lung embryology snd defence

Question 1

whats the first part of the respiratory zone

Answer 1

respiratory bronchioles

Question 2

whats the rule of the respiratory zone

Answer 2

to produce surfactant

Question 3

4 stages of lung maturation

Answer 3

1. pseudoglandular stage (6-16 weeks)
2. canalicular stage (16-26 weeks)
3. saccular stage (26 weeks - birth)
4. alveolar stage (32 weeks-8 years)

Question 4

pseudoglandular stage

Answer 4

creation of bronchial tree

Question 5

canalicular stage

Answer 5

bronchial and terminal bronchiole lumen becomes larger
at least 2 respiratory bronchioles at 24 weeks

Question 6

saccular stage

Answer 6

type II alveolar cells produce surfactant which stops alveoli collapsing

Question 7

what is the role of surfactant

Answer 7

reduced surface tension and prevents alveolar collapse

Question 8

in what 3 ways is amniotic fluid cleared at birth

Answer 8

1. through nose and mouth by vaginal wall pressure
2. into pulmonary circulation
3. into pulmonary lymphatics

Question 9

what lines the respiratory airways

Answer 9

pseudostratified ciliated columnar epithelium

Question 10

what a common pathogen seen in CF patients

Answer 10

pseudomonas aeruginosa

Question 11

what are the precursors to macrophages

Answer 11

monocytes

Question 12

the optimum height of ASL for efficient clearance

Answer 12

7 micrometers

Question 13

whats the primary embryology al original of respiratory tract epithelium

Answer 13

endoderm

Question 14

what germ layer gives rise to the connective tissue and smooth muscle of lungs

Answer 14

mesoderm

Question 15

what stimulates the production of surfactant by type II pneumocytes

Answer 15

glucocorticoids

Question 16

what propels the mucus along the respiratory tract in the mucocilliary escalator

Answer 16

ciliary muscle

Question 17

which cell type secretes the mucus that traps inhaled particles in the resp tract

Answer 17

goblet cells

Question 18

what are the accessory muscles of forced inhalation

Answer 18

sternocleidomastoid,scalene, pectoralis minor

Question 19

what is the strongest muscle of forced exhalation

Answer 19

rectus abdominus

Question 20

pneumotaxic centre - upper pons

Answer 20

regulates and fine tunes breathing

Question 21

apneustic centre - lower pons

Answer 21

signals for inspiration to occur- longer, deeper breaths

Question 22

respiratory mechanoreceptors

Answer 22

in walls of bronchi and bronchioles, prevent over inflation of lungs

Question 23

hering-brewer reflex

Answer 23

• stretching of walls (air coming in) activates mechanoreceptors
• impulses sent from receptors to DRG via vagus nerve
• inspiration stops
• expiration starts, reduces stretch, inactivates receptors, vagus stops sending signals
• inspiration starts

Question 24

where are peripheral chemoreceptors found

Answer 24

in bifurcation of carotid artery and arch of aorta

Question 25

where are central chemoreceptors located

Answer 25

on surface of medulla, exposed to CSF

Question 26

ventilation

Answer 26

how much air gets from inhaled air to alveoli

Question 27

perfusion

Answer 27

how much air from alveoli gets across into capillaries

Question 28

shunt

Answer 28

perfusion of poorly ventilated alveoli eg pneumonia, acute asthma

Question 29

physiological dead space

Answer 29

ventilation of poorly perfused alveoli eg COPD, pulmonary embolism

Question 30

whats the main area of the brain used for voluntary breathing

Answer 30

cerebral cortex

Question 31

tidal vol

Answer 31

amount of air in/out of lungs in single inspiration/expiration

Question 32

functional residual capacity

Answer 32

vol air that remains in lungs at end of normal respiration