8 - Control of Respiration Flashcards
What factors influence the ventilatory response to CO2?
- hypoxemia makes the response more sensitive to CO2
- narcotics decrease response to CO2
- sleep - response is the same, but at a higher CO2 level (more tolerant of CO2)
- anesthesia decrease response to CO2
What does the pneumotaxic respiratory center do? What happens when it doesn’t work?
Regulates medullary respiratory output - switches off inspiration to regulate inspiratory volume
Dysfunction leads to deep, prolonged inspiration
What does the apneustic respiratory center do? What happens when it doesn’t work?
Regulates medullary respiratory output - excitatory effect on DRG and VRG to prolong ramp action potential
Dysfunction leads to shortened inspiration
What does the medullary respiratory center do? What happens when it doesn’t work?
Generates respiratory rhythm and is responsible for automatic control of respiration; dorsal respiratory group generates ramp action potentials and sends signals to diaphragm and other inspiratory muscles; ventral respiratory group generates rhythm and innervates the expiratory muscles (during quiet breathing, the VRG does not stimulate expiratory muscles)
Dysfunction leads to irregular breathing patterns and apnea (ataxic breathing)
What are the factors that influence the ventilatory response to O2?
- hypercapnia - increases response to decreased PO2
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What are the factors that influence peripheral and central chemoreceptors?
Peripheral chemoreceptors (aortic and carotid bodies) will stimulate breathing in the cases of low O2, high CO2, and low pH
Central chemoreceptors will stimulate breathing in the cases of high CO2 and low pH
What is eupnea?
normal, quiet breathing
What is tachypnea?
increased respiratory rate
What is hyperpnea?
increased respiratory rate and depth
What is dyspnea?
sensation of breathlessness; labored breathing
What is orthopnea?
dyspnea at rest while recumbent
What is Cheyne-Stokes respiration?
an abnormal pattern with waxing and waning tidal volume and periodic apnea due to a lack of coordination in central and local CO2 sensation; usually indicates a severe CNS disorder, causes central sleep apnea
What is Kussmaul breathing?
a regular rapid rate with large tidal volume, usually caused by metabolic acidosis
What is ataxic breathing?
highly irregular respirations, usually separated by long periods of apnea; usually seen with lesions to the medulla
What is apneusis?
prolonged inspirations separated by brief expirations
What is the Bötzinger Complex?
It is the rhythm generator in the ventral respiratory group of the medulla respiratory center (similar to pacemaker cells in the heart)
Stretch receptors in the lungs [stimulate/inhibit] medullary respiratory action.
inhibit
Irritant receptors in the lungs [stimulate/inhibit] medullary respiratory action.
inhibit
Irritant receptors in the lungs [stimulate/inhibit] medullary respiratory action.
inhibit
[Aortic/Carotid] bodies are more sensitive to hypoxia.
Carotid
What happens to respiration when PaCO2 is above 100 mmHg?
Respiratory response is reduced, leading to CO2 narcosis
What is the Hering-Breuer reflex?
Overinflation of lung stimulates slowly adapting stretch receptors to send signals to pneumotaxic center to terminate inspiration
The sneeze and cough reflexes are activated by [slowly/rapidly]-adapting stretch receptor stimulation
Rapidly-adapting
What is the function of J receptors?
Respond to interstitial edema and engorgement of pulmonary capillaries –> mediate closure of layrnx and apnea followed by rapid shallow breathing; also mediate tachypnea in response to pulmonary embolism
What are the functions of chest wall mechanoreceptors?
- detect impediments to breathing in the chest wall and stimulate increased inspiratory activity
- provides conscious sensation of respiratory movements to the cortex, allowing for voluntary breathing
