Prenatal Development

Question 1

When does development begin?

Answer 1

Traditionally thought at birth, more recently - in the womb.
Some argue it begins before conception with influence of social, economic and cultural factors

Question 2

Germinal stage

Answer 2

sperm and egg unite in the fallopian tube to form the zygote

Question 3

Weeks 1-2, zygotic stage

Answer 3

The fertilised egg travels down the fallopian tube, at the same time it divides and implants itself in the uterine wall

Question 4

Two process which sperm undergo as they travel through fallopian tubes

Answer 4

Capacitation - where it’s outer layer is changed

Hyperactivation - which changes the way the sperm’s tail moves.

Question 5

To enter the egg, the sperm must do two things:

Answer 5

1. Break through a group of cells known as the cumulus oophorous that surround the egg. The sperm dissolves these cells using an enzyme.
2. Break through the outer membrane of the egg. The sperm essentially fuses to and digests this membrane using an enzyme.

Question 6

The sperm’s nucleus

Answer 6

Where chromosomes are stored. Enters the egg cell looking for the egg’s nucleus. Once it meets the egg, the nuclei from the egg and sperm merge and share their genetic material.

Question 7

Implantation

Answer 7

It takes 6-12 days for the fertilized egg to travel to the uterus and attach to the uterus. The egg is pushed back towards the uterus by the cilia. The egg must attach to the uterus to become a viable pregnancy.

Question 8

When the uterus defects the blastocyst

Answer 8

It releases enzymes to break down the blastocyst’s outer membrane. Once the barrier is broken down, the blastocyst can attach to the endometrium.

Question 9

Weeks 3-5, embryonic stage

Answer 9

Embryo is just 2/3mms long and has a yolk sack. By the end of the 2nd week the chorion develops - a protective layer surrounding the amnion; small blood vessels emerge from it and later form the placenta

Question 10

Nutrients to the embryo

Answer 10

At first the embryo uses nutrients from the yolk sac and then once the placenta develops, uses that for oxygen and nutrients.

Question 11

Outer layer =

Answer 11

Ectoderm

Central Nervous System and skin, nails, eye lenses, tooth enamel

Question 12

Middle layer

Answer 12

Mesoderm

Muscles, skeleton, and circulatory system, organs

Question 13

Inner most layer

Answer 13

Endoderm

Digestive system, lungs and respiratory system, urinary tract, glands, stomach

Question 14

Gastrulation

Answer 14

The ectoderm develops a groove and folds, creating a tube aka the neural tube - this will become the brain and spinal cord.

Question 15

embryo at 3-5 weeks

Answer 15

Has some blood vessels; some start to connect to the uterus and will become the umbilical cord. The embryo is surrounded by fluid inside the amniotic sac, that is the sac that becomes the placenta.

Question 16

Weeks 6-9 embryonic

Answer 16

Rapid development of the beginnings of:

• CNS
• Limbs
• Eyes, ears, nose
• General development of systems and organs

Question 17

Weeks 9-12, foetal stage

Answer 17

• placenta is now fully formed
• organs connect
• foetus moves
• finer details such as nails, eyelids and ears form
• at the end of week 12, all the structures are there, now they have to mature and the foetus has to gain weight

Question 18

Week 12 when 2nd trimester starts

Answer 18

At this point the embryonic stage is over, all the ground work is laid out and the foetus can start maturing, gain weight and strength

Question 19

Teratogen

Answer 19

an environmental agent (e.g., a substance) that can cause damage during prenatal period.

Question 20

Sensitive/critical period

Answer 20

Each body part forms at a particular time. During that time, it is very sensitive to damage. A period of time when a part of the body of the developing organism (embryo/foetus) is developing and is particularly vulnerable and sensitive.

Question 21

Prescription drug

Answer 21

Any drug with molecules small enough to penetrate the placenta can enter the embryonic or foetal bloodstream. However, many people continue to take over the counter medication.

Question 22

Non prescription drugs can potentially cause

Answer 22

Contractions of the uterus which can affect blood supply, which in turn can cause pre-term birth, birth defects, miscarriage.

Question 23

Tobacco

Answer 23

Nicotine constricts blood vessels, lessens blood flow and affects placenta. This affects nutrients being delivered to the foetus and it can develop poorly.

Question 24

Tobacco consequences

Answer 24

Low birth weight, premature birth, impaired heart rate and breathing, infant death, asthma in later childhood.

Question 25

Low birth weight

Answer 25

The stronger and more developed the child is, the higher chances of following typical developmental trajectories and not being delayed.
Organs may not be dully developed, or simply not strong enough. The baby may need to be in an incubator, on ventilators or even intubated to help it breathe.

Question 26

Neonatal abstinence syndrome

Answer 26

Babies are born addicted to the drug. Suffer withdrawal after birth. May last 1 week to 6 months.

Question 27

Alcohol

Answer 27

Foetal alcohol spectrum disorders is a term that encompasses a range of physical, behavioural and mental outcomes caused by prenatal alcohol. CNS damage, distinct facial features, slow growth, low IQ, lifelong health problems.

Question 28

Foetal alcohol syndrome characterised by

Answer 28

Slow growth, Three specific facial features (short eye lid openings, thing upper lip, smooth or flat philtrum), brain injury

Question 29

Maternal factors

Answer 29

Age - over 50s
Nutrition - malnutrition can cause miscarriage, CNS damage, organ damage, lower birth weight
Exercise - moderate: increased birth weight, vigorous: low birth weight

Question 30

Intense anxiety

Answer 30

Higher rate of miscarriage, premature birth, low birth weight, respiratory and digestive illnesses, sleep disturbances.

Question 31

Low concentration of cortisol

Answer 31

leads to reduced physiological capacity to cope with stress

Question 32

Depression

Answer 32

growth delays, prematurity, low birthweight, sleep problems. difficult temperament, attentional, emotional and behavioural problems.