Muscular System

Types of Muscular Tissue

Characteristics of Muscle

Connective Tissue of Muscle

Function of Muscle

Anatomy of Muscle Fibers

Types of Body Movement

Motor Neuron

Motor Unit

Neuromuscular Junction

Muscle Contraction

Sliding Filament Theory

Muscle Relaxation

Cardiac-Cells are long, cylindrical, branched, has single central nucleus, has striations,forms heart wall, joined to another cells at inter-located disc, Involuntary

Smooth-Spindle-shaped cells with single central nucleus, has no striations, found mainly in hollow walls of organs and eyes (controls size of pupil), involuntary

Skeletal-Cells are long, cylindrical, parallel and multi nucleated, attached by tendons to bones, striated-visible bonding, voluntary-subject to conscious control

Motion-Change in body position

Movement-Of substances within the body

Stabilizing-Joints, body posture, regulating organ volume

Thermogenesis-Heat production

Irritability-Ability of muscles and nerves to respond to stimulus b producing electrical signals action potentials

Contractility-Ability to shorten when adequate is recived

Epimysium-Covers the entire skeletal muscle , three layers come together to form tendons

Tendons-Attach muscle to periosteumof bones

Perimysium-Around a fascicle (bundle of muscle fiber)

Aponeurosis-Broad band of CT which form a flat layer of tendons

Endomysium-Around single myocyte=muscle fiber=muscle cell

Fascia (bandage)-Thin band of fibrous CT under the skin or around organs

Naming of Skeletal Muscle

Location of the muscle: Many muscles are named for bones (Temporalis)

Shape of the muscle: Deltoid (Triangular)

Location of the muscle origin and insertion: Sterno (On the Sternum)

Relative size of the muscle: Maximus (Large)

Action of the muscle: Flexor and extensor (Flexes or extends a bone)

Direction of muscle fibers: Rectus (Straight)

Number of origins: Triceps (Three heads)

Hyperextension-Extension beyond 180 degrees

Rotation-Movement of a bone around a longitudinal axis

Extension-Movement that increases angle of joint

Abduction-Movement of limb away from midline

Flexion-Movement that decreases angle of joint

Adduction-Movement of limb toward the midline

Circumduction-Proximal end of a limb is stationary and the distal end moves in circles

Dorsiflexion-Lifting the superior surface of foot towards shin

Plantar flexion-Pointing toe

Inversion-Turn sole of foot medially

Eversion-Turn sole of foot laterally

Supination-Forearm rotates laterally so palm faces anteriorly

Pronation-Forearm rotates laterally so palm of hand faces posteriorly

Opposition-Movement of thumb to touch tips of other fingers

Nerve cell that stimulates skeletal muscle

Made of one motor neuron and all muscle fibers

Large-Controls large movements

Small-Control precise movements

Synaptic cleft-Gap between neuron and sarcolemma

Acetylcholine-Neurotransmitter for skeletal muscle

Neurotransmitter-Chemical messenger sore and release by synaptic vesicles into synaptic cleft

Axonal terminals-Ends of axons, mainly branches

Axon-Long portion of nerve, releases a chemical called neurotransmitter

Synaptic end bulb-Found in axonal terminal(Contains synaptic vesicles)

Synapse-Connection between nerve with muscles and other organs

Motor end plates-Region across synaptic cleft from the synaptic end bulb (On muscle fibers)

Nerve impulse or action potential travles down sarcolemma and into T-tubles, causing sarcoplasmic reticulum to release Ca++ into Sarcoplasm

Ach is broken down by an enzyme called Acetylcholinesterase, Actin potentials are no longer generated so the Ca++ channels in SR close, Resting potential is reached when Na+ returns to its initial position

Nerve impulse reaches synaptic end bulbs and causes synaptic vesicles to fuse with neurolemma and release ACH

Myofibrils- Made of myofilaments

Thin Myofilaments-Primarilt actin

Thick Myofilaments-Myosin

Myosin-have cross bridges (links thin and thick filaments

Sarcolemma-cell membrane of muscle

Sarco=flesh

Sarcoplasm-cytoplasm of muscle cell

Sarcoplasmic reticulum-specialized smooth endoplasmic reticulum storage and release of calcium when muscle contracts, fuse to form cisternae

Transverse tubules(T-tubules)-infoldings of sarcolemma that penetrate into muscle fiber; filled with extracellular fluid

Myofibril-bundles of myofilaments aligned to give distinct bands

Sarcomere-one contractile unit or section of myofibril, extends from z line to z line

I band= Light band (Thin filament only)

Z line- dark midline of I band

A band= Dark band (thick and thin filaments)

H zone-lighter central area of A band (thick filaments only)

M line- central line of H zone