M2 - Muscle Tissue Flashcards
Cardiac muscle (myocyte shape)
Small, short, branched
Smooth muscle (myocyte shape)
Small, spindle shaped, wide in middle + tapered on end
Skeletal muscle (myocyte shape)
Large, long, cylindrical
Which muscle groups have striations
Skeletal & cardiac
Which muscle groups have voluntary movements? Involuntary?
Voluntary - skeletal
Involuntary - smooth & cardiac
Skeletal muscle (location)
Muscles acting on limbs & trunk, muscles of facial expression, external sphincters regulating passage out of body
Smooth muscle (location)
Walls of many internal organs and passageways
Cardiac muscle (location)
Heart wall
Skeletal muscle (fxn)
Movement or stabilization of skeleton; guard entrances/exits for digestive, respiratory, urinary systems; heart production; protects internal organs
Smooth muscle (fxn)
Move food, urine, reproductive secretions thru systems; control diameter of blood vessels and respiratory tracts
Cardiac muscle (fxn)
Circulate blood
Cardiac muscle has this one special feature
Connected by intercalated discs w gap junctions
Which muscle groups are NOT capable of cell division to produce more muscle cells?
Not - Skeletal & cardiac
Is - Smooth
Endomysium
CT that surround muscle fibers
Fascicle
Fiber and endomysium bundled together
Perimysium
CT that surround fascicles
Epimysium
CT that surround skeletal muscle
Muscle fiber
Muscle cell, long and cylindrical, span entire length of muscle
Myofibrils
Cylindrical structures extending the entire length of muscle fiber
Myofilaments
Actin and myosin proteins organized into repetitive groupings, results in striations
Sarcomeres
Fxnal unit of skeletal muscle tissue; each individual sarcomere can contract, actin and myosin overlap and shorten sarcomere, when many sarcomeres shorten the entire muscle shortens
Tendons
Dense regular CT formed by merging all of CT layers surrounding muscle - epimysium, perimysium, endomysium
Sharpey’s fibers
Collagen fibers penetrating deep into cortical bone (outer layer of bones), anchors tendon to bone @ muscle origin and insertion pts
Neuromuscular junction
Where motor neuron meets the muscle fiber
Motor neuron
Nerve cell carrying electrical impulse to skeletal muscle to cause muscle to contract
Motor unit
Single motor neuron and muscle fiber it controls
All or none principle
All muscle fibers in a motor unit contacts completely if the motor neuron is innervated
Relationship between # of muscle fibers in motor unit and degree of control
The larger the motor unit, the more fibers contract at once, leading to large movement but less precise (ie shoulder)
Vice versa (ie hands and eyes)
Slow oxidative (SO) fibers
Aerobic, endurance, ie postural muscles
Fast glycolytic (FG) fibers
Anaerobic, glycogen broken down in glucose for fuel for muscle, instantaneous power, ie quads
Muscle atrophy
Reduction of muscle size, tone, power
Muscle hypertrophy
Myofibrils and myofilaments increase in #, resulting in muscle size incr
Parallel fascicle
All fibers lined up in one direction, flat, ie biceps brachii and rectus abdominus
Convergent fascicle
Fibers fanned out @ origin and converge onto one common tendon, ie pectoralis major
Pennate fascicle
Fibers merge w tendon @ an angle, gives muscle a larger cross sectional area = more force can be produced
Unipennate
Meet w tendon @ one angle
Bipennate
Meet w tendon @ two angles
Multipennate
Meet w tendon @ multiple angles
Circular fascicle
Make a circle, ie sphincters - when they contract, something closes
