Fetus

Question 1

What is fetal Hb normal range?

Answer 1

17-19

Question 2

Where does blood entering RV from the SVC go?

What is the oxygen content of this blood?

Answer 2

Via ductus arteriosus to the aorta distal to L subclavian
Then to the trunk and lower limbs
Less well oxygenated

Question 3

Where does oxygenated blood in the umbilical vein go?

Answer 3

Via ductus venosus to IVC then via foramen ovale to L side of heart then to head and neck

Question 4

What is the oxygen content of blood in the portal vein?

Answer 4

Deoxygenated

Question 5

When does fetus start swallowing?

Answer 5

10-14w

Reaches 250ml/day at term

Question 6

When does immature suck-swallow start?

Answer 6

33-36w

Question 7

When does stomach motility and secretion and pancreatic zymogen granules start?

Answer 7

20w

Peristaltic activity develops gradually, mature by third trimester

Question 8

When does bile metabolism start?

Answer 8

11w

Question 9

When does bile secretion start?

Answer 9

22w

Question 10

When does small intestine transport start of
Amino acids
Glucose
Fatty acids ?

Answer 10

14
18
24

Intestinal villi start at 7w and mature by 20w
Absorptive processes mature by 26w

Question 11

When does urine production begin?

Answer 11

9-10w

Question 12

When does reabsorption in LoH begin?

Answer 12

12w

Question 13

Proportion of fetal vs adult blood flow to kidneys

Increase in early postnatal period

Answer 13

2-3 vs 20%
10% 4days
20% 2w

Question 14

Main organ of fetal electrolyte balance?

Answer 14

Placenta

Question 15

Main source of amniotic fluid
before 16 weeks
after 16 weeks

Answer 15

Skin, placenta
Fetal urine, lung

Oligohydramnios not usually evident before 16w

Question 16

Tonicity of fetal urine and cause

Answer 16

Hypotonic

Fetal kidney poor concentrating ability

Question 17

Gestation at which number of nephrons reaches adult

Answer 17

34w however functional maturity not complete until postnatally

Question 18

Main haemopoietic organ in fetus

Answer 18

Liver

Question 19

Composition of meconium

Answer 19

75% water
Intestinal secretions
Squamous cells
Lanugo hair
Bile pigments 
Pancreatic enzymes 
Blood

Question 20

Start of meconium production

Answer 20

10-12w

Moves into colon 16w

Question 21

Incidence of meconium stained liquor

Answer 21

12% overall
30% post-term
Aspiration 5% - mechanical blockage and chemical pneumonitis

Question 22

Formation of vernix

Answer 22

17w - sebaceous secretions and desquamated cells
Skin nearly 100% water <20%
Increase in connective tissue, keratinisation, vernix.
Skin still contributes to amniotic fluid

Question 23

Most active period fetal neuronal proliferation

Answer 23

12-16w (from 8-20)
Cortex majority neurons 20w along with spontaneous EEG activity, synchronised 26w, sleep/wake cycles 30w
Cerebellum not until 1yr pn
Synapse formation from 12w
Myelinisation 24w

Question 24

Peripheral ganglia origin and appearance

Answer 24

Neural crest 4-5w
Ventral motor
Dorsal sensory

Question 25

Body and limb movement

Answer 25

7w, 9w

Question 26

Maternal perception FMs

Answer 26

16-24w

Question 27

Development smell, taste, gearing, vision

Answer 27

23-26w

Question 28

Touch sensation | Pain repsonse

Answer 28

Afferents synapses from 10 | Physiological stress response from 19w

Question 29

``` Amniotic fluid volume 12w 16w 34w Term ```

Answer 29

50ml 150ml (then inc 50ml/wk) 1000ml 500ml

Question 30

Composition amniotic fluid

Answer 30

``` >98% water Minerals Na, K, Cl CHO glucose, fructose Proteins alb, glob Lipids cholesterol, lecithin Hormones Enzymes ALP,lysozyme, peroxidase Suspended materials ```

Question 31

Effect of fetal age on osmolarity

Answer 31

Decreases with gestation

Question 32

1st period fetal hematopoiesis

Answer 32

Mesoblastic in yolk sac 12d-14w

Question 33

2nd period fetal hematopoiesis

Answer 33

Hepatic from 6w | Peak 10-18

Question 34

3rd period fetal hematopoiesis

Answer 34

Myeloid 8w-adult

Question 35

Site of fetal EPO production

Answer 35

Initially liver then kidneys | Increases from 20w

Question 36

Start and site of fetal WBC formation

Answer 36

6w liver, also spleen thymus lymphatic system

Question 37

Surfactant production and composition

Answer 37

Lipoprotein produced by type II pneumocytes 90% lipids DPPC 2/3 10% protein including surfactant proteins A-D

Question 38

Function of surfactant

Answer 38

Reduces surface tension - mainly DPPC | Increases compliance

Question 39

Factors stimulating fetal lung maturation

Answer 39

Glucocorticoids Thyroid hormones Prolactin Catecholamines

Question 40

Factors delaying fetal lung maturation

Answer 40

Androgens - male infants increased resp distress | Maternal diabetes