Week 2 - Birth

Question 1

What must a foetus do before birth?

Answer 1

• mature its lungs
• prepare the gut for feeding
• generate heat
• develop ability to concentrate urine

Question 2

What glucocorticoids accelerate foetal maturation?

Answer 2

• Corticotrophin Releasing Hormone (CRH)
• Adrenocorticotrophic Hormone (ACTH)

Question 3

What does the placenta producing CRH lead to?

Answer 3

stimulates foetal pituitary to produce ACTH and adrenal cortex to produce cortisol

Question 4

What does cortisol do in regards to foetal maturation?

Answer 4

• promotes differentiation and dev of foetal organs
• slows growth towards end of pregnancy

Question 5

Summary of the effects of Glucocorticoids on Foetal Maturation

Answer 5

Question 6

Mechanisms of Birth summarised

Answer 6

Question 7

How long does a normal pregnancy last?

Answer 7

around 40 weeks

Question 8

What is Parturition?

Answer 8

the action of giving birth to young; childbirth.

Question 9

Complication in the labour ward summarised

Answer 9

Question 10

Initiation of Labour

Answer 10

• Throughout pregnancy Progesterone levels rise -> exert inhibitory effect on uterine contractions
• Late in pregnancy, progesterone levels fall due to changes in expression of progesterone receptors or signalling co-factors in myometrium
• Increase in Estrogen stimulates smooth muscle contractions, activates enzymes breaking down collagen fibres of cervix allowing it to become flexible
• Near term and during labour, uterus secretes prostoglandins -> smooth muscle contraction
• Stretch receptors in cervix signal to hypothal to release oxytocin (stimulates muscle contractions)

Question 11

Stages of Labour

Answer 11

1. Dilation Stage:
   - weak but regular contractions increasing intensity and rapidity as labour progresses
   - amniotic sac ruptures releasing fluid
2. Expulsion Stage:
   - from dilation to childbirth
   - strong contractions every 2-3 minutes
3. Placental Stage:
   - Strong uterine contractions after birth compresses blood vessels to limit bleeding
   - placenta detaches and all placental fragments are removed

Question 12

What adjustments does the baby need to make to extrauterine life?

Answer 12

• First imperative is to breathe -> CO2 builds up in baby’s blood -> central acidosis excites resp system -> first inspiration
• For first 6-8 hours, baby’s have alternating periods of increased activity and sleep (during activity periods, vital signs are irregular

Question 13

What is lactation?

Answer 13

= production of milk by hormone-prepared mammary glands

• alveoli in breasts are sites of milk secretion

Question 14

Mammary histology visualised

Answer 14

Question 15

How does a female gain mammary glands and alveoli?

Answer 15

During puberty,
- increased estrogen -> stimulates duct growth and branching and breast enlargement
- increased progesterone stim growth of alveoli

Question 16

What happens regarding lactation in pregnancy?

Answer 16

Rising estrogen, progresterone and lactogen levels ->
- stim siginificant breast enlargement
- promote dev of ductal and alveolar structures
- also increase in prolactin

Question 17

What does prolactin do?

Answer 17

• promotes breast growth
• major hormone stimulating milk production but only once estrogen and progesterone fall

Question 18

Lactation summarised

Answer 18

Question 19

HORMONES INVOLVED IN GROWTH AND FUNCTION OF
MAMMARY GLANDS

Answer 19