Week 2: Movement System, Motor Status, and Muscle Disorders

Concentric Contraction

Concentric Contraction

• motions occurs as the muscle shortens and the muscle's proximal and distal insertion points move closer towards each other

• positive contraction

• force > resistance

Eccentric Contraction

• lengthening activation of muscle

• negative contraction or negative work

• force < resistance

Isometric Contraction

• muscle produces force with no apparent change in the joint angle

• static, or holding contraction

Potential Difference

imbalance of ions from one side of a cell membrane to the other.

-60 to -90 mv

resting membrane potential.

Irritability

ability to react to a stimulus.

Depolarization

change of cell membrane's resting potential to a more positive charge.

Action Potential

nerve impulse due to continued depolarization.

Repolarization

return to its original resting membrane potential.

Neurotransmitters

chemicals that are responsible for action potential or for the generation of nerve or muscle impulse.

Dopamine

neurotransmitter responsible for Parkinson's disease.

Cell Body Axons Dendrites

parts of a neuron.

Axons

transfers information from the cell body to the outside.

Dendrites

receives information towards the cell body.

Neuroglia

• has the ability to regenerate and divide

• usually the cause of tumors

Astrocytes

• brace neurons together

• act as a chemical mediator among the ions that penetrates your brain

• maintain chemical activity in the brain

• forms the blood-brain barrier

Microglia

acts as macrophages of the cell.

Oligodendrocytes

produces myelin sheath in the CNS.

Schwann Cells

produces myelin sheath in the PNS.

Ependymal Cells

circulate the flow of CSF in the brain.

Central Nervous System

consist of the brain and the spinal cord.

Peripheral Nervous System

• the section of the nervous system lying outside the brain and spinal cord

• emit efferent and afferent neurons

Upper Motor Neuron

• cortex to spinal cord

• PUSH (define)

Lower Motor Neuron

• spinal cord to the effector organ

• FLAN (define)

Afferent

• 1st, 2nd, and 3rd order neuron

• ascending neurons

• sensory

Efferent

• regulates movement and behavior

• descending neurons

• motor

Interneuron

• neurons within the ventral horn and intermediate areas of the spinal cord

• bridge between UMN and LMN

Myelin Sheath

is a white lipid substance that insulates the neural axon.

Nodes of Ranvier

• spaces between myelin sheath

• responsible for saltatory conduction

Sensory Nerves

• afferent nerve fibers

• carry impulses arising from various receptors in the skin, muscle, and special sense organs to the CNS

Motor Nerve

• efferent nerve fibers

• conduct impulses from the spinal cord to skeletal muscles fibers for voluntary muscle activity control

• LMN - final common path between the NS and the muscular system

Autonomic Neurons

concerned with the involuntary control of glandular activites and smooth muscles, including smooth muscles surrounding arterioles and venules within muscles.

Type A and B

myelinated nerve fibers.

C fibers

unmyelinated nerve fibers

Alpha Beta Delta Gamma

types of type A nerve fibers.

Gate Control Theory

only one type of painful sensation at time.

Muscle Spindle

sensitive to stretch.

Golgi Tendon Organ

sensitive to tension.

Autogenic Inhibition

the GTO is responsible for inhibiting the agonist muscle to facilitate the antagonistic muscle.

Alpha

extrafusal fibers.

Gamma

intrafusal fibers.

Association Neurons

these are nerves that communicate with each other within the brain and literally create associations between neural area.

White Matter

• whitish nervous tissue of the CNS consisting of neurons and their myelin sheaths

• subcortical structures within the cerebral cortex

Nuclei

clusters of nerve cell bodies found within the CNS.

Ganglia

clusters of nerve cell bodies found within the PNS.

Gray Matter

• makes up the outer most layer of the brain

• makes up the Brodmann's area

Commisural Fibers

connect the right side of the brain to the left side.

Association Fibers

connects the structures on the same side of the brain.

Projection Fibers

connects the superior portion to the inferior portion.

Endomysium

covering that surrounds the skeletal muscles.

Perimysium

surrounds the fascicles.

Epimysium

surrounds the specific muscle fiber.

Tendon

attachment from muscle to bone.

Aponeurosis

flattened tendon.

Sarcoplasm

cytoplasm of the myofiber.

Sarcoplasmic Reticulum

• ER of the muscle fiber

• where calcium is stored

Sarcolemma

plasma membrane of the striated muscle.

Myoglobin

responsible for the distribution of oxygen to tissues.

Sarcomere

basic contractile unit

Z disc

• border

• inside this is the sarcomere

A band

anisotrophic band.

I band

• isotrophic band

• composed of both actin and myosin

H zone

composed of pure myosin filaments.

M band/line

• point of attachment of myosin filaments

• where the actin move towards during shortening contraction

Troponin and Tropomyosin

regulatory proteins.

Myosin and Actin

contractile proteins.

Myoneural Junction

• neuromuscular junction

• point of connection between the nerve fiber and the muscle fiber

• mediated by ACH and acetlycholinesterase

Size Principle

the smallest motor units are activated first.

Recruitment Principle

number of motor units is directly proportional to the strength of the contraction.

Excitatory Input/Rate Coding Principle

increasing the frequency of stimulation.

Stretch Reflex

• a simple reflex arc mediated at the spinal cord level

• responsible for deep tendon reflex

Muscle Tone

constant state of readiness of the muscle.

Hypertonicity

increased muscle tone.

Hypotonicity

decreased muscle tone.

Atonicity

no muscle tone.

Postural Tone

term used to describe the development of muscular tension in specific muscles that maintain body segments in their proper relationships to maintain posture.

Kinesthesia

• awareness of dynamic joint motion

• deep sensation

• movement sense

Position Sense

• awareness of static position

• deep sensation

Proprioception

refers to the use of sensory input from receptors in muscle spindles, tendons, and joints to discriminate joint position and joint movement, including direction amplitude, and speed, as well as relative tension within tendons.

Postural Equilibrium

• somatosensory and proprioception

• visual system

• vestibular system

Lead Pipe Rigidity

resistance to passive movement is smooth.

Cogwheel Rigidity

on passive movements there are regular jerky "gives" in the resistance due to intermittent yielding of muscle.

Decorticate Rigidity

extension of the LE and flexion of the UE.

Decerebrate Rigidity

rigid extension of UE and LE.

Spasticity

• hypertonic motor disorder characterized by velocity-dependent resistance to passive stretch

• clasp-knife phenomenon

• injury to the corticospinal pathway

Clonus

characterized by cyclical, spasmodic alternation of muscular contraction and relaxation in response to sustained stretch of a spastic muscle.

Cerebrovascular Accident

• defined as a sudden focal neurologic deficit resulting from ischemic or hemorrhagic lesion the brain

• 3rd most common cause of death and most common cause of disability in the US

Ischemic Stroke and Hemorrhagic Stroke

types of CVA

Parkinson's Disease

disorder of the extrapyramidal system with loss of pigmented cells in the substantia nigra that produces dopamine and degeneration of the nigrostriatal pathway.

Bradykinesia

slowness of movement

Kinetic Tremor

tremor that manifests when the pt is moving.

Resting Tremor

tremor that manifests when the pt is resting.

Multiple Sclerosis

• demyelinating disease of the central nervous system usually affecting young adults

• degeneration of myelin sheath

Cerebral Palsy

• infantile cerebral paralysis or little's disease

• persistent disorder of movement and posture appearing early in due to a developmental, non-progressive lesion of the brain

• 7 years old and below