First breath

Question 1

What do lungs develop from?

Answer 1

Respiratory diverticulum
Foregut

Question 2

What time period do lungs develop?

Answer 2

Week 4-5

Question 3

Define atresia?

Answer 3

Failure trachea and oesophagus to seperate

Question 4

What occurs during the pseudoglandular phase (5-17 wks)?

Answer 4

Development of conducting airways

Question 5

What occurs during the cannalicular phase (16-25 wks)?

Answer 5

Capillaries, vasculature and alveoli form
Alveoli develop until 5

Question 6

What reduces surface tension in alveoli?

Answer 6

Surfactant

Question 7

What is the function of surfactant?

Answer 7

Reduce surface tension
Allow equal aeration alveoli

Question 8

What cell secretes surfactant?

Answer 8

Type 2 pneumocytes

Question 9

What is more numerous type 1 or type 2 pneumocytes?

Answer 9

Type 1- 70%

Question 10

Function type 1 pneumocytes?

Answer 10

Responsible for gas exchange between alveoli and capillaries

Question 11

What is blood flow in utero?

Answer 11

RA-FO-LA-LV-AORTA-DA

Question 12

What is the purpose of having different blood flow in utero?

Answer 12

Bypass lungs and liver- not fully developed

Question 13

What allows lung to be bypassed

Answer 13

Foramen ovale

Question 14

What allows pulmonary circulation to be bypassed

Answer 14

Ductus arteriosus

Question 15

What does failure of foramen ovale lead to?

Answer 15

Persistent hypertension- lead hypoxia

Question 16

What is Eisenmenger’s syndrome?

Answer 16

Ventricular septum defect cause intracardiac shunt
Blood continues bypass pulmonary circ. after birth
Causes cynosis, clubbing, polycythemia (raised haematocrit)

Question 17

At birth what occurs?

Answer 17

Closure placenta- clamp umbilical vein and arteries
1) Increase systemic circulatory pressure 11.5lPa
2) Amniotic fluid in lungs expelled
3) Entry O2 into lungs cause pulmonary circulation pressure decrease- increases flow
4) Reduced pressure prevents cardiac shunting
5) Foramen ovale closes, ductus arteriosus constricted