CLASSIFYING THE SKETAL MUSCLE SYSTEM Flashcards
Outline smooth muscle
absence of striations, innervated by ANS, slow rhythmic contractions
walls of hollow organs
blood vessels, eye muscles, respiratory
Outline cardiac muscle
transverse striations with intercalated discs. contraction regulated by pacemaker cells influenced by ANS. quick continuous rhythmic contraction.
heart
Outline skeletal muscle
transverse striations. innervated by motor neurons, voluntary contraction. move bones, stabilise joints
attached to bone via tendon
Functions of skeletal muscle
movement
Maintain posture and position
Support soft tissues
Guard entrances and exits
Maintain body temperature
Store nutrient reserves (metabolic tissue)
Sub unit order of skeletal muscle
Skeletal muscle
Fascicles
Skeletal muscle fibres/cells
Myofibrils
Sarcomeres
Surrounding tissues of skeletal muscle
Epimysium: covers entire muscle
Perimysium: covers fascicles, contains blood vessels and nerves
Endomysium: covers individual muscle fibres/cells
Make up motor units
Skeletal muscles are innervated by motor nerves. motor nerves are made up of motor neurons.
more strength = more motor neurons = motor nerves recruited = innervate more fascicles
Physical components of a muscle
Belly
Tendons
Fascia
Outline belly of muscle
Fleshy part of muscle, which is the contractile part, vascularised
Outline tendons of muscle
bands of CT connection muscle to skeleton. poorly vascularised
Outline fascia of muscle
A fibrous membrane covering, supporting and separating muscles
What is an aponeurosis
broad tendinous fascia sheet
joins muscles
or joins muscles with large are attachment to bone
Outline the implications of a longer myofibril
longer myofibril = greater range of motion
myofibrils still contract the same, no difference due to length
what is contraction force related to
cross sectional area of muscle (having more fascicles to innervate)
What is an isometric contraction
tension produced, no length change, no movement
static contraction as joint stays the same
What is an isotonic contraction
Tension produced, change in length.
dynamic contraction because joint will move
concentric = shortening
eccentric = lengthening
What are the 3 types of muscle fibres
Slow oxidative (slow twitch, type 1)
Fast oxidative-glycolytic (intermediate twitch, type IIA)
Fast glycolytic ( fast twitch, type IIX)
Which fibre type has the highest fatigue resistance
Slow oxidative.
What are the different types of fascicle arrangements
parallel flat convergent pennate fusiform digastric circular quadrate
outline parallel fascicles
parallel to long axis of muscle
contracts = shorten = larger in diameter
outline convergent fascicles
fascicles converge at common attachment.
stimulating different portions can change pull
outline pennate fascicles
diagonal direction to tendon, pull angled, greater force due to more fibres
uni, bi or multi
outline circular fascicles
concentrically arranged around opening, guards entry, exit to the body
outline flat fascicles
flat muscle, parallel fascicles, often have an aponeurosis
outline quadrate fascicles
all sides are equal size, tendinous intersections, parallel fascicles
outline fusiform fascicles
spindle shaped muscle (thick belly, thinner at tendons), parallel fascicles
outline digastric fascicles
two different bellies connected by a tendon, fascicles are fusiform (parallel).
What are intrinsic muscles
only cross one joint, tendons and bellies in one region
What are extrinsic muscles
muscles that cross one or more joints, tendons and bellies are indifferent compartments
4 groups of muscle actions
agonist
antagonist
synergist
fixators
outline agonists
prime mover
muscle whose contraction is mainly responsible for producing particular movement
outline antagonists
muscle whose action opposes particular agonist
outline synergists
muscle that assists agonist to work efficiently
outline fixators
act as a stabiliser in one part of the body during movement of another part.
