Integumentary System Lecture Notes PDF

September 5, 2023 1. Lecture #4 – The Integumentary System. 2. I clicker questions at end of lecture  Integumentary System Lecture 4 MTT, chap. 4, pgs. 88 - 110 I. Introduction A. largest organ system B. compos...

September 5, 2023 1. Lecture #4 – The Integumentary System. 2. I clicker questions at end of lecture  Integumentary System Lecture 4 MTT, chap. 4, pgs. 88 - 110 I. Introduction A. largest organ system B. composed of epithelial, muscle, nervous & connective tissues C. significant effect on self image D. clinically relevant as an indicator of disease as well as site of many disorders II. Tissue Layers epidermis, dermis, hypodermis. epidermis 1. cell types a. keratinocytes – 90% i. deepest layers are mitotically active ii. produce keratin b. melanocytes – 8% i. synthesize melanin ii. protect from UV radiation c. Langerhan’s cells (Dendrocytes) – macrophages d. Merkel’s cells – sensory receptors 2. sparse vascularizaiton 3. organization a. stratum basale (stratum germinativum) (1) single, deepest layer, in contact with dermis (2) mitotically active, cuboidal cells b. stratum spinosum (1) layers of stratified squamous cells (2) appear spiny upon preservation (3) limited mitotic activity c. stratum granulosum (1) three to four layers of granulated cells (2) cells produce keratin and keratohyalin d. stratum lucidum (1) flattened, densely packed and keratin filled cells (2) only present in palms & soles e. stratum corneum (1) 25 – 30 layers of flattened, dead, interlocking cells (2) only contain keratin B. dermis 1. deeper and thicker than epidermis 2. elastic and collagen fibers 3. extensive vascularization 4. contains sweat and sebaceous glands, hair follicles, sensory receptors, nerves C. hypodermis 1. loose connective and adipose tissues 2. attaches to underlying structures 4. skin colorization a. melanin i. black pigment produced by melanocytes ii. color variation due to amt of melanin produced iii. protects stratum basale from UV radiation iv. radiation stimulates melanin synthesis v. other melanocyte induced skin changes (1) freckles - melanocyte aggregations (2) albinism - lack of tyrosinase (3) vitiligo - lack of melanocytes in area (4) hyperkeratosis – benign melanocyte proliferation b. carotene i. yellowish pigment from some plants ii. accumulates in stratum corneum iii. amt present determined genetically c. hemoglobin i. oxygen binding pigment in erythrocytes ii. oxyhemoglobin pink in color iii. cyanosis – bluish hue occuring with hypoxia III. Functions of Skin A. physical protection 1. barrier against microorganisms, water & radiation 2. friction increases thickness (callus) B. hydroregulation 1. virtually waterproof 2. prevents dehydration or water absorption C. thermoregulation 1. effector for temperature control 2. evaporative heat loss via perspiration 3. radiant loss, controlled by vasoconstriction D. synthesis 1. products of skin include melanin and keratin 2. UV radiation required for Vitamin D activation E. absorption 1. UV light, respiratory gases, steroids, fat-soluble vitamins, certain toxins and pesticides 2. used as drug delivery mechanism, i.e. transdermal patches a. fentanyl – analgesic b. birth control c. nicotine d. nitroglycerine F. sensory reception (discussed in lecture #15) 1. dermis contains sensory receptors, including a. temperature b. pressure c. touch d. vibration e. pain G. communication 1. facial muscles muscles produce expressions of love, hate happiness, etc. 2. emotions expressed in skin color (blush, pale) VI. Epidermal Derivatives A. hair 1. function a. protection b. filters particulates c. sensation d. sexual attraction 2. anatomy a. shaft – column of keratinized cells b. root – portion of hair below surface c. follicle – tube like depression d. arrector pili i. smooth muscle cells attached to follicle ii. contracts with cold and emotional crisis 3. hair color a. result of amt and type of pigment b. black vs. blond – determined by amt of melanin present c. red – trichosiderin (iron containing pigment) d. grey – lack of pigmentation, air bubbles B. nails 1. function a. protects end of fingers b. object manipulation 2. anatomy a. nail body(plate) d. eponychium (cuticle) b. lunula e. hyponychium c. nail root C. glands 1. sebaceous glands a. oil glands associated with hair follicles b. holocrine – secrete “sebum” c. product contains lipids, antibiotic 2. sebaceous follicles a. secrete onto skin directly b. inflammation leads to acne Leonardo diCaprio 3. sudiferous (sweat glands) a. secrete aqueous solution onto skin b. function (1) evaporative cooling (2) excretion c. types (1) merocrine (eccrine) (a) common in forehead, back and neck (b) most dense in palms and soles (c) function i. thermal regulation ii. excretion - water, electrolytes, trace amts of metabolic byproducts, some drugs  (2) apocrine (a) axillary and pubic areas, associated with hair follicles (b) viscous, cloudy odorous secretion (c) contain pheromones (d) not functional until puberty (e) secrete during stress & sexual excitement 3. mammary glands a. specialized sudiferous glands producing milk b. discussed w/i reproductive system 4. ceruminous glands a. restricted to external auditory meatus b. secrete cerumen c. fn as water and insect repellent  Clinical Considerations Pathology is abnormal physiology Burns classification 1st degree epidermal damage, redness, pain edema 2nd degree epidermis and dermis, blisters 3rd degree destroy entire integument and possible muscle ulcerating wound, scarring etiology redness - vasodilation swelling - capillary filtration dizziness, syncope, shock - dehydration systemic infection I clicker question 1. The figure above has been derived from which class of tissue? a. epithelial c. nervous b. connective d. muscle I clicker question 2. The figure above is indicative of which type of connective tissue? a. adipose d. loose (areolar) b. regular dense fibrous e. blood c. reticular I clicker question 3. The above figure is indicative of: a. skeletal muscle d. smooth muscle b. dense regular connective tissue e. cardiac muscle c. dense irregular connective tissue I clicker question 4. The arrow indicates an intercalated disk which is composed of a cluster of _________ junctions. a. adherins d. tight b. gap e. desmosomes c. occlusion I clicker question 5. You would expect to find simple cuboidal epithelium lining: a. mucosa of the small and large intestine b. body surface (skin) c. oral cavity d. renal tubules e. respiratory bronchioles