Musclar System Structure Flashcards
Skeletal Muscles System
Striated, Somatic, Voluntary
Function- To move & stabilize bones
Cardiac Muscles
Striated, Visceral, involuntary
Forms the heart- Myocardium
Function- Pump the blood
Smooth Muscles
Smooth, Visceral, Involuntary
Forms the walls of blood vessels and viscera.
Function- Movement (peristalsis) Controls flow.
Head or Bellies of Muscles
Fleshy, reddish, contractile portion composed of skeletal muscle.
Tendon
White, non-contractile portions composed of organized collagen.
Attaches muscles to the bones
***Continuation of CT (Connective Tissue) that surrounds each muscles.
***Included when measuring the length of a muscle.
Aponeurosis
Flattened tendon that attaches muscles to bones and other muscles.
Naming of Muscles
Named by bones to which they are attached.
Size – gluteus maximus m.
Shape – trapezius, rhomboid, deltoid mm.
Location – rectus abdominis, occipitalis and subclavius mm.
Action – abductor digiti minimi and adductor pollicis mm.
Length – extensor carpi radialis longus and flexor pollicis brevis mm.
Flat Muscles
Flat has parallel fibers, often with an aponeurosis
Fusiform
spindle shaped with a round, thick belly (bellies) and tapered ends
Pennant Muscles:
Unipennate
Bipennate
Multipennate
feather-like in arrangement. May be:
o Unipennate – fibers on one side of tendon
o Bipennate – fibers on both sides of tendon
o Multipennate – radiating fibers that converge on a central tendon
Quadrate
Have four equal side
Circular (Sphincteral)
surround body opening or orifice, constricting it when contracted
Multi-headed (Multi-bellied)
have more than one head of attachment or more than one
contractile belly
Attach of Muscles:
Origin-
Insertion-
O- Proximal attachment and usually remains fixed during muscular contraction.
I- distal attachment and some muscles have dual origin and insertions
Reflexive Contraction
automatic aspect of certain skeletal muscle activity
Myotatic Reflex
movement of a muscle after a stretch to tendon has been induced by tapping with a hammer
Tonic Contraction
slight contraction present in muscles even when “relaxed”.
Does not produce movement or active resistance
Gives muscle a certain firmness to stabilize joints and maintain posture
Keeps muscles ready to respond
Absent when in deep sleep, under anesthesia and after paralysis
Paralysis would result in atrophy (wasting) of the muscle
Isometric Contraction
Muscle length remains the same.
Muscle tension is increased above tonic levels.
Resists gravity or other antagonistic force
Isotonic
2 types:
Muscle changes length in relationship to production of movement.
Concentric- movement occurs as a result of muscle shortening.
Eccentric- Lengthening of a contracting muscle.
Flat Muscles
Flat has parallel fibers, often with an aponeurosis
