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Human Biology Unit 2 - Semester 2 > Chapter 18 - Development Of A Human Foetus > Flashcards

Chapter 18 - Development Of A Human Foetus Flashcards

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1
Q

Baby; what happens during the 3rd month of pregnancy?

A
  • forelimbs well developed,
  • eyelids closed
  • outer ears completed
  • bone marrow formed
  • blood cells formed in bone marrow
  • length from the crown of the head to the buttocks grows from the 3cm to 50cm (doubles in size)
  • weight is increased from 4g to over 3400g
  • the proportions of the body change gradually with head becoming proportionately smaller
  • Limbs longer
  • straightens so that head no longer bends forward
  • posture is more upright
  • toenails and fingernails + hair appear
  • mother can detect her enlarging uterus at this stage
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2
Q

Baby; what happens during the 4th month of pregnancy?

A

Woman’s abdomen begins to bulge

Baby

  • Arms and hands fully shaped
  • skeleton completed
  • exercising muscles evident
  • ears stand out from head
  • 18cm length
  • 100g weight
  • posture is erect
  • fingerprints appear
  • foetus moves - stretching its arms and legs ; mother may begin begin to detect theses movements

Heart beats strongly at 120-160 beats per minute (2x rate of mother)

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3
Q

Baby; what happens during the 5th month of pregnancy?

A
  • Fine hair covers the body
  • gripping reflexes are developed
  • increased growth
  • foetal movements such as kicking, turning can now be felt clearly by Mother.
  • foetus is 25cm long
  • weighs approx 300g
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4
Q

Baby; what happens during the 6th month of pregnancy?

A
  • respiratory movements
  • digestive glands begin to function
  • tooth buds evident
  • eyebrows and eyelashes formed
  • length 27-35cm long
  • weighs 565-680g
  • ## mother showing obvious signs of pregnancy
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5
Q

Baby; what happens during the 7th month of pregnancy?

A
  • period of faster growth
  • all systems functional except respiratory system
  • moves vigorously within uterus
  • brain enlarged considerably, its surface now furrowed with developed functional areas.
  • in males testes usually descend into the scrotum during this period
  • 38 cm length
  • weighs over 1000g
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6
Q

Baby; what happens during the 8th month of pregnancy?

A
  • accumulation of fat beneath skin
  • growth slowed
  • 41-45cm long
  • weighs 1800-2200g
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7
Q

Baby; what happens during the 9th month of pregnancy?

A
  • Eyes open
  • nose well formed,
  • sucking and grasping reflexes apparent
  • fine body hair is shed
  • full term baby at 40wks
  • foetal activity diminished - lack of space to move
  • 50cm length and weighs approx 3400g

Boys - heavier by 100g

Birth weight can differ from 2500g-4500g

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8
Q

What is the diffence between 1wk-8wk vs 9wk-40wk

A

During first 2 months of embryonic life - general external features and body form of the infant develop
- the basic plan of the organ systems in place, and from this stage onwards the term FOETUS is used to describe the developing individual

The foetal period from the 9th week through to birth is characterised by a great increase in size and maturation of the organ systems

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9
Q

Shortly before birth

A
  • foetus changes its position in the uterus and comes to lie with its head resting since the curved shape of the pelvis
  • the movements of the foetus in this position are even more restricted
  • growth of foetus is very slow asn placenta begins to fail and become more fibrosis
  • antibodies from mother diffuse across placenta into baby’s blood these give the newborn child temporary immunity against disease to which the mother is immune
  • after 6months the effects of the antibodies gradually decades as the child begins to develop own immune system.
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10
Q

Why are there changes in mother?

A

During pregnancy baby grows remarkably
- it needs to be supplied with oxygen, nutrients and needs to have CO2 and other wastes removed.

After birth
- continued nourishment is required.

During pregnancy Changes in the mother accomodate for all these requirements

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11
Q

What are some changes in the mother during pregnancy?

A
  1. Growing abdomen (Obvious)
    - abdomen bulges as a result of growth of the uterus
    - stomach, liver and intestines are being forced upwards and outwards
  2. Enlargement of breast (Obvious)
    - hormones of pregnancy result in the development of the milk-secreting tissues which leads to an in carded size.
  3. Increase in size of heart and blood volume production
    - to cater for the extra blood that is flowing through the placenta
  4. Increased blood flow to the kidneys and increased urine production
    - pressure on the bladder causes an increase in the frequency of passing urine
    - 1st three months of pregnancy, the expanding uterus presses on the bladder so that the it feels as if it is filled with urine.
    - as the uterus grows, it moves up the pelvic cavity, releasing this pressure
    - then the last stage of pregnancy the foetus presses on the bladder
  5. Change in Emotional state.
    - changes in mood may be due to the changes in hormonal balance
    - natural fears accompanying pregnancy about baby’s development, problems that may occur at birth, effect of newborn child to rest of family and life
    - many factors are beyond the control of the pregnant woman - supportive reassurance from family and friends are very important in maintaining a positive
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12
Q

What occurs in woman’s body to ensure baby receives nutrients? And disadvantages

A
  1. As EMBRYO develops in uterus changes occur in MOTHER’S BODY to allow her to ADJUST to the NEEDS of PREGNANCY.
    - STARTS very EARLY
    - changes will take place AHEAD of the TIME FOETUS DEMANDS for OXYGEN, NUTRIENTS and WASTES REMOVAL

2.During EMBRYONIC PERIOD (when organ systems are developing) - MOTHER can EASILY SUPPLY REQUIREMENTS of embryo.

  1. LATER weeks of FOETAL DEVELOPMENT - LARGE AMOUNTS of O2 and nutrients are NEEDED, ADJUSTMENTS are REQUIRED in FUNCTIONING of WOMAN’S BODY.
    - her own FUNCTIONS SLOW DOWN to allow NUTRIENTS to STAY in BLOOD for a LONGER PERIOD of time - enables them to be MORE EASILY DIFFUSED ACROSS placenta for USE by THE

SLOWING BODY FUNCTIONS has DISADVANTAGEFOR mum

  • ALIMENTARY CANAL is LESS ACTIVE; stomach empties slowly and CONSTIPATION is common.
  • CONCENTRATION of NUTRIENTS in BLOODSTREAM is HIGHER, more tend to be FILTERED out BY KIDNEYS and are LOST in URINE.
  • LOSS can be easily COMPENSATED by well-BALANCED DIET
  1. For developing foetus TO OBTAIN the NUTRIENTS it REQUIRED a LARGE QUANTITY of BLOOD NEEDS to FLOW THROUGH PLACENTA.
    - is MET BY a GRADUAL INCREASE in the VOLUME of the mother’s blood and a FASTER RATE of CIRCULATION THROUGH her blood VESSELS.
    - results from an INCREASE in both the RATE of HEART BEATS and AMOUNT of BLOOD PUMPED PER BEAT
    - at END of R mother’s blood VOLUME INCREASED by 40%.
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13
Q

Requirements in diet for pregnancy woman

A

Balanced diet important- but influences birth weight and survival of baby is MINIMAL

  • average pregnant woman needs an increase of energy intake of approx 850Kj per day (especially in 2nd half)
  • required increase protein intake to ensure foetus is adequately supplied
  • should contain 65g of protein each day
  • Increased intake of Ca, Fe and folic acid (folate)
  • fluoride tablets after 12th week of pregnancy will help protect foetus from future dental problems.
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14
Q

Explain what makes woman gain weight in pregnancy

A

Mother will gain weight as pregnancy progresses

  • especially from contribution of foetus, placenta, larger uterus and amniotic fluid
  • increase in blood volume
  • increased size of Breasts
  • Hormonal changes involved in pregnancy promote conversion of energy to fat
  • retention of water in the body

Best of mother can keep her weight gain to about 0.5kg a week in 2nd half of pregnancy.

Excessive weight gain is very hard to lose after child is born - particularly if mother not breastfeeding

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15
Q

What things does mother need to be doing during pregnancy?

A
  1. need to be careful about exposure to chemical substances
    - should avoid smoke, alcohol, drugs for benefit of developing baby
  2. Exercise (even vigorous) is healthy during pregnancy
    - safe to exercise
    - women who exercised vigorously during pregnancy were more likely to carry babies to full term than those who did not/less
    - helps maintain her stamina during labour
    - women will re-gain pre-pregnancy shape more quickly than those who did not exercise
    - do not start immediately and Intensely if had not done before
  3. Ensure PROGESTERONE is available
    - hormone that is essential for marinating pregnancy
    - placenta is major source of it
    - rising progesterone levels prevent the premature shedding of uterus lining
    - if they drip production then a miscarriage or premature birth can occur
    - mother’s at Risk are given synthetic progesterone (progestin) to ensure mother retains foetus until full term.
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16
Q

What are congenital disorders?

A

Congenital disorders are defects of diseases that are present at birth

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17
Q

What are some causes if congenital disorders?

A
  1. Child inherits a defective gene/s from parents
  2. Mutations - spontaneous changes that occur to a gene or chromosome
  3. Environmental factors affecting foetus during uterine development - Eg alcohol, smoking, drugs, dietary insufficiency (teratogens)
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18
Q

What is a teratogenic agent or teratogen

A

An environmental agent which causes physical debts in the developing embryo.

Wide range - hormones, antibiotics, oral anticoagulants, anticonvulsants, anti-tumour drugs, thyroid drugs, thalidomide, LSD and marijuana

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19
Q

When are agents identified as teratogens?

A

After an increased prevalence of a certain birth defect.

Eg. Increased prevalence of cerebral palsy in babies born to mothers living around Minamata Bay in Japan led to researchers identifying methyl mercury as offending agent.

A local factory was discharging this chemical into the water in the bay contaminating the fish.

After pregnant women ate the contaminated fish, the methyl mercury passed across the placenta and affected the developing foetus.

Affected babies were born suffering convulsions, intellectual disabilities and general brain damage.

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20
Q

How and when can a teratogen disrupt foetal development.

A

Can cause physical defects in the developing embryo however the range of actions and effects of teratogens vary significantly.

Eg a dose of a particular agent often determines the severity of the damage and the type of defect that occurs.

In most cases the GREATER TYE DOSE, THE GREATER THE EFFECT.

THE TIME AND LENGTH OF EXPOSURE - can affect certain stages of embryonic and foetal development are more vulnerable than others.
- in general the embryonic stage is more vulnerable than the foetal period

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21
Q

How does environmental factors affect foetal development.

A

Environmental factors may cause malformations in babies but do not necessarily involve any change in genes or chromosomes.

They may however change the way in which a gene, or genes, is expressed an may therefore be passed on to subsequent generations, a process known as epigenetics.

The placenta allows many dangerous organisms and chemicals to pass from mother to foetus.
Eg viruses easily pass across tye placenta . These have the potential to cause serious problems for a developing Baby.

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22
Q

What are some teratogens that affect normal foetal development?

A
  1. INFECTIONS — Some Viruses are known to cause birth defects, while others are suspected of contributing congenital disorders.
  2. MATERNAL DIET
  3. ALCOHOL
  4. SMOKING
  5. CHEMICALS
23
Q

What is rubella?

A

Rubella is a viral infection that was frequently contracted by school-aged children.

It is a fairly mild disease although highly infectious.

24
Q

How is Rubella a TERATOGEN

A

If contracted by a pregnant woman it can have disastrous consequences for the child
- may be born DEAF, BLIND or with HEART MALFUNCTIONS

The rubella virus tends to grow in tissues that are just forming.
- 9/10 babies infected during the first 10 weeks of pregnancy have a major problem such as Deafness, blindness, heart defects or brain damage.

The risk of damage decreases as the pregnancy progresses.
- the risk of 61% if infection occurs in the fourth month and 10% towards the end of pregnancy

VACCINE - is recommenced in the AUSTRALIAN STANDARD IMMUNISATION SCHEDULE for children from birth to 4yrs is MMR - measles, mumps and rubella.
- the vaccine injected under the skin at 12 months and against at 4yrs, gives lifelong protection against the disease.

A definite link between viral infections and birth defects is often difficult establish.
Influenza, infectious hepatitis and mumps are all thought to have adverse effects on the foetus.

There is some evidence to suggest that the influenza virus may be linked with brain damage to the foetus if contracted by the mother during early pregnancy.

25
Q

Why is FOLIC ACID IMPORTANT FOR MATERNAL DIET?

A 
Folic acid (Folate) - essential for normal cell division and for the manufacture of protein.
- lack of folic acid before and during pregnancy can also contribute to SPINA BIFIDA and other neural tube defects.

SPINA BIFIDA - the bony arch of the vertebrae around the spinal cord does not develop

Mother’s can help protect their babies from this -

  1. INCREASING FOLIC ACID intake at ONE MONTH BEFORE PREGNANCY
  2. Increase folic acid intake for the FIRST THREE MONTHS

**Eat foods rich in folic acid such as WHOLEGRAIN BREADS and CEREALS, GREEN LEAFY VEGETABLES, AND LEGUMES

26
Q

Why is Calcium important for maternal diet?

A

Adequate amounts of calcium are necessary for NORMAL BONE GROWTH

  • otherwise calcium is taken from mother’s bones
27
Q

Why is VITAMIN A important for maternal diet?

A

Deficiencies in Vitamin A and Folic Acid can cause deformities.

Vitamin A is necessary for NORMAL GROWTH OF CELLS
* since little is stored in the body, a steady intake is necessary.

During pregnancy - the demand increases considerably as gestation progresses - ESPECIALLY IN THE LAST 10 weeks

Level of this Vitamin decreases in the woman’s blood tends to fall.

Balanced diet - good quantities of green and yellow vegetables; no need for concern.

28
Q

What is LISTERIOSIS? And effects on preg women

A

Listeria infection (Listeriosis) is a very mild illness caused by eating food contaminated with the bacterium LISTERIA MONOCYTOGENES.

Infection in a pregnant woman has the potential to cause MISCARRIAGES AND STILL BIRTHS.

To guard against this infection - eat food that has been FRESHLY PREPARED OR COOKED. Carefully read any warnings on food labels

AVOID;

  • salads from salad bars
  • pre-packaged salads
  • soft cheeses
  • pâté
  • smoked seafoods
29
Q

What are the Main features needed in a preg diet?

A
  1. Folic acid
  2. Vitamin A
  3. Calcium
  4. Freshly prepared and cooked foods
  5. Iron
30
Q

How is alcohol a teratogen?

A

FOETAL BLOOD ALCOHOL SYNDROME (FAS) is a term used to describe the effects of foetal exposure to alcohol.

  • 1/1000 births may be affected by FAS
  • one or two drinks may not cause harm to baby, however health authorities advise preg and planning preg women to avoid drinking
  • Excessive alcohol drink- ‘binge drinking’ early in pregnancy has definitely marked on child.
    Most obvious effect is LOWER THAN NORMAL BIRTH WEIGHT
    other symptoms include:

Physical

  • SLOW GROWTH BEFORE AND AFTER BIRTH
  • SMALL HEAD
  • IRREGULARITIES OF FACE EG. NARROW EYE SLITS, SUNKEN NASAL BRIDGE
  • DEFECTS ON HEART AND OTHER ORGANS
  • MALFORMED ARMS AND LEGS
  • MENTAL RETARDATION

physiological - behavioural problem

  • HYPERACTIVITY,
  • EXTREME NERVOUSNESS,
  • POOR ATTENTION SPAN
31
Q

Why is smoking considered a teratogen?

A

Affects

  • birth weight of babies; significantly LOWER BIRTH WEIGHT than to women who don’t smoke
  • INCREASED RISK OF ABORTION

CHILDREN of MOTHERS WHO SMOKE AND BREASTFEED
- more than likely to SUFFER from GASTROINTESTINAL PROBLEMS than other children

  • HIGHER INCIDENCE OF RESPIRATORY PROBLEMS Eg. BRONCHITIS, PNEUMONIA during first year of life

STRONG ASSOCIATION between smoking and SIDS (SUDDEN INFANT DEATH SYNDROME)
- if mother resumed smoking

32
Q

Explain the effect of THALIDOMIDE. CHEMICAL T

A

Eg THALIDOMIDE- (1958) chemical originally made for the use in sleeping pills

  • was found to be effective in the prevention of morning sickness during the 1st months of pregnancy
  • after 2 years of sale: sharp rise in the incidence of certain very rare limb malformations was noticed
  • if malformations were SUBTLE then they may have not aroused medical attention so quickly
  • two doctors Widukind Lenz (Germany) and William McBride (Sydney Aus) were responsible for linking these malformations to thalidomide
  • 1961 taken of shelves estimated 7000 babies had been affected
  • 40 yrs after ban of the drug Thalidomide - now being used for the treatment of LEPROSY and for a type of BLOOD CANCER
  • available in Australia but only for very restricted use
33
Q

Explain how the babies were affected by THALIDOMIDE CHEMICAL

A

Good example for the TIME of EXPOSURE to the teratogen DETERMINES the TYPE of DEFECT.

  • the thalidomide acts on embryo between the 28th - 42nd days of development - TIME WERE FUTURE LIMBS START TO APPEAR
  • first as microscopic buds - gradually developing into readily recognisable forms by day 42.
  • ARMS DEVELOP FIRST, THE. ONLY FOLLOWED BY LEGS - therefore may be reason why thalidomide affects arms more than legs
34
Q

How are ILLEGAL DRUGS (chemicals) considered a TERATOGEN?

A

Eg HEROINE and LSD, as well as MEDICAL DRUGS

  • can cause DAMAGE TO FOETUS when taken during pregnancy
  • most doctors are extremely careful when prescribing drugs to women of Child bearing age

— MOST DRUGS CAUSE THE GREATEST HARM DUEING EARLY PREGNANCY when women do not know that they are pregnant

  • Any sexually active woman not taking contraception should be very careful about using drugs of any kind w/o seeking medical advice first
  • labels on most medicinal products now have a clear warnings about possible side effects, and a pregnant woman should read such labels carefully to ensure there is no risk to her developing child
35
Q

What is an Ultrasound? How does it monitor baby?

A

Ultrasound uses INAUDIBLE, high frequency sound waves to produce an image of the foetus

  1. Probe is placed on the abdomen of the pregnant woman
  2. The sound waves are reflected by the foetal tissues to obtain a visual ‘echo’ of what is inside the uterus
  3. Doctor feeds theses reflected sounds, or echoes into a computer to produce a screen image of the foetus for study
  4. By careful examination of the image, malformations of the Brain, Spina BIFIDA can be diagnosed
36
Q

What are the three different types of CHROMOSOME ANALYSIS

A
  1. Karyotype
  2. Amniocentesis
  3. Chorionic villus sampling (CVS)
37
Q

What occurs during a Karyotyping process?

A

A photograph, or drawing of the chromosomes displayed in order is called a KARYOTYPE

  • FOETAL CELLS can be OBTAINED for analysis via Amniocentesis or chronic villus sampling (CVS)
  • Chromosomes of cells from a foetus can be examined to detect defective, missing or additional chromosomes

Eg. Down syndrome can be identified if KARYOTYPE has an additional chromosome 21.

38
Q

What happens during Amniocentesis? When, who, what, risks, detection, how.

A

Amniocentesis- obtain foetal cells

  • is carried out between the 16th and 20th weeks of pregnancy
  • by which time the foetus is floating in about 130mL of amniotic fluid

It involves the removal of 10-20mL of the FLIUD

  • floating in the FLIUD are LIVING CELLS from the FOETUS
  • can EXAMINE these CELLS for DEFECTS or ABNORMALITIES in the NO. of CHROMOSOMES or in chromosomes STRUCTURE.
  • RISKS
    1. Miscarriage
    2. Infection
    3. Damage to rate baby

Therefore only performed in high risk pregnancies - women who have a higher risk of delivering a baby with a birth defect (older age or genetics)

Can detect

  1. Down syndrome
  2. Cystic fibrosis
  3. Neural tube Eg SPINA BIFIDA
  4. genetic disorders Eg sickle cell, phenylketonuria, Tay -Sachs, Duchenne muscular dystrophy
39
Q

What happens during CHORIONIC VILLUS SAMPLING ? When, who, what, risks, detection, how.

A

Obtains a SPECIMEN OF FOETAL CELLS FROM CHORION and examined in a Similar way to amniocentesis

Advantages over amino…

  • Testing can take place at 9-19weeks
  • foetal tissue gained can be tested more quickly than of amniotic FLIUD specimen — thus reduces time between the testing procedure and examination of the results
  • especially important if a birth defect that may require termination of pregnancy involved

Disadvantage

  • risk of miscarriage following the procedure is 2%
  • cannot diagnose Spina BIFIDA

Detects
- genetic disorders
- biochemical abnormalities
-

40
Q

What happens during Fectoscopy? When, who, what, risks, detection, how.

A

Fectoscopy involves looking directly through a small, telescope- like instrument with a diameter about the size of a hypodermic needle.

The instrument is a Fetoscope and is introduced into the uterus through the abdominal wall

Examination of the outward appearance of the foetus may enable such conditions as CLEFT LIP, PALATE, MISSING OR ABNORAML EARS, DEFORMED OR ABSENT LIPS AND SPINAL ABNORMALITIES (Spina BIFIDA) to be detected

If decision takes place in early pregnancy a decision about termination can then be made

41
Q

Foetal blood sampling.

A

Fetoscope first was used to obtain foetal blood samples from placenta.
- More recently foetal blood has been directly obtainable

Refinements to the Fetoscope technique resulted in a procedure now referred to as ‘PERCUTANEOUS UMBILICAL CORD SAMPLING’ (PUBS)

  1. is usually performed surfing weeks 18-22
    2.a sample of foetal blood is extracted from the umbilical vein in umbilical cord using a fine needle via the abdomen of the mother
  2. extracted blood can then be used to decked certain abnormalities including CHROMOSOMAL ABNORMALITIES and BLOOD DISORDERS
    And METABOLIC DISORDERS

DETECTS
- CHROMOSOMAL ABNORMALITIES - Down syndrome

  • BLOOD DISORDERS - foetal haemolytic disease, intrauterine infection, growth retardation
  • BIRTH DEFECTS
  • METABOLIC DISORDERS

FOETAL BLOOD for CHROMOSOMAL ANALYSIS enables RESULTS to be PROVIDED FAR MORE QUICKLY THAN with OTHER techniques.
- Eg some biochemical disorders can be diagnosed on the day the foetal blood sample is obtained

Benefits
- fast diagnosis for early treatment where possible, or quicker action if pregnancy needs to be terminated

42
Q

Sampling of mother’s blood

A

Blood test of mother’s have also been devised to detect genetic disorders in foetus.

Can detect 6weeks after conception

Simpler than CVS AND AMNIO.

  1. only involved taking BLOOD SAMPLE from ARM of preg WOMAN.
  2. The SAMPLE is TREATED with SPECIAL ANTIBODIES that ADHERE ONLY to the FEW FOETAL CELLS CONTAINED WITHIN the mother’s BLOOD.
  3. ANTIBODIES have MAGNETIC BEADS ATTACHED to them to ENABLE the FOETAL CELLS to be ISOLATED FROM the OTHER CELLS in the blood by the use of the magnet.
  4. The foetal CELLS can be then CULTURED and the CHROMOSOMES AND then EXAMINED for GENETIC ABNORMALITIES.
43
Q

Explain foetal monitoring

A

Foetal monitoring is the regular recording of a baby’s heart rate in order to detect indicators of stress
- aim is to identify any risks of injury to the foetus so appropriate action can be taken

Monitoring usually takes place during labour and birth using ultrasound and ELECTROCARDIOGRAPHY

ELECTROCARDIOGRAPHY is a procedure for recording electrical changes in the heart.

The record, which is called a ELECTROCARDIOGRAM (ECG) shows series of waves that reacts to the electrical impulses that occur during each heartbeat.

Results are printed on paper or displayed on monitor.
- FOETAL MONITOR may be USED DURING LABOUR and BIRTH to RECORD the BABY’S HEART RATE and sometimes MOTHER’S CONTRACTIONS

A detailed heart rate analysis enables medical staff to CHECK whether there is any chance of OXYGEN DEFICIENCY during birth which may RESULT in BRAIN R OR STILLBIRTH.

44
Q

Explain biochemical analysis

A

The assessment of marker proteins occurs with all newborns in Australia and in many countries

Technique is used to detect PHENYLKETONURIA (PKU)

  • either by testing the blood for excessive amounts of PHENYLALANINE
  • or analysing urine for phenylPyruvic Acid

Another marker protein is ALPHA-FETOPROTEIN (AFP) which can be measured in samples of amniotic FLIUD

The concentration of this protein is very high when the foetus has a malformation of the spinal cord Eg SPINA BIFIDA

45
Q

Explain DNA PROBES

A

More recent innovation that enables the detection of a range of genetic disorders such as DUCHENNE MUSCULAR DYSTROPHY and THALASSAEMIA

PROBES are based on RECOMBINANT DNA TECHNOLOGY
1. a segment of DNA is used that us STRUCTURALLY IDENTICAL TO THE GENE being tested.

  1. Some UNITS of the DNA segment are ‘labelled’ with a DYE or RADIOISOTOPE
  2. the DNA probe is then JOIN TO the GENE IN QUESTION
  3. IF NORMAL PROBE JOINS DNA SEGMENTS with which it is STRUCTURALLY IDENTICAL and SHOWS UP.
  4. If it ABNORMAL GENE it DOES NOT SHOW UP and is IDENTIFIABLE as a GAP in the DNA begin tested.
46
Q

What are the DIAGNOSIS TECHNIQUES OF FOTEAL HEALTH

A
  1. MOTHER’s Blood sampling (chromosomes analysis)
  2. CHORIONIC VILLUS SAMPLING (chromosomes analysis)
  3. AMNIOCENTESIS (chromosome analysis)
  4. FETOSCOPY (face - physical)
  5. FOETAL BLOOD SAMPLING (chromosome analysis)
  6. Ultrasound (physical)
  7. FOETAL MONITORING (EC AND ECG - heartbeat recordings)
  8. Biochemical analysis (blood protein PKU AND AFP)
  9. DNA PROBES (gene)
47
Q

Why do some couples experience infertility and how to solve

A
  1. Physical defects may stop sperm and egg from uniting AND/or Man produces few sperm
    - Microsurgery can be used to solve BLOCKED UTERINE TUBES, SPERM DUCTS can be OPENED, TUMOURS REMOVED
    - CERVICAL MUCOUS HOSTILE TO SPERM may HAVE to BE TREATED
  2. Problems due to ovulation
    - frequently solved by MEDICATIONS USED TO STIMULATE OVULATION
    Eg Clomiphene is a drug that a woman takes orally to stimulate her body to make more hormones that cause eggs ti mature in ovaries
    - if not successful GONADOTROPINS may be INJECTED TO STIMULATE EGGS TO GROW leading to ovulation
  3. in certain woman ovulation may not occur due to abnormally high levels of hormone PROLACTIN
    - certain medications, kidney disease, thyroid disease can cause high levels of prolactin.
    - oral medication available to restore normal levels of prolactin. And once this occurred women normally ovulate.
48
Q

Explain ARTIFICIAL INSEMINATION BY DONOR

A

If man’s sperm are unable to fertilise the egg, a couple may decide to have a child through semen donated by another man.
PROCEDURE KNOWN AS ARTIFICIAL INSEMINATION BY DONOR (AID)
- increasingly common and pregnancy rate is high - 70-80% coupled using AID eventually have child with this method.

MAJOR RISK
- transmission of disease from donor to recipient
For this reason donors are carefully screened for sexually transmitted infections and genetic disease, mental problems and general health

Physical characteristics of donor are matched to those of the sterile man
- most cases donor is never seen or known by couple and donor does not know to whom sperm has been given

At about time of expected ovulation the woman visits her doctor and on each day for 3-4 successive days the donors semen is injected into her upper vagina

Unusual for pregnancy to occur the first time AID is used
On average three insemination a month for three months are necessary

49
Q

Types of assisted reproductive technologies

A

Assisted reproductive technology (ART) types

  1. IVF
  2. GIFT
  3. ICSI
  4. Surrogacy
  5. Donor egg
  6. Most techniques have require women to take a fertility drug to increase the number of eggs produced and released by ovaries
  7. Eggs can be harvested at ovulation and mixed with sperm - VARIATION in techniques relate to WHEN AND WHERE egg-sperm mixture OR embryo is placed in woman’s reproductive system

Because of chances of failure most of these procedures require a LARGE NUMBER OF EGGS

  • often means that more embryos are available than are required for implantation into the woman’s uterus
  • excess embryos are frozen for later use in case of successful pregnancy did not eventuate
  • if embryos are not needed ethical and moral questions are raised and at some time a decision must be made about what is to happen to unsigned embryos as they cannot be stored forever (only up to 5yrs Aus) approx 120 000 stored rn
50
Q

What happens during IN-VITRO FERTILISATION

A

Man’s sperm used to fertilise woman’s collected egg and make embryo in a glass dish outside of woman’s body

Then implanted into woman’s uterus

25th July 1978 (35yrs) first test tube baby

51
Q

What happens during GAMETE INTRAFALLOPIAN TRANSFER

A

Eggs and sperm are collected then mixed together immediately after collection

Mixture is then injected into woman’s uterine tube

Allows mixture and fertilisation to occur naturally

Any fertilised eggs pass down the uterine tube to the uterus in usual way

52
Q

What happens during INTRACYTOPLASMIC SPERM INJECTION

A

If sperm count insufficiently low or insufficient quality of sperm to attempt IVF for man

A single sperm is injected into a single egg and resulting embryo is then transplanted into woman’s uterus

Fertilisation rates 20-30% can be achieved but concern has been expressed that technique may increase birth defects

53
Q

What happens during donor egg

A

Donor egg or embryo is used when woman is unable to conceive using her own eggs

Egg donated by another woman is mixed with partners some resulting in embryo implanted in her uterus (also done with donated embryo)

54
Q

What happens during SURROGACY

A

Woman may agree to bear a child for a couple when the female partner is unable to become pregnant

Man provides semen naturally or through artificial insemination

Surrogate mother agrees to give child to couple who have asked for her help
- in some cases After giving birth surrogate mother decided to keep baby craving legal and emotional problems

Human Biology Unit 2 - Semester 2 (12 decks)

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