving the fusion of the nuclei of two gametes to form a zygote, producing genetically dissimilar offspring.

  
• What are gametes?

  Gametes are sex cells produced in reproductive organs called gonads.
• Where are sperms produced?

  Sperms are produced in the testes.

  
• Where are eggs/ova produced?

  Eggs/ova are produced in the ovaries.
• What is fertilisation?

  Fertilisation is the fusion of the nuclei of the male and female gametes to form a zygote.

  
• What is the diploid number of chromosomes in normal human cells?

  Normal human cells have a diploid number of chromosomes.
• What is the haploid number of chromosomes in gametes?

  Gametes have a haploid number of chromosomes.
• What are the structures and functions of the male reproductive system?


  • Scrotum: Keeps the testis at a lower temperature for optimal sperm production.
  • Testis: Produces sperms and male sex hormones such as testosterone.
  • Sperm duct: Pathway for sperm from the testis to the urethra.
  • Urethra: Pathway for urine or semen to exit the body.
  • Penis: Deposits semen into the vagina during sexual intercourse.
  • Prostate gland: Releases fluid that activates the sperms.

  
• What are the structures and functions of the female reproductive system?

  • Ovary: Produces eggs and female sex hormones such as oestrogen and progesterone.
  • Oestrogen: Repairs and grows the uterine lining after menstruation.
  • Progesterone: Maintains and thickens the uterine lining for embryo implantation.
  • Oviduct (fallopian tube): Where mature eggs are released and fertilisation occurs.
  • Uterus: Where the foetus develops during pregnancy.
  • Uterine lining (endometrium): Needed for embryo implantation.
  • Cervix: Enlarges to allow delivery.
  • Vagina: Where semen is deposited during sexual intercourse.

  
• What is puberty?

  Puberty is the stage of human growth and development when a person's body becomes capable of reproduction.

  
• What happens during puberty?

  During puberty, the sex organs mature and sex hormones are released.

  
• What results from the release of sex hormones during puberty?

  The release of sex hormones results in the development of secondary sexual characteristics.

  
• What are the key events in the menstrual cycle?

  1. Menstruation: Discharge of blood and uterine lining from the uterus.

  2. Ovulation: Release of an egg from the ovary, occurring on day 14.

  3. Cycle length: Ranges from 21 to 33 days, average is 28 days.

  4. Fertile phase: Between day 11 to day 17, when fertilisation is most likely.

  5. Hormonal changes: Oestrogen is secreted before ovulation; progesterone is secreted after ovulation.

  6. Cycle repetition: If no fertilisation occurs, hormone production decreases and the cycle repeats.

  
• What is the process of menstruation?

  Menstruation is the process whereby blood and uterine lining that is broken down is discharged from the uterus via the vagina.

  
• When does ovulation occur?

  Ovulation occurs on day 14 of the menstrual cycle.

  
• What factors can affect the length of a female's menstrual cycle?

  The length can be affected by stress, illness, and malnutrition.

  
• What role does oestrogen play in the menstrual cycle?

  Oestrogen helps to repair and grow the uterine lining before ovulation.

  
• What role does progesterone play in the menstrual cycle?

  Progesterone thickens and maintains the uterine lining for implantation of the embryo if fertilisation occurs.
• What happens if no fertilisation occurs after ovulation?

  If no fertilisation occurs, hormone production decreases and the uterine lining is not maintained, leading to the cycle repeating.

  
• What is fertilisation in humans?

  Fertilisation occurs when the nuclei of the sperm fuses with that of an ovum to form a diploid zygote.

  
• What is the development process of the embryo after fertilisation?

  1. The zygote travels down the oviduct.

  2. It divides by mitosis and develops into an embryo (formation of a ball of cells).

  3. The embryo reaches the uterus and gets embedded in the uterine lining (implantation).

  
• What is a sexually transmitted infection (STI)?

  A sexually transmitted infection (STI) can be transmitted from an infected person to an uninfected person via semen, vaginal fluid, or blood.
• What causes Acquired Immunodeficiency Syndrome (AIDS)?

  AIDS is caused by the Human Immunodeficiency Virus (HIV).
• How can AIDS be transmitted?

  AIDS can be transmitted via unprotected sexual intercourse, sharing hypodermic needles, blood transfusions, and from mother to foetus during pregnancy.
• What are the methods to prevent HIV infection?

  • Keeping to a single sex partner or abstaining from sex.
  • Using a condom during sexual intercourse.
  • Not abusing drugs and sharing needles.
  • Not sharing instruments that can break skin and get contaminated with blood.
  • Ensuring needles used for hypodermic purposes are sterilised.
• What do the testes produce?

  Sperms (male gametes) and male sex hormones like testosterone
• What is the role of male sex hormones?

  They are responsible for the development and maintenance of secondary sexual characteristics
• Where are sperms stored?


  In the epididymis
• What is the function of the scrotum?

  It holds the testes outside the body at a lower temperature
• Why is a lower temperature essential for sperm production?

  Because sperm production requires a temperature lower than body temperature
• What is the function of the sperm ducts (vas deferens)?

  To transport sperm from the epididymis to the urethra