reproduction Flashcards
Where is sperm stored and made
A man has two testes where sperm is made, sperm is stored in the epididymis, and a penis is used to deposit sperm inside the woman’s body. An ejaculation of semen contains 50 million sperm, on average
The foreskin on the penis will be absent in males who have been circumcised. Circumcision is the religion of foreskin by surgery
At onset of puberty male
hypothalamus gland begins to release hormones that target the pituitary gland
this releaser hormone stimulates the pituitary gland to release interstitial stimulating hormone in males. ICSH stimulates the testes to produce testosterone.
causing development of male sex organs and male secondary sexual characteristics
they start to produce sperm during puberty
Signs of puberty in males
Shoulders get wider
Growth rate increases
Emotional changes due to hormones changes
Voice breaks (gets deeper)
Testes start to produce sperm
Female reproductive system
more complicated it has more functions
it makes eggs, receives sperm, protects and feed the unborn baby
then birth and assist with production of milk
Ovaries produce eggs usually once a month, the fimbria at the end of the oviduct . It takes a few days for the eggs to be pushed along the oviduct which leads to the womb.
functions of female reproductive system
The womb is made of strong muscular walls with a narrow space in the middle (10 cm long and 6.5cm wide)
narrow space is lined with rich layers of blood vessels; they swell and thicken each month to prepare for a baby. This tissues lining the uterus is called the endometrium.
The cervix is a closed area of muscle at the neck of the womb, tiny opening for period blood to pass out and sperm to pass in, called the OS
The vagina is a stretchy muscular tube which leads to the outside, it stretches to allow the baby to be born
At onset of puberty Female
the hypothalamus gland begins to secrete a releaser hormone which targets the pituitary gland to release two hormones
Follicle stimulating hormone(FSH)and Luteinising Hormone (LH)
they travel from the blood to the ovaries
LH stimulates ovaries to produce oestrogen.
Causes development of female sex organs and secondary sexual characteristics,
The ovaries also produce progesterone which works in maintaining the uterus lining.
Menstrual cycle
takes 28 days to complete
produces an egg and prepares uterus to receive the egg if its fertilised
the lining of the uterus is built up to receive the egg. If egg is not fertilised then the lining breaks down and is removed from the body by menstruation.
Menstruation
monthly bleeding of the uterus. Blood comes from rich uterus lining which builds up in prep for baby
when not fertilised lining breaks and is shed from the body
between 10 and 16 girls have periods
common to be irregular and light at the start
gradually become regular
may stop for illness, poor diet or emotional upsets
uterus sheds its lining with help of muscle contractions called cramps
period pain can cause feelings of dizziness or sickness
Ovulation
egg is released from one of two ovaries: happens halfway through menstrual cycle
egg then moves slowly along fallopian tube
Day 1
period begins. Blood and fragments of uterus lining leave the body, a new egg begins to ripen
Day 5
period ends, new uterus lining grows, new egg is still ripening
Day 14
Ovulation. lining is getting thicker and egg is released
Day 21
the egg travels to uterus, lining is ready to receive a fertilised egg
Day 28
the unused lining in the uterus begins to break up.
Hormones
hormones are substances that act as chemical messengers, which play and important part in controlling the menstrual cycle , pregnancy, birth and breast feeding
produced in endocrine glands and circulate bloodstream
carrying messages to various body parts
Oestrogen
responsible for development and functioning of female sex organs
responsible for production of eggs
strengthens and controls uterus
helps uterus respond to oxytocin in labour
Progesterone
helps prepare uterus to receive the fertilised egg
strengthens pelvic floor muscles ready for labour
helps with baby’s development
causes increase in blood flow to the womb
Oxytocin
eases pain and relaxes pelvic joints during labour
can be used to induce labour
stimulates uterus to grow during pregnancy and contract during childbirth
reduces stress, calms you down and helps with pains during labour
Prolactin
helps with bonding
produced in pituitary gland to promote milk production
increases during pregnancy and peaks at birth
acts on reproductive system to regulate immune system during pregnancy
How conception takes place
Sperm from enlarged penis travels into the vagina through cervix and into fallopian tube
Egg that has been released from the ovary travels along the fallopian tube where the sperm and ovary meet, in the fallopian tube, conception takes place here
Fertilised egg then travels to uterus where it embeds in the lining of the uterus for the foetus can grow.
How fertilisation occurs
> At ovulation a ripe egg is released from ovary into the oviduct
Millions of sperm are ejaculated from penis, sperm enter the vagina during sexual intercourse
many sperm leak out or die, it only takes one sperm to fertilise the egg
some sperm swim through the cervix into uterus and up into the fallopian tube
sperm meets an egg
One of the sperms penetrate the ovum’s outer membrane
The nucleus of the sperm joins with the ovum and the egg has been fertilised, they become one.
A membrane forms round the egg to prevent other sperm from entering
Implantation
embedding of fertilised egg in the uterus wall, this occurs about 6 days after conception Once implanted, the mother is now able to supply all the food and oxygen required so the embryo can grow and develop into a baby
Gender/ sex determination
Human body cells have 23 pairs of chromosomes in nucleus. 22 pairs are known as autosomes, and control characteristics, but one pair carries genes that determine whether offspring is male or female
An X chromosome from mother and X chromosomes from father produce a girl
An X chromosomes from mother and a Y chromosome from father produce a boy.
Benefits of family planning
prevents pregnancy related health risks in women. A Women’s ability to choose if or when to become pregnant
allows spacing of pregnancy, provides control over number of children too. This can be good for health, economic and personal reasons
prevents unintended pregnancies , reducing abortion rates
Helps prevent HIVs/AIDS , results in fewer infected babies
empowers people and enhances education, allowed informed choices about sexual and reproductive system
helps reduce teen pregnancy
The world health organization definition of infertility
a disease of the reproductive system defined by failure to achieve a clinical pregnancy after 12 months or more of regular unprotected sexual intercourse
Causes of male infertility
testicular cancer
low sperm count
sperm tube blocked
hormone imbalance
cancer treatments
causes of female infertility
ovarian cancer
endometriosis
stress
blocked fallopian tube
polycystic Ovary Syndrome
Fibroids
Hormone imbalance
Fertility medication
this a non invasive form of treatment for infertility in males
fertility medication is a drug given to stimulate egg production(ovulation) however this can result in the chance of multiple eggs being fertilized resulting in twins or triplets.
Females with polycystic Ovary syndrome may be treated with metformin to improve chance of conceiving with this condition
In vitro fertilization (IVF)
IVF takes place outside the body and in a lab. A daily hormone injection is given to female to stimulate egg production: once these eggs have matured, the are removed from the body in a processing called harvesting
Harvesting is done by using a fine hollow needle and an ultrasound to access the ovary
The lab requires the mans sperm sample, the most mobile sperm will be chosen to increase the chance of success
the females eggs are then fertilized with the sperm in the petri dish, the petri dish will now be incubated, and eggs checked to see if fertilization worked. The egg will become an embryo.
They will then be planted back into the women’s uterus to grow and develop
IVF can be very expensive and may require multiple rounds before success
Couples may find it stressful if unsuccessful
Donor insemination
Males can donate their sperm for use and females can donate their eggs for use in IVF. Sperm can be used to fertilize eggs through the same process as IVF or through intrauterine insemination
As with egg donation a child created with the sperm from a doner has the right to mind the identity of the donor upon their 18th birthday
Intrauterine Insemination
IUI involves the female being given a hormone injection to stimulate the production of eggs(ovulation). This will increase the chance of an egg being fertilized. A sample of the male sperm will be collected, analyzed, and the fasted moving sperm selected for insemination
This sperm will be injected directly into the uterus through the cervix during ovulation as this will also increase the chances of fertilization
method is often used whenever a couple is using a sperm donor or unable to have intercourse due to physical disability
Fallopian tube surgery
This may be an option if a female’s fallopian tubes are blocked or have scar tissue due to PCOS which can prevent eggs passing through them to be fertilized
breaking down the scar tissue will allow more eggs to move through the fallopian tube for fertilisation
Intra Cytoplasmic Sperm Injection(ICSI)
Used to treat male infertility, used in cases where there is a low sperm count, poor sperm mobility and if sperm are struggling to penetrate the egg.
carried out in lab, works by a high quality sperm being selected and injected directly into the single egg
fertilized egg will then be placed into uterus
Gamete Intra Fallopian Transfer
GIFT is very similar to IVF however fertilization occurs in the fallopian tube rather than in a petri dish
the female is given a hormone injection to stimulate egg production, the eggs will be harvested and analyzed. The male is required to produce sperm, which will then be placed with the eggs in the fallopian tube and hope that fertilization will occur
