Task 5 Flashcards
What factors play in the human sensorimotor system?
The skeletal system, the spinal cord, brain stem and the higher brain regions
What does the skletal system have attached to itself?
skeletal muscles
what are skeletal muscles?
muscles connected by tendons
Where can bones move?
At joints
what are joints surrounded by?
a set of motor neurons
how do antagonist muscles pair up?
as flexors and externsors (biceps tricpes)
what are synergists?
muscles that work together for the same movement
what muscles are controlled by the autonomic nervous system?
smooth muscles and cardiac muscles
where are smooth muscles found?
in bronchi blood vessels stomach etc
where are cardiac muscles found?
only in the heart
what is contained in the skeletal or striated muscle?
extrafusal muscle fiber which controls the muscle´s contraction with the help of alpha motor neurons
what is the intrafusal muscle fiber sensitive to?
to muscle length
how does the intrafusal muscle fiber oinnervates contraction?
with the help of gamma motor neurons
from who does the intrafusal muscle fiber also gets infromation?
from mechanoreceptors like the parcian corpuscle
what does the parcian corpuscle reacts to?
vibration and pressure of skin
where are intrafusal musclzfibers found?
within muscle spindles
where are extrafusal muscle fibers found?
nuscle spindles on the outside
what is locate at the end of a muscle?
the golgi tendon organs which are also sensitive to stretch
what provides the force of contraction of the executed in the myofibril ?
long protein molecules actin and myosin
what happens when actin and myosin bind?
the muscle shortens and therefore contracts
what is a motor unit?
a motor neuron its axon and a muscle fibre
how do you measure a motor units activity
by the innervation ratio
what is the motor pool?
the muscle fiber a single motor neuron is connected to
what is every muscle fiber to?
a motor neuron but a motor neuron is connected with several muscle fibers
what is muscular dystrophy?
q disorder where a person suffers muscular atrophy
where is a contraction initiated?
at the neuromuscular junction
what is the neuromuscular junction?
point where the motor neuron and the muscle fiber meet
what happens when an action potential arrives?
voltage gated channels (ca2+) open releasing acetylcholine to the receptors of the muscle fiber leading to a reaction of the myofibril
what does isometric contraction and exercise imply?
that a joint and a muscle are not being moved hence a contraction strength is improved
what is a dynamic contraction?
change in mucgle legth and joint angle
which muscle fibers contract rapidly and fatigue readily?
Fast twitch muscle fibers
what muscle fibrs contract slowly and fatigue slowly too?
slow twitch muscle fibers
what factors play a role for the movement mechanism ?
accuracy and speed
what mechznism ensures accuracy of conscious or unconscious movement and how?
the closed loop control mechanism through error detection and error correction
what makes it possible to move more accurately as long as a negative feedback takes place?
the senosry feeback the stretch receptors in the golgi tendon and muscle spindle
what happens when the sensory feedback received is positive?
unlike negative feeback positive feedback doesn´t oppose a deviation but increases it
what does the open loop control mechanism imply?
ballistic movements
what are baliistic movements?
preprogrammed reflexes hence happen fast and unconscious
what does a reaction towards stimuli akways has to have?
an afferent part sensory neuron(passes info to the CNS) and an efferent part motor neuron (induces response to the stimulus
what is the stretch reflex or myotatic reflex?
a monosynaptic reflex
how does a stretch or myotatic reflex work?
the spinal cord regulates the muscle by getting the sensory information of an afferent neuron linking it directly to the excitatory efferent alpha motor neuron which is observable as the reflex
how are polysinaptic reflexes different to to monosynaptic reflexex?
they involve several neurons and are inhibitory or excitatory
why do relate excitatory and inhibitory with the polysinaptic reflex?
on the pathway of the polysynaptic reflex the senosry neurons bind to interneurons that either react excitatory or inhibitory
example of monosynaptic reflex?
ankle jerk reflex
example of polysinaptic reflec-x?
withdrawal reflex
what is recurrent collateral inhibition?
the inhibition of the interneuron renshaw cell in order to prevent an overreaction
what is reciprocal innervation?
the rebalancing muscle contraction of antagonistic muscles after unexpected loading
what is the central pattern generator?
the spinal cord
what does flaccid paralysis indicate?
loss of reflexes below the level of transection
what destroys motor neurons belonging to the spinal cord?
polioviruses
what is diagnosed when motor neurons in the brainstem and spinal cord die?
ALS amyotrophic lateral sclerosis
what is the pyramidal system or corticos^pinal system?
system that consists of four corticospinal tracts two dorsolateral and two ventromedial
what is induced by the two dorsolateral tracts?
limb movement of the contralateral side
what do the ventromedial tracts coordinate?
movement of the head eye upper legs and trunk thus proximal limb muscles
what are the names of the two dorsolateral tracts?
corticospinal and corticorubrospinal tracts
which dorsolateral tract goes directly from the brain to the spinal cord?
corticosipinal
what does the corticospinal tract ensure?
movements of wrist hands fingers and toes (distal muscles)
which of the two dorsolateral tracts is the indirect one?
the corticorubrospinal tract
what is the corticorubrospinal tract connected to?
to the red nucleus ( where its name comes from ) as well as to the nuclei of cranial nerve motor neurons . i e to the face muscles arms and legs
two names for the ventromedial tracts?
ventromedial corticospianl tract and ventromedial cortico-brainstem-spinal tract
which ventromedial tract is directly connected to the spinal cord?
the ventromedial corticospinal tarct
what dies the ventromedial corticospinal tract coordinate?
ipsilateral movement
what does the ventromedial cortico-brainstem-spinal tract introduce?
bilateral movements that are more diffused due to a higher amount of interneurons.
from who does the ventromedial cortico-brainstem-spinal tract receive information?
from the tectum reticular formation vestibular nucleus and motor nuclei of cranial nerves
in what can the sensorimotor system of the brain be divided into?
primary motor cortex and the secondary or non-primary motor cortices
what type of organization does the primary motor cortex has?
somatotopic organization
what does a somatotopic organization imply?
the activation of certain parts causes the execution of movements.
what are the neurons in the primary cortex even predisposed to?
for the direction of movement
what does the secondary motor system focuses more into?
planning and learning of movements
what is part of the secondary motor cortex?
the supplementary motor area
what information does the supplementary motor area receive?
info from the association are in the temporal and parietal lobe
what is the secondary motor cortex further involved in?
learning and preforming sequences of moovement that have yet to come
what does the pre SMA control?
spontaneous movements and voluntary behavior as well as being involved in unconscious processes for choosing the spontaneous movement
what is the motor association cortex or premotor cortex involved in?
planning of behavior imitating and function of behavior
from where does the premotor cortex receive info?
as the sma from the parietal and temporal lobes
what could be existent in the premotor cortex?
the so called mirror cells that some argue a lack of could be the cause of autism
what is the dorsolateral prefrontal cortex involved in?
planning of movements and directly receives all sensory information of the parietal lobe
what does the parietal lobe do?
organizes the interaction with the environment and collects the visual audiotry and spatial information
what other parts are involved in the sensorimotor system?
the basal ganglia, cerebellum and the brainstem
what is the cerbellum mainly responsible for?
motor and non motor learning thus corrects and coordinates movement
what does the brainstem cpntrol?
semiautomatic and automatic processes like respiratio sneezing coughing and vomiting
