Lecture 4: Brainstem Flashcards
What are the divisions of the brainstem?
Midbrain (Mesencephalon)
Pons and cerebellum (Metencephalon)
Medulla (Myelencephalon)
What is the dorsal midbrain called? Ventral?
Tectum
Tegmentum
What is found within the tectum?
2 rostral colliculi
2 caudal colliculi
What does the rostral colliculi do?
Visual reflex activity
What does caudal colliculi do?
Auditory reflex activity
What are the motor tracts originating from the brainstem?
Rubrospinal tract Pontine reticulospinal tract Medullary reticulospinal tract Vestibulospinal tract Tectotegmentospinal tract Tectospinal tract
What does the pontine reticulospinal tract go to?
Extensor muscles
What does the medullary reticulospinal tract go to?
Flexor muscles
What does the tectotegmentospinal tract do?
SANS to T1-2 to sympathetic trunk for pupillary dilation
What does the tectospinal tract do?
Reflex auditory and visual activity to muscles of neck to turn head
What is the motor tract originating from the cerebral cortex?
Corticospinal tract
What is the path of the corticospinal tract down the brainstem?
Corona radiata Internal capsule Crus cerebri Longitudinal fibers of the pons Pyramids
What are the functions of the reticular formation?
Wakefulness/ARAS
Motor function
Respiratory and cardiovascular control
Urination
Describe wakefulness/ARAS
Nonspecific thalamic nuclei
Diffuse cortical projection system
What tracts are involved with motor function controlled by reticular formation?
Pontine and medullary reticulospinal tract
What do chemoreceptors from carotid (CN 9) and aortic (CN 10) bodies do?
Increase respirations in response to decreased PaO2 or increased PaCO2
What do baroreceptors from carotid sinus (CN 9) and aortic arch (CN 10) do?
Regulate heart rate and vascular resistance in response to blood pressure
What controls the parasympathetic innervation of urination?
Pontine micturition center
What controls the sympathetic innervation of urination?
Medullary micturition center
Describe the pontine micturition center
PSANS, sacral cord to pelvic nerve to contract detrusor muscle for voiding
Describe medullary micturition center
SANS, TL cord to hypogastric nerve to inhibit detrusor muscle and excitatory to bladder neck for filling
