20. Muscular System Flashcards
Epimysium
-Connective tissue over the muscle that connects twitch the tendon
-reduces friction between the muscle and surrounding body parts
Perimysium
-Connective tissue inside the muscle
-Surrounds Fascicles
Fascicle
-a bundle of muscle fibers surrounded by perimysium, capillaries, and nerve endings
-lies parallel to other fascicles
Endomysium
-connective tissue within a fascicle that surrounds muscle fibers (myofbrils)
Myofiber
-aka muscle cell
-multiple nucleuses (nuclei)
-cell membrane: sarcolemma
-intercellular fluid: sarcoplasm
-contains Myofibrils that contains the ability to contract
*surrounded by Sarcoplasmic Reticulum
Myofibrils
-located within muscle fibers
-contains sacromeres
Sacromere
-basic units of muscle contraction
-located within myofibrils
-Z Lines/Disc/Bands border the sacromere
-contains myofilaments of Actin/Troponin (Thin) filaments and Myosin (Thick) filaments
-I Bands: thin filaments only
-H Bands: thick filaments only
-A Bands: includes entirety of thick filaments
Origin
-Tendinous attachments on the less moveable bone or bone more stable during muscle contraction.
-usually located more medial or proximal
-usually larger and more extensive
Insertion
-tendinous attachments on more moveable bond during muscle contraction
-usually more lateral or distal
-usually moves toward origins
-usually smaller than origin
Agonists
-prime movers
-muscles causing the desired action
-Example: brachialis is agonist for elbow Flexion
Antagonist
-muscles that lengthen while prime movers shorten
-usually reside on the opposite side of the moving joint to create opposing action
Synergist
-muscles that assist prime movers by performing the same movement at the same time.
-usually neighboring muscles of prime movers and smaller in size
-example: pronation teres is synergist to biceps brachialis
Atrophy
Muscle Anatomy Hierarchy
Muscle > fascicle > muscle fiber > myofibril > sacromere > myofilaments
Sarcolemma
-Cell membrane surrounding muscle fibers.
-its folds are motor end plates that receives signals from motor neurons to contract
Sarcoplasm
-intercellular fluid within the muscle fibers
Sarcoplasmic Reticulum (SR)
-surrounds myofibril within muscle fibers
-system of interconnected hallow tubes
-stores and releases calcium ions
-has indentations called transverse tubules (T tubules)
-allows impulses to travel into the center of the muscle fibers
Connective Tissues
-Epimysium: surrounds muscle
-Perimysium: surrounds fasciculi
*allows for muscular vascularization and innervation
-Endomysium: surrounds muscle fibers
*continuous with fascia surrounding tendons
Aponeurosis
-a broad, flat tendon (Tendons are chord like)
-attaches muscle to bone, muscle to muscle, muscle to skin
Retinacula
-bands of connective tissues that stabilize tendons (bracelets)
-also functions as pulleys
-located around elbows, knees, ankles, wrists
Parts of a Muscle
-Belly: wide central portion
-origin: attachment on less moveable bone
-insertion: attachment on more moveable bone
Muscle Contraction
-generation of tension in muscle fibers through movements between myosin and actin
-schema describing muscle contraction: sliding filament model
-extensibility: muscle fibers can be stretched
-elasticity: muscle fibers can reform to original length
- Neuromuscular junction
- Excitation of the Motor End Plate
- Contraction
- Relation
Sliding Filament Theory
-myosin filaments use ATP to “walk” along the actin filaments with their cross bridges
-z lines are closer together, shortening sacromeres
-the number of muscle fibers that contract, the stronger the force
All-or-None Law/Response
-true for motor units, not the muscle itself
-a muscle fiber always contracts fully or not at all (no partial contraction)
Recruitment
-the process of motor unit citation based on need
-numerous motor units are linked to a single skeletal muscle
-nervous system only activates the number of motor units needed to perform action.
-recruitment: recruiting more motor units to meet need
Atrophy
Loss of muscle mass from lack of use, poor nutrition, or inadequate nerve innervation
Contracture
-joint condition in which a muscle is fixed in a flexed contraction
Ganglion Cyst
-benign tumor occurring on a tendon such as in the wrist or dorsal of the foot
Headaches
Pain in the head from any cause
Muscle Spasm
Increase in muscle tension with or without shortening that results in a rigid zone
Muscular Dystrophy
Characterized by the progressive atrophy of skeletal muscles
Repetitive Strain injury
Related to inefficient biomechanics, including general posture, sporting movements, and work habits
Spasticity
Increased muscle tone and stiffness; resists stretching
Posture Muscles
- Adductor Longus and Magnus
- Illiopsoas
- Lavatory Scapulae
- Lumbar Erector Spinae
- Oblique Abdominals
- Pectoral is Minor
7.Piriformis - Quadratics Lumborum
- Rectus Femoris
- Sternocleidomastoid
- Tensor Fascia Lata
- Upper Trapezius
Type 1 Muscle Fibers
-able to sustain low-level muscle contractions
-darker red color
-high capacity to generate ATP
-High resistance to fatigue
-High Number of Mitochondria
-More prominent in postural muscles
-rich capillary supply
-slow twitch fibers
-tend to tighten and shorten when stressed
-uses aerobic metabolism
Type 2 Muscle Fibers
-depends on anaerobic metabolism
-fast twitch fibers
-fatigue easily
-have fewer mitochondria
-larger fibers with more actin and myosin filaments
-lighter color
-more prominent in physic muscles
-produce powerful, fast contractions
-vulnerable to muscle strains and tendonitis
Posterior
Behind or in back of
Dialator
That which expands or enlarges
Inferior
Situated lower
Oblique
At an angle
Levator
That which lifts
Dorsal
Behind or in back of
Superior
Situated above
Medial
Pertaining to the middle or center
Distal
Farther from the center or medial line
Depressor
That which presses or draws down
Proximal
Nearer to the center or medial line
Anterior
Before or in front of
Extensor
To Straighten
Class Levers
-Class 1 Lever: Load-Folcrum-Pull (bending head back)
-Class 2 Lever: Pull-Load-Folcrum (calf raises)
-Class 3 Lever: Load-Pull-Folcrum (bicep curls)
Shape Classifications of a Muscle
- Parallel : (most) (fusiform) along the long axis of the bone
- Convergent: fibers spread like a fan from one small and spread out. Pull in several directions
- Spiral: twist between points of attachment
- Circular: rounded fiber arrangement
- Pennate: muscle fibers emerge diagonally from 1 or more central tendons.
De Quervain Tenosynovitis
Inflammation of the tendinous sheath located on the radial side of the wrist
Fibromyalgia Syndrome
Localized areas or tender points, widespread pain, joint stiffness, and fatigue, with affected person having no signs of inflammation or degeneration in the tissues
Myofascial Pain Syndrome
Presence of trigger points and muscular pain
Osgood-Schlatter disease
Involves patellar tendinitis at the tibial tuberosity in immature bone
Plantar Fasciitis
Chronic inflammation of the fascia on the bottom of the foot
Shin Splints
Pain along medial tibia
Strain
When muscles or tendons become overstretched or torn
Tendinitis
Inflammation of a tendon
Torticollis
Spasms of the sternocleidmastoid
Whiplash
Strain of the clavical spine, most commonly at the junction of the 4th and 5th cervical vertebrae
Sherrington’s Law
When one set of muscles is stimulated, muscles opposing the action of the first are simultaneously inhibited.
Gate Control Theory
a mechanism, in the spinal cord, in which pain signals can be sent up to the brain to be processed to accentuate the possible perceived pain, or attenuate it at the spinal cord itself.
Proprioceptors
a sensory receptor which receives stimuli from within the body, especially one that responds to position and movement.
Gogli Tendon
Junction between the muscle and the tendon
Muscle Spindles
stretch receptors within the body of a skeletal muscle that primarily detect changes in the length of the muscle.
Pain Spasm Pain Cycle
Pain>
voluntary muscle contraction >
circulatory retention of metabolites (heat, swelling, redness) >
involuntary spasm >
restricted movement >
dysfunction >
