Demonstrator of anatomy: Elham G. El-yamany Muscle Demonstrator of anatomy: Elham G. El-yamany

(A) Skeletal Muscle  Produce the movements of skeleton.  Voluntary muscles.  Has 2 attachments at least; origin & insertion.  Fleshy part of muscle called belly.  The ends of ms. Are attached to : bone, cartilage or ligaments.

 The attachment of ms. to bone may take one of following shapes : 1.Tendon; a cord of fibrous T. 2.Aponeurosis;Strong sheet of fibrous T.

3. Raphe; interdigitation of tendinous ends of fibers of flat muscles.

Internal structure of skeletal muscle  Muscle is formed of muscle fibers.  ms. fibers are adherent together by C.T. called endomysium.  ms. fibers are arranged in bundles which are connected together by perimysium.  all ms. bundles form the ms. which is enveloped from outside by a C.T. layer called epimysium.

Classification of skeletal muscles (according to direction of ms Classification of skeletal muscles (according to direction of ms. fibers) (A) Parallel : ms. fibers are parallel to the long axis of ms. as sternocleidomastoid, rectus abdominis and sartorius.

(B) Pennate : ms. fibers run obliquely to the line of pull (resemble a feather). 1. Unipennate : tendon lies along one side of ms. & ms. fibers pass obliquely to it; as extensor digitorum longus. 2. Bipennate : tendon lies in center of ms. & ms. fibers pass to it from both sides as rectus femoris. 3. Multipennate : as a series of bipennate ms. lying alongside one another or as a tendon lying in its center and ms. fibers passing to it from all sides; as tibialis anterior.

Nerve Supply of Skeletal Muscle  nerve trunk to a ms. : is a mixed nerve containing: 1. motor fibers (60%). 2. sensory fibers (40%). 3. some sympathetic fibers.  motor point : is point of entrance of nerve to muscle. This usually lies at the middle of its deep surface near the margin of the ms.  naming of skeletal ms. : is according to : shape, size, heads, position, depth, attachments or actions.

(B) Smooth Muscle ● Long spindle-shaped cells, closely arranged in bundles. ● In G.I.T, it is responsible for peristalsis, which is a wave of contraction that runs along the digestive tube. ● This movement is responsible for : 1. propelling contents through lumen. 2. mixing ingested food with digestive juices.

● In storage organs, such as urinary bladder & uterus, its contraction is slow & helps in expulsion of the contents of the organ. ● In walls of blood vessels, smooth muscles modify caliber of the lumen. ● It is involuntary in action, and its stimulation to contract is either by autonomic nerves or by hormonal stimulation.

(C) Cardiac Muscle ● Striated muscle consisting of muscle fibers which branch & unite with each other. ● Forms myocardium of heart. ● Has property of spontaneous & rhythmic contraction. ● Conducting system of heart is formed of specialized cardiac muscle fibers. ● Involuntary & supplied by autonomic nerve fibers.