Integumentary System Notes PDF

The Integument I. Introduction to the Integument A. THE SKIN VERSUS THE INTEGUMENT epidermis dermis SKIN (Cutaneous Membrane)= 2 layers:...

The Integument I. Introduction to the Integument A. THE SKIN VERSUS THE INTEGUMENT epidermis dermis SKIN (Cutaneous Membrane)= 2 layers: ________________, ___________ INTEGUMENT= 3 layers: _______________, ___________, _______________ epidermis dermis hypodermis B. GENERAL PURPOSES of the Integument getSurface Film or 1. Protection of underlying tissues and organs Acid Mantle: _______ & _______ 2. Excretion of salts, water, and wastes (urea, ammonia, uric acid) in sweat sweat w/ pH 4-6 oil that helps prevent 3. Maintenance of normal body temperature by altering blood flow bacterial & fungal a. Vasodilation: To release heat from the body; growth. (Also buffers caustic f An increase mayhavepinkorredappearance e in blood flow to the skin irritants, toxins). b. Vasoconstriction: To keep (conserve) heat in the body;bluepurple A decree serve decrease in blood flow to the skin so that blood is sent to ORGANS 4. Synthesis of Vitamin D for Ca+2 absorption by intestine; Important for hardening of bones sunlight 5. Sensitivity to touch, pressure, pain, and temperature using nerves (nerve receptors) II. General Structure of the Integument A. EPIDERMIS Keratincells 1. Tissue Type: Stratifiedsquamous stratified squamouseepithelium; pithelium 25-50 layers of keratinocytes 2. Strata (Layers): Stratum Corneum Stratum Lucidum Stratum Granulosum Stratum Spinosum Stratum Basale 3. Strata Germinativum: Two layers, the Basale and Spinosum, the location of germ (stem) cells that produce new cells by mitosis 4. Reason for Strata The strata shows that a process known as keratinization is happening to the epidermal cells, often called keratinocytes. The cells are formed/born in the basale and move upward as they mature and have keratin added to them.  2 B. DERMIS fibers crisscross collagen dense irregular 1. Tissue Types: a. Mainly __________________________ C.T. b. A small amount of _______________ areolar C.T. 2. Other Components: Small blood vessels, nerve endings, hair follicles, glands, lymph vessels C. HYPODERMIS notapartoftheskin Hypodermis= Subcutaneous or under ___________ the___________ 1. Other Names: Subcutaneous layer; superficial fascia skin (skin=cutaneous membrane). 2. Tissue Types: a. Mainly ________________ C.T. areolar b. _________________ C.T. in varying amounts adipose 3. Functions: a. Acts as a foundation or support for the skin 45 b. Stores up to _________ of total body fat or50 c. Attaches skin to muscle and bone d. Since it has a larger amount of ________________ areolar C.T. than the dermis, the hypodermis is the layer of the integument that provides blood for the ___________________. epidermis 4. Medical Use: Medicines are injected into this layer due to its loose, spongy texture and rich blood supply; Thus the reason for the term “hypodermic syringe.” GROWTH III. Keratinization of the Epidermis A. OVERALL PROCESS (ON AVERAGE, TAKES 35 DAYS) *Keratinocytes= 1. Purpose of Keratinization: a.strengthens epidermis Cells of the epidermis b. waterresistant (stratified squamous 2. Change in Cell Location---Keratinocytes move from the basale upward to the epithelial cells) corneum. 3. Change in Cell Composition---Keratinocytes become encased in keratin inside and out. Cells die as keratin replaces their living components. 4. Change in Cell Shape---Keratinocytes start out cuboidal/columnar but flatten out to a squamous shape.  3 B. Step 1: RAPID MITOSIS (CELL DIVISION) IN STRATUM BASALE *BASE LAYER 1. A single layer o hasthemostgermcells singledays offccolumnar 14 to 19 layer cells with rapid mitosis, producing new cells every cells olumnar * 1 cell thick 2. This line of cells is wavy due to dermal papillary layer beneath it wavy 3. Melanocytes are found here for melanin production 4. Merkel Cells/Discs serve as receptors; They stimulate __________________ sensory nerves Tactilecell so that the brain knows when the skin being touched. C. Step 2: DESMOSOME DEVELOPMENT IN STRATUM SPINOSUM *SPINY/PRICKLY LAYER Lameanscells havesharpedges 1. Desmosome Formation (Intercellular Cement/tough glue that holds cells together) *8-10 cells thick TEphderth.isestlayer As these cell connections are made, the cell shape becomes stretched and becomes spiny or prickly in appearance 2. Limited Mitosis (small amount of cell division) 3. langerhans __________________ cells are found here; Macrophages for clean-up of bacteria, foreign materials, damaged cells. D.Step 3:KERATIN SYNTHESIS BEGINS IN STRATUM GRANULOSUM *GRAINY LAYER 1. Production of Keratohyaline---This substance gives the cells a grainy appearance, and is the reason behind the *2-5 cells thick stratum name. *1st step in keratin production waterproof 2. Production of Lamellated granules—Make a _______________________ for cells which prevents blood nutrients from reaching the higher cell layers. As a result, the cells begin to die. 3. Breakdown of Cell Contents---The nucleus and other cell components begin to disintegrate as the cells die 4. Changes in Cell Shape---The cell begins to become thinner and flatter as it dies E. Step 4: CONTINUED KERATIN SYNTHESIS IN STRATUM LUCIDUM *CLEAR/GLASSY LAYER Keratohyaline inside the cells becomes eleidin, a clear substance. *2-5 cells thick *2nd step in keratin production *Missing in thin skin/ Only found in thick skin (palms & soles) *HORN-LIKE/HORNY LAYER Thickestlayer 4 * 20-30 cells thick in most places F. Step 5: KERATINIZATION AND DESQUAMATION IN STRATUM CORNEUM 1. Keratinization Completed---Eleidin is turned into keratin, forming a hard envelope around the cell 2. Desquamation Occurs---After 40-56 days the desmosome connections break and the keratinocytes are shed off of the surface e ofsquamousepithelialcells G. Additional Note on Thick and Thin Skin Types 1. Thick Skin---Contains all five strata, stratum corneum especially thick, NO oil glands or hairs; Only on palms and soles. 2. Thin Skin---Stratum lucidum is missing and each strata has fewer cell layers 3. Note: “Thick” and “thin” does NOT refer to the total thickness of the skin, only the thickness of the epidermis. The total thickness of the skin differs according to the thickness of the dermis. IV. The Dermis in Detail page2 matchingabyetween papillary A. PAPILLARY LAYER (superficial layer) meansnippleorhill 1. Structure----Areolar connective tissue with collagen fibers forming mounds (papillae), or FOLDS in the overlying epidermis. These papillae/folds can also be said to form a wave pattern of ridges in the epidermis 2. Significance---The folds in the epidermis formed by dermal papillae: epidermis a. Strengthen the connection between the __________________ dermis & ___________. frictionridges b. Are also called _______________________ because they give a ______________________ to the skin’s surface which helps when grasping raised texture objects and when walking on a slick surface. c. fingerprints Are useful as _____________________ in forensic science. B. RETICULAR LAYER (deep layer) *Stretch Marks: Tears/separation bottom80 of collagen 1. Structure---Dense irregular connective tissue bundles with scar tissue forming in 2. Significance: between; Happens when a. Gives skin its overall 1) strength and 2) stretch the epidermis b. Cleavage or Tension Lines---The collagen fibers form definite, distinct patterns grows faster than which have been mapped out on the human body. the dermis Tears naturally separate along these lines. Cutting across them causes gaping in wounds, making scar tissue more likely to form. surgeons needto cutin same direction as collagen fibers to avoid bad scars  5 C. SENSORY RECEPTORS (NERVES) OF THE DERMIS 1. Receptor Types Grouped By Stimulus Detection a. Mechanoreceptors Respond to any mechanical stimulus, or something that ______________ the nerve such as touch, pressure, stretch, vibration, or itch. b. Nociceptors (Pain Receptors) Respond to any intense stimulus that causes ____________________. Especially important as a ______________________ receptor. Also responds to chemicals. Causes pain sensation to be felt. 2. Receptor Types Grouped By Structure a. Free Nerve Ending Receptors *Free Nerve Endings: All located in the A nerve cell (neuron) with “nude” endings (called dendritic knobs) TOP of the dermis except Merkel Disc; (1) Nociceptor---Detects pain mostly but also temperature, itch, tickle, etc. Are more sensitive/ (2) Root Hair Plexus---Detects hair movement better at responding to stimuli than (3) Merkel Disc encapsulated types ► A special type of ______________ cell, unlike other receptors ► Only type located in ________________________ of epidermis ► Respond to ___________________________ *Two Nerve Receptors are TONIC: ► Give Discriminative Touch: Detailed, precise information about 1) Merkel Disc the object touching the skin, including SIZE, TEXTURE, EXACT LOCATION, MOVEMENT 2) Ruffini Corpuscle ► Are Tonic Receptors: Keep you ____________________________ of an object on the skin; Active as long as 30 minutes. b. Encapsulated Nerve Ending Receptors A nerve cell with layers of connective tissue covering the dendritic knobs 1) Meissner’s Corpuscle (Tactile Corpuscle) ► Respond to gentle pressure & __________ (soft vibrations) ► Have a coiled or spiral nerve ending ► Found in _________________________ (TOP of dermis)  6 PHASIC RECEPTORS: ► Give Discriminative Touch like the Merkel Disc Smell Receptors are good examples of phasic ► Are Phasic Receptors: ________________ respond to an object receptors: placed on the skin but STOP responding after a short period of time After 7 scents, you can no longer tell different odors apart from each other. (2) Krause’s End Bulb (Bulboid/Bulbous Corpuscle) ► Not well understood; Thought to respond to ____________________ ► Besides skin, also found in mucous membranes of ______________ , __________________, as well as lips and tongue making all of these especially sensitive (3) Pacinian Corpuscle (Lamellated Corpuscle) ► Have circular layers of connective tissue wrapped *Both Pacinian & Ruffini around the nerve ending corpuscles are located in ► Found in the ______________________ (BOTTOM of dermis) bottom of dermis (reticular layer) ► Respond to deep pressure , May be used to detect smooth versus rough texture. ► Give Crude Touch: Less specific, more vague information about the object touching the skin ► Are Phasic Receptors: Allow you to be ______________________ of an object placed on the skin (4) Ruffini’s Corpuscle ► Especially important in fingers and joints IN THE FINGERS, RUFFINI CORPUSCLES MONITOR ► Found in the _____________________ (BOTTOM of dermis) _____________ OF OBJECTS. __________ ADJUSTMENTS ► Respond to deep pressure ARE THEN MADE, ALLOWING ► Give Crude Touch information YOU TO HOLD ON TO OBJECTS FOR LONG PERIODS OF TIME, ► Special function: Found in joints; Provide brain with precise information on the slightest ________________________ LIKE A ________________. in joints as they move for _________________________________. ► Respond to _________________ especially ► Key difference from Pacinian corpuscle: Are Tonic Receptors, keeping you ___________________ of an object on the skin  7 D. SKIN GLANDS OF THE DERMIS (and Hypodermis) 1. Sudoriferous/Sweat Glands foundinthedermis Sudoriferous Glands: a. Merocrine/Eccrine---Most common type; Sweat’s purpose is to regulate body temperature but also to eliminate wastes. *Most numerous of the 3 Sweat contains dermicidin, a natural antibiotic _____________ gland types: Each square (kills bacteria). This is part of the surface film/acid mantle. inch of skin has ~3000 sweat glands. b. Apocrine----1) Become active at puberty *Found everywhere except 2) Are attached to hairs in the AXILLARY, ANOGENITAL, & AREOLA of Part thenipple external genitalia & nipples AREAS, PLUS FACES OF MATURE MALES (BEARD HAIRS) notfound 3) Are the cause of unique body ______________ odor (due to bacteria) 4) Pheromone-like substances in the sweat may be linked/ used in sexualattraction _______________________ 2. Sebaceous/Oil Glands sebumoilmacidicpH a. Found everywhere except palms and soles b. Oil is antifungal & antibacterial due to its slightly acidic pH (4-6 pH); This is the second part of the surface film/acid mantle. c. May or may not be connected to hair follicles d. Prevents excessive water loss from skin e. Oil lubricates the hair and skin Of all the gland types, ONLY Apocrine sweat glands are always attached to 3. Ceruminous/Wax Glands hairs. a. Wax is actually a combination of both cerumen and sebum b. Wax protects the ear from dehydration E. ACCESSORY STRUCTURES OF DERMIS 1. Hair Follicle (Tiny organ covering the hair which is the source of germ cells for hair growth) a. Hair Follicle Layers Hair Follicle: (1) Dermal Root Sheath/ Peripheral Connective Tissue Root Sheath A tiny tube-like structure in Outer layer; Made of collagen the dermis that covers the White (2) External Epithelial Root Sheath---Contains same epithelial layers as root and bulb of the hair. epidermis of skin (all strata) Since it is under the skin (like a plant root), its layers (3) Internal Epithelial Root Sheath--- Contains only strata germinativum are called ROOT SHEATHS. of skin; Original location of the germ cells that grow the hair. These germ cells start out in the IERS and move to the HAIR MATRIX of the Hair Bulb to grow the hair.  8 b. Hair Bulb (Round base section of hair follicle) (1) Hair matrix—Made up of germ cells from the Internal Epithelial Root Sheath layer of the hair follicle; Area of mitosis (where new cells are made), causing hair growth (2) Hair papillae—Tiny blood vessels that supply blood to the hair matrix 2. Hair Layers: (1) Cuticle (outer layer)—A single layer of overlapping epithelial cells that helps keep hair from matting/forming dreads (2) Cortex (middle layer)---Largest layer of hair; Made of epithelial cells; Where melanin is found (3) Medulla (inner layer)---Loosely arranged epithelial cells with air pockets 3. Arrector Pili Muscles---Tiny smooth muscles that are attached to the base of hairs (at hair bulb). Used to release OIL from sebaceous glands onto skin & hair. Also contract in response to cold or emotions (like fear), causing hairs to stand upright. V. DERMATOSES (SKIN DISORDERS) matchingsection A. MICROBIAL DISORDERS Lcausedby bacteriavirusfungi 1. Acne---Caused by bacteria, especially Cutibacterium that use oil as food. These bacteria clog oil ducts, causing irritation (inflammation) in them. Antibiotics can be used to kill the bacteria or topical treatments like Retin-A are used to slow down the oil production. 2. Impetigo---Highly contagious, yellow crusting blisters due to a combined infection of both staph and strept bacteria types. Especially around the nose & mouth in young children. 3. Tinea/ Mycoses---A fungal (yeast) infection of the skin. Examples include: Athlete’s foot, Jock itch, Vaginal yeast infection Sometimes called “Ringworm” because of circular/round rash. 4. Seborrhea--- Dandruff” in mild cases; Besides scalp, may also be on face, oil How chest or back. Overactive, irritated oil glands cause flaky scales. Often caused by the Malassezia yeast on the scalp. 5. Warts----Growth (and thickening of) the skin caused by papillomavirus. caused virus by  9 B. VASCULAR AND INFLAMMATORY DISORDERS flow blood Affects 1. Eczema---An itchy, blistering rash; Often an allergy (allergic reaction) of unknown cause; Often linked to asthma and nasal allergies. Allergyinlungs 2. Decubitus ulcers---Tissue death, commonly called bedsores. down lying Extended pressure put on ankles, elbows, hip bones causes a reduction in BLOOD FLOW (____________) which is enough to cause tissue death herS (________________________). An ulcer is dead and gangrene dying tissue that has become infected with bacteria. 3. Scleroderma---Literally, “hard skin.” Autoimmune disease that self causes the connective tissues (especially collagen) of WBestroattachormal EII.I YIFEEEEE.IE structure the skin to harden and stiffen as scar tissue is added tobody them. May become deadly if the problem spreads to internal organs. scayptigyeinlungsski 4. Psoriasis---Autoimmune disease. Itchy, painful scales that crack and bleed. hyperkerf8 gs've mitosis Caused by too rapid cell division (________________________) and too much keratin (___________________) of skin cells This results in a very thick stratum corneum that peels off in large, silver sales. Especially found on elbows, knees. 5. Vitiligo---Autoimmune disease that causes a gradual and total bleaching of the skin (loss of skin color) because melanocytes are being killed by WBCs. 6. Rosacea---Idiopathic; Red, puffy areas, Caused by repeated flushing of causes dermal blood vessels (_______________), bloodcoolin especially in unknown skin of cheeks and nose. Leads to spider veins often with rhinophyma (growth of nose) and flaking of the skin. 7. Birthmark---A.k.a. Hemangioma; Caused by a benign (nondeadly) tumor of blood vessels; Blood leaks out of capillaries & G eiior is trapped in the dermis. inelderly Angioma V. INFLAMMATION & TISSUE HEALING A. INFLAMMATION tissue'shealing 1. What is it? The tissue’s response to injury or infection; A process that brings in white blood cells (WBCs) for PHAGOCYTOSIS. WBCs clear the injured tissue area of microbes bacteria and dead tissue so that ___________ can begin. _______________ healing Inflammation looks red (_____________) and has swelling (___________), pain, and feels hot. evythmia edema  10 2. What happens? (The Four Steps of Inflammation) a. Vasodilation: Blood vessels dilate causing increased blood flow into the area. This increase in blood brings a large number of WBCs close to the injured tissue. Chemotaxis: Chemicals from the b. Increased Vascular Permeability: damaged Capillaries become "leaky" (temporary holes form in them), allowing WBCs to tissue cause leave the blood vessels and enter the damaged tissue. WBCs flatten and movement of squeeze through the holes to enter the tissue (____________________). diapedesis WBCs into the walkthrough injury area c. Chemotaxis: Chemical cues from the damaged tissue attract WBCs to the injury site d. Phagocytosis: Harmful bacteria and debris are swallowed & digested by two kinds of WBCs: neutrophils and macrophages 3. What causes it? Mast cells start inflammation by releasinghistamine ________________, which causes steps a. and b. The damaged tissue releases chemicals that cause chemotaxis, step c. These chemicals include ___________________ & _____________________, Kinins cytokines which attract white blood cells into the injured tissue so they know where to go. kin tosetinmotion B. TISSUE HEALING 13 Once platelets 1. CLOT FORMATION Fibrinogen ---------------------> Fibrin + Platelets stick to fibrin, liabiloggotion factors shrinasto a clot is formed GRANULATION 2. FIBROSIS (Formation of Granulation Tissue) TISSUE: Fibrosis: A repair process where granulation tissue grows so that the wound can be quickly filled in. 1) Main Feature— Lots of bloodvessels _________________________ to ______________ 3. REGENERATION (Regrowth of original tissue) increase blood flow to tissue Granulation tissue should be replaced by the original tissue (regeneration) but if it remains, it is called _____________________. 2) Also made of: Scar tissue Many fibroblasts ________________ Abilityto regenerate & ___________________ collagenfibers Ability of Tissues to Regenerate: ♦ BEST (little to no scar tissue): AreolarCTBone BestEpitheliaDenseirregular ♦ POOR: muscle ♦ WORST: Poor.cat 5Te WorstNervoustissueBrain nerves  11 VI. SKIN NEOPLASMS (SKIN CANCERS) AND BURNS A. SKIN CANCERS Carcinoma: Mostcommon 1. Basal Cell Carcinoma Cancer ofepithelial ______________ cells (They form the tumor) epithelialcells a. Tumor originates in stratum basale least COMMON b. Lesion is raised and erodes to form a crater in the center with a gram Spinosum *Skin Cancers are pearly (shiny, white) edge listed from most to c. Less likely to metastasize (spread to other organs); 99% are cured least common & by cutting out (excision). from least deadly to most deadly* 2. Squamous Cell Carcinoma a. Commonly occurs on: scalp, forehead, lower lip, back of hands least deadly b. Tumor originates in stratum spinosum c. Lesion is scaly, red, and raised d. Tends to grow rapidly e. Can metastasize Melanoma: mostdeadly 3. Malignant Melanoma Cancer of __________________ melanocytes mostcommondeadlyskincancers Sarcoma: a. Causes death in 1 of 4 cases Cancer of b. Tumor originates in melanocytes ___________________ c. Lesion is flat, spreading brown or black patch ___________________ d. Develops from a mole in about 1/3 of cases e. Highest incidence in fair-haired & fair-skinned F f. Most likely to metastasize 4. Kaposi Sarcoma a. Tumor originates in dermal capillaries b. Lesion is purplish in color c. Possibly triggered by a herpes virus d. Very likely to metastasize eincrease in cases ledto discover 5 MerkalCell nervecell of Hiv virus f inpast leading Rarebutonrise causeof death in Asdeadly asMelanoma aids patients isn't skin cancer known caused tobe bypolyomavirus that a virus everyonehason skin  12 B. BURNS Matchingtypes Ofburns 1. Burn Classifications repidermise a. First-degree: Damage to epidermis only Ex: Mild burn or sunburn chemilpton b. Second-degree: Damage to epidermis and upper dermis; Always blisters hurtthemost c. Third-degree: Complete destruction of epidermis and dermis and partial destruction of hypodermis nopain 2. Lethal Consequences of 2nd & 3rd Degree Burns The loss of integument layers means fluids evaporate out of the body. Blood volume falls, causing circulatory shock, or organ failure due to lack of blood. Renal failure, infection & a diminished immune system contribute to death. 3. Burns are considered critical (life-threatening) if: a. Over 25% of body has 2nd degree burns b. Over 10% of body has 3rd degree burns or c. Any % of 3rd degree burns exist on the face, hands, feet, or perineum 9 1 parklandformula or 11 rule of 9s used to know how 19 to 9 much fluidneeds be replaced c 1 15 11 9 18 18 1 179047 ChildSyrsold