Pregnancy

Question 1

What is cleavage?

Answer 1

Cleavafe is a sequence of cell divisions that begins immediately after fertilisation

During this, the zygote becomes a pre-embryo, which develops into a multicellular complex know as a blastocyst

Question 2

What is Implantation?

Answer 2

Implantation begins when the blastocyst attaches to the endometrium of the uterus

The process continues as the blastocyst invades maternal tissue

Question 3

Describe the development of the foetus in each trimester

Answer 3

Frist Trimester

Major organ systems appear
Embryonic and early foetal

Second Trimester

Development organs and organ systems

Third Trimester

Rapid growth
Most organ systems fully functional

Question 4

How does Pregnancy affect the circulatory system?

Answer 4

Blood volume increases

Blood flow to placenta reduces blood volume in
systemic circulation

• foetal metabolic activity reduces PO2 & increases
PCO2

• Stimulates erythropoitein from kidney
• maternal volume increased by 30 - 50% by term

Question 5

Why do pregnant women need to urinate more frequently?

Answer 5

Pregnant women need to urinate frequently because of the extra urine produced by the foetus and the foetus pressing on the bladder

Question 6

What stimulates smooth muscle contraction?

Answer 6

Oxytocin

Prostaglandin

Question 7

What does Oestrogen and relaxin do as preparation of the baby being delivered?

Answer 7

• oestrogen:

• increases sensitivity
myometrium
• increases sensitivity to oxytocin

• relaxin:
• relaxes pelvic articulation • dilates cervix

Question 8

What are the three stages of labour?

Answer 8

Dilation (of cervix)

Expulsion (of baby)

Placental Stage

Question 9

Describe the dilation stage

Answer 9

Cervix dilates (widens), stretches and thins

Engagement: foetal head enters pelvis

Until cervix = 10cm open

Question 10

Describe the stage of Expulsion in pregnancy

Answer 10

Contraction of myocetrial smooth muscle

Crowning at vulva

Had extension

Baby is born and umbilical cord is clamped & cut

Question 11

What happens in the placental stage?

Answer 11

Expulsion of placenta, umbilical cord and membranes

Uterus continues to contract - Oxytocin

The blood vessels (umbilical and placental) constrict

Uterine contractions help compress vessels & restrict blood flow

Question 12

What are the main 4 steps in pregnancy?

Answer 12

1. Fertilisation
2. Implantation
3. Change sin mother
4. Induction and birth