Lecture 2: Skin & Fascia (PowerPoint) PDF

Lecture-2 Skin & fascia Prof Omnia Sameer Asst. Prof. Dr. Marwa El-sayed Abd El-kader Learning Outcomes At the end of the lecture, the students should be able to: Identify the function and structure of the skin. Describe the different skin appendages....

Lecture-2 Skin & fascia Prof Omnia Sameer Asst. Prof. Dr. Marwa El-sayed Abd El-kader Learning Outcomes At the end of the lecture, the students should be able to: Identify the function and structure of the skin. Describe the different skin appendages. Describe the types & function of fascia. Compare different types of muscles.  General anatomy for dental students BMS112 Midterm OSPE=20 Final=40 Quizzes=20 =20% % % % 1) Function of the skin. 2) Structure of the skin. 3) Skin appendages. 4) Superficial Fascia. 5) Deep Fascia. 6) The Muscles.  The skin ❖ Definition: It is the largest organ that covers the whole body. Epidermis ❖ Structure: Dermis It is formed of dermis & epidermis.  Function of the skin Protection Protection Excretion Skin Absorption Heat Vit D Regulation Formation Sensation  The Epidermis ❖ Definition: It is the superficial layer of the skin The superficial layer Formed of flat cells filled with keratin The deep layer Cells has the capacity for regeneration Avascular but has sensory nerve endings  The Dermis ❖ Definition: It is the deep layer of skin ❖ Formed of: Connective tissue ❖ Content: 1. Blood vessels 2. Lymph vessels 3. Sensory nerve endings 4. Smooth muscle 5. Hair follicles 6. Sweat gland 7. Sebaceous gland  lines of cleavage (langer’s lines) ❖ Definition: The collagen fibers in its deep part are arranged in parallel rows; longitudinally in the limbs & circumferentially in the neck & trunk. ❖ Importance Determine the direction for an incision (cut) during surgery to avoid obvious scars. Appendages of the skin  1. Hairs ❖ Parts Root: embedded in the skin. Shaft: project on the surface. Hair follicles: is formed by the root of the hair and surrounding sheath of epidermal cells. Arrector pili muscle: A band of smooth muscle innervated by sympathetic nerve fibers, so it is involuntary. Its contraction moves the hair to a more vertical position and squeezes the sebaceous gland to extrude its secretion.  2. Sebaceous Gland Its duct opens in the hair follicle. It secrets sebum (an oily material that softens the skin and lubricates the hair)  3. Sweat glands ❖ Its duct open on the surface of skin. ❖ It secretes sweat. ❖ Apocrine sweat glands (in axilla, external genital organs) function at puberty & its sweat has a characteristic odor.  4. Nails ❖ Definition : Keratinized plate ❖ Site : On the dorsal surface of the distal phalanx of the fingers & toes. Self- Assessment 1) Which of the following structures could be found in the epidermis? a) Blood vessels. b) Lymph vessels. c) Muscles. d) Glands. e) Free nerve ending. 2) The cleavage lines present in………. a) Epidermis b) Superficial part of the dermis c) Deep part of the dermis d) Superficial fascia e) Deep fascia 3) The duct of Sebaceous gland opens into………… a) Hair Root b) Hair Shaft c) Hair Follicles d) Hair Papilla e) Surface of the Skin The fascia  Superficial Fascia Character: Loose except in some areas (eg: sole, palm, scalp) Functions: 1. Bad heat conductor (keeps the body temperature). 2. Gives the body smooth rounded appearance (particularly in females). 3. Facilitates movement of the skin over the underlying structures. Content: Nerves Blood vessels Fat Content of Superficial Fascia Blood Vessels Nerves Muscles as Platysma  Deep Fascia Characters Dense and usually form membranes Forms special structures Investing fascia Intermuscular septa Sheathes for neurovascular bundles  Deep Fascia Characters Dense and usually form membranes Forms special structures Aponeurosis Aponeurosis  Functions of the deep fascia 2) Intermuscular septa prevent spread of blood or pus 1) Gives attachment to some muscles 3) Muscle pump helps venous return  Functions of the deep fascia 4) Retinacula hold the tendons in place to 5) The palmar and plantar aponeuroses facilitate the action of muscles protect the deep structures The Muscles  The Muscles Definition: the red fleshy contractile tissue which is responsible for movements. 1. Smooth 2. Cardiac 3. Skeletal Site Wall of internal viscera & Heart (In myocardium) Attached to the skeleton blood vessels Nerve Supply Autonomic Autonomic Somatic Contraction Involuntary Involuntary Voluntary Striation Absent Present Present  The Skeletal Muscles Definition Muscles attached to the skeleton to generate movement Parts of skeletal muscle: 1) Red fleshy contractile part between the two tendons called muscle belly. 2) White fibrous non contractile part called tendon (rounded cord like) or aponeurosis (flat sheet). Attachment Origin: is the more fixed attachment. Insertion: is the more mobile attachment. The muscle may be attached to: Bone, Cartilage, Ligament, Fascia, Skin, Other muscle.  Classification (Types) of skeletal muscles 1. Prime movers: - Initiate particular movement. 2. Antagonists: - Oppose the action of prime movers. 3. Fixators (Stabilizers): - Help the prime mover by fixing (stabilizing) its origin.  Type of injections (Applied Anatomy) Site Angle Example Intradermal Dermis 10-15o Botox Subcutaneous Superficial fascia 45 o Insulin Intramuscular Muscle 90 o Antibiotic Self- Assessment 1) One of the functions of superficial fascia is a) Gives the body smooth rounded appearance b) Forms intermuscular septa c) Forms sheathes for neurovascular bundles d) Forms palmer aponeurosis e) Forms retinacula 3) ……….hold the tendons in place to facilitate the action of muscles a) Intermuscular septa b) Retinacula c) Aponeurosis d) Investing fascia e) lines of cleavage 4) Muscles opposing action of prime movers are called: A. Synergists. B. Fixators. C. Antagonists. D. Stabilizers. E. Prim mover