Foetal development assessment

Question 1

define fertilisation

Answer 1

Is the fusion of the sperm and ova

Question 2

define implantation

Answer 2

The process whereby an embryo (blastocyst) sinks into the endometrium

Question 3

where does fertilisation occur

Answer 3

The fallopian tubes

Question 4

where does implantation occur

Answer 4

Occurs at the endometrium

Question 5

define zygote

Answer 5

The fertilised ovum from which a new individual develops

Question 6

define embryo

Answer 6

The early stage of development of an organism in humans.

Question 7

define foetus

Answer 7

The developing individual after the second period of pregnancy

Question 8

Relate a zygote to the stages of development

Answer 8

A zygote goes through many divisions after fertilisation during the cleavage stage. 2 cells - 4 cells - 8 cells - 16 cells. A solid ball of cells will form called a morula. The morula moves down the fallopian tubes and changes to a blastocyst.

Question 9

describe the embryonic cycle

Answer 9

After the cleavage stage, the blastocyst will embed itself into the endometrium. The embryonic knot will transform into the primary germ cells. The amniotic membrane and yolk sac will form. The germ layer will bend to form a cylinder shape, which causes the amniotic membrane to increase in size and the yolk sac to decrease in size.

Question 10

define differentiation

Answer 10

The process of stem cells becoming specialised and developing special characteristics to suit their functions

Question 11

define specialisation

Answer 11

When cells replicate over and over to give rise to specialised cells

Question 12

what are the three germ layers

Answer 12

• ectoderm
• mesoderm
• endoderm

Question 13

what is the function of the germ cell

Answer 13

Their function is to differentiate and specilise into different cells

Question 14

what does the ectoderm form

Answer 14

• skin
• hair
• nervous system

Question 15

what does the endoderm form

Answer 15

• alimentary canal
• the lining of the lungs
• epithelium of gall bladder

Question 16

what does the mesoderm form

Answer 16

• bones
• muscles
• blood

Question 17

what are the different stem cell classifications

Answer 17

• totipotent
• pluripotent
• multipotent

Question 18

what are stem cells

Answer 18

stem cells are unspecialised. They are capable of repeated divisions by mitosis.

Question 19

what are totipotent stem cells

Answer 19

form any part of the embryo and surrounding membranes

Question 20

what are pluripotent stem cells

Answer 20

form any part of the embryo

Question 21

what are multipotent stem cells

Answer 21

Give rise to cells with a particular function

Question 22

the foetus development - monthly changes

Answer 22

3 months - 
- forelimbs develop 
- bone marrow formed 
4 months - 
- arms and hands fully shaped 
- skeleton completed 
5 months - 
- fine hairs cover the body
- gripping reflexes developed 
6 months - 
- respiratory movement s
- eyebrows 
7 months - 
- all systems functional - except respiratory 
8 months - 
- accumulation of fat underneath the skin 
9 months - 
- eyes open 
- nose well-formed

Question 23

roles of the placenta and hormones to establish viable pregnancy

Answer 23

The placenta is an organ that supplies nutrients and removes wastes from the foetus. Chorionic villi develop from the chorion membrane and contain blood vessels. As the baby’s chorionic villi penetrate the endometrium, it becomes surrounded by the mother’s blood. The placenta is attached to the foetus via the umbilical cord, which consists of umbilical veins and arteries. The arteries release wastes and CO2 and absorb nutrients and O2 through the veins, all by diffusion and active transport.

Question 24

the embryo development - structural changes

Answer 24

week 4 -

• development of muscle segments
• brain begins to form
• heart and liver begin to form

week 5 -
- arm and legs begin to form

week 6 -

• all organs are present (not all functional)
• eyes appear like slits

Question 25

why are cells produced by initial cell divisions totipotent

Answer 25

These cells are totipotent as they must form parts of the embryo and surrounding membranes. Membranes include the amniotic membrane, yolk sac and chorionic membrane.

Question 26

what is the function of the amniotic fluid

Answer 26

This fluid serves to protect the embryo against physical injury by acting as a shock absorber

Question 27

how long is the embryonic period

Answer 27

8 weeks

Question 28

how long is the foetal period

Answer 28

30 weeks

Question 29

what is the major difference between both embryonic and foetal development

Answer 29

Differentiate greatly in terms of growth. During the embryonic period, the baby grew from 4mm to 3cm. During the foetal period with grows from 3cm to 50cm. The weight increases from4 grams to 3400 grams

Question 30

what are 4 indications that a woman is pregnant

Answer 30

1. Her growing abdomen
2. Enlargement of breasts
3. Increases heart size + increase in blood volume
4. Increase in urine production