Motor 1
What are brains for?
Brains are for moving
Sea Squirt = egg, then the tadpole-like creature with a brain, a spinal cord &
an eyeball; it swims… UNTIL…It attaches itself to a surface… then it literally
eats its own brain!
Types of muscles
Aout 640 types
Skeletal muscles: connected to bones via tendons, to move bones around
Somatic motor system: Skeletal muscles & associated parts of the nervous
system
Smooth muscle: walls of hollow organs (stomach, air ways, blood vessels,
digestive track), moves matter around
Cardiac muscle: highly synchronized muscles that contract together &
automatically, pump blood into the heart
Flexprs & extensors
Muscles only pull: they can either contract or relax
Antagonist pairs:
Flexors: move bone towards body
Extensor: moves bone away from the body
Act in opposite, if one contracts the other relaxes
Multiple muscles working together to either flex or extend = Synergists
Composition
Myofibrils: tiny threads within muscle fiber
Motor 1 1
, Muscle fiber: Muscle cells made up of myofibrils
Fascicle: Bundles of muscle fiber
Muscle: a combination of fascicles
Lower motor neurons
Alpha motor neruons: trigger the contraction of muscles
Cell bodies exist in the spinal cord
Axons exit the ventral horn of the spinal cord
Are bundled together to make the ventral root
Synapse into muscle fibers
Motor unit
The axons of motor neurons can branch to control more than one muscle fiber
Motor Unit = one alpha motor neuron and all the muscle fibers it innervates
The smaller the # of muscle fibers in a motor unit, the more precise the contro
Motor pool
All the aloha neurons that innervate a muscle
Neuromuscular junctions
more reliable than those in the brain
Synapses between motor neurons and muscle fibers
Motor neurons release acetylcholine into synapse
For the dendrites, Muscles have end plates
Folds that fit around the dendrites of an alpha motor neuron
Have Nicotinic Acetylcholine receptors
Allows sodium to flow in
Motor 1 2
What are brains for?
Brains are for moving
Sea Squirt = egg, then the tadpole-like creature with a brain, a spinal cord &
an eyeball; it swims… UNTIL…It attaches itself to a surface… then it literally
eats its own brain!
Types of muscles
Aout 640 types
Skeletal muscles: connected to bones via tendons, to move bones around
Somatic motor system: Skeletal muscles & associated parts of the nervous
system
Smooth muscle: walls of hollow organs (stomach, air ways, blood vessels,
digestive track), moves matter around
Cardiac muscle: highly synchronized muscles that contract together &
automatically, pump blood into the heart
Flexprs & extensors
Muscles only pull: they can either contract or relax
Antagonist pairs:
Flexors: move bone towards body
Extensor: moves bone away from the body
Act in opposite, if one contracts the other relaxes
Multiple muscles working together to either flex or extend = Synergists
Composition
Myofibrils: tiny threads within muscle fiber
Motor 1 1
, Muscle fiber: Muscle cells made up of myofibrils
Fascicle: Bundles of muscle fiber
Muscle: a combination of fascicles
Lower motor neurons
Alpha motor neruons: trigger the contraction of muscles
Cell bodies exist in the spinal cord
Axons exit the ventral horn of the spinal cord
Are bundled together to make the ventral root
Synapse into muscle fibers
Motor unit
The axons of motor neurons can branch to control more than one muscle fiber
Motor Unit = one alpha motor neuron and all the muscle fibers it innervates
The smaller the # of muscle fibers in a motor unit, the more precise the contro
Motor pool
All the aloha neurons that innervate a muscle
Neuromuscular junctions
more reliable than those in the brain
Synapses between motor neurons and muscle fibers
Motor neurons release acetylcholine into synapse
For the dendrites, Muscles have end plates
Folds that fit around the dendrites of an alpha motor neuron
Have Nicotinic Acetylcholine receptors
Allows sodium to flow in
Motor 1 2
