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Biology > Grade 12 Human Reproduction Part 6 Birth (Parturition) and Birth Control (Contraception) > Flashcards

Grade 12 Human Reproduction Part 6 Birth (Parturition) and Birth Control (Contraception) Flashcards

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1
Q

Define birth:

A

The expulsion of the foetus, its surrounding membrane and the placenta from the uterus

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2
Q

When is the baby usually ready for birth?

A
  • Approx. 9 months after fertilization – baby ready for birth
  • Placenta is less efficient at end of gestation period
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3
Q

What is distinctive about human birth?

A

1) Baby born helpless, relatively immature stage**
* In order to successfully leave mother’s body, human pelvis is narrower, narrower birth canal – bipedal and upright
* Relatively large brain at foetal stage

2) Baby usually born head-first

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4
Q

Discuss different birth options:

A

Vaginal childbirth
* Natural (drug free)
* With pain medication

Cesarean section (C-section)
* Process
* Abdomen and uterus of mother cut open
* Baby removed from uterus
* Cut stitched up
* Rrecommended if:
* Vaginal childbirth puts mother/ baby life at risk
* Complications (awkwardly positioned baby)

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5
Q

How does birth / parturition occur?

A
  • Foetus moves into birthing position 2 – 3 weeks before birth
  • High levels of oestrogen in mother’s blood just before birth
  • This causes the hypophysis to release oxytocin (promotes contraction of the uterine wall)
  • Birth process can take from a few hours to well over a day.
    3 Stages of the Birth Process​
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6
Q

Explain stage 1 of the Birth Process:

A

Dilation of cervix
* Myometrium contracts (muscular layer) – becomes more intense & frequent
* Amnion and foetus forced towards cervix
* Causes cervix of uterus to dilate (full dilation is about 10cm)
* “Water (amnion) breaks” due increased pressure & releases amniotic fluid through the vagina

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7
Q

Explain stage 2 of Birth Process:

A

Delivery of baby
* Cervix fully dilated – baby pushed out through vagina (uterine & abdominal muscles contract)
* Umbilical cord tied & cut immediately after birth
* Becomes naval/ belly button (part still connected shrivels up)

  • Non-fused skull aids natural birth (*Flat bones of baby’s skull separated by connective tissue & not fused
    Head changes shape to be able to pass through birth canal – process called moulding
    Misshapen head of new-born returns quickly to normal )
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8
Q

Explain stage 3 of the Birth Process:

A

Expulsion of placenta – final stage
* 10 – 20 minutes after delivery
* Placenta with remaining umbilical cord detaches from uterine wall
* Afterbirth – uterine contractions forcing the placenta & co. out
* Short ( seldom longer than 15 minutes)

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9
Q

Study diagram on page 115 of your textbook to show birth of baby.

A
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10
Q

Discuss the process of breast feeding:

A
  • Mammary glands are made up of milk-secreting cells
  • Lactation - milk formation
  • Oestragen and progesterone stimulate development of milk glands and ducts
  • Prolactin, from pituitary, stimulates milk production
  • Oxytocin, from hypothalamus, causes release of milk from glands and maintains flow of milk
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11
Q

What are the advantages of breast-feeding?

A
  • Contains antibodies
  • Contains nutrients
  • Is free!
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12
Q

The Control of Human Fertility - What is birth control?

A
  • Voluntary regulation of the number of births by preventing pregnancy.
  • The prevention of fertilisation or implantation after sexual intercourse has taken place
  • Not always 100% effective
  • 100% effective when abstaining
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13
Q

List the four main methods of birth control:

A
  1. Natural methods
  2. Barrier method
  3. Chemical substances
  4. Surgical methods
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14
Q

How do contraceptives work?

A
  1. Prevent the egg from being released, which will prevent ovulation
  2. Prevent the sperm from reaching the egg, which **prevents fertilisation **
  3. **Prevent embryo implantation **or development
  4. **Other **methods
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15
Q

What natural methods of birth control exist?

A

**Withdrawel **- penis withdrawn from vagina just before ejaculation
Very unreliable method - small quantities of sperm-containing semen may be released prior to ejaculation. Ejaculation also difficult to control.

Rhythm method - Sexual intercourse restricted to SAFE days in the female’s menstrual cycle, when fertilisation is unlikely to occur = about 5 days before menstruation and 3 days after mestruation. Unsafe days 3 - 4 days before ovulation, ovulation and 3 - 4 days after ovulation.

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16
Q

To prevent sperm reaching the egg, the Barrier method is used as well as Sterilisation.

List the options under the** BARRIER method:**

A
  • Male condom
  • Female condom
  • Cervical cap
  • Diaphragm
  • Intra-uterine device (IUD)
17
Q

To prevent ovulation, the PILL is an effective contraceptive. Explain.

A
  • Pill contains two hormones - oestrogen and progesterone.
  • Prevent pregnancy by inhibiting ovulation and thus fertilisation.
  • One of the most commonly used.
  • Very reliable if taken daily
  • Not suitable for all women.
  • Does not protect against STDs.
    *
18
Q

One way to prevent the sperm from reaching the egg is through SERGICAL methods e.g. STERILISATION. Explain.

A
  • Usually permanent.
  • It does not affect the reproductive physiological processes and is not harmful.
  • Is cheap.

Male sterilisation - VASECTOMY - Sperm duct is cut, preventing sperm from being expelled. Sperm made is broken down and absorbed back into body.

Female sterilsation - Tubal ligation. Fallopian tubes tied off which prevents egg and sperm meeting.

19
Q

What is the condom used for?

A
  • A barier device used during sexual intercourse.
  • Reduce probability of pregnancy
  • Reduce probability of spreading sexually transmitted infections (STI’s) such as gonorrhoea, syphilis, HIV
  • Get male and female condom
20
Q

What is the male condom?

A
  • Thin rubber sheath that fits over erectile penis
  • Capturing sperm in the female and thus fertilisation of the ovum
  • Excellent and reliable method - especially if combined with spermicide.
  • Prevents pregnancy of female
  • Provides protection against sexually transmitted diseases (STD’s) e.g. HIV Aids
21
Q

What is the female condom?

A
  • Resembles an elongated balloon and is larger than male condom
  • Captures sperm and prevents them entering cervix and fertilising the ovum
  • Lines the vagina and also covers part of hte external vulva - provide some protection against STD’s
22
Q

What is the cervical cap?

A
  • Small, flexible rubber structure that is interserted before intercourse
  • Fits over cervix and prevents entry of sperm
23
Q

Another method to prevent sperm from reaching egg is a diaphragm. What is a DIAPHRAGM?

A
  • Shallow, bendable cup
  • Placed over the cervix before sex and left in palce for at least six hours after sex
  • Prevents sperm from reaching egg
  • Moderately effective.
  • Effective if used with spermicide.
24
Q

What is SPERMICIDE?

A
  • Chemicals that kill sperm.
  • Creams, foams and gels - put in vagina
  • Often used with condoms
  • Not effective if used on own - use with condoms.
25
Q

Which contraceptive mehtods are used to prevent implantation?

A
  • Intrauterine devices (IUD’s)
  • RU 486 (mifepristone)
  • Morning After Pill (MAP)
26
Q

How does MAP work as a contraceptive?

A
  • Morning After Pill
  • Course of pills e.g. Ovral 28
  • Must be strated within 72 hours of unprotected intercourse
  • Oestrogen-Progesterone combination confuses the normal hormonal signals
  • Thus either fertilisation is prohibited or fertilised egg cannot implant.
27
Q

What is an **IUD **and how does it work as a contraceptive?

A
  • Small object made of plastic, copper or stainless steel.
  • Inserted into the uterus.
  • Some are T shaped - Copper T
  • Must be placed by qualified health worker
  • Some secrete hormones that affect the endometrium and prevent implantation
  • **Prevents implantation of the blastocyst **
  • Recommended for women who have already given birth
  • Very reliable BUT do not protect against STD’s
  • Needs replacing every 5 years (depending on device)
28
Q

Why do some religions not accept IUDs?

A
  • Fertilisation has already occurred.
  • IUD prevents implantation
  • Prevention of implantation is seen as termination of life
29
Q

What is RU486 / MIFEPRISTONE?

A
  • Pill taken within first 7 weeks of pregnancy
  • **Blocks action of progesterone so that if implantation has occurred, the endometrium will disintegrate resulting in miscarriage. **
  • Success rate of 96%
  • 98% no side effects
30
Q

What are other contraceptive devices?

A

Injectables - every three months.
Natural methods such as withdrawel and rhythm method.

31
Q

What is the INJECTION and why is it recommended for teenagers?

A
  • Contains progesterone.
  • **Hormone will prevent ovulation and increase the thickness of the cervical mucus to block sperm from getting to the uterus. **
  • Two injections - Depo Provera (lasts 12 weeks) and Nur Isterate (lasts 8 weeks)
  • Teenagers? **Easy **- for forgetful teenagers - not a daily task.
  • BUT dont protect against STD’s
32
Q

Which contraceptive methods are used to prevent sperm from reaching the egg, for males?

A
  1. Vasectomy
  2. Condom
33
Q

Which contraceptive methods are used to prevent sperm from reaching egg, for females?

A
  1. Tubal ligation
  2. Female codom
  3. Spermicide
  4. Diaphraghm
34
Q
A

Biology (25 decks)

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