ILA respiratory failure

Question 1

Describe the anatomical structure air will pass through as it travels from the nose to the alveoli

Answer 1

External nares, nasal cavity, internal nares, nasopharynx, oropharynx, laryngopharynx, trachea, main bronchi, lobar bronchus, segmental bronchus, subsegmental bronchus, conducting bronchiole, terminal bronchiole, respiratory bronchioles, alveolar ducts, alveolar sacs and alveoli.

Question 2

Upper airway structures

Answer 2

nose, nasal passages, paranasal sinuses (frontal and sphenoid), pharynx (naso, oro and laryngo), larynx above vocal cords

Question 3

Paranasal sinuses

Answer 3

Sphenoid and frontal

Question 4

Nasal chonchae

Answer 4

superior, middle and inferior

Question 5

Lower airway structures (sequence)

Answer 5

larynx below vocal cords, trachea, main bronchus, lobar bronchi, segmental bronchi, subsegmental bronchi, conducting bronchiole, terminal bronchiole, respiratory bronchioles, alveolar ducts, alveolar sacs and alveoli

Question 6

Where are lower airway structures derived from?

Answer 6

developing foregut

Question 7

Number of generations in respiratory tree

Answer 7

23 on average

Question 8

Proximal divisions

Answer 8

closest to top of tree - bronchi. Transmit air to lower airways

Question 9

Distal divisions

Answer 9

respiratory bronchiole, alveolar ducts and alveoli. Specialised for gas exchange

Question 10

Structure of trachea and its divisions

Answer 10

C shaped tracheal rings of hyaline cartilage. Branches into left and right main bronchus. Bronchi branch into smaller sections (bronchioles). Bronchioles lead to air sacs and alveoli.

Question 11

Tracheal rings

Answer 11

C-shaped hyaline cartilage, Prevents trachea from collapsing.

Question 12

Suspension of lungs

Answer 12

suspended within pleural cavity of thorax

Question 13

Pleurae

Answer 13

2 thin membranes, one cell layer thick, surrounding the lungs.

Question 14

Inner and outer pleurae

Answer 14

Inner is visceral pleura covering the lungs. Outer is parietal pleura lining inner surface of chest wall.

Question 15

Function of pleura

Answer 15

Secretes fluid, which allows the lungs to move freely within the pleural cavity while expanding and contracting

Question 16

Lung lobes

Answer 16

Right lung has three - superior, middle and inferior. Left lung has two - superior and inferior, and portion of superior lobe (lingula). Divided into bronchopulmonary segments.

Question 17

Carina

Answer 17

Point where two mainstem bronchi branch off from base of trachea.

Question 18

Lung surfaces

Answer 18

costal surface - adjacent to ribcage, diaphragmatic surface - downward toward diaphragm, mediastinal surface - toward centre of chest, againts heart, vessels and carina

Question 19

Costal surface

Answer 19

Adjacent to ribcage

Question 20

Diaphragmatic surface

Answer 20

Faces downwards toward diaphragm

Question 21

Mediastinal surface

Answer 21

Faces toward centre of chest, lies against heart, great vessels and carina

Question 22

Airway resistance formula

Answer 22

R(AW) = deltaP/volumetric airflow

Question 23

deltaP formula

Answer 23

atmospheric pressure - alveolar pressure

Question 24

Determinants of airway resistance

Answer 24

diameter of airways

airflow being laminar or turbulent

Question 25

Laminar airflow

Answer 25

Less resistance. Fluid flows in parallel layers w/out disruption between them.

Question 26

Turbulent airflow

Answer 26

Large changes in pressure difference. Increased resistance.

Question 27

Airways prone to turbulent airflow

Answer 27

Larger airways more prone to turbulent airflow

Question 28

Where is the greatest resistance to airflow? (+explanation)

Answer 28

Bronchi of intermediate size, between 4th and 8th bifurcations. Individual small airways have greater resistance than large airways - more small airways than large ones.

Question 29

Medullary respiratory centre function

Answer 29

Sets basic rhythm for breathing

Question 30

Ventral respiratory group function

Answer 30

Generates breathing rhythm and integrates data coming into the medulla

Question 31

Dorsal respiratory group

Answer 31

Integrates input from stretch receptors and peripheral chemoreceptors

Question 32

Pontine respiratory group

Answer 32

influences and modifies medulla oblongata functions. Controls involuntary respiration

Question 33

aortic and carotid bodies

Answer 33

monitor blood pCO2, pO2, pH

Question 34

hypothalamus

Answer 34

monitors emotional state and body temp

Question 35

cortical areas of the brain

Answer 35

control voluntary breathing

Question 36

proprioceptors

Answer 36

send impulses regarding joint and muscle movements

Question 37

pulmonary irritant reflexes

Answer 37

protect respiratory zones from foreign material

Question 38

inflation reflex

Answer 38

protects lungs from over-inflating

Question 39

where is involuntary respiration controlled?

Answer 39

not under concious control. respiratory centre in upper brainstem: medulla oblongata and pons

Question 40

where are chemoreceptors located?

Answer 40

central: ventrolateral surface of medulla oblongata. peripheral: aortic and carotid bodies

Question 41

medulla oblongata function and components

Answer 41

sends signals to muscles controlling respiration and controls reflexes for non-respiratory air movements. contains ventral respiratory group (VRG) and dorsal respiratory group (DRG)

Question 42

VRG function

Answer 42

stimulates expiratory movements. neurons stimulate accessory muscles to contract --> forced inspiration or expiration. exhalation

Question 43

VRG neurons

Answer 43

rostral retrofacial nucleus caudal nucleus retroambiguus nucleus paraambiguus pre-boetzinger complex

Question 44

where do VRG neurons send their impulses to?

Answer 44

inspiratory - down the phrenic nerve: laryngeal and pharyngeal (from nucleus ambiguus) diaphragm and external intercostals (from rostral area of nucleus retroambigualis) expiratory - output stops: abdominals and internal intercostals (caudal area)

Question 45

where is the DRG located?

Answer 45

dorsomedial region of medulla. composed of cells in solitary nucleus.

Question 46

what is the solitary nucleus?

Answer 46

series of purely sensory nuclei in the medulla oblongata. solitary tract runs through it, w/ nerves innervating it from facial, glossopharyngeal and vagus. forms circuits contributing to autonomic function

Question 47

DRG function

Answer 47

generation of respiratory rhythm and inhalation

Question 48

DRG stimulation and inhibition

Answer 48

stimulated by apneustic centre in lower pons. inhibited by pneumotaxic centre. SN appropriates responses from chemoreceptors and mechanoreceptors

Question 49

DRG inspiration and expiration mechanisms

Answer 49

increase in firing of cells in solitary tract and VRG --> contraction of respiratory muscles. DRG neurons send impulses down the phrenic and intercostal nerves to stimulate diaphragm and external intercostals to contract. exhalation - cells stop firing.

Question 50

pneumotaxic centre location

Answer 50

upper part of the pons

Question 51

pneumotaxic nuclei

Answer 51

subparabrachial nucleus and medial parabrachial nucleus

Question 52

pneumotaxic centre function

Answer 52

controls rate and pattern of breathing. limits inspiration - inspiratory off-switch. limits bursts of action potentials in phrenic nerve.

Question 53

pneumotaxic centre and increasing rate and length of breathing

Answer 53

signals drg to speed up | bursts of drg activity are elongated

Question 54

pneumotaxic centre and tidal volume

Answer 54

decreases tidal volume

Question 55

apneustic centre location

Answer 55

lower pons

Question 56

apneustic centre function

Answer 56

promotes inspiration by stimulation of DRG in medulla - delays switch off signal of inspiratory ramp provided by pneumotaxic centre. Controls intensity of breathing. inhibits expiratory neurons

Question 57

Apneustic centre inhibition

Answer 57

inhibited by pulmonary stretch receptors