Nervous System V: Brain II Flashcards
what pases through the brain stem?
-nerve fibers pass from the cerebral hemispheres to the spinal cord through this
brain stem components
- diencephalon
- midbrain
- pons
- medulla oblongata
diencephalon components
- thalamus
- hypothalamus
thalamus location
-superior to midbrain (beneath corpus callosum)
thalamus function
-contains neurons that act as relay center for all sensations except smell
hypothalamus location
-inferior to thalamus
hypothalamus function
- nuclei control sleep/wake cycle
- controls eating
- controls ANS
midbrain location
-superior to pons
midbrain components
- auditory and visual reflex centers of the head and neck
- inferior to hypothalamus
- nuclei of cranial nerves
pons location
-superior to medulla oblongata
pons components
- part of respiratory center
- bridges cerebellum
- nuclei of cranial nerves
medulla oblongata location
- inferior most portion of brain stem
- at level of foramen magnum
medulla oblongata components
-cardiovascular centers, motor, and sensory decussation of nerve fibers
reticular activating center
- aka RAS
- column of neurons
- located in the middle of brain stem from the thalamus to the medulla
what happens when the RAS is damaged?
-may result in a coma
cerebellum
- found on posterior aspect of the brain stem
- coordinates movement (i.e. controls flec/extensor muscles)
types of tracts/pathways
- dorsal column
- corticospinal tract
dorsal column pathway type
-medial lemniscus pathway
dorsal column components
- medial lemniscus
- fasciculus gracilis and cutaneous
dorsal column origin
-spinal cord
dorsal column decussation
-medulla
dorsal column destination
-area 3, 1, 2
corticospinal tract pathway type
-descending motor pathway
what is the difference between sensory impulses and motor signals?
-motor signals pass from the cortex to the spinal cord without synapsing
what two neurons is the innervation of the skeletal muscle dependant on?
- upper motor neurons
- lower motor neurons
upper motor neurons function
- cell body located in the gray matter of the cortex (precentral gyrus)
- its axon synapse on a lower motor neuron
lower motor neurons function
- cell body is the brainstem or spinal cord
- its axons synapse on skeletal muscle fibers
branches of the right middle cerebral artey cupply which of the precentral gyruses?
-leftside, upper, and motor
branches of the left anterior cerebral artery supply which posterior gyruses?
-rightside, lower limb, parietal