Be 3142 muscle system

·       What are 4 characteristics of muscle tissue: contractability, extensibility, excitability, elasticity.

·       Contractability: the ability of muscle tissue to shorten or contract.

·       Extensibility: the ability of muscle tissue to be extended or stretched within limits.

·       Excitability: the susceptibility of muscle tissue to react to external stimuli allowing it to react instantly when stimulated.       

·       Elasticity: the ability of muscle tissue to return to its original state after being stretched.

·       Skeletal muscle: Muscle that acts on the skeletal system, striated, voluntary

·       Cardiac muscle: muscles of the heart, striated involuntary

·       Smooth muscle: lines organs, vessels, and gland ducts, not striated, involuntary

·       Actin: Found in Thin filaments of sarcomeres within myofibrils, 2 regulatory proteins, tropomyosin and troponin

myosin: Found in Thick filaments of sarcomeres within myofibrils

·       Myofibril: One of the longitudinal fibrils found in skeletal and cardiac muscle fibers.

·       myofilament: A protein filament that makes up the myofibrils in skeletal muscle.

·       Muscle fiber: myofiber/muscle cell consists of bundles of myofibrils
surrounded by sarcolemma

·       The origin of a muscle: the more stable (less moveable) point attachment to the skeleton.

·       The insertion of a muscle: the point of attachment that is more moveable (less fixed).

·       fascia: Sheath of dense connective tissue that envelops the body beneath the skin, encloses muscles, and separates their various layers or groups.

·       What are the criteria used in naming muscles: structure, function, shape, location, and number of heads.

·       Example of structure in muscle name: Rectus abdominis

·       Example of function in muscle name: Depressor labii inferioris

·       Example of shape in muscle name: deltoid

·       Example of location in muscle name: tibialis anterior

·       Example of number of heads in muscle name: quadriceps

·       Circular muscle: Fascicles arranged concentrically around an opening, acts as a sphincter to close a passageway or opening (e.g., orbits, mouth, anus).

·       Parallel muscle: Fascicles are parallel to the long axis of the muscle, Body of muscle increases in diameter with contraction, High endurance, not very strong

·       Convergent muscle: Triangular muscle with common attachment site, Direction of pull of muscle can be changed, Does not pull as hard as equal-sized parallel muscle

·       Pennate Muscle: muscle body has one or more tendons, Fascicles at oblique angle to tendon Pulls harder than a parallel muscle of equal size

·       Unipennate muscle: All fascicles on the same side of the tendon

·       Bipennate muscle: Fascicles on both sides of the tendon

·       Multipennate muscle: Tendon branches within the muscle

·       Ligaments: attach bone to bone and increase joint stability during action.

·       Muscle tendons: attach muscle to bone.

·       Aponeurosis: are large sheets of connective tissue that act as ligaments for larger muscles.

·       Somatic Motor neuron – a neuron that innervates that extends from the brain and spinal cord to innervate skeletal muscle fibers

o   Has a long extension called the axon

o   Nerve fiber that branches extensively at its terminal end

·       Neuromuscular junction – the junction between the axon and the muscle fiber

o   Created when the synaptic knob of a nerve cell (neuron) contacts and innervates muscle fiber

·       Muscle fibers – individual muscle cell that receives signals from the neuron and contracts

·       Flexion – angle between articulating bones decreases

·       Extension – angle between articulating bones increases

·       Lateral flexion – vertebral column moves (bends) in a lateral direction along the coronal plane

·       Abduction – lateral movement of a body part away from the midline

·       Adduction – medial movement of a body part toward the midline

·       Circumduction – continuous movement that combines flexion, abduction, extension, and adduction (circular movement)

·       Pronation – rotation of the forearm where the palm is turned posteriorly

·       Supination – rotation of the forearm in which the palm is turned anteriorly

·       Depression - Movement of a body part inferiorly

·       Elevation - Movement of a body part superiorly

·       Dorsiflexion - Ankle joint movement where the dorsum (superior surface) of the foot is brought closer to the anterior surface of the leg

·       Plantar flexion - Ankle joint movement whereby the sole of the foot is brought toward the posterior surface of the leg

·       Inversion - Twisting motion of the foot that turns the sole medially or inward

·       Eversion - Twisting motion of the foot that turns the sole laterally or outward

·       Protraction - Anterior movement of a body part from anatomic position

·       Retraction - Posterior movement of a body part from anatomic position

·       Opposition - Special movement of the thumb across the palm toward the fingers to permit grasping and holding of an object

·       Muscles develop from the mesoderm, and they organize into muscle tissue

·       Primordial muscles migrate down the developing limb bud and construct groups (compartments) around the underlying skeletal structures

·       Dense (fascia) connective tissue separates individual muscles from one another

·       Deep (fascia) connective tissues divide compartments of muscle from one another – and creates passageways for neurovascular bundles

·       Agonists:  muscles whose sole, or primary movement, elicits a particular action.

·       Synergists: Muscles in the same compartment often have the same action, or similar actions

·       Antagonists: Muscle compartments on opposing surfaces of the body, or appendages, have opposing actions.

•        Laterally placed/inserting mm. are generally abductors that move the appendages _____ from the midline:  away

•        Medially placed/inserting mm. are generally adductors that move the appendages _____ from the midline: toward