Human Anatomy Introduction PDF

INTRODUCTION TO HUMAN ANATOMY BY PROF.DR. ABEER EL-SAID EL-MEHI PROFESSOR OF ANATOMY AND EMBRYOLOGY FACULTY OF MEDICINE MENOUFIA UNIVERSITY INTEGUMENTARY SYSTEM  Integumentary system Skin Skin appendages  skin...

INTRODUCTION TO HUMAN ANATOMY BY PROF.DR. ABEER EL-SAID EL-MEHI PROFESSOR OF ANATOMY AND EMBRYOLOGY FACULTY OF MEDICINE MENOUFIA UNIVERSITY INTEGUMENTARY SYSTEM  Integumentary system Skin Skin appendages  skin ✓ It is the largest organ of the body. ✓ It covers the external surface of the body. Functions of the skin: ✓ Protection of the body from environmental effects e.g. invasion by micro-organisms and ultraviolet irradiation. ✓ Prevents excessive evaporation of water from skin surface, thus guarding against dehydration. ✓ Body temperature regulation by dilatation (cooling) and constriction (warming) of blood vessels. Moreover, heat induces sweat glands to secrete more, thereby cooling the body. ✓ Perceives external sensations e.g. pain and touch via sensory receptors. ✓ Synthesis and storage of vitamin D.  Layers of the skin Epidermis Dermis ▪ The ▪ The deep superficial layer. layer. ▪ Thicker. ▪ Thinner. ▪ Composed of ▪ Composed of connective epithelial tissue. tissue. ▪ Vascular. ▪ Avascular.  Skin appendages Hair and hair follicles Sweat glands Sebaceous glands Nails  Fascia Superficial ▪ Hypodermis or subcutaneous tissue. ▪ Lies just deep to and is attached to the dermis of the skin. ▪ It is made up of loose connective tissue containing a variable amount of fat. Fascia Deep ▪ A tough dense fibrous membrane deep to the superficial fascia. ▪ In the limbs, it sends inward extensions (intermuscular septa) which form separate compartments for groups of muscles with similar functions and innervations. ▪ It may be absent e.g. face & anterior abdominal wall. ▪ Forms thickened bands (retinacula) around wrist and ankle to keep tendons in place. ▪ Thickened in palm and sole for protection of underlying structures. MUSCULAR SYSTEM  Types of muscles Skeletal Cardiac Smooth ✓ Mostly attached to ✓ In the wall of the heart In the walls of blood the skeleton. (myocardium). vessels and hollow organs ✓ Acts voluntarily. ✓ Acts involuntarily. (viscera). ✓ Supplied by ✓ Supplied by autonomic Acts involuntarily. somatic nerves. nerves. Supplied by autonomic nerves.  Skeletal muscles ✓ The most abundant muscle type in the body. Parts of the muscle: ✓ Origin: usually the proximal end of the muscle, which remains fixed during muscular contraction. ✓ Insertion: is usually the distal end of the muscle, which is movable. ✓ Belly: the fleshy part of the muscle.  Skeletal muscles Types of muscle attachment: ✓ Tendon: a rounded cord of fibrous tissue. ✓ Aponeurosis: a thin sheet of fibrous tissue often with flattened muscles. ✓ Raphe: an interdigitation of the tendinous ends of fibers of flat muscles holding the muscles together.  Skeletal muscles Action of skeletal muscles: A muscle may work in the following ways: ✓ Prime mover (agonist): is the main muscle responsible for producing a specific movement of the body. ✓ Antagonist: A muscle that opposes the action of prime mover is an antagonist. ✓ Fixator: A muscle that contracts isometrically to increase the tone but not produce movement to stabilize the origin of the prime mover to act efficiently. ✓ Synergist: assists the action of a prime mover.