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Lecture 2 Integumentart7tv7v7v6vy System.pptx
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- 2. Arrangement of variousstructures of body 1. Skin 1. Epidermis (thinner outer layer of skin) 2. Dermis (thicker connective tissue layer) 2. Hypodermis (subcutaneous layer or Superfacial fascia) 3. Deep fascia 4. Muscles 5. Nerves, vascular& lymphatics 6. Bones
- 3. Skin or integument Skin •First layer of body • Largest organ of the body in surface area and weight. • Skin is 16% of total body weight. • Complex cutaneous membrane composed of two types of tissues. i. Epithelium ii. Connective tissue • Surface area of skin is 1.5 to 2 square meter.
- 4. Skin Physiology.. Function RegulateBody Temp – Sweat glands (Evaporation) – Changes in peripheral blood flow • Vasoconstriction • Vasodilation – Adipose tissue- insulates – Hair- insulates Protection- Physical barrier – Abrasion – Infectious agents – UV radiation – Dehydration Sensation – Nerve endings and receptors detect • Temperature • Touch • Pressure • Pain Excretion – Heat – Water – Salts – Organic Compounds
- 5. Skin Physiology.. Function BloodReservoir – 8-10% of total blood – Skin blood flow easily varied Vitamin D3 (cholecalciferol) synthesis – Precursor molecule(7-dehydrocholestrol) in skin – Must be activated by UV light Cutaneous Membranes – Protect internal and external tissues
- 6. INTEGUMENTARY SYSTEM This systemis divided into: 1. Skin 2. Hair 3. Glands 4. Nails 5. Nerve endings Dermatology is the medical specialty concerned with the diagnosis and treatment of skin disorders.
- 8. 1. Epidermis (stratifiedsquamois epithelium) • Epidermis is avascular keratinized epithelium with five distinct layers. 1. Stratum corneum 2. Stratum lucidum 3. Stratum granulosum 4. Stratum spinosum 5. Stratum basale 2. Dermis (true skin) 6. Papillary layer 7. Reticular layer Skin
- 9. A. Cells ofEpidermis 1. Keratinocytes • Produce Keratin • Fibrous Protein 2. Melanocytes • Synthesize the pigment Melanin • Accumulate in granules called Melanosomes • Protect Nucleus from UV Radiation 3. Merkel Cells Light Touch Receptor 4. Langerhans’ Cells • Macrophages • Activate Immune System 1. Epidermis
- 11. B. Five layersof the epidermis: 1. Stratum corneum (horny layer) - This layer has many rows of dead cells filled with keratin - Continuously shed and replaced (desquamation) - Effective barrier against light, heat and bacteria - Dandruff and flakes 2. Stratum lucidum - Seen in thick skin of the palms and soles of feet - “Keratohyalin” (precursor) to keratin
- 13. 3. Stratum granulosum -Keratohyalin granules (darkly stained) accumulate - These granules secrete glycolipids into extracellular spaces to slow water loss in the epidermis 4. Stratum spinosum: - “spiny layer, spinous layer/prickle cell layer” 5. Stratum basale: deepest epidermal layer - Attached to dermis - Rapid mitotic division (also called as stratum germinativum) - Contain Merkel cells and Melanocytes
- 15. • Cells: fibroblasts,macrophages (WBC),mast cells (histamine). • Nerves, blood and lymphatic vessels 2. Dermis /Corium A. Cells of Dermis • Flexible, elastic and strong connective tissue • Oil and sweat glands originate
- 16. 1- Papillary layer: •Loose connective tissue with surface projection called dermal papilla. • Capillaries • Contain pain & touch receptors • Dermal ridges- epidermal ridges- pattern called fingerprints B. Two layers of the dermis: 2- Reticular layer: • Dense irregular connective tissue • Collagen fibers offer strength & holds water • Dermal tearing causes stretch marks.- striae • Blood vessels • Sweat glands
- 17. Skin color: 1. Yellowtinge due to Carotene 2. Reddish hue or pinkish tone is due to blood (Haemoglobin)- blushing 3. Brown shade due to melanin 4. Redness (erythema) - reddened skin, embarrassment, fever, hypertension, inflammation, or allergy 5. Pallor/blanching - pale skin, emotional distress or anemia, low blood pressure 6. Jaundice - liver disease, bile deposited in tissue 7. Bronzing - bronze coloration (Addison's disease) hypo-function of adrenal cortex 8. Black & blue - bruises, escaped blood clots in tissue spaces (clotted blood masses = hematomas)
- 18. Other characteristics Finger prints •Ridges &groves found on finger tips, palm, toes and sole • Appear in 3rd & 4th month of development • Identification of individuals Creases • Flexor lines over joints • Skin is thin & attached to deep fascia Langer’s lines • Tension lines • Incision parallel to these heals quick & have less marks • Circumferential in trunk and neck, longitudinal in limbs
- 19. Appendages of skin •Hair • Cutaneous glands • Nails
- 20. Hair..pilus or pili •Elastic, keratinized thread like structures • Develop from epidermis • Present on entire body except palm, soles. • Main function is protection • Each hair has two parts – Shaft is superficial and Root is embedded portion • Root is enclosed in a tubular hair follicle, lower part of which is hair bulb. • Papillae are present in the bulb, sites for blood supply nourishment. • Hair follicles have sebaceous glands. • Arrector pilorum are muscles responsible for erection of hair in fear and cold. • Normal hair loss is 70-100 per day.
- 22. Two types ofglands exist in the integument. 1. Sebaceous glands (oil glands) 2. Sudoriferous glands (sweat glands) 3. Ceruminous glands 1. Sebaceous glands: (holocrine glands) - Connected to hair follicle - Not found on palms and soles of feet - Secretes sebum (oily material) - Keep hair from drying out, keeps skin moist - Whiteheads, blackheads and acne Glands:
- 24. Whitehead: When thetrapped sebum and bacteria stay below the skin surface, a whitehead is formed. Blackhead: A blackhead are formed when the trapped sebum and bacteria partially open to the surface and turn black due to melanin, the skin's pigment.
- 25. 2. Sudoriferous glands:exocrine glands –Millions located throughout the skin A. Merocrine (more common) –Originate in subcutaneous layer –Duct empties on skin surface –Palms and soles of feet –Sweat is watery (99% H20) –Sweating regulated by sympathetic nervous system B. Apocrine –Axillary and pubic region –Duct empties onto hair follicle –Viscous fluid –Causes body odour when bacteria break it down
- 27. 3. Ceruminous glands –Located in ear only – Modified apocrine glands – Originate in sub cutaneous layer – Ducts open onto ear. – Produces cerumen (ear wax) • Brown sticky substance that prevents foreign material from entering.
- 28. • Specialized keratinplates present on the dorsal surfaces of distal phalanx of fingers and toes. • Produced by cells in the epidermis 1. Nail plate (body): visible portion 2. Nail root: hidden under cuticle in nail groove 3. Nail folds: skin folds bounding the nail grooves 4. Free edge; overhangs 5. Nail bed: located under nail plate 6. Lunula: half moon crescent shaped white portion under cuticle 7. Nail matrix: growing portion below proximal nail fold Hypoxia: Rate of growth; Nails:
- 30. Blood and nervesupply of skin: • Blood supply through a network of vascular plexus by arterial blood from subcutaneous arteries and drained to subcutaneous veins. • Skin contain numerous nerve endings for secretions and sensations.
- 32. Superfacial fascia • Subcutaneoustissue is the second layer of body beneath the skin. – Outer fatty layer – Inner fibrous layer • Fat more in women than in men • Most abundant in buttocks • Absent in eyelids, pinna of ear, male genitalia. • Adherent to skin and deeper structures. • Mostly thin but thick in anterior abdominal wall • Contains nerves, blood vessel and lymphatics • In face and neck contains skeletal muscles
- 33. Main functions • Padding •Storage of fuel in the form of fat. • Non conductor - stores body heat
- 34. Deep fascia • Thirdlayer • Thick and in-elastic • Several layers of dense fibrous connective tissue • No fat • Continuous throughout body • ill defined in face and trunk, well defined in limbs and neck
- 35. Deep fascia Inlimbs • Tight sleeves • Inter-muscular septaum • Retinacula • In palm and soles • Muscles attachment on deep fascia
- 38. Functions • Invests theanatomic structures • Bind together two or more structures. • Sends partitions & form fascial compartments e.g; pectoral fascia, flexor retinaculum.
Editor's Notes
- #11 Keratohyalin is associated with eleidin, the intermediate between keratohyalin and keratin; histological location is in the stratum lucidum, thick skin. Keratohyalin is a protein structure found in granules in the stratum granulosum of the epidermis, which may be involved in keratinization, and in Hassall's corpuscles in the thymus.