Lecture 11 2/5/24 Flashcards
What are the three major parts of the respiratory control system?
-central controller: pons, medulla, other parts of brain
-effectors: resp. muscles
-sensors: chemoreceptors, lung, etc.
What type of control does the brainstem have over respiration?
unconscious control
What type of control does the cerebral cortex have over respiration?
voluntary control
What are the four primary centers of the brainstem for respiratory control?
-dorsal resp. groups (medulla)
-ventral resp. groups (medulla)
-apneustic center (caudal pons)
-pneumotaxic center (rostral pons)
What are the characteristics of the dorsal respiratory group?
-involved in inspiration/inspiratory rate
-helps set basic rhythm of breathing
-output travels to diaphragm via phrenic nerve
-input received form vagal and glossopharyngeal nerves
-inhibited by pneumotaxic center
What are the characteristics of the ventral respiratory group?
-mainly involved in expiratory function
-sends inspiratory impulses to laryngeal and pharyngeal muscles, diaphragm, and external intercostals
-sends expiratory impulses to abdominal muscles and internal intercostals
-pre-Bötzinger complex regulates respiratory rhythm
What are the characteristics of the apneustic center?
-involved in deep inspiration
-lower pons
-prevents inspiratory neurons from being switched off
-prolongs inspiration
-shortens expiration
-held in check by vagal and pneumotaxic center impulses
What are the characteristics of the pneumotaxic center?
-inhibit inspiration
-upper pons
-inhibits impulses to medullary inspiratory neurons
-controls length of inspiration
What will a strong pneumotaxic center signal do?
-increase resp. rate
-shorten inspiration and expiration
-lower tidal vol.
What will a weak pneumotaxic center signal do?
-prolong inspiration
-increase tidal vol.
What are the characteristics of the cerebral cortex?
-voluntary control of respiration
-allows for hyperventilation and hypoventilation
What are the characteristics of pulmonary stretch receptors?
-inspiration reflex
-inflation of lungs stops inspiration
-deflation of lungs brings on inspiration
-slowly adapting
What are the characteristics of the Hering-Breuer reflex?
-lung stretch sends inhibitory signals through vagus to DRG
-most important during increased tidal vol.
-stops inspiration and increases expiration
What happens when a disease decreases compliance and increases elasticity?
-more stretch receptor stimulation
-increased resp. rate
What are the characteristics of irritant receptors?
-rapidly adapting
-impulses travel up vagus nerve
-stimulation leads to clearance responses
What are the characteristics of peripheral chemoreceptors?
-located at carotid and aortic bodies
-signals travel via vagus nerve to aortic bodies and glossopharyngeal nerve to carotid
-release neurotransmitters in response to hypoxia
-increase heart rate
What is detected by peripheral chemoreceptors?
-elevations in CO2 and H+ (low pH)
-lower PaO2
Why is CO2 said to act as an acid?
high CO2 will lead to greater production of H+ ions
What are the characteristics of central chemoreceptors?
-located in medulla
-surrounded by CSF
-monitor pH and CO2 levels in the CSF
-CO2 is most important
-does not respond to changes in PaO2 directly
What is the ventilatory response to increased CO2?
increased breathing to expel CO2
