L20 - Control of breathing Flashcards
name for shortness of breath
dyspnea
what 3 changes does breathing need to accomodate
and give examples
metabolic - blood gases and pH
mechanical - postural changes
episodic non-ventilatory - speaking, sniffing, eating
local control of gas transport - how does inc in CO2 affect blood flow
triggers vasodilation
incerases blood flow
more CO2 removal and more O2 delivery
local control of gas transport - lung perfusion
is there’s not much PP of O2 in a certain area in lungs
vasocontriction occurs
so decreases blood flow in that area
but directs blood flow to areas with more O2
local control of gas transport - alveolar ventilation
inc CO2
causes bronchodilation
which increases air flow
and directs airflow to areas of high PP of CO2
so it can be removed
central control of ventilation - what are the sensors
central and peripheral chemoreceptors
mechanoreceptors (respond to stretch)
central control of ventilation - what are the central controllers
resp centres in the pons and medulla
central control of ventilation - what are the effectors
muscles of ventilation
central chemoreceptors - location and what they repond to
medulla
respond to
- change in pH (acidic conditions)
- hypercapnia (too much CO2)
- no effect of hypoxia, these receptors dont respond to that at all
peripheral chemoreceptors - location and what they repond to
aortic and carotid body
respond to
- hypoxia
- hypercapnia
- change in pH
mechanoreceptors - location and what they repond to and types
lung receptors
respond to stretch
- rapidly adapting receptors
- slowly adapting receptors
- C-fibres receptors
which blood is important to look at when checking levels of CO2, H+ and O2
arterial blood
if O2 falls below ____mmHg partial pressure it is a problem
60mmHg
only then will receptors be triggered
central chemoreceptors: what nerves are they located close to
VIII and XI cranial nerve
so damage to these can cause resp problems
central chemoreceptors: how can they directly be triggered by CO2
CO2 can cross the blood brain barrier
indirectly via its effect on decreasing pH
how come the CSF is sensitive to blood pH
its vry weakly buffered
so pH in CSF similar to blood pH
peripheral chemoreceptors: where are they
aortic and carotid body
peripheral chemoreceptors: what are they innervated by
carotid body:
carotid sinus nerve
which is innervated by
glossopharyngeal (one of our cranial nerves)
aortic body:
innervated by vagus nerve
whats the result of too much H+ in the blood from too much CO2?
respiratory acidosis
what could be a result of hyperventilation?
decrease in CO2
so incerase in pH
respiratory alkalosis
what happens when PO2 is too high (e.g. breathing O2 rich gas mixtures_
could generate free radicals
whcih damages cells
coma and death
mechanoreceptors: what reflex is slowly adapting mechanoreceptors related to
Hering Breuer reflex
mechanoreceptors: where are the slowly adapting mechanoreceptors found
visceral pleura, bronchioles and alveoli
mechanoreceptors: purpose of slowly adapting mecahnoreceptors
prevent overinflation of lungs
trigger exhalation
fires quite slowly (hence the name) cuz we want to be able to breathe in duh, but after a certain point it fires faster
mechanoreceptors: what are rapidly adapting stretch receptors responding to and whats the result
respond to irritants
e.g. smoke, dust, cold air etc
cause bronchoconstriction
coughing reflex
mechanoreceptors: wehre are rapidly adapting located
airway epithelia
mechanoreceptors: where are c fibre receptors located
alveoli wall
and conducting airways
mechanoreceptors: what do c fibre receptors respond to and cause
chemical and mechanical stimuli
mainly mechanical
so, left sided heart failure -> cuases engorgemnt of pulmonary caps
triggers recpetors to fire
causing bronchoconstriction
shallow breathing
mucus secretion
which central controller located in the medulla
rhythmicity centre
what type of breathing does the rhythmicity centre control
automatic breathing
I neurons control inspiration
E neurons control expiration
what central controller located in the pons
pneumotaxic and apneustic centres
what do pneumotaxic and apneustic centres do
modify firing pattern of medullary centres#
not involved in normal resp
only when increased demand
so it’ll promote inspiration and stuff
in rhytmicity centre, where are I neurons located
dorsal respiratory group
in rhytmicity centre, where are E neurons located
ventral respiratory group
(contains some I neurons too but whatever)
what do I neurons regulate
the phrenic nerve
which then innervates the diaphragm
so it stimulates muscles of quiet inspiration
what do E neurons regulate
expiration is a passive process (elastic recoil)
but
E neurons will inhibit I neurons
how do you calculate ventilation rate
VR = tidal volume x respiratory rate (f)
