13.5- Brainstem Flashcards
What does the brainstem connect?
Cerebrum, diancephalon, and cerebellum.
Midbrain- other name
Mesencephalon- superior portion of the brain stem
Cerebral peduncle- location
Anterolateral surface of midbrain
Motor tracts
Superior cerebral peduncles
Connect the midbrain to the cerebellum.
Substantia Nigra
Bilaterally symmetric nuclei in the midbrain.
Almost black appearance due to melanin pigmentation
Houses cluster os neurons that produce the neurotransmitter dopamine (which controls movement, emotional response, and ability to experience pleasure and pain)
Degeneration here is connected to Parkinson’s.
Tegmentum
Sandwiched between the substantial nigra and the periaquiductal gray matter.
Pigmented red nuclei and reticular formation.
Red is due to blood vessel density and iron pigmentation
Integrates info from cerebrum and cerebellum and issues involuntary motor commands to the erector spinae muscles of the back.
Maintains posture, standing, bending at the waist, and walking.
Cerebral aqueduct
Extend through the midbrain.
Connects the third and fourth ventricles
Surrounded by periaquiductal gray matter.
Houses the nuclei of the oculomotor (III) and trochlear (IV) nerves.
Tectum
Most posterior region of the midbrain.
Contains the superior and inferior colliculi (called tectal plate)
Relay stations in the pathway of visual and sensory auditory input.
Superior colliculi
Visual reflex centers
Help track moving objects and control reflexes like turning eyes and head in response to visual stimulus
Inferior colliculi
Auditory reflex centers
Control reflexes that turn head and eyes toward source of loud.
Pons
Bulging part of the brain stem
Contains sensory and motor tracts
Middle cerebral peduncles
Transverse axons that connect the pons the the cerebellum.
Pontine respiratory center
Respiratory center housed in the pons. Controls skeletal muscle breathing.
Regulates smooth transition between inhalation and exhalation.
Superior olivary nuclei
Located in the inferior portion of the pons.
Receives auditory input and is responsible for sound localization.
What other nerves do the pons house?
trigeminal V, abducens VI, facial VII
Mudula oblongata
Most inferior part of the brain stem.
All communication between brain and spinal cord involve tracts that pass thought this region.
Pyramids
Two ridges on the anterior side of the medulla oblongata.
House motor projection tracts
Decussation of the pyramids
Anterior point in the medulla where most of the axons of the pyramidal tract cross to the opposite side of the brain.
This is why the brain controls opposite sides of the body.
Olive
Bulge immediately lateral to the pyramids
Contains large folds of gray matter called the inferior olivary nucleus.
Olivary nucleus
Relay ascending nerve signals- especially proprioreceptive info the the cerebellum.
Inferior cerebral peduncles
Paired with olivary nuclei-tracts that connect the medulla oblongata to the cerebellum.
Medullary respiratory center
Made up of ventral and dorsal respiratory groups.
Groups influence by the pontine respirator center.
Causes breathing.
This area also controls coughing, sneezing, salivation, gaging, and vomiting reflexes.
What cranial nerves does the medulla oblongata contain?
Vistibulocochlear VIII, glossopharyngeal IX, vagus X, accessory XI, and hypoglossal XII.
Nucleus cuneatus and nucleus gracilis.
Contained in the Medulla
