chapter 18 - development of a human foetus Flashcards
1
Q
what are changes in the mother that occur
A
- mood swings: hormones or fear of what pregnancy brings
- bigger abdomen: due to uterus enlargements, other organs being forced up / out
- breast enlargement: due to hormone secretion
- heart / blood volume: increases (to cater for extra blood to placenta)
- urine production: increases due to increased flow to kidneys
- bladder: first 3 months uterus presses on bladder -> urination, then uterus moves up -> less urination, end of pregnancy foetus applies pressure -> increased urination
2
Q
what is the foetal period
A
- week 9 (start of month 3)-birth
- characterised by increase in size and maturation of organs
- foetus grows from 3->50cm, weight increases from 4->3000g, proportions change
3
Q
what is a healthy pregnancy
A
- achieving the goal that ones baby is born healthy, the mother needs to look after their own baby
- increased nutrients, balanced diet, weight gain, avoiding chemicals, exercise and progesterone
4
Q
how does increased nutrients ensure a healthy pregnancy
A
- causes increased blood flow through the placenta, increased blood flow (increased by 40% by end of pregnancy)
- functions slow down -> nutrients stay in blood longer -> increases diffusion across placenta, may lead to constipation
5
Q
how does a balanced diet, weight gain and avoiding chemicals ensure a healthy pregnancy
A
- BD: increased energy intake (~850kJ / day), increased protein intake (~65g / day), increased calcium, iron, folic acid (folate), fluoride if not in water already
- WG: ~0.5kg / week (2nd half), foetus (3.4kg), placenta (0.7kg), amniotic fluid (1kg), increased blood volume (1.6kg), tissue fluid (1.6kg), uterus (1kg), fat (3.2kg) breasts (0.9kg) = 13.4kg
- AC: mother should not smoke, or consume alcohol or drugs
6
Q
how doses exercise ensure a healthy pregnancy
A
- maintaining normal work out, walking regularly, vigorous exercise -> woman carry to full term
- allows mother to maintain stamina during labour and will get back into shape more quickly after birth
7
Q
how does progesterone ensure a healthy pregnancy
A
- placenta is the major source of progesterone, maintains pregnancy
- increased progesterone prevents premature shedding of uterine lining -> can lead to premature delivery or a miscarriage
8
Q
what are congenital disorders
A
- defects or diseases that are present at birth, can be due to inheritance of defective genes, mutations of genes and environmental factors
- teratogenic agent: one that causes physical defects in the developing embryo
9
Q
how do infections disrupt normal foetal development
A
- some viruses can cause birth defects, while others cause congenital disorders
- rubella: viral infection, frequently contracted by school aged children, however if contracted by a pregnant woman disastrous consequences (deaf, blind, heart , malformations)
10
Q
how does maternal diet disrupt normal foetal development
A
- important factor in normal foetal development
- folic acid: required for normal cell division, lack of folic acid before or during pregnancy can result in Spina bifida
- eating whole grains, green vegetables, cereals, take folic acid one before and three months during pregnancy
- calcium / vit. A: normal bone / cell growth, balanced diet, take vit A in last 10 weeks
- listeria infection: can cause miscarriages or still births, avoid eating pre-packed salads, soft cheese, pate, raw / smoked seafood, eat freshly prepared food
11
Q
how does alcohol disrupt normal foetal development
A
- suspected teratogen, relationship has been found between alcohol intake and malformations
- foetal alcohol syndrome: describes effects of foetal exposure to alcohol (birth weight is lower, slower growth, small head, defects of heart, malformed limbs, mental retardation)
12
Q
how does smoking and chemicals disrupt normal foetal development
A
- S: results in lower birth weight, addictions can be passed on to offspring, risk of abortion, gastrointestinal problems, respiratory probers, links to sudden infant death syndrome (SIDS)
- C: besides alcohol and smoking there are other teratogenic agents
- thalidomide: originally developed as a sleeping pill effective in preventing morning sickness, causes limb malformation, acts on limbs between the 28th-42nd day (limbs start developing at 10 days), it is now used to treat leprosy and some blood cancer
13
Q
what is an ultrasound
A
- a probe that is placed on the abdomen and sound waves are reflected by the foetal tissue to obtain a visual ‘echo’
- fed into computer to produce an image
- malformations of brain, head and limbs can be detected
14
Q
what is a fetoscopy
A
- involves looking directly at the foetus through the fetoscope (small telescope like instrument)
- detects cleft lip, palate, abnormal ears, deformed / absent limbs, Spina bifida
15
Q
what is foetal monitoring
A
- regular recording of the babies heart rate, tales place during labour / birth using ultrasound or electrocardiography (records electrical changes)
