Control of Respiration Flashcards
how is rhythmic breathing generated?
- muscles: the diaphragm & intercostal muscles are STIMULATED (via nerves)
** injury to nerve = paralysis to respiration**
- nerves are stimulated from action potentials origniating in the pons and medulla of the brainstem
** APs are responsible for the stimulation and rest cycles of respiration**
- chemoreceptors: central and peripheral play a role in fine tuning the breathing (when to in and out, how deep, etc.)
- some role of the cortex can drive breathing
3 aspects of the medullary center which assist in breathing
- dorsal respiratory group
- ventral respiratory group
- pacemakers (pre-Botzinger complex)
explain how the pacemaker of spontaneous breathing works
- pacemaker = collection of cells on either side of the medulla
** protection mechanism so that it cant be knocked out via one-sided stroke** - assocaited with ventral respiratory group
- directs rhythmic respiration
- directs shifting of tonue and glottis (to assist in breathing)
- directs the 2 seconds in 3 seconds off rhythm
explain how the dorsal and ventral respiratory groups in the medulla work with breathing
dorsal group: activate inspiration
ventral group: complex function (with pacemaker, some inspiration assist and some expiration assist)
- gets input from the dorsal group –> sends to spinal neurons
- has some expiratory neruons –> become active if necessary for increased ventilation (like exercise)
explain the role of the Pons in regulation of respiration
(apenustic and pneumotaxic areas)
pons modifies the information from the medulla
- apenustic: responsible for modulation the duration and depth of inspiration and when its finished
- pneumotaxic: responsible for making the switch from inspiration to expiration
how are higher brain centers incorporated with the pons and medulla in breathing?
- the higher brain (cortex) can override the medulla and pons for specific situations
1. voluntary activity (holding breathe, purposeful breathing)
2. speech
3. emotion (anxiety)
** only to a specific extent – you cant hold your breath forever– the brainstem will take back over**
how do stretch receptors play a role in respiration
- located in the smooth airway muscles
- activated by excessive inspiration
- send action potentials TO the medulla to limit the inspiratory neurons
** youve hit the max inhale!!**
what are some drugs which can impact the inspiratory neurons within the brain? how do they work?
inspiratory neurons within the brain are located within the medulla –> specifically in the dorsal respiratory group
drugs like barbituates and morphine INHIBIT the actions of the inspiratory neurons –> thererfore slow the signals to trigger inspiration leading to death
where are the chemoreceptors loacted for triggering ventilation? how do they work?
- central chemoreceptors = within the brain
- responsible for responding to amount of CO2 within the body (via H+ in the CSF) - peripheral chemoreceptors = within the body
- responsible for responding to O2 levels (minor role) within the blood
how do central chemoreceptors regulate normal breathing?
central receptors = in the medulla
- respond to the ALVEOLAR CO2 levels
- via the H+ concentration that gets into the CSF because CO2 crosses BBB and becomes HCO3- + H+ in the CSF
- increased H+ associated with metablic acidosis
- a change in CO2 in the alveoli will trigger an increase in H+ in the CSF –> to which these receptors will increase the rate of breathing
how do peripheral chemoreceptors influence breathing? where are they specifically located?
peripheral chemoreceptors = within the carotid body & aortic body
- respond to changes in the O2 levels within the blood
- will increased breathing and ventilation (and herat rate)
what are other triggers besides O2 levels in the blood that peripheral chemorecptors respond to?
- increasing CO2 levels –> respiratory acidosis
- increasing H+ concentrations
- increasing ventilation
what are other receptors within the body (besides central and peripheral chemo.) which play a role in how we breath?
- irritant receptors ! = irritant triggers cough or sneeze
- joint and muscle receptors = triggered in early forms of exercisue to stimulate breathing
explain the mechanism behind sneezing and coughing
- both begin with a sustainable large inspiration
- sneezing: the glottis is continuously open
- coughing: the glottis closed
- both followed by forced expiration at 600 MPH
how is breathing regulated during sleep? what are some normal and abnormal breathing/ventilation patterns?
- respisration is less rigorous controlled during periods of sleep –> thus it is mainly controlled by the brainstem
normal patterns
- snoring
- BRIEF periods of apnea are normal
abnormal patterns
- sustained apnea (longer periods)
