108 - The Normal Child

Question 1

What are the two structures that allow blood to bypass the lungs in the fetus?

Answer 1

• Foramen Ovale - Between the atria.
• Ductus Arteriosus - Between the Pulmonary Artery and the arch of the Aorta.

Question 2

What changes occur in the lungs and heart after birth?

Answer 2

• The baby takes it’s first breaths, the lungs fill with air and empty of alveolar fluid.
• The oxygenation of the pulmonary capillaries cause the pulmonary arterioles to dilate, greatly reducing pulmonary vascular resistance.
• Blood flows into the pulmonary system, and returns to the heart.
• The oxygenated blood passes from the aorta into the pulmonary artery, through the ductus arteriosus, due to reduced PVR.
• The oxygen causes the ductus arteriosus to close, by contraction of smooth muscle.

Question 3

How does the foramen ovale get closed after birth?

Answer 3

• The increase in blood return from the lungs raises the pressure in the left atrium.
• The decrease in blood return from the placaenta reduces the pressure in the right atrium.
• This causes the septum primum against the septum secondum, causing the foramen to close.

Question 4

What occurs, in relation to blood glucose control, after birth?

Answer 4

• Loss of constant supply of food and an increased demand.
• Plasma insulin decreases.
• Catecholamines increase.
• An increases in pancreatic glucagon secretion.

Question 5

What is colostrum and what is its composition?

Answer 5

• It is the initial breast milk.
• Low volume, High energy concentrate, rich in proteins, immune cells and immunoglobulins.
• Contains growth factor.

Question 6

Normal Child: What is physiological anaemia and is it normal?

Answer 6

• Move from oxygenation from placaenta to lungs.
• Increased O2 saturation results in negative feedback response for erythropoietin production.
• This drops to very low levels, caused anaemia at 6-8 weeks.
• Erythropoietic production starts again.

Perfectly normal.

Question 7

What are the four main causes of neonatal jaundice?

Answer 7

• High Hb load.
• Shorter RBC lifespan.
• Immature liver enzymes.
• Bruising around birth.

Question 8

If jaundice appears <24hrs is it physiological or pathological?

Answer 8

Physiological.

Question 9

What type of inheritence is cystic fibrosis?

Answer 9

It is an Autosomal recessively inherited Mendelian disease, and one of the most common single gene disorders in the UK.

Question 10

Cystic Fibrosis is a recessively inherited single gene disease. If two unaffected, carrier parents were to have a child what chance do they have to be a sufferer?

Answer 10

1 in 4.

Question 11

What is the abnormal gene identified for cystic fibrosis, and what chromosone has it been located on?

Answer 11

• CFTR - Cystic Fibrosis Transmembrane Regulator
• Chromosone 7

Question 12

How is Huntington disease inherited?

Answer 12

It is a dominantly inherited disease, meaning that the offspring of a sufferer have a 50% chance of being a sufferer themselves.

Question 13

How is familial hypercholesteraemia inherited?

Answer 13

Dominant.

Question 14

What is long QT syndrom and how is it inherited?

Answer 14

• It is a congenital abnormality that causes an abnormally long QT interval leads to ventricular tachyarythmias, which can cause syncope, sudden death or cardiac arrest.
• It is dominantly inherited.

Question 15

What are the four nucleobases of DNA and which binds to which?

Answer 15

• Adenine, Cytosine, Thymine, Guanine
• Cytosine - Guanine
• Adenine - Thymine (Uracil in RNA)

Question 16

What are transcription and translation?

Answer 16

• Transcription - The synthesis of RNA from a strand of DNA.
• Translation - The synthesis of proteins from RNA.

Question 17

What are the five categories of genetic disorders?

Answer 17

1) Single Gene defect.
2) Multifactorial disorders.
3) Chromosone disorders.
4) Somatic cell gene defects.
5) Mitochondrial mutations.