Physiology Of Respiration

Question 1

What makes up the LRT

Answer 1

Trachea onwards

Question 2

What is the name of the area of the lung which pulmonary nerve plexus and blood vessels and bronch enter

Answer 2

Hilum of the lung

Question 3

Sympathetic nerves have what affect on bronchi?

Answer 3

Bronch dilation

Question 4

What cells make up the alveoli?

Answer 4

Type 1 alveolar pneumocytes (squamous epithelium) and type 2 pneumocytes which secrete surfactant

Question 5

Goblet cells release mucus to form a 10-15micrometer layer containing what?

Answer 5

Antitrypsins, lysozyme, IgA

Question 6

What muscles make up the accessory respiratory muscles?

Answer 6

Scalene and sclaternomastoid muscles

Question 7

What law means that we requires surfsctant to reduce surface tension otherwise transmittal pressure would collapse alveoli?

Answer 7

Laplace’s law

Transmutation pressure = (wall tension * wall thickness)/radius

Question 8

Mucus is made up of two layers called phases which are?

Answer 8

The deeper sol phase and the superficial gel phase

Question 9

What does the central pattern generator of the medulla do?

Answer 9

Sets the basic rate and rhythm of breathing

Question 10

What modulates the activity of the CPG?

Answer 10

Chemoreceptors, lung mechanoreceptors, cortex, limbicc system

Question 11

The neurones for inspiration and expiration exhibit reciprocal inhibition, what does this mean?

Answer 11

Which one type is active it inhibits the opposite type and visa versa

Question 12

What is the DRG responsible for?

Answer 12

Initiation of breathing with secondary help of the VRG. Also incorporates info from chemo and mechano receptors. Sends impulses down phrenic and intercostal nerves to the muscles of inspiration. Inhibited by pneumotaxic area

Question 13

What is the VRG responsible for?

Answer 13

Secondary to DRG in initiating breathing, also contains centres for control of breathing in exercise I.e. Expiratory muscles

Question 14

Voluntary motor control from cortical motor neurones travels via what?

Answer 14

The pyramidal tract

Question 15

Alveolar PaCO2 usually is what?

Answer 15

5.3KPa / 40mmHg

Question 16

What is normal alveolar PaO2?

Answer 16

13KPa / 105mmHg

Question 17

What does raised PCO2 cause

Answer 17

Raised rate of ventilation and acidity which makes the chemoreceptors more sensitive to CO2 increases and thus causes greater increase in RR at lower PCO2

Question 18

At what partial pressure does O2 become a respiratory drive?

Answer 18

8KPa / 60mmHg

Question 19

Where are the central chemoreceptors located?

Answer 19

The venterolateral surface of the medulla where the CN IX and X exit

Question 20

The central chemoreceptors detect what?

Answer 20

O2 and H+ therefore detecting CO2 indirectly. (H+ and HCO3 can’t cross BBB therefore via equilibrium reaction CO2 when raised increases CSF acidity)

Question 21

What percentage of CO2 stimuli is detected by the central chemoreceptors?

Answer 21

80% they are the primary modulator of normal healthy breathing

Question 22

The peripheral chemoreceptors of the carotid bodies are formed by what two cell types?

Answer 22

Type 1 glomus sensory cell and type 2 sheath cell

Question 23

The carotid bodies are in recanted by what nerve?

Answer 23

Glossopharyngeal CN IX

Question 24

What innervates the aortic bodies?

Answer 24

The vagus nerve CN 10

Question 25

What do the peripheral chemoreceptors detect?

Answer 25

PO2, PCO2, H+

Question 26

Pain does what to breathing if only momentarily?

Answer 26

Apnea

Question 27

Which receptors are responsible for the Hering-Breur reflex and are innervates by ehic nerve?

Answer 27

Stretch receptors innervates by the vagus. They inhibit the inspiratory centre

Question 28

What do the juxto pulmonary receptors do?

Answer 28

Depress respiratory activity, causing shirt shallow breathing/apnea, reduction in HR, relaxation of skeletal muscle and laryngeal constriction

Question 29

What stimulates the juxtapulmonary receptors?

Answer 29

Increased alveolar fluid, inflammation, micro embolisms and oedema

Question 30

What nerves carry impulses from juxtapulmonary receptors?

Answer 30

The unmyelinated C-fibres

Question 31

What do irritant receptors do?( innervates by rapid vagal fibres)

Answer 31

Cause cough, bronchial+laryngeal constriction and rapid breathing to expel irritant. They also cause large breaths every 5-20 mins at rest to prevent lung collapse

Question 32

What do proprioceptors in the chest do for breathing?

Answer 32

Maintain optimal tidal volume and frequency and do this by being in muscle spindles and joints

Question 33

What hypoxic reflex helps prevent excessive Va/Q mismatch

Answer 33

Hypoxic pulmonary vasoconstriction

Question 34

What makes up the URT

Answer 34

Nose pharynx larynx