HUMAN BIOLOGY- REPRODUCTION AND PREGNANCY:

STAGES OF THE MENSTRUAL CYCLE:

1) menstruation- 1-4 days- uterine bleeding, shedding of the endometrium 2) preovulation- 5-12 days- endometrium repair begins, development of ovarian follicle, uterine lining thickens 3) ovulation-13-15- rupture of mature follicle, release egg 4) secretion- 16-20- secretion of watery mucus by glands of the endometrium,cervix and uterine tubes. movement and breakdown of unfertilised egg 5) premenstruation- 21-28- degeneration of corpus leteum, deterioration of the endometrium

STAGES OF FOETUL DEVELOPMENT:

- 3 months- forelimbs well developed, eyelids closed, outer ear complex, bone marrow formed, blood cells formed in bone marrow, sex distinguishable -4 months- arms and hands fully shaped, skeleton complete, exercising of muscles evident, ears stand out from head -5 months- fine hair covers body, reflexes developed and increase growth in baby -6 months- respiratory movement, digestive glands start to function, tooth buds, eyebrows and lashes evident -7 months- period of greatest growth, all systems function except respiratory -8 months- accumulation of fat beneath the skin, growth slowed -9 months- eyes open, nose well formed, fine body hair is shed

ASSISTED REPRODUCTIVE TECHNOLOGY:

- IVF (in-vitro fertilisation) mans sperm and eggs being mixed in lab - then planted in women uterus - GIFT-(gamete intrafallopian transfer) where eggs and sperm are mixed together immediately after eggs are collected then injected into female - allows eggs and sperm to mix naturally and any fertilised egg will pass to the uterus - most require women to take fertility drugs - eggs can then be harvested - most procedures require lots of eggs - excess are frozen for later - if male sperm count is low a procedure called intracytoplasmic sperm injection may be used - single sperm is injected in single egg and resulting embryo is then put in uterus - donar egg is when a women who is unable to conceive using own egg - egg donated is mixed by partners sperm and planted in uterus - surragacy- another women carries another couples baby - paid - great emotional and legal problems involved

THE MENSTRUAL CYCLE:

- a cycle were changes in the lining of the uterus are closely associated with the stages of the ovarian cycle - changes in the uterine lining, endometrium, are in preparation for a developing embryo to be released at fertilisation - when embryo reaches the uterus it emplants its self - in the first stage of the ovarin cycle, is the period where the follicle is maturing, the endometrium lining become thicker and softer - increase in the number of blood vessels and mucus secreting glands - after ovulation, the endometrium continues to thicken and the glands secrete thick mucus -if the egg is not fertilised by the sperm, the corpus leteum degenerates which reduces the amount of hormone influencing the build up of the endometrium which results in its breakdown - around 14 days after ovulation, blood from the broken down capillaries mucous secretions and cell debris from the uterine lining are lost through the vagina - this is menstruation - when menstruation first begins, it marks the beginning of puberty - female will have continual period every month unless going through pregnancy -cycle last until menopause between 45 and 55 - women has potentially 35 years to get pregnant

TERMINATING PREGNANCY:

- abortion- stretching cervix and removal of the contents of the uterus by suction through the vagina - inside of uterus is then scraped and whole procedure takes about 15 minutes - can also take a drug - without progesterone the lining of the uterus breaks down and embryo can't continue - effective in first 9 weeks of pregnancy - earlier the abortion the safer for the female - emotional problems after abortion

FROM EMBRYO TO FOETUS:

- after one month of growth, the human embryo is under 4 mm long - the most obvious feature is the development of muscle segments on either side of the tube that is to become the brain and spinal cord - these blocks of mesodermal tissue increase in number over time - by the end of the fourth week there are 30 pairs of them, representing the beginning of muscles and vertebrae of the spinal column - in addition, the brain is beginning to form, tail is evident and the heart and liver begin to develop - the throat region contains a number of pharyngeal arches with clefs between them - as the development proceeds, arches form the structural elements of the face and throat, pouches that develop in the clefts will give rise to the epithelial linings and glands associated with the throat - during the fifth week, the arm and leg buds start to appear the arm buds are slightly more advanced - by the end of the embryonic period, the embryo has a reasonably human form and all organs are present although not functioning yet - head is almost half the size it was at the beginning, eyes appear like slits, jaw, nose and earlobes are almost fully developed - toes and fingers developed and the sex organs to determine whether it is a boy or girl - by the end of the first two months of embryonic life, the body form has developed and basic organ system is in place, developing baby is now a foetus - stem cells are present in the blood in the umbilical cord and foetus - once a baby has been born, these cells can be used for the benefit of adults and children who suffer from bone marrow and blood diseases - stored in case the baby needs them later in life

CHLAMYDIA:

- cause of this was difficult to identify - the organism is highly specialised bacteria - can only reproduce when living inside the human cell - worlds most common STI - both men and women can be infected and is common in people under 25 - when infection is diagnosed it can be treated with antibodies -men can develop infection of the urethra called non-specific urethritis - urethritis means swelling of the urethra, but cause is not known - when micro organism is identified, it is usually chlamydia - yellow mucus discharge from the penis and burning during urination - if chlamydia in males is not treated the bacteria can spread to the epipydidymis where it causes inflammation - causes pain and swelling - epidydymitis- chlmidia is most common cause in men under 35 - infertility can also be the result - in females no symptoms occur so they don't know they have the disease - makes it dangerous and if not treated it can lead to infertility, eye infection and arthritis - some women shows signs of pelvic inflammatory disease with is inflammation of uterus etc. - implantation of uterus outside uterus- ectopic pregnancy cane also occur - if infected women is pregnant there is a 70% chance it will be passed on - can also lead to premature or still birth - correct diagnois and treatment of clymidia is important - if it is suspected a urine sample can be taken - also swab of vagina, cervix, penis and observed in lab - if infected usual treatment is course of antibiotics, however it may never be removed from the body

CHANGES TO BABY AT BIRTH:

- at birth the baby can no longer depend on the placenta for food and oxygen - the lungs and liver must now become fully functional and for this to occur blood must flow through them - the first breathe of birth is triggered by the shock of birth - failing this the clamping of the umbilical vessels allows the level of carbon dioxide in the babies blood to rise - stimulates respiratory centre in the brain and as a result the lungs begin to function - as the lungs expand, they no longer offer the same resistance to blood flow and so the blood flowing through the ductus arterious decreases - a few weeks after birth all that it left is the DA in some fibrous tissue - as larger amounts of blood return to the heart from the lungs the pressure in the left atrium increases - this increased pressure forced the flap of the foramen oval against the wall of the atrium, closing of the opening - eventually the FO becomes permanently cllosed - if the FO fails to close the baby may be born with a hole in the heart - the first indication of this is the baby has a high bluish colour due to insufficient oxygen in the blood - not enough blood can flow to the lungs, surgery can be used to prevent this - with the cutting of the umbilical cord, the blood no longer flows through the umbilical vessels - as no blood is being flowed through it the ductus venosus constricts until perminately closed of - bypass around the liver is lost and all blood in the blood vessel to the liver must pass through the liver - following birth the baby breathes rapidly for the first two weeks - heart rate is also high - the rate is high because more oxygen is needed to keep baby warm - number of red blood cells increases to carry oxygen to tissues - white blood count is high but also decreases

CHANGES IN BABY AT BIRTH:

- before birth the baby is dependent on the mother, but after it must be independent -before birth the lungs don't function and it gets oxygen from the placenta - after birth circulation must change when the baby is born - before birth, blood is carried to the placenta in two umbilical arteries - as it circulates through the placenta, carbon dioxide and others wastes are exchanged for oxygen and nutrients - the blood then returns to the foetus via the umbilical vein - blood retuning from the foetal heart enters the right atrium, it can follow several pathways: - blood may flow into right ventricle and then to the lungs like normal, however the lungs are collapsed and not functioning so there is resistance - most of the blood from the right ventricle flows through the ductus arterious to the aorta - blood in the right atrium of the heart may flow directly into the left atrium through an oval opening between the two chambers - called a foramen ovale - this is beneficial as blood coming from the placenta is highly oxygenated and cake flow to the developing foetus quickly

TREATMENT OF INFERTILITY:

- blocked uterine tubes and sperm ducts can be removed - sometimes infertility is due to ovulation problems - if mans sperm can't fertilise an egg, they may use AID which is having a child through the semen of another man - disease is a problem - female gets the sperm injected in vagina for 3-4 days

SYPHILIS:

- caused by thin flexible bacteria - begins when bacteria enters through any small break in the skin - bacteria multiples and spreads to whole body - first symptom is small sores - appear on sex organs - second stage includes skin rashes, so, fever - second stage can last 2 years - hidden stage then follows body is still infected - can last for years or life - can cause heart and blood problems if comes back later in life - antibiotics treat all stages

PUBLIC LICE AND SCABIES:

- causes intense itching - scabies caused by a mite - prefer genetial areas - both can be transmitted by sex - can be treated with lotion

CHROMOSOME ANALYSIS:

- chromosomes of cells from a foetus can be examined to defect defective, missing or additional chromosomes - photograph of the chromosomes displayed in order ic called karyotype - foetal cells can be obtained for analysis using amniocentesis or chronic villus sampling - amniocentesis is carried out between the 16th and 20th weeks of pregnancy, by which time the foetus is floating it 130ml of amniotic fluid - involves the removal of 10-20ml of fluid which can be examined for abnormalities in the number of chromosomes on the chromosome structure -procedure involves small risk of infection or miscarriage - only performed on women through to be at high risk of delivering a baby with a defect - some disorders detected are down syndrome - chrorionic villus sampling is a specimen of foetal cells from the chorion by foetal membranes - cells are examined and rested quickly - especially important if a birth defect may require a termination of pregnancy - blood tests of the mother have been devised to detect genetic disorders in the foetus, can detect abnormalities 6 weeks after contraception - sample is treated with special antibodies that adhere to few foetal cells contained in the mothers blood - antibodies have magnetic beads to enable the foetal cells to be isolated from other cells

GENITAL HERPES:

- common STI caused by herpes simplex virus - type one and two - herpes 2 produces blisters on genital organs and is transmitted from skin to skin contact - first episode of herpes is most severe and is very painful and distressing - blisters develop in penis and vagina - can be accompanied by flu symptoms or rash - blisters then break forming scabs - healing occurs over 1-2 weeks - can remain in nervous system for life - reoccurances are not as bad - herpes can be transmitted from infected mother to baby during birth which is life threatening -no removal once body is infected - treatment includes medication , saline dressings and sexual abstinence, don't cure

MECHANICAL BARRIERS:

- condom- made from thin rubber latex which is rolled on the penis before intercourse - effective in stopping semen from entering the vagina providing it does break - diaphragm- mechanical barrier used by female, thin rubber cap that fits across the top of the vagina must be perscribed and used with a jelly - cervical cap- fits directly over the cervix and prevent sperm from reaching uterus, must remain for 6 hours - female condom- lubricated and lines the vagina, at each end is a flexible ring that fits over the cervix and surround the entrance of the vagina - effective in stopping STIS

DISRUPTIONS TO NORMAL FOETUL DEVELOPMENT:

- congenital disorders, are present at birth - some occur due to inheritance - others because of mutations - if during pregnancy a mother smokes, consume alcohol or suffer diet problems the developing foetus may be affected - teratogenic agent causes physical defects in the developing embryo e.g antibodies - many agents cause defects - placenta allows for dangerous agents and chemicals to pass from the mother to foetus

CONTINUED EMBRYONIC DEVELOPMENT:

- continued development of the blastocyst depends on the endometrium being maintained - high levels of hormones in the blood stop the endometrium from breaking down and so the menstrual cycle ceases - during the early stages of pregnancy, the the corpus luteum produces these hormones until the developing placenta can take over the role of maintaining the endometrium - first two months of pregnancy are referred to as the embryonic period, after the second month the developing individual is called a foetus

DNA PROBES:

- defects range of genetic disorders - segment of DNA is tested - if the gene is normal the DNA probe jobs with the DNA segments and an abnormal join doesn't show or join up

DIAGNOSIS OF HIV/ TREATMENT:

- drugs can be taken within 3 days pf exposure to HIV - drugs prevent replication of virus - body responds to HIV by producing antibodies - should have blood test at lead 2 weeks after exposure - no cure or vaccine - usually given combination of drugs

THE PREGNANT MOTHER:

- during pregnancy, the baby needs to be supplied with oxygen and nutrients and have carbon dioxide and wastes removed - changes in the mother accommodate all of these changes - not all the bulge in the stomach is due to the enlargement of the abdomen, but also the internal organs like the liver, stomach and intestines being forced upwards and outwards - another obvious change is the enlargement of the breasts, hormones of pregnancy result in the development of milk secreting tissues which leads to an increase in size - also affects mother in less obvious ways - increase in size of the heart, and blood volume - caters for extra blood flowing from the placenta - also results in increased blood flow to the kidneys and increased urine production - pressure on the bladder causes increase in need to pass urine - expanding uterus presses on the bladder so it feels like its filed with urine - as the uterus grows, moves up the pelvic cavity, releasing pressure - during last stages of pregnancy the baby also presses on the bladder - changes in mood of mother are due to hormone in balance e.g worried about baby development etc.

THE FIRST STAGE OF LABOUR:

- during the first 3 months of gestation, the uterus undergoes weak, irregular contractions - these contractions eventually become stronger and occur every 30 minutes - beginning of labour pains - the first stage, the dilation of cervix, is the time from the onset of labour to the complete dilation of the cervix - lasts as average of 8-9 hours for 4 for second children - waves of contractions travel from the upper part of the uterus towards the cervix - with each contraction, the muscle fibres that make up the uterus shorten a small amount pulling on the cervix - this pull on the cervix, shortens it so that it no longer projects down in the vagina, cervix opens - cervical dilation allows for foetus to move deeply into the pelvis - as contractions become stronger, the head of the foetus is pushed more against the dilating cervix - eventually the cervix is completely dilated and the uterus, cervix and vagina form a single curved passage - passage termed the the birth canal, is the route where the foetus will pass aided by contractions of the uterus and voluntary contractions of the abdominal muscles of the mother - complete dilation of the cervix marks the end of this stage

THE DEVELOPING FOETUS:

- during the fourth month, the uterus expands and the mothers abdomen begins to bulge - foetus grows rapidly, posture is more erect, fingerprints appear and foetus moves stretching its arms and legs - heart beats twice of that of the mothers - by week 20, end of 5th month, foetus is about 25cm long and kicking and turning can now be felt by the mother - after 24 weeks of development, mother shows obvious signs of pregnancy, foetus has grown to 27-35 cm - by week 28 it is about 38cm long and weighs 1000 grams and moves around a lot in the uterus - brain has enlarged considerably, in males the testes usually descend into the scrotum - by the end of week 32, the foetus is about 41-45 cm long - by week 40, the pregnancy is full term - foetus now has no room to move - boys are often heavier than girls - birth weight of a baby varies, head is now smaller than the body - before birth, the baby changes its position in the uterus so it lies with its head resting in the curved shape of the pelvis, movements of baby are more restricted then before as growth and placenta start to stop - during the later stage of pregnancy, antibodies from the mother diffuse across the placenta into the baby blood - gives baby temporary immunity - after 6 months baby does this on its own

EMBRYONIC MEMBRANES:

- early in the embryonic period, four embryonic membranes form - these lie outside the embryo and serve to protect and nourish it as it develops - the amnion is the first membrane to develop - by the eighth day after fertilisation it surrounds the embryo, enclosing a cavity into which it secretes amniotic fluid - this fluid protects the embryo against physical injury by acting as a shock absorber - helps to maintain a constant temperature and all the baby to move freely - the amnion expands as the growth takes place, it usually ruptures just before child birth - another embryonic membrane is the chorion, formed from the outer layers of the blastocyst together with a layer of mesodermal cells - the chorion surrounds the embryo and the other membranes as the amnion enlarges, it fuses with the inner layer of the chorion, eventually the chorion becomes the main part of the placenta - in addition, there are two other membranes, not important and become part of the umbilical cord

FUNCTIONS OF THE PLACENTA:

- endocrine- secretes a number of hormones necessary for maintaining pregnancy - excretory- transports nitrogenous wastes like urea from the foetal blood to the mothers blood for excretion from the mothers kidneys - immune- transports antibodies from the mother into the foetal blood supply so that the foetus has immunity from infectious diseases - nutritional- transports nutrients like glucose from the mothers blood to the foetal blood, stores essential nutrients early in pregnancy and releases them later on when needed - respiratory- transports oxygen from the mother to foetus and carbon dioxide from foetus to the mother

STRUCTURE OF THE BREAST AND MILK PRODUCTION:

- female breast consists of 16-25 sections called lobes, each of which is subdivided into a number of lobules - the wall of each lobule is made up of a large number of glandular alveoli which are milk secreting enzymes of the breast - the lobules and lobes are surrounded by fatty connective tissue which gives the breast the rounded countour - from the lobules breast opens into wide spaces - these milk spaces serve as resovious for milk produced by the alveoli - from each space, a short, straight duct leads to the nipple - between 15-25 openings on the nipple for the secretion of milk

ALCOHOL:

- foetal alcohol syndrome describes the effects of exposure to alcohol - excessive alcohol intake has serious affects on the child - most obvious is lower than normal birth weight - others include: slow growth before and after birth, defects of heart and other organs, small head, malformed arms and legs and mental retardation - child may have behavioural problems like hyperactivity, extreme nervousness and a poor attention spam

MATERNAL DIET:

- folic acid is essential for normal cell division and manufacture of protein - lack of folic acid during pregnancy can result in spina bifida and other neural tube defects - wholegrain bread, cereal, green leafy vegetables and legumes are rich in folic acid - calcium is needed for bone growth - vitamin A for normal growth of cells - listeriosis- mild illness caused by eating food contained with the bacteria listeria monocytogenes, can cause still birth and miscarriage - to avoid this, pregnant women should eat fresh cooked foods and avoid pre packed items

SEXUAL INTERCOURSE:

- for sexual intercourse to take place, and for sperm to go into the vagina, the penis must be enlarged and firm - when sexual stimulation of the penis becomes intense, rhythmic contractions of the epidydimus, vas deferential, seminal vesicles and prostate gland occur - contraction propels the contents of the ducts and glands into the urethra and then out of the body - called ejaculation - semen contains sperm - accompanying ejaculation is rapid heartbeat, increase in blood pressure and breathing rate known as an orgasm - ejaculation usually expels 3mls of semen containing 250-300 million sperm - seminal vesicle produces thick fluid containing nourishment for the sperm - when female is sexually stimulates, erectile tissue in the vagina opens up and fills with blood - this reduces the size of the vagina opening and tends to increase the stimulation of the penis during sexual intercourse - secretions of mucus etc. lubricate the epilethiul lining and allow for easy entry by the penis - female undergoes an orgasm - female does not need to reach an orgasm for fertilisation to occur

CHARACTERISTICS OF NEW BORN BABY:

- head makes up one quarter of the overall length of the new baby, - from the moment the baby is born, it can breath, suck, swallow and get rid of wastes on its own - it can hear, see, smell and taste - baby also cries signals of help

HORMONAL CONTRACEPTION FOR MEN:

- implantation of the hormone testosterone being placed under the skin every four months - effective in stopping sperm production

PUBERTY AND DEVELOPMENT OF SECONDARY SEXUAL CHARACTERISTICS:

- in females secondary development starts with the enlargement of the breasts, broadening of the hips, growth of pelvic bones and deposition of fat to have a more rounded shape to the female - pubic hair beings to grow in males and females, becomes thick, dark and curly

HORMONE REGULATION CONTINUED:

- in males the same hormones are secreted by the pituitary gland - follicle stimulating hormones stimulates the epithelial tissue of the seminiferous tubules in the testes to produce sperm - luteinising hormone stimulates celss in the testes to secrete the hormone testosterone - testosterone is important for the development of immature sperm cells into sperm and maintaining the male reproductive organs and sex drive - at puberty, the secretion of hormones stimulates a number of changes, both physical and psychological in males and females - in males production of testosterone influences sexual maturity

TRICHOMONIASIS:

- infection caused by protozoan, causes inflammation of the mucous membranes in vagina and urethra in men - causes great discomfort in women - can be cured quickly with tablets - spread by vagina intercourse

STI'S:

- infections contracted by close body contact using genital organs - caused by virus, bacteria, fungi and parasites passed on during sexual activity - syphillis and gonorrehea used to be the most common - young people are most at risk

FETOSCOPY:

- involves looking at foetus through a small telescope instrument with a large needle - introduced into the uterus through the abdominal wall - enables things like cleft pellet, missing or abnormal ears or deformed limbs to be detected

SECOND STAGE OF LABOUR:

- involves the delivery of the foetus and stage of expulsion - begins with the bursting of the membrane surrounding the foetus and a gush of fluid from the vagina - second stage, from full dilation of the cervix to birth lasts from 20 minutes to 2 hours - as the foetus moves through the cervix, its head stretches the vagina - this distention of the vagina stimulates the women to contract her abdominal muscles - these contractions together with the contractions of the uterus push the foetus through the vagina, baby head turns to face mothers back - with each contraction, the head advances a small amount - between contractions it retreats a little,but the head gradually moves towards the external opening of the vagina - as this occurs more and more head becomes visible - mothers pulse rate increases and she begins to sweat - the tissue becomes stretched over the foetus head as it is forced out - once the head has emerged, it turns sideways again to face the mothers hips - rotation allows the shoulders and rest of the body to come out - as the foetus is pushed out the pressure on the head may cause it to be pushed out of shape - head resumes to normal shape a few days after birth - head being downwards allows it to be delivered first and to act as a wedge to force open the cervix and vagina - head down allows foetus to start breathing on its own

GONORRHOEA:

- mainly affects the mucous membranes of the excretory and reproductive systems, the rectum and eyes and throat - transmitted during sex - affects males and females and symptoms occur 10-12 days after exposure - in females it might not be recognised - in males, bacteria enters urethra during sex with infected partner - inflammation results in burning during urine - yellow discharge or pus from penis - if not treated it cane result in difficulty urinating - lack of treatment also spreads across the body - in females it is more serious - starts in urethra and cervix - no pain or symptoms - untreated the infection spreads - can cause blockage - antibodies used to treat this infection provide an effective cure if begun early - becomes difficult to sure sometimes

MALE REPRODUCTIVE SYSTEM:

- male gonads consist of 2 testicles, within each testis, sperm is produced - testis are supported and held in a skin covered pouch called the scrotum - production and development of sperm requires temperatures at 2 degrees lower than normal body temperature - internally testis are divided into lobules or compartments filled with fine tubes called the seminiferous tubules - tubules are lined with cells that produce male gametes - penis is the organ that passes urine and transfers sperm from male to female - urethra carries semen and urine out of the body - foreskin covers the head of the penis - seminal vesicle secretes fluid that is rich in sugars and is the main component of semen - prostate gland secretes an alkaline fluid that helps activate fluid - epidydymis stores sperm while they finish maturing - between the seminiferous tubules are clusters of cells that secrete testosterone - epidydimis is sperm entering testis via this tube - vas deferens carries sperm away from the testis - for sperm to transfer into a females body, it must turn into a liquid or semen which aids the transport of sperm - mixture of secretions from 3 glands - seminal vesicles- pair of such like organs behind the bladder they secret fluid - prostate gland- where two of the vas deferential join the urethra, secretes thin milky alkaline fluid - cowpers gland- too small yellow glands the size of a pea, located beneath the prostate, secrete clear mucus carried to the urethra through a duct, acts as a lubricant - urethra carries sperm and semen to the end of the penis - erectile tissue has a large number of sponge like spaces which fill with blood during sex - this causes the penis to stiffen and then when erect it can be introduced to the vagina

SPEMICIDES:

- may be used with the condom, diaphragm and cervical cap - cream/tablet/foam - destroys sperm, but very unreliable

CONTRACEPTION:

- measures to prevent a women from having children - abstinence- not having sex at all - some methods of birth control require a female to know exactly when she is ovulating - she can then abstain from sexual intercourse on those days - number of ways of determining the safe period: - rhythm method-egg is available for fertilisation during a period of only 3-5 days in each menstrual cycle, sexual intercourse should not take place between 4 days before and after ovulation if pregnancy is to be avoided - not all cycles are regular - temperature method- refinement of the rhythm method - female can take her body temperature each morning to determine the time of ovulation - ovulation is accompanied by a sharp drop in body temperature then a rise, women can safely have sex three days after temperature rise - mucus method- observe change in the mucus of the cervix - immediately after menstruation the tissues of the vagina are dry - as ovulation comes mucus can be detected - at first it is cloudy and sticky but becomes clearer and sticky to touch - on the day of ovulation the peak of clear mucus is reached and sexual intercourse is safe when there is no mucus - symptothermal method uses all 3 methods to predict the fertile period of the females cycle more accurately, monitor can now measure things described above - none of these methods are very reliable

EMERGENCY CONTRACEPTION FOR WOMEN:

- morning after pill- works by preventing or delaying ovulation, prevents sperm from reaching an egg, and prevents implantation of embryo

THE THIRD STAGE OF LABOUR:

- once born the baby starts to breathe with its own lungs even though its still connected to the placenta by the umbilical cord - the amnion, chorion and placenta are still in the uterus at this stage - umbilical cord is cut and clamped - arteries and veins in the umbilical cord contract before or after they are cut - at birth the baby is covered in a waxy material called vernix - protective layer and will wash of when the baby has its first bath - leaving a thin layer protects the baby from skin infections - uterus continues to contract and five minutes after delivery the placenta, other membrane and remains of the umbilical cord are expelled - these are called the after birth - blood clots then form to stop all leakage of blood - with such a large area of exposed tissue, infection can occur

BIRTH AND INFANT DEVELOPMENT:

- period of pregnancy is the time that the embryo or foetus is carried in the uterus is called gestation - during this time, the developing baby growths to about 50cm to an average weight of 3400g - growth and development takes about 280 days - in preparation for labour, several hormonal changes occur - changes cause pelvis to soften ready for birth - hormonal changes also increase to the uterus and strengthen the contraction of the muscles - before labour begins, the foetus has probably settled with its head in the mothers pelvis - cervix has softened, shortened in length - foetus usually faces mothers right of left hip bone with legs crossed - one side of head is against bladder and the other against her bowel

STERILISATION:

- perminant method of birth control for men and women - vasectomy- involves small removal of each vas deferent - small cut is made on each side of the scrotum and then vas deferens are cut - cuts in scrotum are then closed - can still have sex - women- tubal ligation - small incision is made in abdomen and uterine tubes are cut and tied - after this sperm can't reach the egg or uterus - Essure uses a device with a coil of wire it is inserted in the cervix via each uterine tube - uterine tube then grows around the device - all of these are permanent and can't be un done - castration is the removal of the testes - oophorectomy is the removal of the ovaries - hysterectomy- removal of uterus - MEMORISE TABLES ON PAGES 282-283

HORMONAL CONTRACEPTION FOR WOMEN:

- pill is very effective - contains hormones similar to two female hormones oestrogen and progesterone - when taken for the first 21 days of the menstrual cycle, the hormones prevent the release of the mature eggs from the ovary - cervical mucus becomes thick and sticky making it difficult for sperm to travel up the vagina - protect female from unwanted pregnancy if used regularly - mini pill contains only progesterone - makes cervical mucus thicker so sperm can't enter - implantation of a capsule beneath the upper arm and diffuses progesterone for 3 years, can be removed easily - vaginal ring- placed in the vagina and releases low doses of oestrogen and progesterone - small amounts released prevent ovulation and change the lining of the uterus so implantation can't occur - pill gives 100% protection

GENETIAL WARTS;

- usually found on vagina, penis etc. - can be found in throat and anus - may be raised or cauliflower shaped growths - warts are caused by human papilomavirus - passed on by virus - warts can be inside penis and vagina and therefore not seen - risk of being unaware

FOETAL BLOOD SAMPLING:

- quicker to diagnose - quicker action if pregnancy needs to be terminated - taken from the umbilical vein using a fine needle via the abdomen of the mother - detects abnormalities

LACTATION:

- refers to the initiation and maintenance of milk secretion and the delivery of milk to the infant - during the pregnancy the lobes become more complex and larger in size and oil secreting glands around the nipple enlarge - 1-2 days after birth milk secretion begins - first secretion is watery and yellowish white fluid called colostrum - contains little or no fat but has a high level of mothers antibodies - antiobodies can be absorbed through the infants incentive to give temporary immunity to diseases which the mother is immune - milk is stored in the breast until the sucking begins - once the nipple has been sucked the milk begins to flow - as the baby sucks the nipple, nerves in the nipple are stimulates and message is sent to the brain - brain instruct the pituitary gland to release a hormone called oxytocin - oxytocin triggers the contraction of the small muscles surrounding the milk filled lobes of the breast - milk is ejected into the ducts - 1.5L milk may be formed each day - mother must have a balanced diet

FOETAL MONITERING:

- regular recording of the babies heart rate to detect indicators of stress - takes place during labour and birth using ultrasound and echocardiography - echocardiography records electoral changes in the heart - identifies risks to foetus so action can be taken - also checks oxygen deficiency

COITUS INTERRUPTUS:

- removal of the penis before ejaculation occurs - highly unreliable

INFECTIONS:

- rubella- viral infection, if contracted by a pregnant women can have serious consequences for the child like blind, deaf or heart problems - influenza virus may be linked with brain damage to the foetus if contracted by the mother during early pregnancy

CONTROLLING STI'S:

- safe sex- take precaution and use condom

OVARIAN CYCLE:

- series of events that takes place in the ovaries - includes maturation of the egg and release into the uterine tube - associated with these events is the development of follicles in the ovary - length of cycle depends on many factors, can range from 20-40 days with an average of 28 days - other cells in the ovary surround each egg called a primary follicle - during puberty, some of the follicles undergo development - cells forming the wall of the primary follicle begin to enlarge and divide creating a layer of cells around the developing egg - secretions of cells gradually force the the egg to the end of the follicle called a secondary follicle - as more fluid accumulates in the follicle, it continues to enlarge and and move towards the surface of the ovary - a bulge on the surface of the ovary is know a mature follicle takes 10-14 days - when the mature follicle bursts, is expels the egg called ovulation - sometime more than one egg is released - following ovulation, the ruptured follicle collapses and the blood forms a clot - clot is absorbed by remain follicle cells which forms the corpus letuem - hormones are secreted by this structure - if fertilisation has not occurred, the corpus luteum reaches its maximum development 10 days after fertilisation - corpus letuem reaches peak in third month of pregnancy after this it degenerates

GENERAL:

- sex cells, called gametes are produced in the sex organs, called gonads - fusion of a male gamete and a female gamete at fertilisation results in a zygote, from which a new individual forms - primary sex organs produce gametes - secondary sex organs store gametes

INTRAUTERINE DEVICES:

- small devices made from copper or plastic inserted in the uterus - hormonal IUD made up of a plastic frame with a core that slowly releases progesterone - copper IUD - once an IUD is inserted in the uterus it is not felt by the women or partner - have threads attached so they can be check and easily removed - hormonal IUD works by realising hormone at a steady rate that makes the lining of the uterus, endometrium thin and insuitable for implantation - can also stop ovulation all together - copper IUD affects the movement of sperm an prevents them from moving through uterus - sometimes used as an emergency contraceptive - 99% affective

SMOKING:

- smoking during pregnancy also has severe effects on the baby - birth weight is significantly lower - increases risk of abortion - children of mothers who smoke and breastfeed there baby are more likely to suffer from gastrointestinal problems than other children - also have a higher risk of respiratory problems like pneumonia - infant death syndrome

SPREAD OF HIV:

- spread to all parts of the world - transmitted through air and water - blood transfusions can carry HIV - unprotected sec with infected person - sharing needles with infected - infected mother to child stop HIV: - don't have sex - use condom - don't share needles

CELL DIFFERENTIATION:

- stem cells are very different for 3 main reasons: not specified for any particular role, capable of repeated division by mitosis, can differentiate into specialised cells - events of mitosis ensure each daughter cell receives the same genetic information that is contained in the parent cell - as stem cells proliferate, different genes become activated , this results in cells that form specific functions in the body

STEM CELLS AND THE PROCESS OF DIFFERENTIATION:

- stem cells can either divide for indefinite periods or create more stem cells - after fertilisation, the fertilised egg is a totipotent stem cell which means it has the potential to create any type of cell necessary for embryonic development, including the embryo itself - in the first few hours after fertilisation, the egg undergoes several cell divisions that produce identical cells - because these cells are totipotent any one of them has the ability to develop into an entire human being - identical twins are formed when two cells separate and develop into two identical embryos - totipotent cells undergo several rounds of cell division - outer layer of cells will eventually form the placenta and other tissues needed for the baby - inner cell mass will form all tissues of the human body - cells of the inner cell are pluripotent stem cells - this means they can give rise to many but not all cell types necessary for foetal development - each pluripotent stem cell then undergoes further specialisation into another part of the stem cell, multipoint stem cell - multipotent stem cells give rise to cells that have a particular function, they exist in embryos and adults - MEMORISE TABLE ON PAGE 224

LACTATIONAL AMENORRHOEA:

- temporary infertility that follows the birth of a child - occurs when women is not menstruating and is breast feeding - relies on the fact that breastfeeding affects the production of hormones so ovulation is suppressed - change of pregnancy is reduced

CHEMICALS:

- thalidomide- effective in stopping morning sickness - causes limb malformations - illegal drugs like heroin and LSD and others can cause damage to the foetus when taken during pregnancy

ULTRASOUND:

- uses inaudible, high frequency sound waves to produce image of foetus - probe is placed on the abdomen of the women and the sound waves are reflected by the foetal tissue to obtain a visual echo of the uterus - by careful examination of the foetus, malformations of the head and brain or malformed limbs can be detected

HORMONAL REGULATION:

- the menstrual and ovarian cycles and other features of the female reproductive system, depend on the endocrine glands, for their regulation and control - these glands empty hormones into the extracullar fluid that surrounds the cells making up the glands - secretion then passes into the capillaries by blood - pituitary gland- small organ that lies in the pit in the bone below the brain and above the roof of the mouth - the hormone it secretes include some that stimulate parts of the reprductive system - when hormones enter the blood, it circulates the body until it reaches its target organ - main target organs in the reproductive system are testes and ovaries - two hormones secreted by the pituitary gland of the gonads is called gonadotropic hormones - one of the follicle stimulating hormone, in females, stimulates the development of the maturation of the ovarian follicle - during its development, the ovarian follicle secretes its own hormone, oestrogen - secretion of the follicle stimulating hormone is reduced as the level of oestrogen increases in the blood - the second pituitary hormone is luteinising hormone which promotes final maturation of the ovarian follicle, ovulation and the formation of the corpus letieum - corpus letium also secreted progesterone - corpus letium is maintained by human chorionic gonadotropin a hormone produced in the placenta - MEMORISE DIAGRAM ON PAGE 214

DEVELOPMENT OF THE PLACENTA:

- the placenta is the organ that supplies nutrients to and removes waste from the foetus - it is a combination of foetal and maternal tissues - the foetal portion of the placenta develops from part of the chorion - by the end of the third month, the placenta is completely formed - the placenta also produces a number of hormones needed to maintain pregnancy - the foetal part of the placenta, begins to develop as the blastocyst is implanted in the endometrium -small, branching, finger like projections develop from the outer layers of the cells - these projections in which numerous blood vessels develop, are called chorionic villi - they grow into the endometrium - as the villi penetrate the endometrium they surrounded by pools of the mothers blood which is collected in spaces in the endometrium - in this way the villi are bathed in the mothers blood, however the foetal and maternal blood don't normally mix because a few layers of cells separate the two blood supplies - the exchange of materials takes place by diffusion and active transport - oxygen and nutrients from the mothers blood diffues into the foetal blood, and wastes leave the foetus by diffusing into the maternal blood - the placenta is attached to the foetus by the umbilical cord - inside the umbilical cord are 2 umbilical arteries which carry blood to the capillaries of the chronic villi - a single umbilical vein carries blood from the placenta, through the umbilical cord, back to the foetus - on the maternal side, blood from the mother enters the placenta through the uterine arteries, flows through the blood spaces where the exchange of substances occurs and leaves through the uterine veins

CHANGES TO THE MOTHER AFTER CHILDBIRTH:

- the reproductive organs slowly return to normal - this period lasts about 8 weeks it is called puerperium - after delivery the uterus continues to contract - within two weeks the mother no longer able to feel swelling in the abdomen and the uterus completely shrinks - contractions bring about the shrinking - discharge of fluid from shrinking uterus - fluid is a mixture of blood and breakdown of productive tissues stops around third week - blood volume that increased during pregnancy returns to normal - the pulse is slower and body temperature is above normal - depression can start after birth - if mother breastfeeds menstrution will take longer to return, those not breast feeding it will start about 10 weeks after the delivery

RELIABILITY/ETHICAL ISSUES:

- vary greatly in reliability and side effects - some people think contraception is morally wrong

HIV:

- weakens bodys imune system and infected person is likely to get other infections - eventually results in AIDS - HIV contains a rare RNA core rather than DNA one - similar to other viruses - HIV infects white blood cells and inside cells it uses an enzyme to convert RNA to DNA - DNA produces millions of copies of itself and is then released in the blood - after a month, the infected person may experience flue like symptoms and the virus continues to destroy cells until immune system can no longer stop infection so they now have AIDS - anyone with HIV is infected for life, time to develop into AIDS is varied

FERTILISATION:

- when the male ejaculates, the sperm released in the vagina at the entrance of the uterus is called insemination - once in the vagina, the sperm travels to the cervix and into the uterine tubes - only a few thousand reach the uterine tube - fertilisation occurs when the egg is a third of they way down - since ovulation, muscular contractions of the uterine tube transport the egg to the uterus - when several thousand sperm surround the egg there is enough enzyme to allow one sperm into the egg to complete fertilisation - entrance of one sperm stimulates the formation if a fertilisation membrane around the egg, which prevents the entrance of more than one sperm - once the sperm has entered the egg, the tail is absorbed and the head moves through the cytoplasm of the egg - entrants of sperm stimulates the egg to complete the second mitotic division - fertilisation is completed and the egg is called a zygote

PRIMARY GERM LAYERS:

- while the blastocyst is implanting in the lining of the uterus, the inner cell mass undergoes changes resulting in the formation of three layers of cells - primary germ layers- these layers, called the ectoderm, mesoderm and endoderm are the embryonic tissues that will differentiate into all tissues and organs of the body

MAINTAING A HEALTHY PREGNANCY:

- while the embryo develops in the uterus, changes in the mothers body allow her to adjust to the needs of pregnancy - most of them take place ahead of the demand that the foetus places on the mother for oxygen, nutrients and waste removal - in the later weeks of development, large amounts of nutrients and oxygen are needed so adjustments are made to functioning of the body - own functions slow down, allowing nutrients to stay in the body for longer - easily diffused into the placenta for the baby - as the mothers alimentary canal is less active, her stomach empties more slowly and constipation is common - concentration of nutrients is filtered out by the kidneys and lost in the urine - for baby to maintain nutrients, a large quantity of blood needs to flow to the placenta - increase in rate of heat beat and blood pumped per minute - by end of pregnancy, mothers blood volume would have increased by 40% - a balanced diet is needed - women needs to increase energy increase per day to 850KJ especially in second half of pregnancy - also need an increase in protein and calcium, iron and folic acid - weight gain can be a problem for some with an increase from the foetus, placenta, and amniotic fluid - increase in blood volume, size of breasts and uterus also contribute to weight gain - hormonal changes promote the conversion of energy to fat and the retention of water in the body - excessive weight gain is hard to loose after birth - should not consume alcohol or drugs - good exercise plan - placenta becomes a major source for progesterone essential for painting pregnancy - prevents shedding of uterus lining - if progesterone levels drop due to inadequate production a miscarriage could result - mothers at risk are given synthetic hormones

DIAGNOSIS OF FOETAL HEALTH:

- women needs to have regular checks with the doctor - health of foetus can be monitored history of foetal development: - ultrasound - amniocentesis - fetoscopy - chorionic villus sampling - foetal blood sampling

EARLY EMBRYONIC DEVELOPMENT AND IMPLANTATION:

- zygote has the potential to grow into a new individual human being - after fertilisation, the zygote travels down the uterine tube and begins to divide by mitosis - process results in the formation of two cells exactly the same as the original parent cell - these two cells divide again by mitosis into four, then eight etc. - after 6 days of fertilisation, the original zygote has reached the uterus and developed into a blastocyst - blastocyst is a hollow ball of cells that surround a cavity filled with fluid - inner mass cell will develop into the embryo, and the cells that compose it are called stem cells- able to produce any of the different types of body cells - blastocyst remains free within the cavity of the uterus for 2-3 days and then sinks into the soft endometrium to become firmly attached to the wall of the uterus - this process is called implantation, and enables the blastocyst to gain nourishment for growth and development by absorbing nutrients from the uterine lining - implantation of the embryo usually occurs naturally - sperm and eggs can be mixed in a lab and then be placed in the females uterus lining known as IVF

DEVELOPMENT OF A HUMAN FOETUS:

-foetal period from the ninth week of pregnancy through to birth, is characterised by an increase in size and maturation of the organ systems - proportions of the baby change gradually, head becomes smaller and limbs longer - between weeks 9-12 the baby doubles in length - developing baby straightens so the head no longer bends forward and posture is more upright

FEMALE REPRODUCTIVE SYSTEM:

-primary sex organs are the two ovaries - ova is produced in ovaries - uterus holds baby during pregnancy - uterine tube carried eggs to uterus - ovary produces eggs and hormones - every ovary contains connective tissue called the stroma - each germ cell is enclosed in a follicle, - egg is expelled into the funnel like opening of the uterine tube - fimbria help to guide the egg to the uterine tube - wall of the uterus is made up of soft membrane lining called the endometrium - external opening of the vagina is covered by a fold of tissue called the hymen - vulva is made up of external genetil organs of the female, labia majora, labia minora and cliterus - labia majora have glands that secrete oily secretion - labia minora surrounds the space that the urethra and vagina open - cliterus contains erectile tissue, blood vessels and nerve