Unit 2 - Let’s Achieve Flashcards
Sperm
Sperm is the male gamete produced by the seminiferous tubules.
Testosterone function
Testosterone is a hormone produced by the interstitial cells which promote sperm production and activates the prostate gland and seminal vesicles.
What do prostate gland and seminal vesicles do
The prostate glands and seminal vesicles secrete fluids that maintain the mobility and viability of the sperm.
Ova in ovaries
The ovaries contain immature ova in various stages of development.
Each ovum is surrounded by a follicle that protects the developing ovum and secretes hormones.
Location and product of fertilisation
Mature ova are released into the oviduct where they may be fertilised by sperm to form a zygote.
Hormones released by pituitary gland
Hormones released by the pituitary gland at puberty are:
Follicle stimulating hormones (FSH)
Luteinising hormone (LH)
Interstitial cell stimulating (ICSH)
What triggers puberty
A releaser hormone produced in the hypothalamus stimulates the release of hormones by the pituitary gland to trigger the onset of puberty.
Hormanal control of soerm production
FSH promotes sperm production and ICSH stimulates the production of testosterone. Testosterone promotes sperm production and activates the prostate gland and seminal vesicles.
What controls testosterone production
Negative feedback controls the production of testosterone.
Menstrual cycle
The menstrual cycle takes approximately twenty-eight days and the first day of menstruation is regarded as day one.
Menstrual cycle stages
Follicular phase
Luteul phase
Menstrual cycle - role of FSH
Follicle stimulating hormones (FSH) stimulates the development of the follicle and production of oestrogen by the follicle in the follicular phase.
Effects of oestrogen of uterus
Oestrogen stimulates the proliferation of the endometrium (lining of the uterus) preparing it for implantation and affects the consistency of cervical mucus. The mucus becomes thinner and waterier in consistency making it more easily penetrated by sperm.
What triggers ovulation
Peak levels of oestrogen stimulate the surge in the secretion of LH. The surge in LH triggers ovulation.
Ovulation
Ovulation is the release of (ovum) from a follicle in the ovary. It usually occurs around the mid-point of the menstrual cycle.
Luteul phase
The follicle develops into a corpus luteum which secretes progesterone.
What does progesterone lead to
Progesterone promotes further development and vascularisation of the endometrium preparing it for implantation if fertilisation occurs.
What inhibits secretion of FSH and LH and what does this cause
Progesterone and oestrogen inhibit further secretion of FSH and LH to prevent further follicles from developing.
What leads to menstration
The lack of LH leads to degeneration of the corpus luteum with a subsequent drop in progesterone levels leading to menstruation.
Impact of fertilisation on progesterone and the corpus luteum
Progesterone levels remain high and the corpus luteum does not regenerate if fertilisation occurs.
Men fertility
Men show continuous fertility, continually producing sperm from the onset of puberty.
Women fertility
Women show cyclic fertility, only being fertile for a few days during each menstrual cycle.
How does a women change after ovulation
A woman’s body temperature rises by around 0.5oC after ovulation and her cervical mucus becomes thin and watery. This is how the fertile period of a women can be identified.
How do drugs stimulate ovulation
Ovulation can be stimulated by drugs that prevent the negative feedback effect of oestrogen on FSH secretion.
What do other ovulatory drugs do and what can this cause
Other ovulatory drugs mimic the action of FSH and LH.
These drugs can cause super ovulation.
This can result in multiple births of be used to collect ova for in vitro fertilisation (IVF) programmes.
Artificial insemination
Several semen samples are collected over a period of time and injected directly into the uterus/vagina/female reproductive system using a catheter.
This process is used if the male has a low sperm count or if the male is sterile a donor may be used to provide semen.
IVF
Eggs are surgically removed from the ovaries after hormone stimulation. Eggs are mixed with sperm in a culture dish and the zygotes (fertilised eggs) are incubated until they have formed at least eight cells and are then transferred to the uterus for implantation.
What can IVF be used in conjunction with
IVF can be used in conjunction with pre-implantation genetic diagnosis to identify single gene and chromosome abnormalities.
Intra-cytoplasmic sperm injection
ICSI
A process similar to IVF but if the sperm are defective or very low in number, ICSI can be used. The head of the sperm is drawn into a needle and injected directly into the egg to achieve fertilisation.
Physical barriers of contraception
Condom
Female condom
Diaphragm
Cervical cap
IUD
An IUD is a small T-shaped plastic and copper device that is inserted into the uterus.
The IUD releases copper and prevents pregnancy for between 5 to 10 years. They are more than 99% effective at preventing pregnancy.
Sterilisation
Sterilisation is the surgical method to prevent pregnancy.
Female sterilisation
Female sterilisation involves cutting, tying or blocking the oviducts.
Male sterilisation
Male sterilisation involves cutting, tying or blocking the sperm ducts.
Contraceptive pill
The contraceptive pill is a chemical method of contraception. It contains a combination of synthetic oestrogen and progesterone that mimics negative feedback preventing the release of FSH and LH from the pituitary gland. Therefore, it prevents the development of any follicles.
Progesterone only pill
The progesterone only (mini pill) thickens cervical mucus preventing the sperm from entering the uterus.
Emergency/ morning after pill
The emergency or morning after pill prevent or delay ovulation. It can be taken up to 72 hours or 120 hours after unprotected sex depending on which type of pill is used.
Antenatal and postnatal screening
Antenatal and postnatal screening is when a variety of techniques are used to monitor the health of the mother, developing foetus and baby.
What does Antenatal screening identify
Antenatal screening identifies the risk of a disorder so that further tests and a prenatal diagnosis can be offered.
Dating scan
Dating scan – takes place between 8 and 14 weeks. It determines the stage of pregnancy and due date.
This is used with tests for marker chemicals which vary normally during pregnancy.
Anomaly scan
takes place between 18-20 weeks and may detect serious physical abnormalities in the foetus.
Routine blood and urine tests
Routine blood and urine tests are carried out to monitor the concentrations of marker chemicals.
Measuring a chemical at the wrong time could lead to a false positive result.
What can an atypical chemical concentration lead to
An atypical chemical concentration can lead to further diagnostic testing to determine if the foetus has a medical condition.