Lecture 3 muscles and directional terminology Flashcards
Myofibril
the smallest unit of muscle
muscle fibre myofibre
a group of myofibrils incased in a fascial sleeve
fascicle
a group of muscle fibres encased in a fascial sleeve
skeletal muscle
a group of fascicles incased in a fascial sleeve
fascia
fibrous membrane covering supporting and seperating muscle
aponeurosis
sheet like tendon joining one muscle with another or muscle with bone
tendon
white fibrous cord of dense regular connective tissue which attaches muscle to bone
3 types of muscle
skeletal, cardiac, smooth
skeletal muscle description
striated, alternating light and dark bands, voluntary, fibre direction run parallel to direction of muscle pull
cardiac muscle description
striated, involuntary, has intercalated discs at cell bifurcations
smooth muscle description
non striated, involuntary, present in gastrointestinal tract, blood vessels, airways, hair follicles
5 functions of muscles
motion, maintain posture, venous flow, thermogenesis, register volume of internal organs
6 fibre arrangements
longitudinal, quadrate, triangular, circular, fusiform, penniform
longitudinal description
long strap like fibres run parallel to the longitudinal axis
longitudinal examples
sartorius, rectus abdominus
Quadrate description
flat, fan-shaped muscle fibres that run parallel to line of pull
quadrate examples
pronator, quadratus, rhomboids
triangular description
flat, fan- shaped muscle with fibres that radiate from a narrow attachment to a broad attachment
triangular examples
pectoralis major
circular description
circular, typically sphincter muscles that surround an opening
circular example
orbicularis oris
fusiform description
round, spindle- shaped, tapered at both ends
fusiform examples
brachialis, brachioradialis
3 types of penniform
unipenniform, bipenniform, multipenniform
unipenniform description
short parallel fibres originating from one side of tendon
unipenniform examples
extensor digitorum longus, tibialis posterior
bipenniform description
double pennate fibres on both sides of a central tendon
bipenniform examples
rectus femoris, flexor hallicus longus
multipenniform description
several tendons with muscle fibres running diagonally between
multipenniform example
deltoid
origin definition
proximal attachment or stationary bone
insertion
distal attachment or moving bone
prime mover
muscle directly responsible for producing desired motion
synergist
muscle that assists the prime mover