Flashcards in Pgs 21-31 Deck (39):
The ________________________ consists of a diffuse collection of neurons that extend throught the central core of he brainstem, from the medulla to the midbrain.
What does the nerve-net of the reticular formation control?
1) Levels of consciousness and alertness, sleep/arousal cycle
2) Awareness and spreading of pain (ARAS)
3) Control of lower motor neurons
4) Autonomic functions
Lesions in the ARAS or upper brainstem area can cause _______.
_____________ syndrome can be caused by damage to the descending reticulospinal fibers that synapse on the preganglionic sympathetic neurons that control the activity of the superior cervical ganglia.
T/F - Coma can be caused by lesions in the reticular activating system of the brainstem, certain areas of the thalamus, or both hemispheres.
Where is the primary motor cortex?
Precentral gyrus (anterior portion) & paracentral lobule
What is the area for final processing and execution of cortical motor commands?
Primary motor cortex
Where is the premotor cortex located?
Anterior to the precentral gyrus
Where is the supplementary motor cortex located?
Anterior to the paracentral lobule
Premotor and supplementary motor are more involved in motor planning and programming. They send many fiber to the ___________________ cortex.
Where is the primary somatosensory cortex?
Postcentral gyrus & posterior portion of the paracentral lobule
What artery supplies the blood to the precentral gyrus?
Middle cerebral artery
What artery supplies the blood to the paracentral lobule?
Anterior cerebral artery
What would happen if there was an occlusion to the middle cerebral artery?
Paralysis of the contralateral arm, hand, and lower face
What would happen if there was an occlusion to the anterior cerebral artery?
Paralysis of the contralateral leg and fot
What artery gives rise to the middle and anterior cerebral arteries?
What is the tract that descends from the cerebral cortex that synapses on LMN in the spinal cord?
Corticospinal tract (of the pyramidal system)
What is the primary pathway responsible for fine, discrete, skilled movements of the hand and fingers?
More than half of the corticospinal tract fibers end in the ______________________ cell column.
Lateral motor cell column
Where does corticospinal tract cross?
Pyramid of the medulla
Corticobulbar tract fiber run from the cerebral cortex to the __________________.
What LMN come from the corticobulbar tract?
V, VII, IX, X, and XII
All of the corticobulbar fibers mostly distribute bilaterally to the cranial nuclei on both sides of the brainstem except the _____________ nucleus.
Facial - VII
T/F - Corticobulbar fibers distribute bilaterally to LMN of the facial nucleus for the upper face but only contralaterally to the LMNs of of the facial nucleus for the lower face.
Is the corticobulbar tract directly involved in the control of eye movements?
Damage to the corticobulbar tract on one side (cortex, internal capsule, crus cerebri, part of pons) will result in ______________ paralysis of the ________ face.
Contralateral paralysis of the lower face
Damage to the LMNs in the facial nucleus or facial nerve results in ________________ paralysis of ______________________ of the face.
Ipsilateral paralysis of both upper and lower face
What are the fibers from the cell bodies in the brainstem that descend and synapse near or on the lower motor neurons?
Extrapyramidal system of UMNs
T/F - The overall affect of most of the extrapyramidal tracts is bilateral.
What is the extrapyramidal tracts primarily involved in?
Movements of unskilled nature
Posture, tone, balance, and reflexes used to maintain an upright posture, orienting movements of the head and neck, and automatic gait-related movements
What are the 5 different extrapyramidal tracts?
1) Rubrospinal tract
2) Pontine reticulospinal tract
3) Medullary reticulospinal tract
4) Lateral vestibulospinal tract
5) Medial vestibulospinal tract
Which of the extrapyramidal UMNs crosses in the midbrain?
Which of the extrapyramidal UMNs is bilateral?
Medial vestibulospinal tract
Only the __________________ tract is responsible for fine hand movements (independent fingers) and precision grip.
Lateral corticospinal tract
Will fine hand movements ever recover if there is damage to the pyramidal system (lateral corticospinal tract)?
What are some signs/symptoms that there has been UMN damage?
1) Paralysis or weakness of voluntary movements
2) Babinski sign appears while superficial refelxes disappear (cremasteric, abdominal)
3) Increased deep tendon reflexes - loss of inhibitory effect of LMNs on reflexes
4) Increased muscle tone - claspknife and clonus
5) Spasticity - spastic paralysis - slow, disuse atrophy
What will happen if both the corticobulbar and corticospinal fibers are cut before they both cross?
Contralateral paralysis of both the body and face
What will happen if there is a cut just at the corticospinal tract before the cross?
Contralateral body paralysis