Exam #5 Ch. 14 part 2 Flashcards
what do spinocerebellar tracts carry?
proprioceptive information to the cerebellum
what do primary neurons from the thoracic and upper lumbar regions in spinocerebellar tracts do?
synapse in the posterior grey horn with secondary neurons that ascend in the posterior spinocerebellar tract without crossing over
what do primary neurons from the lower limbs and lowr lumbar regions in the spinocerebellar tract do?
synapse in the posterior grey horn with secondary neurons that may cross over and ascend in the spinocerebellar tract and those neurons
what happens to the primary neurons from the lower limbs and lower lumbar regions in the spinocerebellar tract that cross over?
they cross over again
what do primary sensory areas of the cerebral cortex receive?
sensory inputs
what does the primary somatic sensory cortex receive?
general sensory information from the thalamus
what is the general sensory information received from the thalamus in the primary somatic sensory cortex categorized by? (3) (LSP)
1) location of parts of the body on the cortex is the hornuculus
2) size of an area is related to the number of receptors
3) perception provides knowledge of the stimulus and its location
where is the taste area in the cerebral cortex?
in the insula lobe
where are the primary olfactory areas in the cerebral cortex?
in the medial temporal lobe
where is the primary visual cortex in the cerebral cortex?
the occipital lobe
where is the primary auditory cortex in the cerebral cortex?
in the temporal lobe
where does sensory processing occur?
in nearby association areas (evaluation and recognition)
what does the control of skeletal muscles by the motor system produce?
voluntary movements
what do voluntary movements use?
upper motor neurons
what do voluntary movements use upper motor neurons to control?
the lower motor neurons which control skeletal muscle
what does the primary motor cortex and nearby areas contain?
upper motor neurons that form the homonculus
what does the area size in primary motor cortex reflect?
motor unit size
what is the pre motor area?
where motor functions are planned and organized before the upper motor neurons are stimulated
what does the prefrontal area provide?
the motivation and foresight for movements
where are motor pathways located?
they descend from the primary motor cortex to the brainstem or spinal cord
what does the motor pathways descend from the primary motor cortex to the brainstem or spinal cord for?
to control skeletal muscle
what are motor pathways named for?
their origin and termination
what does the motor pathway, direct (pyramidal) pathway control?
muscle tone and precise movements
what does motor pathway, indirect (extrapyramidal) pathways provide?
less control of movements are involved with body coordination and posutre
in direct pathways what do upper motor neurons synapse on?
lower motor neurons
what does the direct pathway, cotricospinal tract control?
muscle below the head
what does the direct pathway, corticobulbar tract control?
muscles in the head and neck
in the corticobulbar tract where do the upper motor neurons synapse?
in cranial nerve motor nuclei
in direct pathways where do most of the upper motor axons cross over?
in the pyramids
in direct pathways, where do the upper motor axons that cross over synapse?
on interneurons and lower motor neurons
in direct pathways where do upper motor axons that don’t cross over travel?
down the anterior corticospinal tract
in direct pathways where do upper motor axons that don’t cross over after traveling down the anterior corticospinal tract?
in the spinal cord before synapsing with interneuorons and lower motor neurons
where do upper motor neurons of indirect pathways synapse?
in an intermediate nucleus in the brainstem with many internconnections and feedback loops
where do neurons of the rubrospinal tract begin? (indirect pathway)
in the red nucleus
what does the rubrospinal tract (indirect pathway) control?
fine motor movements of the distal upper limb
where does the reticulospinal tract (indirect pathway) begin?
in the reticular formation
what does the reticulospinal tract (indirect pathway) function to do?
maintain posture and balance
how does the reticulospinal tract maintain posture and balance?
by controlling the trunk and proximal limb muscles
where does the vestibulospinal tract (indirect pathway) begin?
in the vestibular nuclei
what does the vestibulospinal tract do?
provide control to maintain upright posture and balance
where is the rubrospinal tract located?
beetween the diencephalon and midbrain
what are the tracts of indirect pathways? (4) (RVRT)
1) rubrospinal
2) vesitbulospinal
3) reticulospinal
4) tectospinal
what is an example of movements controlled by the rubrospinal tract?
positioning of the digits and the palm of the hand when reaching to grasp
what is an example of a movement controlled by the vestibulospinal tract?
extension of the upper limb when falling
what is an example of a movement controlled by the reticulospinal tract?
maintenance of posture when standing on one foot
where does the indirect pathway, tectospinal tract begin?
at the superior colliculi
what does the tectospinal tract control?
reflex movements of the head and eyes to visual, tactile and auditory stimuli
what is an example of a movement controlled by the tactospinal tract?
movement of the head and neck away from a sudden flash or light
what do basal nuclei do?
organize and help start voluntary movements
what does the cerebellum do?
helps maintain muscle tone, control balance and adjusts movements to match intention
what type of circuits do basal nuclei produce?
some stimulatory and other inhibitory
what does the basal nuclei stimulatory circuits facilitate?
muscle activity especially at the beginning of voluntary movement (rising from a sitting position or beginning to walk)
what does the basal nuclei inhibitory circuits facilitate?
the actions of the stimulatory circuits
how do the inhibitory circuits of basal nuclei facilitate the actions of stimulatory circuits?
by inhibiting muscle activity in antagonist muscles
what else does inhibitory circuits of basal nuclei do?
decrease muscle tone when the body, limbs and head are at rest
what do disorders of basal nuclei result in?
increased muscle tone and exaggerated, uncontrolled movements when at rest
what is a significant feature of some basal nuclei disorders?
a resting tremor
what are examples of basal nuclei disorders?
parkinsons and cerebral palsy
what are the 3 functional parts of the cerebellum? (VPC)
1) vestibulocerebellum
2) spinocerebellum
3) cerebrocerebellum
what does cerebellum dysfunction result in? (4) (DBTI) (4) (DBTI)
1) decreased muscle tone
2) balance impairment
3) a tendency to overshoot when reaching for or touching an object
4) intention tremor (shaking in hands while attempting to perform a task)
though the cerebellum and basal nuclei both control motor function what differs about them?
they have opposite effects and exhibit opposite symptoms when injured (resting tremor vs. intention tremor)
what does the reticular activating system (RAS) of the brainstem regulate?
the brain’s level of consciousness
what do brainstem nuclei control?
many reflexes (eyes, chewing, pupil diameter etc.)
what can depress or stimulate the RAS?
certain drugs
what drugs depress the RAS?
general anesthetics and many traquilizers
what stimulates the trigeminal nerve endings of the nose?
ammonia (smelling salts) and other irritants
what is a result of the stimulation of trigeminal nerve endings of nose by ammonia or other irritants?
action potentials travel to the reticular formation and the cerebral cortex to arouse an unconscious patient
what does the sensory (wernicke) speech area work to do?
understand and formulate speech
what does the motor (broca) speech area control?
the movements to make speech
what is memory?
the ability to store information for future use
what does working memory store?
bits of information for immediate use
what does short-term memory store?
information for minutes to days
how does short-term memory occur?
by long-term potentiation that facilitates the production of action potentials
what does long-term memory store?
information for a long time
how does long-term memory occur?
by consolidation in which new synaptic connections are formed
where are memories stored?
piecemeal in appropriate cerebral regions
