Endo-Repro L27 Fetal Organ System

Question 1

The intrauterine environment relieves foetal organs of the need to perform certain functions:

Answer 1

1. Placenta
2. Weightless state of foetus
3. Isothermal environment

Question 2

Foetus is not dormant →

Answer 2

→ Foetal systems must develop and mature to sustain life immediately after birth.

Question 3

Adaptations of the fetal cardiovascular system: Ventricles

Answer 3

Two fetal ventricles pump in parallel, not series.

Question 4

Adaptations of the fetal cardiovascular system: Four foetal shunts

Answer 4

1. Placenta
2. Ductus venosus - liver
3. Foramen ovale
4. Ductus arteriosus → pulmonary artery to aorta

Question 5

Adaptations of the fetal cardiovascular system: Foetal shunts ensure

Answer 5

Optimal distribution of oxygenated blood to head and body

Question 6

Changes in foetal circulation at birth:

Answer 6

At birth, the four fetal shunts close to replace the placental circulation with the pulmonary circulation:

1. Placenta ceases to deliver oxygenated blood to newborn
2. Pulmonary vascular resistance falls dramatically
3. Pressure on the right side of the heart decreases
4. Pressure on the left side of the heart increases
5. Flap valve closes foramen ovale
6. Ductus venosus ceases to carry blood to the heart
7. Ductus arteriosus contracts and close

Question 7

Respiratory System: fetal breathing

Answer 7

2. Fetal breathing movements:
   a. Are Rapid and irregular
   b. Occur only during REM sleep
   c. Are diaphragmatic
   d. Move amniotic fluid in and out of the lungs

Question 8

Functions of fetal breathingh

Answer 8

a. Practice

b. Distend the lungs and stimulate growth

Question 9

Maturation of Lung function:

Answer 9

1. Fetal lungs undergo major structural changes during pregnancy
2. Near birth, the pressure required to expand the lung decreases

Question 10

3. Surfactant:

Answer 10

a. Phospholipid synthesized in lung

b. Defiency causes respiratory distress syndrome

Question 11

4. Water reabsorption: in fetus

Answer 11

a. Switch from Cl- secretion to Na+ absorption

Question 12

Foetus salt and water reabsorption

Answer 12

CFTR-driven salt and water secretion.

Question 13

Neonate salt and water reabsorption

Answer 13

Neonate:

Question 14

Gastrointestinal activity during pregnancy

Answer 14

1. The feotus swallows large volumes of amniotic fluid daily.
2. Swallowed salt, water, and small molecules are absorbed in the small intestine

Question 15

Meconium formed from

Answer 15

Swallowed debris and large molecules accumulate in the large intestine to form

Question 16

Defecation occurs

Answer 16

Post utero

Question 17

Function:

Of Process of gastrointestinal

Answer 17

1. Practise
2. Contributes to fetal nutrition
3. Control of amniotic fluid volume

Question 18

The Renal System:

Answer 18

1. During pregnancy, the placenta, not the kidney, is the organ of excretion

Question 19

2. Renal agenesis (Potter’s syndrome) causes:

Answer 19

a. Foetal growth and developmental defects the virtual absence of amniotic fluid

Question 20

3. Function: of renal system

Answer 20

a. Regulation of amniotic fluid volume

Question 21

Water in amniotic fluid turnover

Answer 21

At least once per day

Question 22

Amniotic Fluid production

Answer 22

Renal excretion (~75%)
Pulmonary secretions (~25%)

Question 23

Amniotic Fluid removal

Answer 23

Gastrointestinal tract (~55%)
Amnion (~30%)
Lungs (~15%)

Question 24

Diagnostic Value of Amniotic fluid:

Answer 24

Neural tube defects

Lung maturation
Chromosome abnormalities and genentic diseases

Question 25

Neural tube defects

Answer 25

Elevated levels of alpha-fetoprotein in amniotic fuid are diagnostic of spina bifida or anencephaly

Question 26

Lung maturation

Answer 26

Monitor the lecithin/sphingomyelin ratio of amniotic fluid (ratio >2, surfactant production normal; ratio <2, suggestive of respiratory distress syndrome)

Question 27

Chromosome abnormalities and genentic diseases

Answer 27

Fetal cells recovered in amniotic fluid can be used for karyotyping to detect Downs syndrome or to amplify fetal DNA for mutation screening (e.g. Duchenne muscular dystrophy)

Question 28

The Nervous System:

Answer 28

1. Sensory organs of the fetus are highly developed 2. Fetal movements occur early in pregnancy 3. The fetus shows periods of slow-wave and REM sleep between periods of wakefulness 4. Drugs from the maternal circulation profoundly effect the developing brain of the fetus

Question 29

Relationship between foetal and maternal endocrine systems:

Answer 29

1. Foetal hormones profoundly influence the mother 2. Maternal hormones do not directly influence the fetus except in disease 3. The Foetal endocrine system is autonomous 4. The Foetal endocrine system has specialized functions not present in the adult

Question 30

Hypothalamus

Answer 30

Co-ordinates the activities of endocrine organs

Question 31

Anterior pituitary

Answer 31

Regulates the activity of other endocrine organs

Question 32

Thyroid Gland

Answer 32

Thyroxine is essential for normal foetal development

Question 33

Pancreas

Answer 33

Insulin regulates the rate of glucose utilization

Question 34

Gonads

Answer 34

Ovaries → inactive | Testis: Essential for male sexual differentiation

Question 35

The Fetal Adrenal Gland: Medulla

Answer 35

Adrenaline and noradrenaline

Question 36

The Fetal Adrenal Gland: Cortex

Answer 36

Glucocorticosteroids | DHEA

Question 37

Functions of Glucocorticosteroids:

Answer 37

1. Renal maturation 2. GIT maturationInsulin secretion 3. Glucose storage 4. Thryoxine 5. Lactogenesis 6. Haemoglobin 7. Parturition 8. Adrenaline 9. Lung maturation

Question 38

Preparation for birth:

Answer 38

1. Successful transition from intrauterine to extrauterine life depends on events that preceed birth: a. Maturation of the lungs b. Accumulation of carbohydrate and fat reserves c. Onset of lactation 2. Glucocorticosteroids control the maturation of foetal physiology and its timing 3. Critical anatomical and functional changes occur at birth