Respiratory System

Question 1

What are the two distinct circulations of fetal circulation?

Answer 1

Fetoplacental and uteroplacental

Question 2

What are chorionic villi?

Answer 2

Fetal tissue protruding into the maternal blood

Question 3

What kind of blood do the umbilical arteries carry?

Answer 3

Deoxygenated

Question 4

What is the Po2 in the intervillous space?

Answer 4

30 to 35mmHg

Question 5

What is the fetal Hb saturation at a Po2 of 30?

Answer 5

85%

Question 6

What does the ductus venosus do?

Answer 6

Shunts blood away from the liver

Question 7

What does the foramen ovale do?

Answer 7

Shunts blood between the right and left atria

Question 8

What does the ductus arteriosus do?

Answer 8

Connects the pulmonary artery with the descending aorta

Question 9

Why is the first breath so difficult?

Answer 9

The lungs are fully closed, so the transpulmonary pressure is very high

Question 10

What does surfactant do?

Answer 10

Increases lung compliance and reduces the effort of inspiration

Question 11

What does cortisol do?

Answer 11

Stimulate the production of surfactant

Question 12

What are characteristics of infant respiratory distress syndrome?

Answer 12

Increased work of breathing and impaired gas exchange

Question 13

How do vascular resistance, arterial pressure and right ventricle pressure change at birth?

Answer 13

Resistance decreases, and pulmonary arterial and right ventricular pressure fall

Question 14

How does the foramen ovale close?

Answer 14

The reversal of the pressure gradient pushes a flap of tissue against the septum

Question 15

How does the ductus arteriosus close?

Answer 15

A few hours after birth the muscular wall contracts, which eliminated flow

Question 16

Who described cystic fibrosis?

Answer 16

Dorothy Hansine Andersen

Question 17

What kind of genetic disease is cystic fibrosis?

Answer 17

Autosomal recessive

Question 18

What is the rate of carriers of cystic fibrosis?

Answer 18

1 in 20-30

Question 19

Which channel is mutated in cystic fibrosis?

Answer 19

The cystic fibrosis transmembrane conductance regulator

Question 20

What do CFTR mutations impact?

Answer 20

They reduce calcium and bicarbonate and dysregulate sodium channels in epithelial cells
They cause abnormal Cl homeostasis in neurons
They dysregulate calcium in muscles

Question 21

Which classes of CF are severe and which are mild and why?

Answer 21

Classes 1, 2, and 3 are severe because they have no residual CFTR function
Classes 4, 5, and 6 are mild because they have some residual CFTR function

Question 22

What is the main hypothesis for why CF is still present in the population?

Answer 22

Heterozygotes have an advantage in survival over some diseases

Question 23

Which diseases is heterozygousity to CF an advantage against?

Answer 23

Cholera, typhoid, and tuberculosis

Question 24

How is the mucus in CF patients different?

Answer 24

They do not produce as much, it remains attached to lung tissue, and it is more acidic

Question 25

What does preventing infection in CF patients do?

Answer 25

Reduces the amount of CF related deaths, but it does not prevent lung abnormalities

Question 26

What do potentiators do?

Answer 26

Take mutated CFTR and increase their activity

Question 27

What do correctors do?

Answer 27

Prevent abnormal CFTRs from being destroyed before they are implanted

Question 28

Which drug is newly approved and suspected to be a great help for cystic fibrosis patients?

Answer 28

Elexacaftor-Tezacaftor-Ivacaftor
The name brand is Trikafta
It is used when there is at least one F508del mutation

Question 29

What type of treatment is required for class I mutations of CF?

Answer 29

Gene therapy