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Muscular System. Functions. Muscle Tissue. Refers to all the contractile tissues of the body. Skeletal=attached to skeleton. Cardiac= heart muscles Smooth= muscles of organs. TYPES. Smooth Cardiac Skeletal. Smooth Muscle. Cells are small spindle shaped
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Muscular System Functions
Muscle Tissue • Refers to all the contractile tissues of the body. • Skeletal=attached to skeleton. • Cardiac= heart muscles • Smooth= muscles of organs
TYPES • Smooth • Cardiac • Skeletal
Smooth Muscle • Cells are small spindle shaped • Non-striated (striations are dark lines of tissue ) • Involuntary muscle • Found in organ groups..Example: intestinal, bladder, blood vessels. • Muscle contractions are rhythmic and slow.
Cardiac Muscle • Requires continuous O2 • Only in the heart • Striated • Involuntary • Muscle contractions are rhythmic & automatic
Skeletal Muscle • Attached to the bones of skeleton • Voluntary muscle…contains nerves under voluntary control • Composed of bundles of muscle cells • Each cell is Multinucleated. • Each cell is a muscle fiber • Cell membrane=SARCOLEMMA • Cytoplasm=SARCOPLASM
Characteristics…. • Contractibility: muscles shorten and tighten…which in turn, brings the two ends of the bone closer together..which is movement..
Characteristics…cont’ • Excitability: or irritability.. The ability to respond to certain stimuli..producing signals called action potentials= impulses..(nerve impulses) • Extensibility: The ability of the muscle to be stretched.
Characteristics…cont’ • Elasticity: The ability for a muscle to return to its original shape when relaxing.
Attachments….. • Origin: point where muscle is attached to bone that moves very little • Insertion:point where muscle isattached to bone that moves. • Belly: central part of the muscle
Contraction of Skeletal Muscle • Movement occurs as a result of 2 major events: • Nerve stimulation : message sent thru nerves to the muscle.. • Action potential: the muscle receives the stimuli, and contracts as a result.
Muscle Groups • Head and Neck • Upper Extremities • Trunk • Thorax & Abdomen • Posterior & Anterior • Lower extremities
Major Muscles of theHead & Neck….. • Temporalis: at the temple • Frontalis: forehead • Masseter: cheek • Orbicularis oculi: around the eye • Sternocleidomastoid: Behind the ear to the clavicle • Trapezius: Back of the head (occipital) to the shoulder. • Orbicularis oris: around the mouth • Zygomaticus major: cheekbone to orbicularis oris • Nasalis: muscles of the nose