Pulmonary Pt2 Flashcards
Where does the normal automatic process of breathing originate from?
The Brainstem
Neurons in which part of the brain control unconscious breathing?
Neurons in the medulla and pons in the brainstem
If voluntary control of breathing is needed, which part of the brain can override the medulla and pons?
The cortex
The automatic rhythm of breathing is controlled by neurons located where?
In the Respiratory nuclei of the medulla rhthymicity center.
inspiratory center
-(dorsal respiratory group)
•frequent signals, you inhale deeply
•signals of longer duration, breath is prolonged
expiratory center
(ventral respiratory group)
•involved in forced respiration
rate and depth control
Pons
pneumotaxic center (pons)
•sends inhibitory impulses to inspiratory center, as impulse frequency rises, breaths shorter, faster and shallower (turns of inspiration to prevent overinflation of lungs)
_______ is the reticular formation of the medulla beneath the floor of the fourth ventricle
medullary respiratory center
apneustic center (pons)
•promotes maximal lung inflation and long, deep breaths of Inspiration and expiration (turns off the pneumotaxic
Dorsal Respiratory Group (medullary resp center)
sets the basic respiratory rhythm
Ventral Respiratory Group (medullary resp center)
associated with forced respiration
Dorsal and Ventral Respiratory Groups’ cells have/responsible
•intrinsic periodic firing abilities and are responsible for basic rhythm of ventilation
Pre-Botzinger Complex (medullary resp center)
-(part of Ventral Group) = essential for generation of the respiratory rhythm
T/F Dorsal and Ventral Respiratory Groups’ cells, even when all afferent stimuli is abolished, these cells generate repetitive action potentials that send impulses to the diaphragm and other respiratory muscles
True
pneumotaxic center location/inhibits/limits
- located in upper pons
- inhibits inspiration
- limits the burst of action potentials in the phrenic nerve, effectively decrease the tidal volume and regulating the respiratory rate
Impulses from ____ and _____ modulate the output of inspiratory cells
the Vagus (X) and Glossopharyngeal (IX)
Input to Respiratory Centers from limbic system and hypothalamus
resp effects of pain and emotion
Input to Respiratory Centers from chemoreceptors
Resp effects of blood pH, CO2 and O2 levels
•Rate and depth of breathing adjusted to maintain levels of:
- pH
- Pco2
- Po2
what can exist in absence of pneumotaxic center
-“Fine tuning” of respiratory rhythm because a normal rhythm can exist in the absence of this center
primary stimulus for central chemoreceptors
pH of CSF
Apneustic center location/impulse/promotes/sends
- located in the lower pons
- Impulses have an excitatory effect on the Dorsal Respiratory Group in the medulla
- Promotes inspiration
- Sends signals to the Dorsal Respiratory Group in the medulla to delay the “switch off” signal provided by the pneumotaxic center
CO2 easily crosses
BBB
in CSF the CO2 reacts with water and releases
H+
the cycle of inspiration:
-Crescendo of action potentials leading to a ramp of strengthening inspiratory muscles
-
-Inspiration action potentials cease and inspiratory muscle tone falls
-
-Expiration occurs due to elastic recoil of lung tissues and chest wall
central chemoreceptors strongly stimulate
inspiratory center
“blowing off” CO2 pushes reaction to the
left
Input to Respiratory Centers from airways and lungs
and lungs
-irritant receptors in respiratory mucosa
•stimulate vagal signals to medulla, result in bronchoconstriction / coughing
-stretch receptors in airways - inflation reflex
•excessive inflation triggers stop of inspiration
•J-receptors - juxtapulmonary capillary receptors - increase rapid, shallow breathing
hypoventilation pushes reaction to the
right
ketoacidosis may be compensated for by _____ respirations
Kussmaul
peripheral chemoreceptors
-found in major blood vessels
>aortic bodies (signals medulla via C.N. X)
>carotid bodies (signal medulla by C.N. IX)
central chemoreceptors
-in medulla
>primarily monitor pH of CSF
>inc H+ stimulates ventilation
>dec H+ inhibits it
central chemoreceptors mediate ___ % of ventilatory response
80%
peripheral chemoreceptors mediate ____ % of ventilatory response
20%
normal pH of CSF
7.33
CSF has much less buffering capacity compared to blood, resulting in:
greater change in pH with changes in PCO2
•With _______ disease, the hypoxic drive to ventilation becomes very important
severe lung disease
most important peripheral chemoreceptors
carotid bodies