BAMS: Respiration (mechanics)

Question 1

What are the two meanings of ‘respiration’?

Answer 1

tissue respiration and breathing

Question 2

What is tissue respiration?

Answer 2

the aerobic metabolism in cells

Question 3

what is breathing?

Answer 3

the gas exchange and the associated processes

Question 4

what is the basics of breathing?

Answer 4

the job of the lungs to bring in fresh air rich in oxygen needed to fuel the body AND to expel the waste gas (CO2) produced from cells in the body

Question 5

what must the movement of air in and out of the lungs be coupled with?

Answer 5

cellular respiration

Question 6

what are the two types of circulation in the body?

Answer 6

pulmonary circulation and peripheral circulation

Question 7

what is pulmonary circulation?

Answer 7

moves blood between heart and lungs to exchange O2 and CO2

Question 8

what is peripheral circulation?

Answer 8

process of transporting blood throughout the body, including its distribution, exchange with tissues and storage

Question 9

why is respiratory mechanics important?

Answer 9

to understand how lungs work in normal state and in disease states

Question 10

what does breathing maintain?

Answer 10

blood gas homeostasis (O2, CO2, and pH)

Question 11

what is the partial pressure of O2 at rest?

Answer 11

100 +-2 mmHg (millimeters of mercury)

Question 12

what is the partial pressure of CO2 at rest?

Answer 12

40+-2 mmHg

Question 13

AT REST, how much O2 is used up and how much CO2 is expelled? (exchange)

Answer 13

~250ml O2/min
~200ml CO2/min

–> breathing is stable

Question 14

What is the exchange of gases when walking 3mph?

Answer 14

~800ml 02/min
~750ml CO2/min

–> breathing regulation is continuous

Question 15

What is the exchange of gases during severe exercise?

Answer 15

~5000ml O2/min
~6000ml CO2/min

Question 16

What is the primary function of nasal cavities/paranasal sinuses in movement of air into lungs?

Answer 16

filter, warm, humidify air; detect smells

Question 17

What is the primary function of the pharynx in movement of air into lungs?

Answer 17

conducts air to larynx

Question 18

What is the primary function of the larynx in movement of air into lungs?

Answer 18

protects opening to trachea and contains vocal cords

Question 19

What is the primary function of the trachea (and bronchi) in movement of air into lungs?

Answer 19

filters air, traps particles in mucus; cartilages keep airway open

Question 20

What is the primary function of the lungs in movement of air into lungs?

Answer 20

responsible for air movement through volume changes during movements of ribs and diaphragm; includes airways and alveoli

Question 21

What is the primary function of the alveoli in movement of air into lungs?

Answer 21

act as sites of gas exchange between air and blood

Question 22

What is considered the ‘upper airways’?

Answer 22

everything from nasal cavities to larynx

Question 23

What are the major functions of the upper airways in air movement to lungs?

Answer 23

humidify (saturate with water)
warm (to body water)
filter (to get rid of any debris that may be in it)

Question 24

What epithelium lines the upper airways to the bronchioles?

Answer 24

pseudo-stratified, ciliated, columnar epithelium and have goblet cells

Question 25

how is air filtered in the upper airways?

Answer 25

mucus produced by the goblet cells traps any debris in the air and is moved towards the mouth (by the cilia) where it is coughed out

Question 26

what is ventilation at rest?

Answer 26

~6-7 L/min, ~12-15 breaths of ~500ml

Question 27

what is max ventilation?

Answer 27

160L/min, ~40 breaths of 4L

Question 28

What is cardiac output at rest?

Answer 28

5L/min, 70bpm, 70ml/beat

Question 29

what is the max cardiac output?

Answer 29

25 L/min, 200bpm, 125ml/beat

Question 30

What happens to diaphragm during QUIET BREATHING inspiration?

Answer 30

diaphragm contracts downwards pushing abdominal contents outwards external intercostal muscles (between the ribs) pull ribs outwards and upwards

Question 31

is inspiration during quiet breathing ACTIVE or PASSIVE?

Answer 31

ACTIVE

Question 32

is expiration during quiet breathing ACTIVE or PASSIVE?

Answer 32

PASSIVE

Question 33

What happens to diaphragm in quiet breathing during expiration?

Answer 33

no active recruitment of muscles - the diaphragm returns to a resting position, due to the ELASTIC RECOIL PROPERTIES

Question 34

is inspiration during strenuous breathing ACTIVE or PASSIVE?

Answer 34

ACTIVE

Question 35

is expiration during strenuous breathing ACTIVE or PASSIVE?

Answer 35

ACTIVE

Question 36

What happens to diaphragm during STRENUOUS BREATHING inspiration?

Answer 36

greater contraction of diaphragm (1cm quiet breathing up to 10cm during strenuous breathing) and external intercostals) If breathing is quite strenuous then additional inspiratory accessory muscles might also be recruited and active, e.g., sternocleidomastoid (large muscle running down side of neck), alae nasi (nostrils), genioglossus (extrinsic muscle of the tongue)

Question 37

What happens during STRENUOUS BREATHING expiration?

Answer 37

- Active contraction of expiratory muscles – such as: - Abdominal muscles (rectus abdominus, internal oblique, external oblique, and transversus abdominus) - Internal intercostal muscles oppose external intercostals by pushing down and inwards o To push air out of the lungs so the next breath can be started

Question 38

what is the major inspiratory muscle?

Answer 38

diaphragm

Question 39

what is intrapulmonary pressure (also alveolar pressure)?

Answer 39

pressure within the lungs changes during course of a breath

Question 40

what is intrapleural pressure?

Answer 40

pressure of the little space between the lungs and chest wall

Question 41

what is tidal volume?

Answer 41

volume change that occurs in the lungs when a breath is being taken

Question 42

what are the steps of volume and pressure changes during a breath?

Answer 42

beginning of inspiration, Alveolar pressure = 0 because no flow muscles contract, pleural pressure is negative, alveolar pressure <0, glottis opens, air moves into lung (from higher to lower pressure) flow stops when atmospheric and alveolar pressure are equal. Glottis closes

Question 43

what is the efficiency of breathing at low level breathing (in healthy lungs)?

Answer 43

very efficient - small muscle effort (2% of resting energy expenditure)

Question 44

what is the efficiency of breathing at strenuous breathing (in healthy lungs)?

Answer 44

less efficient - gas flow is turbulent - uses more muscles accessory muscles can fatigue easily - limits exercise

Question 45

What is functional residual capacity (FRC)?

Answer 45

the volume of air in the lungs at the end of expiration during quiet breathing (just before the next inhalation occurs)

Question 46

What happens to functional residual capacity (FRC) in neuromuscular disease (when chest wall muscles are weak)?

Answer 46

FRC decreases (lung elastic recoil is greater)

Question 47

What is tidal volume?

Answer 47

volume of air that moves in and out of the lungs during a normal resting breath (typically ~1/2 a litre (500ml)

Question 48

What is expiratory reserve volume?

Answer 48

if force more air out of lungs after normal resting exhalation - this force of air is the expiratory reserve volume

Question 49

what is the total lung capacity?

Answer 49

the measurement of how much air can maximally be taken into the lungs (volume of lungs)

Question 50

what is the average lung volumes for males and females?

Answer 50

males: 6000ml females: 4200ml

Question 51

what is respiratory mechanics?

Answer 51

the study of mechanical properties of lungs and chest wall

Question 52

what do the mechanical properties of the lungs and chest wall determine?

Answer 52

the ease or difficulty of air movement into lungs

Question 53

why is the measurement of lung volumes important?

Answer 53

to understand normal and 'diseased' lung function

Question 54

what do lung diseases affect?

Answer 54

mechanical properties of lungs