Lecture Ten

Question 1

What happens post fertilisation?

Answer 1

-7 days post fertilization: “Burrowing of the blastocyst into the uterine wall”

Question 2

Describe a zygote, blastocyst, embryo, foetus and what is the length of pregnancy?

Answer 2

• Zygote – once male and female nucleus combine
• Blastocyst – first 2 weeks
• Embryo = 2 – 8 weeks
• Foetus = week 9 to birth
• Length of Pregnancy = 40 weeks

Question 3

What is human chorionic gonadotropin in pregnancy?

Answer 3

-Human chorionic gonadotropin (HCG)
o Secreted by blastocyst and placenta
o Found in urine gives indication of pregnancy
o Stimulates growth of the corpus luteum x2 in size
= increased amounts of oestrogen and progesterone

Question 4

What is human relaxin in pregnancy?

Answer 4

-Relaxin
o Secreted by the corpus luteum and placenta
-Relaxes the ligaments of the body

Question 5

What is human placenta in pregnancy?

Answer 5

-Placenta
o Also secretes
-Estrogen: increase water retention and protein synthesis
-Progesterone: smooth muscle relaxation, raises body temp

Question 6

What happens after 3 months to the corpus luteum?

Answer 6

-After 3 months the corpus luteum is no longer needed the placenta is both
o A point of exchange between the foetus and mother
o An endocrine gland that secretes hormones to maintain pregnancy
= increased levels of oestrogen and progesterone during pregnancy

Question 7

Why do physiological changes during pregnancy occur?

Answer 7

• Why these changes occur
  1. To provide a suitable environment for the growth, nutrition and development of the foetus.
  2. To protect and prepare the mother for the process of pregnancy and support for the newborn.

Question 8

Describe the maternal changes in cardiac position and size

Answer 8

-Cardiac position and size 
o	Diaphragm pushed upwards 
o	Apex of the heart pushed upwards and laterally 
o	Heart enlarges by 70-80 mL 
-Wall thickness 
-Increased venous filling

Question 9

Describe the maternal changes in plasma volume

Answer 9

-Plasma Volume
o Increases by 50% to ~3800 mL
o To accommodate the increased blood flow to the uterus and other organs

Question 10

Describe the maternal changes in heart rate

Answer 10

-Heart Rate

o Increases by 15 bpm

Question 11

Describe the maternal changes in stroke volume

Answer 11

-Stroke Volume

o Increases by 10%

Question 12

Describe the maternal changes in cardiac output

Answer 12

-Cardiac Output
o Increase by 1.5 L (30-50%)
o Falls when lying supine as the uterus compresses the inferior vena cava therefore decreasing venous return

Question 13

Describe the maternal changes in blood pressure

Answer 13

-Blood Pressure
o Mean arterial pressure decreases by 10 mmHg by 8 weeks’ gestation
o 24 weeks it will be at its lowest
o Supine hypotension syndrome
-Mother lying in supine position particularly on the left side

Question 14

Describe the maternal changes in peripheral resistance

Answer 14

-Peripheral Resistance
o Mean arterial pressure / CO
o ~ 50% reduction
o Increase progesterone causes vasodilation = decreased resistance

Question 15

What are the changes in maternal respiratory, what does it increase & decrease in?

Answer 15

-No change 
o	Respiratory rate 
o	Vital capacity 
-Increases in: 
o	Tidal volume (40%) 
o	Inspiratory capacity 
o	Minute volume 
o	Oxygen consumption 
o	Ventilation – ‘over-breathing’ 
-Decreases in: 
o	Expiratory reserve volume 
o	Residual volume 
o	Airway resistance 
-These increases and corresponding decreases all assist with more efficient gas mixing

Question 16

What changes happen during maternity in the renal system?

Answer 16

-As a result of increased vascular volume:
o Kidneys enlarge (volume enlarges)
o Increases in:
-Renal blood flow (30-50%)
-Glomerular filtration rate (50%)
-Evidence of glucosuria during pregnancy
o Not an indication of diabetes
o Possibly due to less efficient tubular reabsorption

Question 17

Describe the maternal changes in thermoregulation

Answer 17

-During pregnancy the metabolic rate increases 
o	= increase in heat production 
-How does the body dissipate additional heat load? 
o	Increase in ventilation
o	Increase skin blood flow 
-Considerations 
o	Keep hydrated 
o	Avoid high environmental

Question 18

Describe the maternal changes in the endocrine system

Answer 18

-Anterior Pituitary:
o Increased plasma concentrations of Prolactin
o Placenta produces CRH and ACTH
o GH, LH, FSH are supressed
-Posterior Pituitary:
o Increased number of oxytocin receptors
-Thyroid function increases

Question 19

What physical changes increase and what can centre of gravity altercations cause?

Answer 19

-Increased: 
o	Weight gain to the anterior 
o	Ligament Laxity - Relaxin 
o	Joint mobility (hypermobility) 
-Centre of gravity alterations 
o	Some contention: 
-Shift backwards to prevent falling 
-More pressure in the heels 
-Shift forwards with enlarged tummy and breasts 
o	Upwards 
-Can cause: 
o	Lordosis of the lumbar 
o	Lordosis of the cervical 
o	Protraction of the shoulders 
o	Hyperextension of the knees 
o	Back pain

Question 20

What does the pelvic floor support?

Answer 20

-Layer of muscles which support the pelvic organs: 
o	Uterus 
o	Bladder 
o	Bowel 
-These muscles can weaken

Question 21

What is menopause, when does it occur, why does it happen and what are the symptoms?

Answer 21

-Cessation of the menstrual cycle
-When:
o 40-50 yrs of age
-Why:
o Remaining number of follicles is small
o Follicles left are less sensitive to FSH and LH
o Reduced amount of estrogen and progesterone
-Symptoms:
o Uncomfortable sweating (hot flushes)
o Anxiety
o Fatigue
o Emotional disturbances

Question 22

What is the post-menopausal osteoporosis?

Answer 22

-Post-menopausal Osteoporosis
o 1 in 3 women
o Reduction in bone mineral density due to hormonal factors
-Reduced estrogen = increased bone loss
o Consequences increased risk of fractures