muscular System Flashcards
Bundle of elastic tissue that has the ability to contract, producing movement or maintaining the position of a body part
Muscle
Connected to bone via tendon
Muscle
Point where muscle meets tendon
Musculotendinous junction
Point where muscle meets bone
Tenoperiosteal junction
Point where muscles attach to more stable bone
Origin
Point where muscles attaches to more mobile bone
Insertion
NO QUESTION. Fact: Insertion moves towards the origin in joint movement
Fact
muscles are named by shape
Trapezius, serratus anterior
Muscles named by action
Extensor carpi radialis, supination
Muscles named by origin/location
Tibialis anterior, rectus abdominis
Muscles named by number of heads
Triceps brachii, biceps femoris
Muscles named for their size
Pectoralis major, pectoralis minor
Parallel arrangement muscles
Strap muscles-long and thin. Ex.) rectus abdominis
Fusiform- rounded and tapered at the ends. Ex.) biceps brachii
Rhomboidal- foursided, flat, broad attachments. Ex.) quadratus, rhomboids, pronator
Triangular- fan shaped, flat, run from a narrow attachment to a broad end at the other side. Ex.) pectoralis major
Oblique arrangement muscle fiber
Unipennate- series of short, parallel fibers extending diagonally from the side of a long tendon. Ex) flexor pollicis longus
Bipennate- long, central tendon with fibers extending diagonally of the tendon. Ex.) rectus femoris, flexor hallicus longus
Multipennate- muscle fibers running diagonally between several tendons Ex.) deltoid, subscapularis
Length of the muscle when it is not shortened or lengthened
Normal resting length
Ability for a muscle to respond to a stimulus
Irritability
Muscles ability to contract and generate force when it receives adequate stimulation
Contractibility
Muscles ability to stretch/lengthen when a force is applied
Extensibility
Muscles ability to recoil or return to normal resting length
Elasticity
Outer layer of muscle tissue, around entire muscle belly
Epimysium
Middle layer of muscle tissue, separates muscle into fascicles
Perimysium
Innternlayer of muscle tissue, wraps each individual fiber
Endomysium
Bundles of myofibrils, that group together to make a muscle
Muscle fibers
Outer layer that forms the groups of muscle fibers
Fascicles
Bundles of sarcomeres, that group together to make muscle fibers
Myofibrils
Sections of myosin and actin filaments, that group together to make myofibrils
Sarcomeres
Lines that separate sarcomeres
Zlines
Outside of the myosin filament. What myosin grabs onto
Actin
Smallest part with a head that hooks into the actin to pull it together
Myosin
Describes the interaction between the actin and myosin and explains how force is produced during a muscle co traction and how the sarcomere is shortened
Sliding filament theory
Composed of a motor neuron and muscle fibers that it innervates
Motor unit
Location in muscle tissue between the muscle fibers. It monitors the length of the muscle and when it is stretched too far, it will contract.
Location and function of muscle spindles
Abrupt stretch of the muscle initiates a burst of activity from the muscle spindle. muscle spindle sends a signal to the spinal cord that excited the motor neuron. Signal sent back to the muscle to respond
Stretch reflex
Located in muscle tendons near the point of attachment of the muscle fiber to the tendon. Monitors the degree of tension in the muscle and relaxes true muscle if too much tension is provided on the muscle
Location and function of golgi tendon organ
Spindle:
Located in belly. Responds to change in muscle length. Excitatory of muscle being lengthened to protect damage. Send signal directly to spinal cord
Golgi tendon organ:
Located in tendon. Respond to change in muscle tension. Inhibitory of muscle with increased tension to protect from damage. Sends signal to nervous system
Where muscle shortenes and myosin heads exert force and pull actin filaments closer together
Muscle contraction
Force built up within a muscle
Tension
Slight tension that is present in a muscle at all times, even when muscle is relaxing
Tone
Distance from maximum lengthening to maximum shortening.
Excursion of muscle
When a musics is in a slight stretch but not overstretched. Increased muscles force-generating capacity
Optimal length
Benefits of a single joint
Capable of moving a joint through its full ROM
Benefits of a multi joint
Can maintain optimal length during contraction by shortnening over one joint while lengthening over another
Drawbacks of single joint
Less powerful at ends of joint ROM
Drawbacks of a multi joint
Subject to active and passive insuffiency, which can limit ROM and movements in the joints the muscle crosses
When muscle is chronically overstretched, it has a decrease in the overlap of actin and myosin so it becomes weak
Adaptive lengthening
When a muscle is left in a shortened position for a long time without moving through its full excursion
Adaptive shortening
Grasp and release of the hand by passive insufficiency or movement. If you supinate the forearm, the weight of the hand and gravity cause the fingers to close creating a grasp
Tenodesis
A muscle contracts producing force without changing the length of the muscle
Isometric
Occurs when there is joint movement, the muscle attachments move toward each other. During flexion
Concentric
Occurs when there is joint motion but the muscle appears to lengthen. Relaxing
Eccentric
Muscle or muscle group that causes the motion
Agonist
Muscle that performs the opposite motion of the agonist
Antagonist
Muscle or muscle group that supports, makes firm, allowing agonist to work more efficiently
Stabilized
Contracts to prevent the unwanted motion if a muscle can do 2 or more actions and only wants to do one
Neutralizer
Muscle that works with 1 or more other muscles to enhance particular motion
Synergist
Muscle or muscle group causing the motion (also known as agonist)
Prime mover
Muscle that is not as effective but does assist in providing that motion
Assisting lover
