MOTOR SYSTEM

How many muscles in the body?

640

Muscles are divided into s_____ and c_______ and s_________.

smooth and cardiac and striated (skeletal)

What are smooth muscles?

Lines internal organs, like intestine

cardiac muscle

heart

striated/skeletal muscle

muscle connected to bones that allow us to move

striated muscles operate in ______. One ______ a joint and one ______ the joint.

pairs

contracts

extends

Flexor is a _____ that ______ the ______

muscle that closes the joint

extensor

muscle that opens the joint

draw the bone, flexor muscle, extensor muscle, tendons

Muscles are attached to _______ which are attached to ______.

tendons, bone

______ horn contains motor neurons.

ventral

muscle ______ get activated in ______ muscles → sensation about that muscle goes through _____ _____ _______ into the ______ _______ → kicked back out to adjust your position through the ______ ________-.

fibers , flexor

dorsal root ganglion , spinal cord

ventral horn

muscles are made up of 2 muscle fibers. they are……

1. slow twitch fibers - more endurance

2. fast twitch fibers - bursts of energy

neuromuscular junction

The neuromuscular junction (NMJ) is a specialized chemical synapse where motor neurons communicate with skeletal muscle fibers to initiate contraction

This type of synapse is a ________ synapse.

cholinergic

what neurotransmitter is used in the neuromuscular junction

acetylcholine

describe the process of how this contraction occurs?

1. Motor neurons in ventral horn sends an axon down to the muscle

2. this directly contacts and activates muscle, releasing Ach

3. Ach binds to 2 receptors and muscle fiber will contract

final common pathway

the lower motor neurons that are in the ventral side of the spinal cord
-have this name because muscles cannot be moved without these neurons. all brain areas must communicate with them in order to move muscles (works like a funnel)

Lower motor neurons - where are they located, what they are etc

• in spinal cord

• Lower motor neurons (LMNs) are nerve cells that directly connect the central nervous system to skeletal muscles

• final common pathway

upper motor neurons

• above ventral horn of spinal cord

• synapse on lower motor neurons

Myasthenia Gravis affects the ______ motor neurons

lower

Parkinsons affects the _______ motor neurons.

upper

proprioception

your body’s way of knowing where your body is in space

muscle spindles detect ______

stretch

Muscle spindles get stretched along with the _____ and send this feedback to the ____ root of the spinal cord

muscle

dorsal

golgi tendon organ tells if if theres ____ on the tendon

stress

if golgi tendon organ cells are activated, ____ _______ open. Then an _____ ____ send feed back to the _______ root of the spinal cord.

ion channels

action potential

dorsal

5 different information tracts

1. corticospinal tract

2. corticorubrospinal tract

3. tectospinal tract

4. vestibulospinal tract

5. reticulospinal tract

1. corticospinal tract

connects with the primary motor cortex/precentral gyrus

runs through the pyramidal decasation

Pyramidal Decasation

Where the crossing over to the other side of the body happens

the dividing point between the brain and spinal cord

after crossing over the tract runs through the

dorsolateral part of the spinal cord

flexor bias: ___________. damage could cause _______

innervation of a forelimb

difficulty flexing fingers

Corticorubrospinal tract : cortex → ______________________ → spinal cord

red nucleus in mesencephalon

Corticorubrospinal tract runs in the ___________ part of the spinal cord

dorsolateral part

both the corticospinal and corticorubrospinal tract have these 2 things

1. flexor bias

2. limb muscles

The other 3 tracts are __________.

ventromedial

Tectospinal tract runs from ________ to ________

tectum

spinal cord

Tectospinal tract is an output system that goes to ______ and _________ body. What does it do to our body?

shoulders

upper

orient it to face stimuli

tectrospinal tract 2 traits

1. flexor bias

2. core muscles

vestibulospinal tract goes from the ______to ________

vestibular nucleus to the spinal cord

vestibulospinal tract 2 traits

1. extensor bias - to balance

2. core muscles

reticulospinal tract goes from the _______ to ___________.

reticular formation to spinal cord

reticular formation is responsible for

arousal, consiousness

traits of this

core muscles