Reproduction in Humans Flashcards

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1
Q

Sexual reproduction

A

Process involving the fusion of the nuclei of two gametes(sex cells) to form a zygote and the production of offspring that are genetically different from each other

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2
Q

Nuclei of gametes and nucleus of zygotes

A

Nuclei of gametes are haploid (1 set/pair of chromosomes). Nucleus of zygotes are diploid (two set/ pair of chromosomes)

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3
Q

Functions of Parts of male reproductive system

A
  • testes: Where male gametes (sperm) is made
  • Scrotum: Where testes are outside the body in two sacs of skin
  • Sperm ducts: The sperm which are carried from testes and join with urethra below bladder
  • Prostate gland: Makes a fluid in which sperm can swim in
  • Urethra: Carries both urine and sperm cells at different times
  • Penis: Pass urine out of the body from the bladder, pass semen into the vagina of a woman during sexual intercourse
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4
Q

Functions of Parts of Female reproductive system

A
  • Ovaries: Contain female gametes
  • Oviduct: Connect ovary to uterus, where fertilization occurs
  • Uterus: Muscular bag with soft lining where fertilized egg (zygote) is implanted to develop into a fetus
  • Cervix: Ring of muscle at lower end of uterus to keep developing fetus in place
  • Vagina: Muscular tube, where semen is deposited
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5
Q

Fertilization

A

The fusion of nuclei from a Male gamete (sperm) and a female gamete (egg cell)

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6
Q

Sperm and egg cell comparison

A
  • Size: Sperm is smaller than egg cell, egg cell is larger
  • Structure: sperm has a Long tail for movement, (powered by mitochondria) has many structural adaptations. In egg cell, Round cell, with few structural adaptations and surrounded by jelly coating
  • Motility: Sperm cell is motile, egg cell is incapable of independent movement
  • Numbers: Sperm is Produced everyday in huge numbers, Thousands of immature egg in each ovary, only 1 released each month
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7
Q

Adaptive features of sperm cell

A
  • Flagellum: produces swimming movements
  • Mitochondria: Release energy for swimming
  • Acrosome: A vesicle containing enzymes that dissolve through jelly coating surrounding egg cell
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8
Q

Adaptive features of Egg cell

A
  • Cytoplasm: Containing yolk - Energy store, Help embryo grow
  • Jelly coating: Egg cell surrounded by jelly coating, which hardens after 1 sperm has penetrated through it, Becoming inpenatratable.
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9
Q

In early development

A

the zygote forms an embryo which is a ball of cells that implants into uterus lining

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10
Q

Functions of umbilical cord, placenta, amniotic sac and amniotic fluid

A
  • Umbilical cord: Connect placenta with fetus
  • Placenta: Provides nutrients for fetus (amino acids & glucose), Acts as a barrier to the blood of the fetus, Allows for removal of waste products (metabolic waste/ carbon monoxide) through umbilical cord
  • Amniotic sac: Encloses the amniotic fluid and is what surrounds the fetus and prevents pathogens from affecting the fetus
  • Amniotic fluid: Maintains temperature and allows for free fetal movement.
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11
Q

growth and development of the fetus in terms of increasing complexity in the early stages and increasing size towards the end of pregnancy

A
  • 6 weeks: all organs have begun to grow
  • 8 weeks: Most organs are now present. some movement occur
  • 10 weeks: All organs are now developed and more movements occur
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12
Q

How toxins affect fetus

A

toxins, e.g. nicotine, and pathogens, e.g. rubella virus, can pass across the placenta and affect the fetus

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13
Q

antenatal care of pregnant women

A
  • Dietery needs: Good amount of protein and carbohydrates should be consumes ( provide nutrients for the growth of the fetus). Iron (required to make haemoglobin in blood), Calcium (bone growth) are essential for fetus.
  • harm from smoking and alcohol consumption: Smoking and alcohol consumptions should be avoided as affects fetus as baby is more likely to have cognitive development, behavior and growth issues. And increased risk of fetal mortality.
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14
Q

processes involved in labour and birth

A
  1. breaking of the amniotic sac
  2. contraction of the muscles in the uterus wall
  3. dilation of the cervix
  4. passage through the vagina
  5. tying and cutting the umbilical cord
  6. delivery of the afterbirth
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15
Q

advantages and disadvantages of breast-feeding compared with bottle-feeding using formula milk

A

Advantages of Breast feeding:

  • Allows antibodies to be passed from mother to child, providing immunity
  • Contains all essential nutrients
  • Free of cost
  • No preparation time ( readily available) and perfect temperature

Disadvantages of Breast feeding:

  • Man be painful to mother
  • Can only occur when the mother is present

Advantages of bottle feeding:
- Anyone can feed baby (father create bond with baby)

Disadvantages of bottle feeding:

  • Baby might not tolerate nutrients in formula milk well
  • Costs money to buy
  • There is preparation time (varies), Not readily available
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16
Q

Similarities and differences of breast feeding and bottle feeding (formula milk)

A

Similarities:
-Both contain almost same lactose value
Differences:
-Bottle feeding (formula milk) Contains high protein value.

17
Q

Roles of testosterone and oestrogen in the development and regulation of secondary sexual characteristics during puberty

A
  • Testosterone: made in testes of males. It is responsible for muscle development and deepening of voice and pubic hair growth.
  • Oestrogen: Made in ovaries of females. Leads to development of breast, widening of hips (broader), and plays a part in menstrual cycle (regulate the menstrual cycle)
18
Q

Sites of production of oestrogen and progesterone in the menstrual cycle and in pregnancy

A

Oestrogen is produced by the ovaries and synthesis endometrium wall. Progesterone maintains the endometrium wall, it is produced by the empty follicle in the ovary after the egg has been released.

19
Q

the menstrual cycle in terms of changes in the ovaries and in the lining of the uterus

A

Menstrual cycle occurs every 28 days, During each cycle and egg is released from the ovaries. Uterus wall thickens, preparing for pregnancy, occur if egg is fertilized. If egg is not fertilized then the egg dies and menstruation occurs, and uterus lining breaks down.

20
Q

role of hormones FSH, LH, progesterone and oestrogen

in controlling the menstrual cycle and pregnancy

A
  • FSH: Follicle stimulating hormone stimulate the development of an egg cell in the ovary. Stimulate Estrogen production in the ovaries. FSH produced in pituitary gland.
  • LH: Leuitinising hormone triggers an egg to be released , as well as progesterone production in the ovaries.
  • Progesteron: responsible for the maintainance of the endometrium wall during menstrual cycle and pregnancy. decreases FSH production.
  • Oestrogen: Stiumulates LH production, whilst decreasing FSH production.
21
Q

Methods of birth control:

A
  • Natural: monitoring body temperature and cervical mucus to predict when ovulation is occurring and avoiding sexual intercourse in this period. Not always reliable. Another method is to abstain from sexual intercourse.
  • Chemical: this includes IUD, IUS, contraceptive pill, implant and injection. These contains hormones that stops pregnancy. Contraceptive pill contains hormones progesterone and Oestrogen, which prevent ovulation. The contraceptive implant, injection, IUS, and IUD both release progesterone and cause uterus lining to thin, preventing fertilized egg to be implanted in uterus wall. IUD also acts as a physical barrier, prevuing sprerm reaching egg.
  • Barrier: Includes condom, femidom, diaphragm. Used as a physical barrier, preventing sperm reaching the egg. They also prevent spread of STI’s
  • Surgical: They prevent the release of sperm and egg cells. Vasectomy involves sperm ducts being tied or cut, preventing sperm exiting from tetses. In women, Ovaries are tied or cut to prevent release of egg cells from ovaries.
22
Q

Use of hormones in contraception and fertility treatments

A

Fertility treatments used for people who want to have children but have difficulty becoming pregnant. IVF (in vitro fertilization) and AI (artificial insemination) are two methods of fertility treatment.

23
Q

In vitro fertilisation (IVF)

A

After ovulation which released in the oviduct, egg cell taken fallopian tube, sperms taken from men. fertilisation takes place external. Zygote and embryo is formed. Embryo implanted into uterus lining. If they ask why FSH is given, FSH is given so women can over ovulate to produce more eggs.

24
Q

Artificial insemination (AI)

A

Sperm is directly inserted into the uterus, the sperm can be from a partner or sperm bank, If their sperm is not of high enough quality

25
Q

The social implications of contraception and fertility treatments

A
  • People believe that IVF, fertility treatment and genetic screening of embryos may lead to “designer babies”, where parents will discard eggs that do not have desired characteristics, certain hair colour or gender. May also avoid having children with inherited diseases.
  • Religious groups do not agree with methods of contraception, as they believe that people are preventing a life that otherwise would have been created, which goes against their beliefs. Fertility treatments are also contentious as during IVF, multiple eggs are taken and fertilized at once, leading to spare embryos, which are after frozen and stored or destroyed.
26
Q

Sexually transmitted infection

A

an infection that is transmitted via body fluids through sexual contact

27
Q

Human immunodeficiency virus (HIV) is an example of an STI

A

28
Q

How the spread of STIs is controlled

A
  • Abstaining from sexual contact
  • Avoiding risky sexual practices
  • Always using protection (condoms)
29
Q

Methods of transmission of HIV

A

-HIV is present in bodily fluids of infected people, in blood or semen. Can be transmitted during sexual intercourse.

30
Q

HIV infection may lead to AIDS

A

HIV infection may lead to AIDS, which makes a person extremely susceptible to other pathogens as WBC can no longer fight of disease, which can be fatal.

31
Q

How HIV affects the immune system, limited to decreased lymphocyte numbers and reduced ability to produce antibodies

A

In blood, HIV attaches to lymphocytes (WBC) and enters the cell. Here, it uses the cell to replicate itself and thus cell cannot carry out its normal functions. Consequently, HIV reduces the number of functioning lymphocytes, as well as reducing the bodies ability to produce antibodies to fight off infections.