RS. Control of Breathing Flashcards
what is breathing regulated by?
relaxes (coughing)
volitional control (breath hold)
vocalisation (singing)
emotional events (crying)
physiological challenges (sleep, excercise)
what do the neural signals from chemoreceptors to the brain do?
provide feedback on blood PO2, PCO2 and pH
what do the neural signals from mechanoreceptors to the brain do?
provide feedback on mechanical status of lungs, chest wall and airways
where do the chemoreceptors and mechanoreceptors send neural signals to?
respiratory muscles - to produce rhythmic breathing movements eg. diaphragm and intercostals
upper airway muscles - eg. laryngeal, pharyngeal and tongue
produces rel=flexes to keep airways patent eg. cough, sneeze, gag
what are chemoreceptors?
sensory receptors that detect chemical changes in the surrounding environment
what is hypoxia?
decrease in oxygen
what is hypercapnia?
increase in carbon dioxide
what are peripheral chemoreceptors and where are they found?
small, highly vascularised bodies in region of aortic arch and carotid sinuses.
how to carotid baroreceptors and chemoreceptors send information to the NTS?
via glossopharyngeal nerve and carotid sinus
where is the information sent to thats coming from the aortic/carotid chemoreceptors and baroreceptors?
nucleus tractus solitarius
how to aortic baroreceptors and chemoreceptors send information to the NTS?
via vagus nerve
where are many important neuronal cell groups (nuclei) with roles in regulation found?
the brainstem
what does peripheral chemoreceptors respond to?
decreases in PO2
what happens in a hypnotic environment?
- reduction in arterial PO2
- peripheral chemoreceptors stimulated
- neural signal sent from carotid and aortic bodies to NTS in brainstem
- ventilation increases to restore PO2 levels
where does a hypoxic response originate?
in the carotid and aortic bodies
what are central chemoreceptors?
clusters of neurons in the brainstem that are activated when PCO2 is increased (hypercapnia) or pH decreased
what is the sequence of steps when there is a increase in CO2 in the blood?
- increases in arterial PCO2
- central chemoreceptors (brainstem neurones) stimulated
- signals processed and information passed on to neuronal clusters in brainstem involved in generating breathing
- ventilation increases to restore PCO2
does a small change in PCO2 or O2 have a bigger effect on ventilation?
PCO2
where do hypersonic responses originate from?
central chemoreceptors in brainstem
what are mechanoreceptors?
sensory receptors that detect changes in pressure, movement and touch
what do mechanoreceptors do in the respiratory system?
detect movement of lung and chest wall
what activates mechanoreceptors?
inflation of lungs
how do mechanoreceptors send neural signals to the brainstem?
via vagus nerve
what are mechanosensory signals essential for?
adapting and adjusting breathing
some mechanoreceptors are present on airway smooth muscle. what is its stimulus and reflex?
stimulus = inflation/ distension of airways
reflex = termination of inspiration
some mechanoreceptors are present on airway epithelium. what is its stimulus and reflex?
stimulus = rapid lung inflation/deflation or oedema
reflex = sigh or shortened expiration
what generates the rhythm of breathing?
clusters of respiratory neurones in brainstem
where is the rhythmic breathing signal sent to when it leaves the brainstem?
respiratory muscles
give the order of integration go information in the brainstem?
- NTS receives info from mechanoreceptors and peripheral chemoreceptors
- info processed in brainstem by respiratory neurons
- cluster of respiratory neurones in brainstem generate rhythmic of breathing
- rhythmic signal is sent to respiratory muscles eg. diaphragm
what are respiratory pattern generating neurons?
the neurons that generate the pattern of breathing by firing at certain points during the respiratory cycle
what are the 2 types of pattern generating neurons?
inspiratory neurons: active during inspiration
expiratory neurons: active during expiration
what do respiratory rhythm generating neurones do?
generate the rhythm of the breathing without being stimulated
what nerves innervates the diaphragm and where does this nerve exit the spinal cord?
phrenic nerve
cervical spinal cord level 3-5
where do the nerves that innervate the intercostal muscles exit the spinal cord?
thoracic spinal cord
what can the NTS also be called?
dorsal respiratory group
what is the ventral respiratory group?
rhythm generating neurons
what are the higher centres and what do they have control of?
- cerebral cortex
- limbic system
- hypothalamus
have control volitional and emotional breathing
why is there a large portion of the motor cortex dedicated to the head?
refined movement
what is the 3 respiratory group we don’t know much about?
pontine respiratory group
