Control of respiration Flashcards
what innervates the respiratory muscles and promotes gaseous exchange between the body and the environment ?
what promotes the respiratory rhythm?
pre-Botzinger in the medulla
generates respiratory
animal stopped breathing.
medulla oblongata
what part of the brain controls the neurons that drive inspiration?
DRG and VRG
dorsal respiratory group
ventral respiratory group
what part of the brain acts as a switch between inspiration and expiration?
pontine nuclei
what controls smooth respiratory rhythm?
in pons pnemotaxix center and apneustic center
what part of brain is for emotional responses?
limbic system and hypothalamus
what receptors lie in smooth muscle layer of airways and fire in proportionate response to transmural pressure?
pulmonary receptors
what kind of receptor is located in the airway epithelium and responds to touch or noxious substances?
irritant receptors
responds to smoke, particle deposition and inflammatory histamines, serotonins and prostaglandins- activated during inflammation..
lung edema can also stimulate these receptors. stimulation results in coughing and gasping.
what kinds of receptors are found in joints, tendons, muscle and inform the brain of the position of the body?
proprioceptors
chest wall proprioceptors signal the breathing effort
what kinds of receptors fire in response to lung injury, over inflation, pulmonary edema, pulmonary embolism, but are not sensitive to inflammatory mediators?
J receptors/ juxtapulmonary capillary receptors/ C fiber endings
what kinds of J receptors are sensitive to inflammatory mediators?
bronchial C fibers
what receptor is related to cough reflex?
upper airway irritant receptor-
cough bronchoconstriction
stimulant: mechanical/chemical irritation
vagus nerve
what receptor is related to sneeze reflex?
Nasal irritant receptor
stimulant: mechanical/chemical irritation
sneeze
trigeminal olfactory
what receptor is related to Hering-Breuer inflation reflex?
airway smooth muscle stretch receptor
stimulant: lung inflation
this stops inspiration
what receptor is related to the Hering-Breuer deflation reflex?
possible J irritant or stretch receptors
stimulant: lung deflation
starts inspiration
what receptor is related to the positional perception?
Proprioceptor
stimulus: stretch of muscle or tendons
allows fine control of muscle groups
what receptor is related to pulmonary vascular congestion?
J receptors
stimulus: edema
Tachypnea, sensation of dyspnea
where are central chemoreceptors located?
ventral surface of the medulla
what kinds of receptor is located in the ventral surface of the medulla and respond to changes in PCO2 and PH of the cerebrospinal fluid?
central chemoreceptors
what separates the cerebral spinal fluid from the blood ?
the blood brain barrier
what ions have the strongest effect on cerebral spinal fluid PH?
PCO2 because the blood brain barrier is very permeable to that and O2
and impermeable to H+ and HCO3, metabolic alkalosis has little effect on CSF PH.
does metabolic or respiratory acid/ base have more impact on PH of CSF?
respiratory like PCO2
an increase in PH causes alveolar ventilation to ______
decrease
where are peripheral chemoreceptors located? what do they do?
located at the carotid and aortic bodies
they detect changes in PCO2, PO2, and pH
glomus cells= chemoreception site
carotid body= small sensory organ at the bifurcation of the carotid artery- afferents feed CNS via the glossopharyngeal nerves.
aortic bodies= multeple bodies along aorta- afferents feed CNS via vagus nerve
how does glomus cells sense hypoxia?
if there is hypoxia it sense it and sends it to vagus and glossopharyngeal nerve ( afferents) and sends signal to respiratory center and PH gets change.
Glomus cells sense hypoxia with decreased PO2, increased intracellular Ca causes exocytosis of neurotransmitter vesicles and activation of afferents leading to CNS.
leads to depolarization and opens voltage sensitive Ca channels. glossapharyngeal turned on to change PH
glomus cell gets depolarized
what becomes very active at low PO2, PCO2, PH and activates ventilation?
carotid body
the activity is potentiated by increased H+ and CO2
what do aortic bodies detect?
low PO2
what detects PCO2 and provides strong ventilatory response
central chemoreceptors
what is held within PCO2 of 3 mmHG?
arterial blood
what increases hypercarbic drive?
low PAO2
what is the most important stimulus to ventilatory drive?
arterial PCO2
COPD with emphysema
- surface area available for gaseous exchange is decreased
- since decreased gas exchange hypoxia ( low o2) and hypercarbia ( high co2)
- the hypoxia and hypercarbia is due to impaired V/Q ( ventilation perfusion mismatch.= hypoxic vasoconstriction
- hypoxic vasoconstriction= body is trying to cut down blood flow
how do you treat patient with COPD with emphysema?
titrate oxygen in a way to maintain PaO2 at 60-65mmHg and achieve saturation of 88-92%
- peripheral chemoreceptors might stop if you provide 100% oxygen because the only thing driving this person to breath is hypoxia… this case would remove the protective vasoconstriction leads to V/Q mismatch and perfusing crappy lung areas.. this leads to carbon dioxide level increase because hypoxia isn’t being corrected. this leads to oxygen induced hypercapnia… ( a lot of CO2)
what is the only chemical drive for ventilation in a patient with COPD and emphysema ?
hypoxia sensed by peripheral chemoreceptors
