Reproduction, fertility and contraception

Question 1

Where and how are sperm cells made?

Answer 1

Sperm cells are made in the testes by meisos.

Question 2

Where and how are egg cells made?

Answer 2

egg cells are made in the ovaries by meisos.

Question 3

how are sperm cells specialized?

Answer 3

• they have a haploid nucleus
• they have a flagellum and are streamlined shape for swimming
• they have mitochondria to provide energy for swimming

Question 4

what does haploid mean?

what does diploid mean?

Answer 4

• a nucleus that is haploid has half the number of chromosomes (23)
• a diploid nucleus has the full amount of chromosomes (46)

Question 5

how are egg cells different to sperm cells?

Answer 5

• eggs have more cytoplasm, so are larger
• eggs cells have no flagellum
• egg cells have a jelly coat and a food store

Question 6

what is fertilization?

Answer 6

fertilization occurs when the haploid nucleus of a sperm cell fuses with the haploid nucleus of an egg cells to form a diploid zygote.

Question 7

in the male reproductive system, what does the prostate gland do?

Answer 7

the prostate gland produces a fluid to nourish the sperm (fluid + sperm = semen)

Question 8

what is the job of the scrotum?

Answer 8

the scrotum is the sac that holds the testes at a slightly lower temperature outside the body.

Question 9

in the female reproductive system, where are sperm cells placed during intercourse?

Answer 9

the penis places sperm in the vagina during intercourse.

Question 10

name the part of the female reproductive system which is the opening to the uterus and dilates during birth?

Answer 10

the cervix is the opening to the uterus.

Question 11

what do the oviducts (Fallopian tubes) do?

Answer 11

carry eggs to the uterus and are where fertilization occurs.

Question 12

following fertilisation, what happens to the zygote?

Answer 12

the zygote divides by mitosis to form a ball of identical cells called an embryo and implantation occurs when the embryo sinks into the uterus lining.

Question 13

how is feotus formed?

Answer 13

the embryo differentiates into a fetus as cells specialize and tissues and organs develop.

Question 14

how is the developing fetus nourished during pregnancy?

Answer 14

The point of attachment in the uterus lining becomes the placenta and umbilical cord. the umbilical cord carries oxygen, glucose and amino acids from the mother to the fetus (and takes waste such as co2 and urea away from the fetus)

Question 15

how is the placenta adapted for the exchange of substances between the mother and feotus?

Answer 15

• placenta provides a large surface area for diffusion by having finger like villi
• the mothers blood and babies blood are in close contact but
• separated by thin membranes to reduce diffusion distance

Question 16

why do the mothers and babys blood never mix?

Answer 16

they may have different blood types

Question 17

what does the umbilical cord do?

Answer 17

• contains the umbilical vein which carries oxygen, glocuse, amino acids and antibodies to the baby
• contains the umbilical artery which carries urea, co2 and other wastes to the mother

Question 18

name the structures that cushion and therefore protect the fetus as it develops.

Answer 18

amniotic fluid which is surrounded by the amniotic sac.

Question 19

name the hormones that cause puberty and where they are produced

Answer 19

males: testosterone produced in the testes.
females: oestrogen produced in the ovaries.

Question 20

what occours in the first five days of the menstrual cycle?

Answer 20

menstruation;

the breakdown of the uterus lining and its passage out the vagina

Question 21

following menstruation, what happens in the womb?

Answer 21

uterus lining rebuilds and thickens again in preparation for implantation and pregnancy.

Question 22

when does ovulation occur (release of an egg from the ovaries)?

Answer 22

day 14

Question 23

what does the hormone oestrogen do?

Answer 23

causes the repair and a rebuilding of the uterus lining and also results in ovulation.

Question 24

from day 14-28, what happens to the uterus lining?

Answer 24

the thick uterus lining is maintained in case the egg is fertilized and pregnancy occurs

Question 25

what hormone maintains the thick lining?

Answer 25

progesterone

Question 26

what causes the lining to break down and menstruation to occur again after day 28?

Answer 26

oestrogen and progesterone levels drop

Question 27

if implantation and pregnancy occurs, what happens to the menstruation cycle?

Answer 27

it stops

Question 28

what are gametes?

Answer 28

sex cells

Question 29

what can cause infertility in females.

Answer 29

• non-production of eggs
• blocked oviducts
• cervical mucus

Question 30

what can cause infertility in males.

Answer 30

• low sperm count
• impotence
• abnormal sperm

Question 31

in IVF, the first step often involves giving the woman fertility drugs or hormones, what do they do?

Answer 31

the stimulate the ovaries to produce more eggs than normal.

Question 32

when should a women be given fertility drugs/treatment only?

Answer 32

fertility drugs stimulate the ovaries to produce more eggs so are appropriate when the problem is low egg production

Question 33

In IVF, how are the eggs collected?

Answer 33

eggs are collected surgically, through the abdominal wall and into the ovaries via an aspiration needle.

Question 34

when the eggs and sperm are mixed together in the fertilization medium, what sort of conditions are necessary?

Answer 34

The temperature, ph and nutrient concentration must be the same as that of the woman’s reproductive system

Question 35

Following the mixing of eggs and sperm, what checks will be made and how will they be made

Answer 35

a microscope will be used to check if fertilization has occurred. they will also check that cell division is occurring and that the cell division is normal.

Question 36

before suitable embryos are placed into the woman’s uterus, what will she have been given?

Answer 36

she would receive hormones to ensure that the uterus lining is ready for implantation.

Question 37

why are two suitable embryos placed in the uterus?

Answer 37

• increases the chance of successful implantation

- only placing two also decreases the chance of multiple pregnancy.

Question 38

to become pregnant, what has to happen?

Answer 38

the embryos must successfully implant into the uterus lining.

Question 39

give arguments for IVF.

Answer 39

• it gives infertile couples the chance to have a child.
• there is no difference between a naturrally conceived
  baby and an IVF baby
• eggs and sperm can be screened for genetic
  defects

Question 40

give arguments against IVF.

Answer 40

• some believe that you are playing god
• the cost of IVF is very high
• what happens to the unused embryos (ethical and
  moral difficulties)

Question 41

what is contraception?

Answer 41

the methods used to prevent pregnancy

Question 42

what are the 3 types of contraception and give an example of each

Answer 42

• mechanical/physical (male condom)
• chemical (pill/implants)
• surgical (sperm tubes or oviducts cut)

Question 43

what are the possible advantages of using condoms?

Answer 43

• protect against STIs
• easily obtained
• very reliable

Question 44

how does the pill and implant work?

Answer 44

contain oestrogen and progesterone to prevent the release of eggs

Question 45

what might be a disadvantage of male or female sterilisation?

Answer 45

once the procedure is carries out it is very hard/impossible to reverse

Question 46

suggest why people may be against contraception

Answer 46

• it may be against their religious beliefs
• encourages sex in young people/sex before
  marriage
• sterilization may be regretted in later life

Question 47

what is an embryo?

Answer 47

a ball of identical cells