respiratory teach - physiology

Question 1

what happens in sneezing?

Answer 1

certain stimulants trigger histamine release in nasal cavity
activate trigeminal nerve to send impulse to brainstem
causes expiratory muscles and vocal muscle to contract = sneezing

Question 2

obstructive disease

Answer 2

increasing resistance
e.g. asthma
FVC same
FEV1 decreases
ratio decreases

Question 3

restrictive disease

Answer 3

decreasing compliance
e.g. pulmonary fibrosis 
FVC decreases
FEV1 decreases
ratio same

Question 4

resistance

Answer 4

ease at which gas flows

Question 5

compliance

Answer 5

expandability of lungs and chest wall

Question 6

spirometry trace for COPD

Answer 6

higher than normal

gentler downwards slope

Question 7

mixed obstructive and restrictive disease

Answer 7

inspiration limited by restrictive disease

expiration limited by obstructive disease

Question 8

wheeze

Answer 8

expiration

from bronchioles

Question 9

stridor

Answer 9

inspiration

from larynx

Question 10

what happens in inspiration

Answer 10

inspiratory muscles contract
increase volume of thorax
intrapleural pressure more negative which increases difference between alveolar and intrapleural pressure
increases transpulmonary pressure
so alveolar volume increase
alveolar pressure decreases
creates a pressure gradient so breathe in

Question 11

what happens in expiration

Answer 11

inspiratory muscles relax
intrapleural pressure becomes less negative
decreases difference between alveolar and intrapleural pressure 
decreases transpulmonary pressure
alveoli get smaller
volume decreases
alveolar pressure increase
makes pressure gradient so breathe out

Question 12

what is transpulmonary pressure

Answer 12

ptp
alveolar pressure - intrapleural pressure
synonymous with alveolar expansion

Question 13

what is Palv?

Answer 13

pressure in alveoli

Question 14

what is Pip?

Answer 14

intrapleural pressure

Question 15

what is Patm?

Answer 15

atmospheric pressure

Question 16

what muscles are involved in inspiration?

Answer 16

diaphragm
external intercostals
sternocleidomastoid
scalenes
pec major
pec minor 
serratus anterior

Question 17

what muscles are involved in expiration?

Answer 17

internal intercostals
innermost intercostals
rectus abdominis
transversus abdominis
external and internal oblique

Question 18

innervation of diaphragm?

Answer 18

phrenic nerve

Question 19

spinal root of phrenic nerve?

Answer 19

C3,4,5

Question 20

V/Q matching

Answer 20

ventilation/ perfusion matching

Question 21

how are ventilation and perfusion matched?

Answer 21

greater ventilation and greater perfusion at bottom of lungs, so they are well matched

Question 22

benefit of V/Q matching?

Answer 22

maximise the exchange of oxygen across alveoli

Question 23

pulmonary shunt

Answer 23

where ventilation is cut off in the lung so blood gets no oxygen so V/Q is 0

Question 24

dead space

Answer 24

where blood supply to alveoli are cut off so V/Q is higher

Question 25

bohr effect

Answer 25

higher CO2 - near respiring cells
decreases haemoglobin affinity for oxygen
oxygen dissociates from haemoglobin
more oxygen released

Question 26

haldane effect

Answer 26

higher O2 - near lungs
increases haemoglobin affinity for oxygen
oxygen combines with haemoglobin and displaces CO2
more oxygen taken up by haemoglobin

Question 27

fetal haemoglobin

Answer 27

greater affinity for O2

polycythaemia

Question 28

what is polycythaemia?

Answer 28

higher concentration of haemoglobin

greater number of RBCs due to more RBCs or less plasma