Motorneurons (Wk 6) Flashcards by Aatif Syed

What are the two types of mechanoreceptors embedded in muscle?

Golgi tendon organ, muscle spindles

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Nervous system mapping in general is _______

topographic

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Distal muscles usually control what sort of movement?

Voluntary movement

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Motor neurons that are responsible for voluntary movement come from the _______ pathway

A) medial
B) anterior
C) lateral
D) posterior

C) lateral pathway

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Proximal muscles usually are involved in what type of movement?

Involuntary movement

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Motor neurons that are responsible for involuntary movement come from the _______ pathway

A) medial
B) anterior
C) lateral
D) posterior

A) medial

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Lateral white matter contain axons from ______ that control activities of ________ neurons

A) brainstem, lateral ventral
B) cerebellum, medial ventral
C) motor cortex, lateral ventral
D) basal ganglia, medial ventral

C) motor cortex, lateral ventral

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Medial white matter contain axons from ______ that control activities of ________ neurons

A) brainstem, medial ventral
B) cerebellum, lateral ventral
C) motor cortex, lateral ventral
D) basal ganglia, medial ventral

A) brainstem, medial ventral

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T/F- Muscles that are close together in the body have motor neurons that are close together in spinal cord

True

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What are the three types of inputs to lower motor neurons?

1) sensory input from spindles
2) input from upper motor neurons in brain
3) input from spinal interneurons

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Axons of a-motor neurons goes to _______ whereas axons of Y-motor neurons goes to ______

A) intrafusal fibres, extrafusal fibres
B) intrafusal fibres, external fibres
C) extrafusal fibres, intrafusal fibres
D) extrafusal fibres, internal fibres

C) extrafusal fibres, intrafusal fibres

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what wraps around intrafusal fibres? What does that form?

Sensory neurons. Forms an anulo-spiral ending

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Muscle spindles detect?

Strech

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which mechanoreceptor (spindle or golgi tendon) is a monosynaptic reflex? How many synapses does it have?

Spindles. has 1 synapse

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Muscles spindles work by reflex _____ of muscle whereas golgi tendon organ work by reflex _____ of muscle

A) excitation, inhibition
B) inhibition, excitation
C) inhibition, inhibition
D) None of the above

A) excitation, inhibition

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When strech is detected, muscle spindles \_\_\_\_\_ antagonistic muscle
A) excite
B) inhibit
C) no response
D) relay message to golgi tendon organ

B) inhibit

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Golgi tendon organ detect ? Where is it located?

Muscle force… in tendon

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T/F- Inputs from tendon organs always goes through interneurons

True

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Are the interneurons in the golgi tendon organ excitatory or inhibitory? Is it different for antagonisitc muscles

inhibitory. However, it excitatory for antagonistic muscle

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Pattern that a person needs to locomote comes from circuits in?

Spinal cord

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Central pattern generators of gait in terrestial mammals even when brain was disconnected from spinal cord came from?

Spindles and GTO

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What are the 3 main ventro-medial pathways of Lower motor neurons?

1) lateral and medial vestibulospinal tracts
2) reticulospinal tract
3) colliculospinal tract

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What is common in lateral/medial vestibulospinal tract and reticulospinal tract?

all innervate an inter-neuron before it innervate motor neuron

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In which vento-medial pathway does neurons directly innervate the motor neuron?

Colliculospinal tract

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All voluntary movements involve a ________ plan to maintain posture

pre-emptive

Premotor cortex is also known as?

Motor association areas

Lateral and medial vestibular tracts carry information about? From where?

Carry information about gravity and acceleration from vestibular apparatus

Colliculospinal tract allows ________ based on visual input mainly A) postural adaption B) postural stability C) postural reflex D) none of the above

A) postural adaptation

Indirect pathway from the motor cortex to the spinal cord are via _______

brainstem

Direct pathway from the motor cortex to the spinal cord involve the _______ and _____ pathway. ____ of these fibres undergo ________ at ______, which then forms the _______ tract. This provides innervation for ______ muscles. However, ______ of these fibres dont, and form the ________ tract, innervating _____ muscles Words to choose: distal, proximal, anterior, posterior, brainstem, corticospinal, cerebullum, corticobulbar, 80%, 20%, 10%, 90%, pyramidal deccusation, pons, cadual medulla, lateral spinocortical, ventromedial

Direct pathway from the motor cortex to the spinal cord involve the CORTICOSPINAL and CORTICOBULBAR pathway. 90% of these fibres undergo PYRAMDIAL DECUSSATION at CAUDAL MEDUALLA, which then forms the LATERAL CORTIOSPINAL TRACT. This provides innervation for DISTAL muscles. However, 10% of these fibres dont, and form the VENTROMEDIAL tract, innervating PROXIMAL muscles

T/F- Topographic map of movement in primary motor cortex is not divided based on number of muscles, but the type of muscles instead

False- they are based on the different movements

What are mirror neurons? Are they found throughout upper motor neurons?

neurons discoered to fire when an action is witnessed and also when the action itself is performed. These neurons can still be the one responsible for eliciting the movement. They are found throughout upper motor neurons

What is the babinski sign used for? What happens in this?

It is used for clinical diagnosis of damage to the motor system. When something under sole of foot is traced all along, normally, you have a plantar flexion response. If your motor system is not functioning properly, you elicit a extensor plantar response (fanning of toes)

What are some signs and symptoms of upper motor neuron lesion/syndrome?

weakness, spasticity (increased tone, hyperactive deep relfexes) and babinski's sign

What are some signs and symptoms of lower motor neuron lesion/syndrome?

decreased tone, hypoactive reflexes, weaknes or paralysis,

What are the 4 main functions of the cerebullum?

1) coordination the timing and sequence of muscle actions and movements 2) maintenance or muscle tone 3) motor learning 4) planning sequence of muscle activation for complex movements

T/F- Cerebullum also projects to spinal cord, and has outputs to spinal cord

False- it doesnt

Where are the outputs of cerebullum?

Deep cerebellar nuclei

Where do the inputs to the cerebullum come from?

pontine nuclei, spinal cord, vestibular nuclei, inferior olive

What are the major descending outputs from the cerebullum?

Cerebral cortex---> deep cerebellar nuclei---> superior colliculus, reticular formation, vestibular nuclei-----> lower motor neurons in medial ventral horn

What is ataxia?

neurological sign consisting of lack of voluntary coordination of muscle movements- cerebellar dysfunction

what are the functions of basal ganglia?

1) allow selection of complex patterns of voluntary movement 2) evaluate success of actions in achieving goals of those actions 3) initiating movements

what are the names of the 5 basal ganglia in the brain?

caudate, putamen, globus pallidus, subthalamic nuclei, substantia niagra

Caudate and Putamen are referred to as the _____ of the basal ganglia, and came from the same _______ A) output nuclei, embryonic tissue B) input nuclei, embryonic tissue C) output nuclei, adult tissue D) input nuclei, adult tissue

B) input nuclei, embryonic tissue

T/F- Caudate and putamen develop as 1 section but are seperated by tracts of white matter

True

Globus palladus are divided into?

Internal and external segments

T/F- Globus palladus is part of extrinsic circuitory of basal ganglia/

False- intrinsic circuitory

Substantia niagra is located in the ______, and consist of two parts; __________ and __________

midbrain, substantia para compacta, substantia pars reticula

Which two cortex does not provide input to the corpus striatum?

Visual and auditory cortex

Direct pathway through basal ganglia ______ movement whereas indirect pathway aims to ____ movement

facilitate/allow, decrease

direct pathway through basal ganglia involves ____ receptors at substantia niagra pars compacta

indirect pathway through basal ganglia involves ____ receptors at substantia niagra pars compacta

The direct pathway through basal ganglia projects the ___________ of globus palladus

internal segment

The indirect pathway through basal ganglia projects the ___________ of globus palladus

external segment

T/F- In both direct and indirect pathways, dopamine helps to facilitate movement

True- in both pathways they aid movement but in different ways

what happens when you have no dopamine, or very few levels of it

no facilitating movement through the direct pathway and also, there is no inhibition of the inhibitory pathway (indirect pathway)

The indirect pathway inhibits movement by activating the ____________, to result in inhibition of the ______.

globus palladus internal segment, thalamus

Parkinsons disease is a result of the degradation of _______, resulting in lower/no level of ______

substantia niagra, dopamine

Huntingtons disease is a result of the degradation of _______

caudate/putamen

How are the bacterial opsins similar to vertebrate visual system opsins?

Both respond to light by isomerisation of retinol resulting in conformational change in opsin protein

Bacterial opsins are _______ channels A) voltage gated B) cation C) ionic D) amiloride

C) ionic

Halorhodopsin ______ in response to light by opening _____ channels A) depolarises, Na B) hyperpolarise, Cl C) depolarise, Na D) hyperpolarise, Cl

B) hyperpolarise, Cl

What are some advantages of using optogenetics?

Genetically defines targeting to neuronal sub types, extraordinary temporal precision in activation, and same neurons can be excited or inhibited

What are some caveats of using optogenetics?

Optic fibre probe is invasive, targetting isnt perfect, and stimulation and inhibition of single neurons may go beyond normal physiological ranges

In the optogenetic manipulation of basal ganglia in transgenic mice, what happened when D1 laser was on?

increased movement (hyperkinetic)

In the optogenetic manipulation of basal ganglia in transgenic mice, what happened when D2 laser was on?

almost complete cessation of movement

Huntingtons disease is a _____ disorder whereas parkinsons disease is a ______ A) hyperkinetic, hypokinetic B) hypotkinetic, hyperkinetic C) cytokinetic, hyperkinetic D) cytokinetic, hypokinetic

A) hyperkinetic, hypokinetic

Motorneurons (Wk 6) Flashcards

Upper, lower, basal ganglia (67 cards)