Chapter 8 Movement Flashcards
aerobic
movements that require oxygen
anaerobic
proceeding without using oxygen at the time of a reaction
antagonistic muscles
Antagonistic muscles
opposing sets of muscles that are required to move a leg or arm back and forth
antisaccade task
Antisaccade task
a voluntary eye movement away from the normal direction
Babinski reflex
Babinski reflex
the extension of the big toe and fanning of the others, by an infant, when the sole of the foot is stroked
Ballistic movements
Ballistic movement
motion that proceeds as a single organized unit that cannot be redirected once it begins
Cardiac muscles
Cardiac muscles
muscles of the heart that have properties intermediate between those of smooth and skeletal muscles
Caudate nucleus
Caudate nucleus
large subcortical structure, part of the basal ganglia
Central pattern generators
Central pattern generators
neural mechanisms in the spinal cord that generate rhythmic patterns of motor output
Cerebellar cortex
Cerebellar cortex
the surface of the cerebellum
Corticospinal tracts
Corticospinal tracts
paths from the cerebral cortex to the spinal cord
extensor
Extensor
muscle that straightens the limb
Fast-twitch Fibers
Fast-twitch fibers
muscle fibers that produce fast contractions but fatigue rapidly
Flexor
Flexor
muscle that flexes the limb
Globus Pallidus
Globus pallidus
large subcortical structure; part of the basal ganglia
Golgi tendon organs
Golgi tendon organs
receptors that respond to increases in muscle tension; inhibit further contractions
Grasp reflex
Grasp reflex
a reflexive grasp of an object placed firmly in the hand
Huntingtin
Huntingtin
protein produced by the gene whose mutation leads to Huntington&rsquos disease
Huntington’s disease
Huntington’s disease
a severe neurological disorder characterized by jerky arm movements and facial twitches and later by tremors, writhing movements, and psychological symptoms
L-dopa
L-dopa
chemical precursor to dopamine
Lateral corticospinal tract
Lateral corticospinal tract
a set of axons from the primary motor cortex, surrounding areas, and midbrain area that is primarily responsible for controlling the peripheral muscles
Medial corticospinal tract
Medial corticospinal tract
set of axons from many parts of the cerebral cortex, midbrain, and medulla; responsible for control of bilateral muscles of the neck, shoulders, and trunk
Mirror Neurons
Mirror neurons
cells that are active during a movement and while watching someone else perform the same movement
Motor Program
Motor program
a fixed sequence of movements
MPP1
MPP1
a chemical that accumulates in, and then destroys, neurons that release dopamine
MPTP
MPTP
a chemical that the body converts to MPP1
Muscle spindle
Muscle spindle
a receptor parallel to the muscle that responds to a stretch
Neuromuscular junction
Neuromuscular junction
a synapse between a motor neuron axon and a muscle fiber
Neurotrophin
Neurotrophin
a chemical that promotes the survival and activity of neurons
Nuclei of the cerebellum
Nuclei of the cerebellum
clusters of cell bodies in the interior of the cerebellum
Parkinson’s disease
Parkinson’s disease
malady caused by damage to a dopamine pathway, resulting in slow movements, difficulty initiating movements, rigidity of the muscles, and tremors
Posterior parietal cortex
Posterior parietal cortex
area with a mixture of visual, somatosensory, and movement functions, particularly in monitoring the position of the body relative to objects in the world
Premotor cortex
Premotor cortex
area of the frontal cortex, active during the planning of a movement
Primary motor cortex
Primary motor cortex
area of the prefrontal cortex just anterior to the central sulcus; a primary point of origin for axons conveying messages to the spinal cord
Proprioceptor
Proprioceptor
a receptor that detects the position or movement of a part of the body
Purkinje cell
Purkinje cell
flat cells in sequential planes, in the cerebellar cortex, parallel to one another
Putamen
Putamen
large subcortical structure, part of the basal ganglia
Readiness potential
Readiness potential
recordable activity in the motor cortex prior to voluntary movement
Red nucleus
Red nucleus
a midbrain area that is primarily responsible for controlling the arm muscles
Reflexes
Reflexes
automatic muscular responses to stimuli
Rooting reflex
Rooting reflex
when an infant&rsquos cheek is touched, the infant turns toward the stimulated cheek and begins to suck
Skeletal (striated) muscles
Skeletal (striated) muscles
muscles that control movement of the body in relation to the environment
Slow-twitch fibers
Slow-twitch fibers
muscle fibers that have less vigorous contractions and no fatigue
smooth muscles
Smooth muscles
those that control the digestive system and other organs
stem cells
Stem cells
undifferentiated cells that divide and produce daughter cells that develop more specialized properties
Stretch reflex
Stretch reflex
a reflexive contraction of a muscle in response to a stretch of that muscle
Substantia nigra
Substantia nigra
a midbrain structure that, similar to schizophrenia, gives rise to a pathway releasing dopamine
Supplementary motor cortex
Supplementary motor cortex
area of the frontal cortex; active during preparation of a rapid sequence of movements
Vestibular nucleus
Vestibular nucleus
cluster of neurons in the brainstem, primarily responsible for motor responses to vestibular sensation
list three categories of muscle.
smooth muscle
cardiac muscle and
skeletal muscle
What is the transmitter at the neuromuscular junction?
neuromuscular junction- synapse between a n=motor neuron axon and a muscle fiber
acetylcholine is the transmitter and acetycholine excites the muscles to contract a deficit of acetylcholine or its receptors impairs movement
Describe the symptoms and cause of myasthenia gravis
a condition causeing abnormal weakness of certain muscles (skeletal)
autoimmune
defect in the transmission of never impulses to muscles
What are two types of treatment for myasthenia gravis?
acetylcholinesterase agents (drugs) such as neostigmine and pyridostigment
these help improve muscular transmission
immunosuppressive drugs–prednisone, cyclosporin etc.
improve muscle strength by suppressing the production of abnormal abs.
List the types of functions of skeletal muscle in fish
3 types of muscles: red, pink and white
Red produces slowest movement
White is the fastest movement but fatigue rapidly
Pink is intermediate
High temp fish rely on red and pink muscles
Low temp they rely on white muscles to maintain its speed
How are mammalian muscles different from those of fish?
8.1
have various kinds of muscle fibers mixed together and not in separate bundles as in fish
Our own muscles range from fast twitch fibers to slow twitch fivers with less vigorous contractions and no fatigue
Contrast muscles of sprinters and marathon runners
Sprinters fast twitch fibers (AnO2)
Marathon runners slow twitch fibers (o2)
8.1
What is a proprioceptor?
receptor that detects the position or movement of a part of the body like muscles
a stretch reflex is caused by a stretch-when a muscle is stretched, the spinal cord sends a reflexive signal to contract it
What is a muscle spindle? What is its effect on the spinal motor neuron that innervates its associated muscles?
muscle spindle is a kind of proprioceptor-a receptor parallel to the muscle that responds to stretch
Whenever the muscle spindle is stretched its sensory nerve sends a message to a motor neuron in the spinal cord which in turn sends a message back to the muscles surrounding the spindle causing a contraction
Explain the knee-jerk reflex
Tap on your knee-stretches your extensor muscles of the leg.
The sensory nerves of the spindles send action potentials to the motor neuron in the spinal cord and the motor neuron sends action potentials to the extensor muscles
What is the golgi tendon organ? What is its effect on the spin motor neuron that innervates its associated muscle? What is its functional role?
they are also proprioceptors and they respond to increases in muscle tension.
located in the tendons at opposite ends of the muscles they act on as a brake against an excessively vigorous contraction
-golgi tendon organ detects the tension during muscle contraction impulse travels to spin cord-excite motor
the internurons that inhibits the motor neurons
i.e. a vigorous muscle contraction inhibits the further contractions by activating the golgi tendon organs
What is a reflex?
automatic response to stimuli
and are involutary
Describe some of the involuntary components of “voluntary’ behaviours, such as walking or talking
compensate for uneven bumps in the road
What is ballistic movement?
a movement that is scented as a whole
once initiated it cannot be altered
eg reflexes are ballistic
What is a motor program? Give examples of “built-in” and learned motor programs
fixed sequence of movements is called a motor program
e.g. drop a chicken and it flaps its wings.
Do humans have any built-in motor patterns
yes we do:
yawning
smiles and frowns
Describe the role of primary motor cortex in the control of movement.
direct electrical stimulation of primary motor cortex the pre central gyrus of the frontal cortex just anterior to the central sulcus- elicits movements
- the motor cortex does not send messages directly to muscles
- its axons extend to the brainstem and spinal cord which generate imposes that control the muscles
to what two processes do neurons in the posterior parietal cortex respond?
posterior parietal cortex-area keeps track of the positions of the body relative to the world
-also important for planning movement
Damage-people have trouble finding objects in space- walking and bumping into things is an example
Describe the roles of the prefrontal, premotor, and supplementary motor cortex.
prefrontal cortex and supplementary motor cortex- also impt for planning and organizing a rapid sequence of movements (note: posterior parietal cortex has this function as well)
premotor cortex-most active immediately before a movement
-receives information about the target to which the body is directing its movement as well as bodies current posture
Where does the dorsolateral tract begin? Where does it cross from one side to the other?
begins in the midbrain (near the pons)
cross in the medulla behind bottom of pons
a set of axons from primary motor cortex and red nucleus
a midbrain area controls arm muscles
corsses over in the bulges of the medulla called the pyramids
From what structures doe the ventromedial tract originate? What is the relationship between this tract and the two sides of the spinal cord?
connects to the cerebral cortex to the spinal cord
inclides axons from many parts of the cerebral cortex and surrounding area-also includes axons from midbrain tectum, the reticular formation and the vestibular nucleus
axons of medial tract go to both sides of the spinal cord
controls mainly muscles of the neck, shoulders and trunk.
Which movements are controlled by the dorsolateral tract and which by the ventromedial tract?
dorsolateral tract controls precise and discreet movements of extremities such as hands, finger and feet
medial tract-cintrols trunk muscles for postural adjustments and bilateral movements such as standing and bending turning and walking.
What kinds of movements are especially affected by cerebellar damage?
-rapid movements that require aim, timing and alternation of movements
eg have trouble tapping a rhythm clapping hands typing, writing, playing a musical instrument.
What are saccades? Describe the effects of cerebellar damage on the control of saccades?
ballistic eye moments from one fixation point to another
- depends on impulses form the cerebellum and the frontal cortex to the cranial nerves
- someone with cerebellar dame has difficulty programming the angle and distance of eye movement
Describe the motor control required to touch he’s finer to one’s nose as quickly as possible.
normal person three steps: 1. the finger moves ballistically to a point just in front of the nose (this move relies on the cerebellar cortex which sends messages tot he deep nuclei (clusters of cell bodies)
- the finger remains steady at that spot for a fraction of a sec (depends on nuclei alone
- finally finger moves to nose–does not depend on cerebellum.
Why may a place officer use the finger to nose test to check for alcohol intoxication?
resembles damage to cerebellar damage
clumsiness slurred speech and inaccurate eye movements
Describe the evidence for a broad role for the cerebellum, beyond motor performance.
MRI measured cerebellar activity when people lifted objects–showed little activity
But when they felt things with both hands to decide wether they were the same or not=the cerebellum was much more active
From what sources does the cerebellum receive input? To which structures do its output fibbers project?
receives input form spinal cord from each of the sensory systems by way of the cranial nerve nuclei and from the cerebral cortex. (the surface of the cerebellum)
Describe the relationship between the purkinje cells and the parallel fibbers. How does this affect movement?
Purkinje cells are flat cells in sequential planes parallel to one another.
Parallel fivers are axons parallel to one another and perpendicular to the planes of the Purkinje cells.
-Depending on how many fibbers are active-they may only stimulate a few Purkinje cells or they may excite a great #of cells greater response.
What structures comprise the basal ganglia?
group of large subcortical structures in the forebrain includes: caudate nucleus putamen and globus pallidus
which are the main receptive areas? the main output areas ? Where does the sensory input come from and where does the output go? In reference to basal ganglia
Cerebral cortex => caudate nucleus AND putamen =>Globus pallidus (releases GABA–which is an inhibitory transmitter)=> Thalamus and Midbrain => and from thalamus foes to motor and prefrontal areas of the cerebral cortex.
What is the role of the basal ganglia in the learning of motor patterns?
helps convert new movements into smooth automatic responses
the basal ganglia are essential for learning motor habits that are difficult to describe in words
How does cerebellar function compare with that of the basal ganglia?
cerebellum-multiple roles in behaviour including sensory functions relating to perception of timing or rhythm
Basal ganglia-important for selecting and inhibiting particular movements
Damage=jerky involuntarily movements
Describe the symptoms of Parkinsons Disease
rigidity muscle tremors slow movements difficulty initiating physical and mental activity slow on cognition loss of olfaction early symptom (smell)
What is its immediate cause? (parkinsons disease)
What is the result of loss of dopamine stimulation of D2 receptors in the caudate nucleus and putamen?
gradual progressive death of neurons esp in the substantial nigra which sends dopamine-releasing axons to the caudate nucleus and the putamen.
Parkinsons patients lose their axons and therefore dopamine
Net result of loss is decreased activity in the thalamus and therefore also other areas of the cerebral cortex.
How strong is the evidence for a genetic predisposition for Parkinsons disease?
there is a link to some genes that may cause early onset Parkinsons (i.e. before 50) but is weak for the more common late onset patients.
How did the experience with a heroin substitute lead to suspicion of an environmental toxin as a cause of this disease?
substance MPTP-a chemical the body converts to MPP+ which accumulates in and then destroys, neurons that release dopamine
(Calif 1982-several young aldults developed symptoms of Parkinsons after using a drug similar to heroin)
More likely explanation is environmental toxins etc cause increased incidence of Parkinson’s
How may herbicides and pesticides be implicated
Parkinsons is more common among farmers. Herbicides and pesticides damage cells of the substantia nigria
What is a problem with the toxin-exposure hypothesis?
people who smoke or drink coffee have less of a chance to develop parkinsons.
What was the unexpected finding concerning cigarette smoking and Parkinsons’s disease? What may the basis for this effect?
it decreases incidence of Parkinsons
What is the rationale for treatment of Parkinson’s disease with L-dopa? What are the side effects?
L-dopa is a precursor to dopamine, crosses the barrier (brain) where as dopamine does not
After it crosses the brain converts it to dopamine
-L-dopa does not stop further neuron loss
nausea, restlessness, sleep problems low BP and repetitive movement hallucinations and delusions are all side effects
List some other possible treatments for Parkinson’s disease?
- drugs that decrease apoptosis
- antioxidants
- drugs that directly stimulate dopamine receptors
- drugs that inhibit glutamate or adenosine receptors
- drugs that stimulate cannabinoid receptors
- gene therapy-neurotrophis-to promote survival of neurons
How successful have brain grafts been in treating Parkinson’s disease in humans? what are some of the problems with the use of fetal tissue? From where win the brain is fetal tissue taken?
- procedure is feasible but need fetal brain cells
- try aborted fetuses
- need 4-8 aborted fetuses
- possible to tissue culture cells
- area of brain cells needed is substantia nigra
What kinds of tissue have been used for brain grafts to treat Parkinson’s disease? what are some potential additional sources for tissue for such grafts?
tried the patients own adrenal gland.
What are the physical and psychological symptoms of Huntington’s disease?
depression, sleep disorders, memory impairment, anxiety, hallucinations and delusions. for psychological symptoms
Also decreased inhibition due to execs damage to the globes pallidus, and therefore involuntary jerky movements
-arm jerks, facial twitches => lead to writhing which gradually interferes with walking and speech
-extensive damage to the caudate nucleus, putamen and globes pallidus and also in cerebral cortex.
Discuss the role of genetics in Huntington’s disease. On which chromosome is the gene located?
dominant gene on chromosome 4-critical area of the gene includes a sequence of bases C-A-G which is repeated 11-24 times in most people.
People with 39 or more repeats of this sequence may bet the disease
the more repeats of this sequence the earlier a person gets the disease.
What is huntingin? What do we know about the base sequence of the gene that codes for it? what may it do inside the cell?
the protein huntington codes for Huntington’s disease.
occurs throughout the body but its mutant form produces no harm outside of the brain.
within the brain it occurs INSIDE neurons
impairs neurons by :-in early stages increases neurotransmitters release => over stimulation of target cells
-later protein forms clusters that impair neuron mitochondria
also impairs transport of chemicals down the axon.
