respiration during exercise- week 7

Question 1

what is the primary purpose of the respiratory system ?

Answer 1

to maintain arterial blood-gas homeostasis

Question 2

how is arterial blood gas homeostasis accomplished ? (4-step process)

Answer 2

pulmonary ventilation

alveolar gas exchange

gas transport

systemic gas exchange

Question 3

what is the epiglottis ?

Answer 3

separates upper and lower respiratory tracts

Question 4

the lungs are enclosed within membranes called …

Answer 4

pleura

parietal pleura - outside membrane

visceral pleura - directly covers lungs

Question 5

what is the pleural cavity ?

Answer 5

space and fluid in-between pleura membranes

reduces friction when lungs move

Question 6

what prevents the alveoli form collapsing ?

Answer 6

intrapleural pressure is less than atmospheric pressure

Question 7

what pets of the airways is part of the conducting zone ?

Answer 7

trachea, bronchi and the bronchioles

Question 8

what parts of the airway is part of the respiratory zone ?

Answer 8

bronchioles and the alveoli

Question 9

what occurs in the respiratory zone ?

Answer 9

gas exchange

Question 10

where does pulmonary gas exchange take place?

Answer 10

across pulmonary capillary

Question 11

what are the types of alveolar calls (pneumocytes) ? (2)

Answer 11

type 1 - 95% of internal surface

type 2 - release surfactant that lowers surface tension

Question 12

what is the volume of gas passing though a sheet dependent on ?? (4)

Answer 12

surface area

thickness

diffusion coefficient

pressure gradient

Question 13

what is ficks law of diffusion ?

Answer 13

volume of gas proportional to ( surface area/thickness) x diffusion x pressure gradient

Question 14

mechanics of breathing is caused by changes in ….

Answer 14

pressure - contraction force

flow - contraction velocity

volume - contraction length

Question 15

wha is the bucket handle motion ?

Answer 15

increased transverse(lateral) diameter of thorax during inspiration

sides go in and out

Question 16

what is the pump handle motion?

Answer 16

increased anteroposterior diameter of thorax during inspiration

front moves forward and back

Question 17

at rest diaphragm contraction is responsible for what ?

what does this mean for expiration ?

Answer 17

majority of pulmonary ventilation

expiration is passive

Question 18

what muscles is the diaphragm assisted by during exercise (pulmonary ventilation)?

Answer 18

external intercostals

scalenes

sternocleidomastoid

Question 19

what muscles is the diaphragm assisted by during exercise (expiration)?

Answer 19

rectus abdominis

internal intercostals

external obliques

Question 20

what does long endurance exercise lead to ?

Answer 20

fatigue in respiratory muscles

de line in muscle pressure

Question 21

what is ohm’s law?

Answer 21

current= voltage(change in pressure)/resistance

airflow dependent on pressure gradient and airway resistance

Question 22

what is poiseuille’s law?

Answer 22

resistance dependent on length and radius of a tube

radius raised to 4th power
- major determinant of airway resistance

Question 23

what can be seen when someone with COPD (chronic obstructive pulmonary disease) expires/inspires air compared to normal lungs ? (3)

Answer 23

someone with COPD has increased airway resistance

people w COPD struggle to expire air as quick as normal

breath higher lung volumes with COPD and need to increase lung pressure to breathe

Question 24

what are the 3 phases of ventilatory response to constant loads steady-state exercise?

Answer 24

phase 1: immediate increase in minute ventilation

phase 2: exponential increase increase in ventilation
- increase in PCO2 too

phase 3: plateau - steady state

Question 25

what is hyperpnoea ?

Answer 25

PaCO2 regulation due to proportional changes in alveolar ventilation and metabolic rate

Question 26

ventilation increases linearly with exercise intensity until a point which is known as...

Answer 26

ventilatory threshold (Tvent)

Question 27

after Tvent, ventilation increases leading to...

Answer 27

hyperventilation decrease PaCO2

Question 28

what is exercise-induced arterial hyperaemia (EIAH) and who does it occur in ?

Answer 28

reduction in PaO2 of ≥ 10 mmHg from rest in highly trained males - high intensity exercise in all females regardless of fitness and intensity

Question 29

why was EIAH originally theorised to occur ?

Answer 29

ventilatory demand exceeds capacity demand vs capacity theory

Question 30

what are the causes of EIAH believed to be due to ?

Answer 30

diffusion limitation - increased CO2, too high blood flow doesn't allow effective diffusion in red blood cells V/Q mismatch - air breathed in has to be matched be blood CO. more perfusion than air in lungs relative hypoventilation - can't increase ventilation efficiently if don't increase breathing enough causing hyperventilation

Question 31

how do you measure mechanical work of breathing ? (2)

Answer 31

oesophageal pressure calculates mechanical work of breathing during exercise

Question 32

what are the 3 groups of neutrons that control breathing ?

Answer 32

ventral respiratory group (inspiratory/expiratory) Dorsal respiratory (inspiratory) pontine respiratory group (modulatory)

Question 33

What is Dalton’s law ?

Answer 33

Total pressure of gas mixture is equal to sum of pressure that each gas would exert independently

Question 34

What is the equation for partial pressure ?

Answer 34

Pgas= fraction of gas in air (Fgas) x barometric pressure (Pbar)

Question 35

What is partial pressure for O2 and CO2?

Answer 35

O2 = 159mmHg CO2 = 0.3 mmHg

Question 36

What happens when oxygenated air mixes with deoxygenated air ?

Answer 36

Causes some impairment Arterial PO2 (100) is less than Alveolar PO2 (105)

Question 37

What are the differences between systemic and pulmonary circulation in terms of pressure and resistance ?

Answer 37

Pulmonary - low pressure low resistance (Pulmonary artery pressure15mmHg) Systemic arterial pressure 100 mmHg High pressure high resistance

Question 38

Why is pulmonary circuit have low pressure and resistance ?

Answer 38

Thin walled and little smooth muscle No need for redistribution of blood flow so low resistance

Question 39

Explain the ventilation perfusion relationship

Answer 39

Gas exchange requires matching ventilation to blood flow Underperfused - (apex of lung) more air than blood Overperfused- (base of lung) more blood than air Blood flow increases disproportionally due to gravity