Reproduction in Humans Male Reproductive System. Objectives: *Identify on diagrams the male reproductive system and state their function **Compare male and female gametes. scrotum. Functions. Produce spermatozoa and make male hormone testosterone which stimulates changes during puberty.
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*Identify on diagrams the male reproductive system and state their function
**Compare male and female gametes
Produce spermatozoa and make male hormone testosterone which stimulates changes during puberty
Sac covering testes which hangs outside the body to keep it cool as sperm can’t develop or be stored at 37 0C or above
Small tubules outside the testes store sperms for maturation. Sperm duct connect these tubules to urethra
Urethra carries urine and sperm but not at the same time. A ring of muscle around the urethra contracts to prevent urine loss during sexual intercourse
Secrete fluid for sperm cell to swim. Prostate secrete mucus and other secrete sugar for respiration of sperm cells. Sperm cell + fluid = semen
Urethra runs down the centre of penis. Its main function is to deliver sperm to the vagina for fertilization
Acrosome (contain enzymes to break the jelly coat
Middle piece (Has mitochondria to power swimming by the tail)
Drives sperm forward
Sperms and eggs are specialised. Which statements belong to a sperm and which to eggs?
Does not move itself . Moved along oviduct by cilia and peristalsis
Swim using tail that lashes from side to side
Has very little – uses sugar in seminal fluid for respiration
Protein and fat in cytoplasm- enough to last till implantation in uterus
Millions produced constantly after puberty often throughout life
One a month after puberty until menopause except when pregnant or taking contraceptive pills
* Identify on diagrams the female reproductive system and state their function
**Describe sexual intercourse in humans
Produce ova and make female hormones progesterone and oestrogen which stimulates changes during puberty. Oestrogen- development of sex organs and sec. sexual characteristics progesterone prepares uterus for receiving the embryo in case of pregnancy
The egg passes out to the funnel shaped opening of the oviduct in a process called ovulation which then either gets fertilised by a sperm or die after passing into the uterus
Foetus develops here. It develops a spongy wall for implantation of the embryo in case of pregnancy
A ring of muscles at the lower end of the uterus leading to vagina
A muscular tube opening outside the body
A separate opening above the vaginal opening for urination
Above urethra a very sensitive area (lot of nerves)
Outer opening of vagina
Each ejaculation contains 2-5cm3 of semen with up to 500million sperm cells
*Describe fertilisation in humans
**Describe early development of the zygote to form a ball of cells for implantation into the uterus wall
What is the role of the acrosome?
What fuse first ?
What is the number of chromosomes after fertilisation?
Why do the other sperms not enter?
Villi or finger like projection of the embryo to penetrate endometrium. They are surrounded by blood vessels which supply nutrients and oxygen
*Describe the ante-natal care of pregnant women
**Describe the processes involved in labour and birth
***Describe the advantages and disadvantages of breast milk and formula milk
Bones of foetus can grow
To make extra red blood cells to carry oxygen to the foetus and so that both mother and baby can make extra haemoglobin
So the mother has enough energy to move her heavy body around
To provide amino acids for both to make tissues. The mother makes muscle tissues in the uterus to prepare for birth and the fetus for growing and developing its organs
The things a mother should not take
Alcohol: can cause birth defects and mental retardation
Drugs: like heroin can give baby an addiction
Cigarettes: nicotine and CO result in premature and underweight babies
A few weeks before birth a fetus turns over inside the uterus with the head towards the cervix. Hormones released by the fetus and the increase in pressure in the uterus stimulate hormonal changes in the mother. A hormone oxytocin is released from her pituitary gland which stimulates uterine muscle to contract. The mother feels the contraction and this is the beginning of labour.
When contractions become stronger and more frequent the opening of the cervix stretches and the amnion breaks to release the amniotic fluid.
The contraction is even stronger now pushing the baby towards the cervix. The cervix widens pushing the baby’s head through the vagina. The baby starts breathing for the first time when born. The airways need clearing of mucus to help the baby breath.
The umbilical cord is cut and tied just above the point where it attaches to the baby. The rest heals to form the naval. After a few minutes the placenta comes away from the uterus wall. It is pushed out of the vagina as afterbirth
It is a painful experience but gentle exercise, special breathing technique, painkillers in form of epidural (catheter between spine and spinal cord) to stop transmission of impulses from pain receptors to the brain.
Causes of premature birth:
*Describe the menstrual cycle in terms of changes in the uterus and the ovaries
**Explain the roles of hormones in controlling the menstrual cycle
Each potential egg is surrounded by small group of cells and together they form a follicle.
At puberty some follicle develop and egg divide by meiosis
Cytoplasm fills with stored food
Each month one or a few follicle will develop
At the beginning of the cycle at the end of menstruation one follicle will develop.
Follicle enlarges and fills with fluid move towards the edge of the ovary
After 2 weeks follicle bursts releasing egg and some fluid into the oviduct
The follicle cells left behind make the yellow body which remains for next 2 weeks in case of pregnancy they are active otherwise they decrease in size
The uterus lining thickens during egg development
If not fertlised the egg passes to the vagina and the yellow body breakdown in the ovary
Yellow body is stimulated in pregnancy by a hormone released by the embryo which in turn stimulates the lining of the uterus to continue to thicken
The menstrual cycle lasts about 28 days. During this time the lining of the uterus thickens and an egg is released.
If, once the egg has reached the uterus it still hasn’t been fertilised by any sperm it will die and the lining of the uterus will start to break up.
Within about 2 weeks, the woman has her period – blood and dead cells pass out through the vagina. This is called menstruation.
A woman’s period can last between 3 and 8 days. Girls normally start their periods between the ages of 11 and 14 (but it may be a little earlier or later for some people).
Day 1: Bleeding starts when the lining of the uterus breaks down and passes out the vagina – “Having a period”
Day 6: The lining starts to build up again and thickens into a spongy layer of blood cells
Day 14 (approx): An egg is released and lasts for around 3 days
Day 16-21: The lining stays thick awaiting the arrival of a fertilised egg. If one doesn’t come then the lining breaks down again in next 6 days
Hormones in the menstrual cycle
FSH – follicle stimulating hormone
Causes release of LH
LH – luteinising hormone
If pregnancy occurs both ovarian hormones continue to be produced to prevent menstrual cycle starting again
*Describe the role of testosterone and oestrogen in developing secondary sexual characteristics at puberty
**Describe artificial insemination and the use of fertility drugs and discuss their social implications
What is secondary sexual characteristics?
Do both sexes develop at the same time? What causes development?
Do all young people grow at a definite age ? What is this time called?
What does the word adolescent mean? When adolescence stops?
h/w complete worksheet and hand in on 20/9
Male Brain/Hypothalamus Female
Pituitary hormones FSH, Pituitary Hormones
Testosterone Oestrogen, Progesterone,
Secondary sexual characteristics Menstruation
The statements below describe changes which happen to girls, boys or both during puberty. Copy the table below into your book and list the statements under the correct headings.
What is infertility?
Regular injections of a fertility drug containing FSH or using tablets which make pituitary gland insensitive to oestrogen. It may cause multiple fertilisation.
Ovaries do not release egg
Due to lack of FSH production
Semen collected from men and placed in the uterus via a plastic tube. This is called artificialinsemination (AI) in the later case or use sperms from a donor who remains unknown. It is also possible to take the nucleus from a defective sperm and inject it into an egg. The zygote is cultured for several days to grow into embryo which is then inserted in the uterus so that implantation can take place.
Do not produce enough sperm or problems with ejaculation
*Describe the methods of birth control by: natural, chemical, mechanical and surgical means
What is birth control?
IUD – A small plastic device wrapped in copper or contains hormones(progesterone). Fitted in uterus prevents either sperm entering uterus or embryo implanting. Progesterone makes mucus in cervix sticky.
Cap or diaphragm – A rubber dome used with sperm killing cream or foam placed over cervix before intercourse prevents sperm from entering uterus
Condom/ femidom – Most common, rubber tube rolled over penis or inserted in vagina stops sperm entering the vagina and stops STDs
The pill – different types available. Contains oestrogen and progesterone in varying concentrations. Inhibits FSH thus no egg matures. Failure to take it regularly may cause pregnancy. Side effects are weight gain, sore breast, painful period depression and heart and circulation problems
Spermicides – Foam, cream or jelly to kill sperms. Not very effective on its own.
Abstinence / rhythm method– during the most likely time of fertilisation. Determine ovulation date by keeping a record of period cycle and abstain 2 days before and after that date. It is unreliable
Sometimes checking symptoms of ovulation like increase in body temperature, change in cervical mucus( less sticky) .Easy for people without access to other methods.
Vasectomy – Operate to cut and tie sperm duct. Irreversible. Ejaculation happens but no sperm released
Sterilisation – Minor operation on women. Oviducts are cut and blocked. Irreversible.
*Describe the methods of transmission of HIV and the ways in which HIV/AIDS can be prevented from spreading
**Describe the symptoms, signs, effects and treatment of gonorrhoea
***Describe how HIV affects the immune system
HIV(human immunodeficiency virus) identified in 1980s leads to AIDS
( acquired immunodeficiency virus syndrome).
It is a collection of diseases due to weak immune system and that is why called a syndrome.
HIV positive- HIV attacks an important type of lymphocytes (T). T-lymphocytes stimulate other lymphocytes to produce antibodies. During HIV infection the number of T lymphocytes decreases and so fewer antibodies are produced every time there is an infection. Therefore diseases as well as cancers , that form can’t be destroyed by the immune system because they fail to recognise them.
Early symptoms of AIDS are very much like flu with swollen glands and hightemperature. Later symptoms include weight loss, various types of cancer and decrease in brain function. Some HIV + people do not develop any symptoms.
Gonorrhoea only transmitted by sexual intercourse. Cause by spherical bacteria Neisseria gonoerrhoea. It can only survive in the moist lining of the male and female reproductive tract. If the bacteria is present in vagina or urethra in female and male respectively it can be transmitted by sexual intercourse.Symptoms after 2-7 days of infection.
In male bacteria multiply within urethra producing an unpleasant discharge and pain when urinating.Sores develop on the penis. If not treated can cause long term damage to both urinary and reproductive system( sterility).
In female bacteria multiply in cervix producing a discharge which is not noticeable and painful but will lead to same kind of damage if not treated.