reproduction in humans Flashcards

1
Q

sexual and asexual reproduction compared

A

both include mitosis, difference is that asexual does not involve specialised gametes or fertilisation

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2
Q

stages of sexual reproduction

A

gametes produced (through meiosis), male gamete transferred to female gamete, fertilisation, zygote formed (which divides several times by mitosis to form all the new cells of the animal)

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3
Q

production of gametes

A

male and female gametes produced in the sexual organs (testes and ovaries). cells in the organs divide by meiosis to produce the gametes.

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4
Q

sperm cells

A

sac of enzymes to penetrate the membrane of the egg, nucleus, mitochondria to provide energy for movement, flagellum for propulsion

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5
Q

mitosis vs meiosis

A

mitosis produces diploid cells which are genetically identical, meiosis produces haploid cells which are genetically unique

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6
Q

main stages of fertilisation

A

sperm approach the egg, a sperm penetrates the cell membrane and the sperm’s nucleus enters, the fertilisation membrane prevents any more sperm from entering. the sperm and egg nuclei fuse to form a zygote.

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7
Q

semen

A

sperm cells travel along the sperm ducts where they are mixed with a fluid from the seminal vesicles. semen is ejaculated through the urethra into the vagina

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8
Q

ovulation

A

each month an egg is released from the ovaries into the oviduct (fallopian tube)

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9
Q

umbilical chord

A

consists of umbilical artery (carrying deoxygenated blood containing waste products from the fetus to the placenta) and umbilical vein (carrying oxygenated blood containing nutrients from the placenta to the fetus)

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10
Q

placenta

A

allows fetus to obtain oxygen and nutrients from mother’s blood and to get rid of waste products e.g urea and CO2. placenta secretes female hormones, in particular progesterone which maintains the pregnancy and prevents the embryo from aborting.

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11
Q

amniotic sac

A

keeps the amniotic fluid around the developing fetus

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12
Q

amniotic fluid

A

cushions the fetus from mechanical shock and maintains a constant temperature around the fetus

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13
Q

pregnancy

A

membrane called the amniotic sac encloses the developing embryo, secretes a fluid called amniotic fluid. when the fetus becomes recognizably human we call it a fetus. At the end of 9 months of development there is no room for the fetus to grow which sends a hormonal signal to the mother to begin the birth process

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14
Q

stages to the birth of a child

A
  1. dilation of the cervix. gets wider to allow the baby to pass through. The muscles of the uterus contract strongly which tears the amniotic sac allowing the amniotic fluid to escape (water breaking)
  2. delivery of the baby. strong contractions of the muscles of the uterus push the baby’s head through the cervix and then through the vagina to the outside world.
  3. delivery of the afterbirth. after the baby has been born the uterus continues to contract and pushes the placenta out.
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15
Q

FSH

A

follicle stimulating hormone, stimulates the growth of the follicle in the ovaries in girls and stimulates sperm production in boys

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16
Q

LH

A

luteinizing hormone, causes the egg to be released in girls and instructs the testes to secrete testosterone in boys

17
Q

testosterone

A

controls the development of the male secondary sexual characteristics (see other card for examples)

18
Q

oestrogen

A

repairs/regrows the lining of the uterus and slows down the production of FSH

produces the female secondary sexual characteristics

19
Q

progesterone

A

develops and thickens lining of the uterus ready for implantations

20
Q

secondary sexual characteristics in boys

A

sperm production starts, growth and development of male sexual organs, growth of armpit, pubic hair, chest and facial hair, increase in body mass, growth of muscles, voice breaks, sexual ‘drive’ develops

21
Q

secondary sexual characteristics in girls

A

menstrual cycle begins, growth and development of female sexual organs, development of ‘rounded’ shape to hips, voice deepens without sudden breaking, breasts develop