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Muscle, classifications of muscle groups acc to their functions,…
Muscle
types of muscle
type 1
slow tonic movement
red in colour due to large amount of myoglobin
rich in mitochondria and oxidative enzymes
poor in phosphorylases
highly resistant to fatigue
type 2
Fast phasic movement
paler in colour due to smaller amount of myoglobin
rich in glycogen and phosphorylases
poor in mitochondria content
gets fatigued very easily
intermediate
simply type 2 muscle fibers but with good amount of resistance to fatiguedness
nerve supply of skeletal muscle
Motor fibers(60%)
large myelinated alpha efferents which supply extrafusal muscle fibers
small myelinated alpha efferents which supply intrafusal muscle
fine non-myelinated autonomic efferents supply smooth
Sensory fibers(40%)
myelinated fibers distributed to muscle spindles for proprioception , also to tendons
nerve supply of smooth muscles
Single unit type seen in intestine impulse reaches one muscle , is transmitted to other cells by mechanical pull through the fused cell membrane
Multi-unit type seen in the muscles of the ductus deferens each muscle cell receives a seperate nerve fibers(rich in nerve supply)
table 4.1
classifications of muscle groups acc to their functions
prime movers(bring desired movement)(when they help opposite action by active controlled lengthening against gravity it is known as action of paradox
Antagonists (oppose prime movers)(active controlled relaxations so that desired movement is smooth and precise(thus they cooperate them rather than oppose which is due to reciprocal innervation of the opposite muscle groups)(spinal cord through reflex arc)
fixators are the group of muscles which stabilizes the proximal joints of a limb so movement may occur at distil joint muscle on shoulder fix it for better movement of digits
synergids (when th eprime movers cross more than one joint the undesired actions at the proximal joints are prevented by certain muscles known as synergids)(during fist making wrist is kept fixed)
classifications of muscles
Spiral or twisted
Found in trapezius, pectoralis major, latissimus dorsi
Oblique Fasciculi(are oblique to the line of pull)
circumpennate(tibialis anterior
multipennate(deltoid)
bipennate(rectus femoris)
Unipennate(palmar interossei)
Triangular(temporalis)
parallel fasciculi(fascicule are parallel to the line of pull)
fusiform (biceps brachii)
strap-like with tendinous intersections(rectus abdominis)
strap-like(sternohyoid)
Quadrilateral(thyrohyoid)
Movement of muscle
isotonic(length of muscle decrease)
isometric(length may remain remain unchanged)
may increase acc to functional demanda
character of muscles
excitability, contractability, conductivity, excitability
Muscles that extend over 2 or more joints are called diarthic or polyarthric muscles
Muscle spindles are spindle shaped sensory end organs of the muscle
Motor point is the site where motor nerves enters the muscle
motor unit is defined as a single alpha motor neuron together with the muscle supplied by it
Hybrid muscle are supplied by 2 different motor nerves with different root values
nerve supply of cardiac muscle is sympathetic and parasympathetic nerve fibers