The Muscular System Flashcards
How much of an adults body weight do muscles make up? What does it depend on?
40-50%
depends on % of fat, gender, exercise
How do muscles work? Why?
transform chemical energy into mechanical energy to generate force, perform work, and produce movement
What is a by product of muscle movement
heat
What is movement
movement out of anatomical postion
What are the three types of muscle tissue
skeletal
visceral
cardiac
What is skeletal muscle tissue
located on skeleton
moves bones
multinuceated and striated
voluntary
What is visceral muscle
organs, one nucleus, no striations, involuntary
What is cardiac muscle?
heart, pumps blood, one nucleus, striated, intercalated discs, involuntary
What are the functions of muscular tissue
- producing body movements
- stabilizing body positions
- storing and moving substances
- generating heat
What are the special properties of muscle tissue
electrical excitability
contractility
extensibility
elasticity
How many skeletal muscles?
700
Endomysium
connective tissue covering each muscle cell
Fascicle
muscle cell arranged in small bundle
perimysium
connective tissue covering fascicles
epimysium
bundles are covered by connective tissue
Tendons
extensions of the three coverings attaching the muscle to the periosteum of bone
aponeurosis
wide, flat tendon
How do skeletal muscles produce movement?
by exerting force on tendons
most muscle tendons:
cross at least one joint
attach to articulating bones to produce movement
Origin
attachment of muscle tendon to the stationary bone
insertion
attachment of the other tendon to moving bone
Usually the origin is ________ and the insertion is ________
Usually the origin is PROXIMAL and the insertion is DISTAL
true or false: muscles cover the moving part
false muscles do not cover the moving part
What must a muscle tendon do to move a joint?
cross the joint it moves
Lever
a rigid structure that can be moved around a fixed point
Effort (E)
causing movement
Load
weight of body or resistance to moving part
Fulcrum
moving joint
When does motion occur in a lever system
when muscle effort applied to bone at insertion exceeds the load
What are the three types of levers
first class:EFL
second classFLE
third classFEL
within a fascicle the muscle fibres are __________ to each other
parallel
What are the patterns of fascicle arrangement with respect to tendons?
parallel fusiform cicular triangular pennate
How does length of fibres affect power and rom
the longer the fibres the greater rom it can produce
How does the amount of fibres affect power and rom
the greater the total cross section the more power it can produce
Agonist
prime mover, contracts to cause desired motion
antagonist
streteches and yields to effects of prime mover
synergist
adds power to agonist or prevents unwanted movements at intermediate joints
fixator
stabilizes origin
compartments
in limbs groups of skeletal muscles, their blood supply, and nerves that have common function
in the upper limb the flexor compartment is
anterior
in the upper limb the extensor compartment is
posterior
in the lower limb the flexer compartment is
posterior
in the lower limb the extensor compartment is
anterior
