Medullary Reflexes Flashcards
What 2 centers control respiration?
- Apneustic center
- Pneumotaxic center
Where is the pneumotaxic center found?
In the pons
Where is the apneustic center found?
In the medulla
Which respiratory center sends stimulation to the inspiratory area?
Apneunstic
Which respiratory center inhibits the inspiratory area?
Pneumotaxic
Which respiratory center causes long deep breaths?
Apneustic
Which respiratory center fine tunes respiration?
Pneumotaxic
How do the respiratory groups in the medulla reach somatic innervation in the body, how does the body communicate back?
- Reticular spinal tracts go to the cervical cord
- Travel by the phrenic nerve to diaphragm and intercostal muscles
- Afferents from alveoli through CN X go to the solitary nucleus, which triages input
What type of reflex is respiration?
Visceral-somatic
Describe the pathway of baroreceptor and chemoreceptor reflexes.
- BP changes/ CO2 changes stimulating baro/chemoreceptor
- Baroreceptors travel up CNs IX or X
- Go to solitary nucleus
- Decrease contractility of heart and blood vessels through the vagal nerve (CN X)
What type of reflex is the baro/chemoreceptor reflex?
Visceral-visceral
Vagal-Vagal
Describe the pathway of a cough reflex.
- GVA info from the trachea, larynx, or pharynx travel to the nucleus solitarius via CN X
- Solitary nucleus projects to upper respiratory centers to activate pneumotaxic center
- Pneumotaxic center causes forced expiration (at diaphragm, intercostals, and abdominals)
- Nucleus ambiguus contracts larynx and pharynx
What initiates vomiting? Where is this structure found?
- Area postrema
- Floor of 4th ventricle
How does the area postrema cause vomiting?
- Stimulation of AP triggers reflex
- Signal projects to reticular formation
- Travels down vagus nerve to contract contents of stomac (also relaxing gastroesophageal sphincter)
- Travels down cord to abdominal muscles to contract
What type of reflex is the vomit reflex?
Visceral-visceral and visceral-somatic
What nerve do the afferents causing the vomiting reflex travel?
CN X
What type of reflex is the pupillary reflex?
Somatic-visceral
How is pupil dilation changed in the pupillary reflex of the medulla?
Touch/ pain receptors of skin in face
What nerve supplies the afferent component of the papillary reflex? What structure do the afferents synapse on?
- CN V
- Reticular formation
Describe the efferent component of the pupillary reflex.
- Descends down cord from RF
- Stimulates betacell in lateral horn (Sympathetic)
- Enters superior chain ganglion
- Contracts muscle in eye
What type of reflex is the carotid-sinus reflex?
Visceral-visceral
What nerve carries the afferent fibers of the carotid-sinus reflex? What structure does it synapse on?
- CN IX
- Reticular formation
- Dorsal motor nucleus of CN X
AND - Nucleus ambiguus
What nerve carries the fibers from the nucleus ambiguus and motor nucleus of CN X to the heart to reduce contractility in the carotid sinus reflex? Where does the nerve synpase?
CN X
- On SA and AV nodes, and atrial muscle
What nervous system is used to dilate blood vessels in the carotid-sinus reflex?
Sympathetic
