Control of Respiration Flashcards
what are some factors that modulate breathing
reflexes like coughing
vocalisation like singing
volitional control like holding the breath
emotional events like crying
physiological challenges like sleep and exercise
what are the two signal senders to the brain in relation to breathing
chemoreceptors
mechanoreceptors
what do chemoreceptors do in relation to breathing
provide feedback on partial pressures of oxygen and carbon dioxide, and pH
what do mechanoreceptors do in relation to breathing
provide feedback on mechanical status of the lungs, chest wall and airways
what do the chemoreceptors and mechanoreceptors send neural signals to
respiratory muscles and upper airway muscles. they also produce reflexes to keep airways patent like coughing and sneezing
what do respiratory muscles do
they produce rhythmic breathing movements like diaphragm and intercostals
what are the upper airway muscles
laryngeal
pharyngeal
tongue
what are some reflexes to keep airways patent
coughing and sneezing
where are many of the important neuronal cell groups found
in the brainstem
what are chemoreceptors
sensory receptors that detect chemical changes in the surrounding environment
what are peripheral chemoreceptors
small, highly vascularised bodies in the region of the aortic arch and the carotid sinuses
how is the information from peripheral chemoreceptors sent
via glossopharyngeal and vagus nerves to the nucleus in brainstem called the NTS
what is the NTS
the nucleus tractus solitatius
label this
what do peripheral chemoreceptors respond to
decrease in the partial pressure of oxygen
what is the term for a decrease in partial pressure of oxygen
hypoxia
describe the peripheral chemoreceptor pathway
reduction in arterial partial pressure
peripheral chemoreceptors stimulated
neural signals sent from the carotid and aortic bodies in the NTS in the brainstem
ventilation increases to restore the partial pressure of oxygen levels
describe the ventilatory response to hypoxia
progressive reductions in inspired oxygen have little effect until about 60mmHg
below 60 there is progressive hyperventilation
hypoxic response originates in carotid and aortic bodies
play little part in the moment to moment control of breathing
what are central chemoreceptors
central chemoreceptors are clusters of neurones in the brainstem that are activated when partial pressure of carbon dioxide is increased or pH is decreased
what is the term for a increase in the partial pressure of carbon dioxide
hypercapnia
describe the pathway of the central chemoreceptors when there is an increase in the partial pressure of carbon dioxide
the central chemoreceptors are stimulated
signals are processed and information is passed on to the neuronal clusters in the brainstem involved in generating breathing
ventilation increases to restore the partial pressure of carbon dioxide levels
describe the ventilatory response to hypercapnia
very small changes in partial pressures of carbon dioxide have large effects on ventilation
hypercapnic response originates in the central chemoreceptors in the brainstem
plays a major role in the moment to moment control of breathing
what are mechanoreceptors
sensory receptors that detect changes in pressure, movement and touch
what do the mechanoreceptors detect in the respiratory system
movement of the lung and the chest wall ie during inspiration the mechanoreceptors detect inflation of lungs and movement of the chest
describe the pathway of mechanoreception
inflation of lungs activates mechanoreceptors
neural signals sent via the vagus nerve to the NTS in the brainstem
ventilation is adjusted accordingly
what are mechanosensory signals essential for
adapting and adjusting breathing
integrating the respiratory pattern with other movements like posture and locomotion
what is the location of respiratory mechanoreceptors
airway smooth muscle
what is the reflex of the mechanoreceptors when there is inflation of the airways
termination of inspiration
describe the pathway of respiratroy mechnoreceptors in the airway epithelium
they detect rapid lung inflation or deflation and lead to a sigh or shortened expiration
what does the NTS do
receive information from mechanoreceptors and peripheral chemoreceptors
what is the NTS
cluster of respiratory neurones in the brainstem that generate the rhythm of breathing.
forms a vertical column of grey matter in the medulla oblongata of the brainstem.
describe information processing in the NTS
processed by the neurones and sent to respiratory muscles
when are inspiratory neurons active
during inspiration
when are expiratory neurones active
during expiration
what are the neurons found in the NTS
rhythm generating neurons that continue to produce a respiratory like rhythmic output when isolated
describe the pathway of the output of signals from the brainstem to the respiratory muscles
neurons produce rhythmic output
rhythmic neural signals sent to the spinal cord
phrenic nerve exits the spinal cord from 3-5
phrenic nerve innervates the diaphragm
nerves exit the thoracic spinal cord to innervate the intercostal muscles
this is the medulla oblongata. label it
describe high centre modulation of breathing
the high centres are the cerebral cortex, limbic system and the hypothalamus
it has volitional and emotional control
describe somatotopic organisation of the primary motor cortex
the area of the motor cortex dedicated to a particular muscle is proportional to the number of motoneurones innervating the muscle
where are the respiratory rhthym generating neurones located
in the brainstem
