February 2025

Contraception: The pill

By |2025-02-12T09:39:17+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Image credit citifmonline.com Image credit citifmonline.com ZIMSEC O Level Combined Science Notes:Contraception: The pill

  • Are also known as birth control pills (BCPs) or
  • Oral Contraceptive Pills (OCPs)

How it works

  • They contain the two female hormones: oestrogen and progesterone
  • They prevent the release of ova/female sex cells
  • They cause growth of an […]
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Injection (Depo Provera)

By |2025-02-12T09:40:01+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Image credit star.ng Image credit star.ng ZIMSEC O Level Combined Science Notes:Contraception:Injection (Depo Provera)

  • Also simply known as Depo
  • It is an injection containing medroxyprogesterone, a contraceptive injection for women that contains the hormone progestin

How it works Depo provera Depo provera injection

  • Prevents the […]
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Contraception: The use of spermicides

By |2025-02-12T09:43:53+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Couple having dinner. Image credit singleblackmale.org Couple having dinner. Image credit singleblackmale.org ZIMSEC O Level Combined Science Notes:Contraception:Ways to prevent pregnancy

  • Spermicides are sperm killing chemicals

How it works

  • Are usually in the form of jelly cream placed into the vagina before sexual intercourse
  • The chemical kills spermatozoa

Effectiveness

  • 60-95%

Advantages

  • Does not require […]
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Contraception: Sterilisation

By |2025-02-12T09:45:27+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Black couple. Image credit blackcouplegetaways.com Black couple. Image credit blackcouplegetaways.com ZIMSEC O Level Combined Science Notes:Contraception:Ways to prevent pregnancy

How it works

  • Can be done in both men and women
  • In men it is known as a vasectomy
    • Sperm duct is cut and tied
    • During sexual intercourse ejaculated fluid contains no sperm

    • […]

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Contraception: Abstinence

By |2025-02-12T09:46:09+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Couple holding hands. Image credit neguswhoread.com Couple holding hands. Image credit neguswhoread.com ZIMSEC O Level Combined Science Notes:Contraception: Abstinence

  • It involves total avoidance of sexual intercourse

Adavantages

  • Many couples agree to wait until marriage
  • There is no risk of contracting  Sexually Transmitted Infections
  • It is 100% effective
  • It is supported by most religious […]
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Causes of infertility

By |2025-02-12T08:57:00+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Sterility can cause strain in a relationship. Image credit colossiansfamilynetwork.org Sterility can cause strain in a relationship. Image credit colossiansfamilynetwork.org ZIMSEC O Level Combined Science Notes: Causes of infertility

  • Sterility is the inability to reproduce
  • There are a number of causes for sterility
  • Low sperm count (makes it […]
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Reproduction in Humans

By |2025-02-12T09:31:34+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

A Zimbabwean family A Zimbabwean family ZIMSEC O Level Combined Science Notes: Reproduction in Humans

  • Human being produce sexually
  • The process involves the fusion (joining) of the nuclei (sex cells) of the male gamete (sperm)
  • and the female gamete (ovum)
  • To form a zygote
  • The human and female sexual organs take […]
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