Lecture 15 Unit 2 Flashcards
how do respiratory and skeletal muscles contract?
by the action of motor neurons
unlike other skeletal muscles, the respiratory muscle are under both______?
automatic and voluntary control
what does automatic respiratory muscle control depend on?
groups of inspiratory and expiratory neurons in the medulla oblongata
where are phrenic motor neurons located?
C3-C5 spinal segments
where are inspiratory neurons localized into?
a functional group known ad the dorsal respiratory group (DRG)
where are expiratory neurons located?
ventral respiratory group (VRG)
what are pre motor neurons?
they synapse on and excite motor neurons to respiratory muscles
since breathing is rhythmic, what does it depend on?
“pacemaker like” activity in brain stem neurons that alternately turn the inspiratory neurons on and off
when are expiratory neurons activated?
when breathing activity must be increased
what happens in the pneumotaxic center
negative effect (inhibition)
what happens in the apneustic area?
positive effect (stimulation)
where are the DRG and VRG located in the brain
pons and medulla
what are the various specialized receptors that inform the neurons about the body’s needs for ventilation?
- pulmonary stretch receptors
- central chemoreceptors
- peripheral chemoreceptors
where are pulmonary stretch receptors located?
in the msotth msucle that lines some of the large conducting airways, bronchi, and bronchioles
what do pulmonary stretch receptors respond to?
when bronchioles are inflated or stretched
