Reproduction, Fertility And Contraception Flashcards
What are the names of the two gametes?
Sperm and eggs (ovum)
What are the parts of the male reproductive system? (6)
- urethra
- penis
- scrotum
- prostate gland
- sperm tube
- testes
What is the urethra?
Tube where sperm leaves the penis
What is the penis?
Organ that introduces sperm into the vagina
What is the scrotum?
The sack that holds and protects the testes at a temperature lower than body temp
What is the prostate gland?
Adds fluid to nourish the sperm
What is the sperm tube?
Carries sperm from the testes to the urethra
What do testes do?
Produce sperm
How are sperm cells adapted? (3)
- they have a flagellum (tail) - allowing them to swim to the egg
- they are haploid
- they have many mitochondria for energy production
What are the parts of the female reproductive system? (5)
- ovary
- cervix
- vagina
- oviduct
- uterus
What is the purpose of ovaries?
Produce eggs (ova)
What is the cervix?
The opening of the uterus, widens during childbirth
What is the purpose of the vagina?
The penis places sperm here during sex
What is the purpose of the oviduct?
Carries the ova (eggs) to the uterus, fertilisation takes place here
What is the purpose of the uterus?
Will nourish the developing foetus if pregnancy results
In terms of chromosomes, what happens during fertilisation?
Haploid cells join to make a diploid cell
Half + half = full
What is formed by fertilisation?
A zygote (first cell)
What happens to a zygote after fertilisation (3)
- divides by mitosis and grows into a ball of cells - embryo
- divides further and differentiates to form tissues
- travels from oviduct to uterus and is implanted for nourishment
What two structures form in the uterus after implantation?
- umbilical cord
- placenta
What forms around the embryo after implantation?
Amnion (protective membrane)
What fluid is contained within the amnion?
Amniotic fluid
What is the purpose of amniotic fluid?
To cushion the embryo
What is the next stage in development after embryo
Foetus
How does the foetus gain useful substances and remove waste?
The umbilical cord and placenta
Name two useful substances required by a foetus
- oxygen
- dissolved nutrients e.g. glucose and amino acids
Name two waste excretory products produced by a foetus
- carbon dioxide
- urea
How is the placenta adapted for diffusion? (2)
- It has a very large surface area
- at the point of contact with the uterine lining due to villi
- (or between the uterus wall and placenta)
What is contained within the umbilical cord? (2)
- umbilical vein
- umbilical artery
What is contained within the umbilical artery?
In what direction does the blood travel?
- Urea, carbon dioxide and other waste products
- from the foetus to the mother
What is contained within the umbilical vein?
In what direction does the blood travel?
- Oxygen, glucose, amino acids and other nutrients
- Mother to foetus
How is the placenta structured?
Rich in maternal blood vessels - rich in oxygen and other nutrients
In the placenta, how is maternal and foetal blood separated? (2)
- Separated by thin membranes
- allowing diffusion of gases and nutrients in both directions
What further increases the surface area between the uterine wall and placenta
Small villi - which extend to the uterus wall
What are the two main sex hormones and where are they produced?
- testosterone - produced by testes
- oestrogen - produced by ovaries
What are the main secondary sexual characteristics in males (5)
- body hair and pubic hair
- sex organs (genitals) enlarge
- body more muscular
- voice deepens
- sex awareness and drive increase
What are the main secondary sexual characteristics in females (5)
- pubic hair and armpit hair
- sex organs enlarge and breasts develop
- pelvis and hips widen
- menstruation begins
- sex awareness and drive increase
How long does the menstrual cycle last?
28 days
How do oestrogen levels change during the menstrual cycle?
- lowest during menstration
- highest during ovulation
How do progesterone levels change during the menstrual cycle?
- lowest during mentration
- highest in the days after ovulation
What two hormones are key to the menstrual cycle?
- oestrogen
- progesterone
What is the purpose of progesterone? (2)
- To build up and maintain the thick uterine lining
- development of the placenta and other structures when pregnant
Why does menstruation occur?
Oestrogen and progesterone levels are low
What is menstruation?
The shedding of the uterine lining
What is ovulation?
When an egg is released from the ovary
What is the first process in the menstrual cycle?
Menstruation
Give two reasons for infertility
Any two from:
- ovaries can’t produce eggs
- oviducts blocked or twisted (can be due to infection)
- STIs cause complications
- uterine lining not developed properly
- uterine lining too acidic or thick (hostile conditions)
- not enough sperm or unhealthy sperm
- impotence
What causes male infertility? (3)
- impotence
- complications from STI/Ds
- low quality or quantity of sperm
What two options are available for couples with infertility problems?
- fertility drugs (hormone treatment)
- In-vitro fertilisation (IVF)
What do fertility drugs do?
- Change hormone levels in women
- to produce more eggs
When is hormone treatment not viable for infertile women?
Other problems such as blocked oviducts mean more eggs doesn’t cure infertility
What happens during IVF? (7)
- women given fertility drugs to produce several eggs
- eggs collected from ovaries surgically
- sperm from a donor mixed with egg in vitro
- the zygote divides and differentiates by mitosis to form an embryo
- while this happens, doctors look for genetic abnormalities - determine if it’s viable
- embryo placed in mother’s uterus (she is given hormones for thickening)
- embryo implants in uterine lining
What are the 3 types of contraception?
Give an example of each.
- mechanical
- chemical
- surgical
- condom (mechanical)
- contraceptive pill (chemical)
- vasectomy (male) (surgical)
What are the advantages of male condoms as a method of contraception? (2)
- easily obtained
- protects against STDs/STIs
What is the disadvantage of male condoms as a method of contraception?
Unreliable if not used properly
How do male condoms work
Acts as a physical barrier for sperm
How do female condoms work?
Acts as a barrier so sperm can’t pass up the female reproductive system
What are the advantages of female condoms as a method of contraception? (2)
- easily obtained
- protects against STDs/STIs
What is the disadvantage of female condoms as a method of contraception?
Unreliable if not used properly
How does a contraceptive pill work?
Prevents ovaries releasing eggs by changing hormone levels
What is the advantage of contraceptive pills as a method of contraception?
Very reliable
What are the disadvantages of contraceptive pills as a method of contraception? (3)
- can have side affects like weight gain, mood swings and increased chance of blood clots
- has to be taken daily to work (for around 21 days)
- don’t prevent STI/Ds
What are implants
and
how do they work?
- Small tubes inserted under the skin in the arm
- Slowly release hormones to prevent development and release of an egg
What are the advantages of implants as a method of contraception? (2)
- very reliable
- can work for up to 3 years
What are the disadvantages of implants as a method of contraception? (2)
- do not protect against STIs/STDs
- can prevent menstruation taking place
What is a vasectomy?
The cutting of sperm tubes, preventing sperm from entering the penis
What is the advantage of vasectomies as a method of contraception?
Virtually 100% reliable
What is the disadvantage of vasectomies as a method of contraception?
Very difficult or impossible to reverse
What is the advantage of female sterilisation as a method of contraception?
Virtually 100% reliable
How are females sterilised? (female sterilisation)
Oviducts are cut, preventing ova from moving down the oviduct and being fertilised
What is the disadvantage of female sterilisation as a method of contraception?
Very difficult or impossible to reverse
What are the two purposes of oestrogen?
- initial buildup of uterine lining
- release of eggs during ovulation
Over which days in the menstrual cycle does:
- Menstruation
- Ovulation occur
- 1 - 5
- 13 - 15
Over which days in the menstrual cycle can pregnancy result?
11 - 17