Foetal and placental physiology

Question 1

What hormones stimulate growth in late pregnancy?

Answer 1

Thyroid hormones

Question 2

Give 3 functions of cortisol

Answer 2

Lung compliance and surfactant release
Induces beta receptor and glycogen deposition in liver
Villus production and induction of digestive enzymes

Question 3

Give 3 modifications of the foetal circulation and describe them

Answer 3

Ductus venous - bypasses liver
Foramen ovale - blood from right to left atria
Ductus arteriosus - blood from pulmonary artery to aorta

Question 4

What keeps the ductus arteriosus patent? (2)

Answer 4

PGE2

Prostacyclin

Question 5

What occurs at birth in the foetal circulation?

Answer 5

Lungs fill with air
Decreased in pulmonary vascular resistance
Closure of DV, FO, DA

Question 6

What is persistent foetal circulation?

Answer 6

DA fails to close

Pulmonary vascular resistance doesn’t fall

Question 7

What does persistent foetal circulation lead to?

Answer 7

Cyanosis, hypoxia, brain tissue death, necrotising enterocolitis

Question 8

What helps the foetal lungs absorb the fluid?

Answer 8

Adrenaline

Question 9

What is surfactant produced by?

Answer 9

Type 2 pneumocytes

Question 10

What does surfactant do?

Answer 10

Decreases surface tension and prevents collapse of small alveoli on expiration

Question 11

What is the prevention for RDS?

Answer 11

Antenatal steroids

Question 12

What can cause pulmonary hypoplasia? (2)

Answer 12

Oligohydraminos

Decreased intrathoracic space

Question 13

What are the 3 sources of foetal blood?

Answer 13

1. yolk sac
2. liver and spleen
3. bone marrow

Question 14

What is the benefit of HbF?

Answer 14

Increased affinity for O2 and releases it at a higher partial pressure (picks up and drops easier)

Question 15

What is HbF made up of?

Answer 15

Two gamma and two alpha chains

Question 16

Which thalassaemia is fatal?

Answer 16

Alpha

Question 17

Read through immune system section

Answer 17

:)

Question 18

What are 4 immunological defences for the foetus?

Answer 18

Amniotic fluid
Placenta
Liver and bone marrow
Interferon

Question 19

What is the role of skin?

Answer 19

Protection and facilitates homeostasis

Question 20

What is vernix?

Answer 20

Desquamated skin cells, cholesterol, glycogen

Question 21

What does the vernix do?

Answer 21

Prevents insensible water loss

Question 22

What are the 3 main problems of prematurity?

Answer 22

Feeding
Heat loss
Breathing

Question 23

Describe the development of the alimentary tract (3)

Answer 23

4th week: straight tube
6th week: midgut herniates into base of umbilical cord
12th week: rotation and re-entry

Question 24

What does failure of re-entry of the gut lead to? (2)

Answer 24

Omphalocoele (sac)

Gastroschisis (no sac)

Question 25

What does a failure in swallowing lead to?

Answer 25

Polyhydraminos

Question 26

What does meconium stained liquor indicate?

Answer 26

Foetal distress Post-term Hypoxia

Question 27

Describe the development of the foetal liver (3)

Answer 27

Week 2-3: diverticulum from duodenum Day 25: T shaped outgrowth invade by blood vessels (large part - parenchymal cells and hepatic ducts, small part - gallbladder) Week 6: involved in haemopoiesis

Question 28

Describe the development of the kidney (2)

Answer 28

Metanephros: collecting system | Mesenchyme of nephrogenic cord: secretory system

Question 29

What can cause oligohydraminos?

Answer 29

Renal agenesis

Question 30

What may diminished foetal movement indicate?

Answer 30

Chronic hypoxia | Growth restriction

Question 31

What are the 4 behaviour states?

Answer 31

1F: no movements 2F: continuous eye, bursts of body movements 3F: eye movements, no body movements, higher HR 4F: ongoing active eye and body movements

Question 32

Which two behavioural states does the foetus prefer?

Answer 32

1F and 2F

Question 33

Describe the development of the amniotic sac

Answer 33

Week 12: amnion comes in contact with chorion

Question 34

Where does the amniotic fluid come from? (3)

Answer 34

1. amnion 2. foetal plasma through skin and umbilical cord 3. foetal kidney and lung fluids

Question 35

What does the choriodecidum do?

Answer 35

Initiation of labour role | Produces PGE2 and PGF2

Question 36

What are the functions of amniotic fluid? (4)

Answer 36

Protection Movement Prevention of adhesions Lung development

Question 37

How is calcium transported and acquired?

Answer 37

Active transport | Increased maternal PTH and absorption

Question 38

What are the functions of the placenta? (5)

Answer 38

``` Protection Nutrition Respiration Excretion Hormone production ```

Question 39

What is the structure of the placenta derived from? (2)

Answer 39

Foetal component: chorion | Maternal component: endometrial adaptations

Question 40

How is water transported across the placenta?

Answer 40

Diffusion

Question 41

How are electrolytes transported across the placenta? (4)

Answer 41

Na: active transport K: diffusion Cl: active transport I: active transport

Question 42

How is iron transported and acquired?

Answer 42

Active transport and increased absorption

Question 43

How is calcium acquired?

Answer 43

Increased maternal PTH and absorption

Question 44

How are water and fat soluble vitamins transported?

Answer 44

Water: active transport Fat: diffusion

Question 45

What are the major and minor energy sources to the foetus and how are they transported?

Answer 45

Major: glucose, facilitated diffusion Minor: amino acids and lactate, active transport

Question 46

How is glucose utilisation regulated?

Answer 46

Foetal hormones mobilise fatty acid stores Maternal tissue less sensitive to insulin Increased blood glucose Foetal insulin resistance

Question 47

How does storage of glucose occur?

Answer 47

Hepatic glycogen and fat storage

Question 48

How is unconjugated bilirubin transported?

Answer 48

Diffusion

Question 49

How is maternal metabolism of amino acids made more efficient?

Answer 49

Progesterone causes decreased urea excretion | Decreased maternal hepatic AA deamination

Question 50

How are amino acids and urea transported?

Answer 50

AA: active transport Urea: diffusion

Question 51

Give 5 hormones the placenta produces

Answer 51

``` Progesterone Oestrogen Lactogen Somatomammatrophin Relaxin ```

Question 52

What do progesterone and oestrogen do?

Answer 52

Stimulate ovarian function | Maintain pregnancy by inhibiting myometrial contractions

Question 53

What does lactose and somatomammotrophin do?

Answer 53

Influences foetal growth Stimulates mammary function Assistes in parturition

Question 54

What does relaxin do?

Answer 54

Softens connective tissue in cervix and pelvic ligaments | Promotes elasticity of pelvic ligaments

Question 55

What maintains the glucose gradient?

Answer 55

Placenta makes lactate from glucose

Question 56

What pH changes cause release and uptake of O2?

Answer 56

Decreased maternal pH | Increased foetal blood pH - uptake

Question 57

Draw the 8 steps of induction to parturition

Answer 57

1. limited space for foetus 2. foetal hypothalamus 3. foetal ACTH 4. foetal cortisol 5. placental oestrogen 6. uterus PGF2alpha 7. progesterone 8. induction of parturition