Pre-natal development Flashcards
Sex cells
Sperm and ova are the names given to the male and female sex cells
What happens to the sex cells during fertilisation
When sex cells are created, they each contain half of the individuals genetic material which will fuse into one cell called a zygote with a complete set of genetic material during fertilisation.
What is fertilisation?
Fertilisation is when a sperm cell penetrates an egg cell and their genetic material fuses to form one cell.
How long is pregnancy?
Gestation period is 38 weeks however menstrual period is also counted so it is 40 weeks
Where does fertilisation occur?
Fertilisation occurs within the fallopian tubes
Name of cell once sperm and ovum fuse together?
Zygote
Stages and weeks of prenatal development
Germinal (0-2 wks)
Embryonic (3-8wks)
Foetal (9-40 wks)
When does germinal stage begin and end
it begins at fertilisation and ends at implantation into the endometrium
summary of the germinal stage
the zygote divides whilst being gently pushed by cilia into the uterus where implantation occurs
Steps of germinal stage
- sperm penetrates egg
- cell divides for the first time
- now called a morula, is 16 cells large
- blastocyst containing 64 cells consists of an inner and outer compartment
- Blastocyst begins to implant into the endometrium (uterus lining
What is the main characteristic of the embryonic stage?
Development of major organs
Why is the embryo especially sensitive to teratogens?
because the major organs are forming during this stage
What are teratogens
environmental influences such as tobacco or alcohol
what happens during this stage? List 3 things
Any 3 of:
- Cells continue to rapidly divide and cells start taking on specialised roles.
- Tissues that will become brain & spinal cord begin to develop.
- Embryo secretes hormones to prevent mother from having a menstrual period and keep the endometrium maintained.
- Buds appear which will form the limbs, heart begins to beat
- Placenta has begun to develop but will not be functional until in a number of weeks
- Brain cells generated at around 100 per minute
- Spinal cord looks like a tail and head is large in proportion to the rest of the body
- Approximately 1.3 cm long
- Blood cells being made in the liver
- Facial features forming
- Tiny muscles formed
- Fingers & toes beginning to form
- Brain is active
- 2.5 cm in length
What is the foetal stage characterised by?
Rapid growth
what is the placentas role
The placenta’s role is to supply the foetus with nutrients and oxygen and to remove wastes such as urine and carbon dioxide
- It is a temporary organ - Umbilical cord consists of 2 arteries and one vein - Umbilical cord attaches placenta to foetus - The blood vessels of the mother and the umbilical cord vessels do not come in contact due to possible different blood type. - Placenta produces progesterone which is responsible for assisting in maintaining pregnancy.
What is the last major organ to develop?
Lungs
main causes of foetal mortality
congenital abnormalities, maternal conditions, spontaneous preterm birth, unexplained antepartum death
Spina bifida
when the part of the neural tube that will become the spine fails to fuse which results in the spine not developing properly and the spinal cord may protrude outside the body
What is classed as a low birth weight
below 2500 grams
What can a low birth weight lead to?
risk of infection, respiratory conditions, Greater likelihood of learning disabilities or growth and motor skill development
Foetal mortality
Refers to the death of babies over 20 weeks gestation
maternal mortiality
Maternal mortality relates to deaths in pregnant women where the cause of death is due to the pregnancy itself.
Maternal morbidity examples (2)
Gestational diabetes: a form of diabetes that occur in women that have not previously been diagnosed with diabetes and it only occurs during pregnancy.
Ectopic pregnancy: When instead of implanting in the uterus, the embryo implants elsewhere such as the fallopian tubes or cervix.
biological determinants of health
genetics:
The genes a child inherits have a significant impact on health & development such as: Rate and timing of development in the uterus, sex of baby, development of genetic conditions, chromosomal abnormalities.
behavioural determinant (4)
Maternal nutrition
A healthy diet prior to becoming pregnant is important for ensuring the body is prepared for the demands of child bearing, and to ensure that the foetus has all of its nutritional needs met.
Smoking during pregnancy
Tobacco smoke contains thousands of chemicals and acts to reduce oxygen flow to the placenta and exposes the foetus toxins. It increases the risk of spontaneous abortion, ectopic pregnancy, foetal mortality
Alcohol use
Can cause foetal alcohol spectrum disorder
Vaccination behaviours
Vaccinations can help prevent the spread of many conditions to the unborn baby which can lead to death or serious complications if the foetus contracts a disease.
Physical environment
Tobacco smoke in the house
Access to health care
social determinant
Parental education
Parental income
