Physiology Of Respiration Flashcards
What makes up the LRT
Trachea onwards
What is the name of the area of the lung which pulmonary nerve plexus and blood vessels and bronch enter
Hilum of the lung
Sympathetic nerves have what affect on bronchi?
Bronch dilation
What cells make up the alveoli?
Type 1 alveolar pneumocytes (squamous epithelium) and type 2 pneumocytes which secrete surfactant
Goblet cells release mucus to form a 10-15micrometer layer containing what?
Antitrypsins, lysozyme, IgA
What muscles make up the accessory respiratory muscles?
Scalene and sclaternomastoid muscles
What law means that we requires surfsctant to reduce surface tension otherwise transmittal pressure would collapse alveoli?
Laplace’s law
Transmutation pressure = (wall tension * wall thickness)/radius
Mucus is made up of two layers called phases which are?
The deeper sol phase and the superficial gel phase
What does the central pattern generator of the medulla do?
Sets the basic rate and rhythm of breathing
What modulates the activity of the CPG?
Chemoreceptors, lung mechanoreceptors, cortex, limbicc system
The neurones for inspiration and expiration exhibit reciprocal inhibition, what does this mean?
Which one type is active it inhibits the opposite type and visa versa
What is the DRG responsible for?
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
What is the VRG responsible for?
Secondary to DRG in initiating breathing, also contains centres for control of breathing in exercise I.e. Expiratory muscles
Voluntary motor control from cortical motor neurones travels via what?
The pyramidal tract
Alveolar PaCO2 usually is what?
5.3KPa / 40mmHg
What is normal alveolar PaO2?
13KPa / 105mmHg
What does raised PCO2 cause
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
At what partial pressure does O2 become a respiratory drive?
8KPa / 60mmHg
Where are the central chemoreceptors located?
The venterolateral surface of the medulla where the CN IX and X exit
The central chemoreceptors detect what?
O2 and H+ therefore detecting CO2 indirectly. (H+ and HCO3 can’t cross BBB therefore via equilibrium reaction CO2 when raised increases CSF acidity)
What percentage of CO2 stimuli is detected by the central chemoreceptors?
80% they are the primary modulator of normal healthy breathing
The peripheral chemoreceptors of the carotid bodies are formed by what two cell types?
Type 1 glomus sensory cell and type 2 sheath cell
The carotid bodies are in recanted by what nerve?
Glossopharyngeal CN IX
What innervates the aortic bodies?
The vagus nerve CN 10
What do the peripheral chemoreceptors detect?
PO2, PCO2, H+
Pain does what to breathing if only momentarily?
Apnea
Which receptors are responsible for the Hering-Breur reflex and are innervates by ehic nerve?
Stretch receptors innervates by the vagus. They inhibit the inspiratory centre
What do the juxto pulmonary receptors do?
Depress respiratory activity, causing shirt shallow breathing/apnea, reduction in HR, relaxation of skeletal muscle and laryngeal constriction
What stimulates the juxtapulmonary receptors?
Increased alveolar fluid, inflammation, micro embolisms and oedema
What nerves carry impulses from juxtapulmonary receptors?
The unmyelinated C-fibres
What do irritant receptors do?( innervates by rapid vagal fibres)
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
What do proprioceptors in the chest do for breathing?
Maintain optimal tidal volume and frequency and do this by being in muscle spindles and joints
What hypoxic reflex helps prevent excessive Va/Q mismatch
Hypoxic pulmonary vasoconstriction
What makes up the URT
Nose pharynx larynx
