1. Chapter 6 (Integument)
SKIN
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2. Introduction to the Integumentary System
Integument = skin
Integumentary system = skin and its appendages
Appendages
Hair
Nails
skin glands
(sweat and sebaceous)
PRIMARY FUNCTION: Protection
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3. Cutaneous Membrane Structure
The skin is called the cutaneous membrane
Two primary layers
Epidermis
Dermis
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4. EPIDERMIS FEATURES Outer, Thinner Layer of Skin Tissue Type
Membranous Epithelium
(Stratified Squamous Epithelium‑Keratinized)
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5. 3 CELL TYPES: KERATINOCYTES
Most Numerous and Important Cells in the Epidermis
Filled with (or in the Process of Becoming Filled with) Keratin (Keratinization)
Keratin
Strong Protein
Protects and Waterproofs the Skin
Keratinization
Process by Which Cells in the Epidermis Become Filled with Keratin and Moved to the Skin's Surface (Cells Die in the Process)
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6. 3 CELL TYPES: MELANOCYTES
MELANOCYTES - Produce Melanin
Functions of Melanin
Responsible for Color of Skin, Hair, and Eyes
Filters UV Light
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8. 3 CELL TYPES: LANGERHANS
LANGERHAN'S CELLS
Provide Defense against Foreign Invaders (Work with the Immune System)
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9. EPIDERMAL CELL LAYERS
5 Layers
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10. CELL LAYERS ‑ STRATUM CORNEUM
1st layer
STRATUM CORNEUM
"Hardened Layer":
Cells in this Layer are Totally Filled with Keratin
(Replaces the Cytoplasm)
Known as the Barrier Area
Cells at the Surface of this Layer are Dead
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11. CELL LAYERS ‑ STRATUM LUCIDUM
"Clear Layer": Cells in this Layer have a Clear Appearance (Keratin Precursor)
Only Present in Thick Skin (palms of hands and soles of feet)
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12. CELL LAYERS ‑ STRATUM GRANULOSUM
"Granular Layer": Cells in this Layer are Filled with Granules (Keratin Precursor)
Keratinization Begins in this Layer
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13. CELL LAYERS ‑ STRATUM SPINOSUM
"Spiny Layer":
Cells in this Layer Have an Irregular Shape (Plasma Membranes Modified To Hold Tightly Together)
Rich in RNA (Preparation for Keratinization)
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14. CELL LAYERS ‑ STRATUM BASALE
"Base Layer": The Innermost Layer of Epidermis
Mitosis Occurs in this Layer
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15. CELL LAYERS ‑ 2 LAYERS MAKE THE GROWTH LAYER
STRATUM GERMINATIVUM
NOT ANOTHER LAYER, ACTUALLY COMPOSED OF 2 EXISTING LAYERS
The growth layer
Composed of s. spinosum and s. basale
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16. EPIDERMAL GROWTH AND REPAIR
TURNOVER (REGENERATION) TIME
Time Required for Epithelial Cells to Form in the Stratum Basale and Migrate to the Skin's Surface
Average Turnover Time = 35 Days (Maintains a Constant Skin Thickness
Application: Shortened Turnover Time Results in Formation of Callus
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17. EPIDERMAL GROWTH AND REPAIR
EPIDERMAL PROLIFERATING UNIT (EPU)
Each Group of 8‑10 Basal Cells Along with the Vertical Columns of Cells Above (Up to the Skin's Surface)
Epidermis Grows in Units ‑ Not as a Whole
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18. DERMAL ‑ EPIDERMAL JUNCTION
The Union Between the Epidermis and the Dermis
A Basement Membrane
Functions:
Tightly "Glues" the Epidermis to the Dermis
Provides Support for the Epidermis
Serves as a Partial Barrier Between the Epidermis and the Dermis
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19. DERMIS FEATURES Inner, Thicker Layer of Skin
Tissue Type: Connective Tissue
Called "True Skin" (Thicker and Gives Strength to Skin)
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20. STRUCTURES PRESENT IN THE DERMIS
SENSORY
RECEPTORS
(Skin Functions as a
Sense Organ)
Specialized Nerve
Endings for
Hot
Cold
Pressure
Pain
Touch
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22. STRUCTURES PRESENT IN THE DERMIS
MUSCLE FIBERS ‑ 2 Types
SKELETAL
Located Only in the Dermis of the Face and Scalp
Function: Voluntary Movement of the Face and Scalp
SMOOTH ‑ ARRECTOR PILI MUSCLES
Involuntary
The Most Abundant of the 2 Types of Muscle Fibers
Form Arrector Pili Muscles
Produces "Goose Bumps"
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23. STRUCTURES PRESENT IN THE DERMIS
HAIR FOLLICLES
Tubes That Hold Hairs (More Detail with Hair)
SWEAT, SEBACEOUS GLANDS
Skin Glands (More Detail with Skin Glands)
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24. STRUCTURES PRESENT IN THE DERMIS
BLOOD VESSELS
The Dermis Contains an Extensive Network of Blood Vessels That Play an Important Role in Regulation of Body Temperature
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25. Dermis is composed of 2 layers
Papillary layers
dermal papillae show through making fingerprints
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26. Dermis is composed of 2 layers
Reticular layer
Inner, thicker layer
dense network of collagenous and elastic fibers
Contains
muscle fibers
hair follicles
sweat and sebaceous glands
blood vessels
sense receptors
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27. Dermal Growth and Repair: Scars
Dermis does not continually shed and regenerate itself.
In the healing of a wound, fibroblasts reproduce and begin forming a dense mass of connective tissue fibers.
If this fiber is not replaced by normal tissue, it remains a scar.
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28. Dermal Growth and Repair-Reticular Layer
Collagenous fibers form Langer’s Lines
the collagenous fibers that characterize the dermal layer line themselves up in lines (sometime called cleavage lines).
If surgical incisions are made along these cleavage lines, there will be a less noticeable scar and healing will be much quicker.
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29. Dermal Growth and Repair-Reticular Layer
Elastic Fibers:
If overstretched and torn, forms stretch marks.
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30. Tattoo Pigment Epidermis Dermis
Tattoo pigment is usually black and is inert and non- polarizable; however, red tattoo pigment often contains cinnabar (which has mercury in it).
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31. Subcutaneous Layer Subcutaneous Layer Hypodermis superficial fascia)
Tissue type: connective
loose areolar
adipose
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32. SKIN LAYERS-Review Primary Layers Epidermis Stratum corneum
Stratum lucidum
Stratum granulosum
Stratum spinosum
Stratum basale
Dermal-Epidermal Junction (not a primary layer)
Dermis
Papillary
Reticular
Subcutaneous Layer (hypodermis; superficial fascia)
Tissue type: connective (loose areolar and adipose)
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33. Skin Color
Skin color is essentially determined by the quantity of melanin produced by melanocytes in the stratum basale.
Determining Factors
Number of melanocytes – all races have approximately the same number of melanocytes.
Amount of melanin produced by melanocytes is determined by:
Heredity – the primary factor
Sunlight – sunlight increase melanin production
Hormones – Adrenocorticotropic hormones (ACTH) and MSH (Melanocyte stimulating hormone)
Age – Increase in age may also influence melanocyte activity (age spots, graying hair)
Temporary Changes
Amount of blood flow to skin, more = pinker
Amount of oxygen in blood, less oxygen = blue (cyanosis)
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34. THE SKIN’S FUNCTIONS: Protection
Protection From:
Microbe infection (by layers of nonvascular keratinocytes)
Harmful chemicals (by layers of nonvascular keratinocytes)
Dehydration (by keratin)
UV light (by melanin)
Mechanical injury (by thick, strong dermis)
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35. THE SKIN’S FUNCTIONS: Protection
SURFACE FILM
A Thin Film of Materials That Covers the Skin’s Surface
Consists of Secretions From Sweat and Sebaceous Glands As Well As Dead Epithelial Cells
FUNCTIONS
Barrier
Antibacterial/Antifungal (D/T Chemical Components)
Lubricates (D/T Oil)
Hydrates (D/T Sweat)
Buffers (D/T Chemical Components)
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36. THE SKIN’S FUNCTIONS: Sensations
Skin Functions as a Sense Organ for the Sensations of Hot, Cold, Pressure, Pain, and Touch - D/T Sensory Receptors in the Dermis
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37. THE SKIN’S FUNCTIONS: Movement
MOVEMENT WITHOUT INJURY
Ehler’s Danlos syndrome
Skin Allows Body Growth and Movement of the Body Without Injury to Underlying Tissues and Organs D/T Elasticity of the Dermis and SQ Layer
Characterized by stretchy skin and loose joints
Watch:
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38. Collagen Mutations in amino acid sequence causes defects in collagen
that can cause problems in these areas:
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39. Collagen & Aging Collagen Theory of Aging
with age, collagen gets older
old collagen gets stiff and not as flexible causing problems such as:
Hypertension-
(vessels cant expand enough)
organs malfunction (stiffness)
hinders metabolic functions
Wrinkles
Due to changes in
reduced collagen
decreased protein synthesis
affect collagen type 1 & 3 in dermis
reduced elastin
general atrophy in extracellular matrix
due to reduced fibroblasts
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40. THE SKIN’S FUNCTIONS: Excretion
Skin Functions as an Excretory Organ D/T Sweat Glands Located in the Dermis
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41. THE SKIN’S FUNCTIONS: Vitamin D
VITAMIN D PRODUCTION (ENDOCRINE FUNCTION)
Mechanism: Precursor Compound in Skin Cells Activated By UV Light  Transported By Blood to Liver, Kidney  Converted to Vitamin D (Needed for Calcium Absorption)
Vitamin D Classifies Loosely as a Hormone)
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42. THE SKIN’S FUNCTIONS: Immunity
Skin Works With the Immune System to Defend Against Microorganisms D/T Langerhans Cells in the Epidermis and Phagocytes
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43. THE SKIN’S FUNCTIONS: Homeostasis
HOMEOSTASIS OF BODY TEMPERATURE
Skin Helps to Maintain Constant Body Temperature (Sweat Glands and Blood Vessels)
BASIC PRINCIPLE
To Maintain a Constant Body Temperature: Heat Production Must Equal Heat Loss
HEAT PRODUCTION: FROM FOOD CATABOLISM
Nutrient Catabolism  Energy
1) Chemical (ATP)
2) Heat (Released)
RELATES TO ACTIVITY
Increased Activity  Increased Catabolism  Increased Heat Production
Cells That Are the Most Active and Produce the Most Heat: Liver, Skeletal Muscle
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44. THE SKIN’S FUNCTIONS: Temperature Control-Heat Loss
HEAT LOSS – 80% Occurs Through the Skin FROM EVAPORATION AND RADIATION
Evaporation
Vaporization of Liquid (Requires Heat Energy)
Example: Evaporation of Sweat
Most Impt. Way Heat Loss Occurs in Hot Temps.
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45. THE SKIN’S FUNCTIONS: Temperature Control-Heat Loss
HEAT LOSS – 80% Occurs Through the Skin FROM EVAPORATION AND RADIATION
Radiation
Heat Transfer (Warmer  Cooler) Without Direct Contact Between 2 Objects
Example: Dilation of Blood Vessels in the Dermis (Text)
Most Impt. Way Heat Loss Occurs in Cool Temps.
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46. THE SKIN’S FUNCTIONS: Temperature Control
HOMEOSTATIC CONTROL OF BODY TEMPERATURE
MECHANISM INVOLVED WHEN BODY TEMPERATURE INCREASES
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47. THE SKIN’S FUNCTIONS: Temperature Control
HOMEOSTATIC CONTROL OF BODY TEMPERATURE
MECHANISM INVOLVED WHEN BODY TEMPERATURE DECREASES
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48. Burns Burns are classified based on depth
1st is just epidermal (top layer)
2nd is deeper, involves both dermal and epidermal layers.
3rd is deepest, involves epidermis, dermis, and sometimes deeper levels.
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49. Burns-1st degree 1st degree causes minor discomfort some reddening
typical sunburn
Peeling
no blistering.
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50. Burns-2nd degree 2nd degree involves the deep epidermal layers
and some dermal layers
may damage sweat glands, etc
blistering
swelling
scarring.
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51. Burns-3rd degree 3rd degree burns full-thickness burns
complete destruction of dermis and epidermis
no pain due to destruction of nerve endings
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52. Rule of 9s
Estimation of body surface area is accomplished by the rule of 9s.
Victim’s palm size is roughly 1% Of body surface.
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53. Rule of Nines
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54. Appendages: Hair-Follicle
HAIR FOLLICLE & GERMINAL MATRIX
Hair Follicle
Tubelike, Holds Hair Root
Formation: Cells from the Epidermis Push Down into the Dermis
Follicle Wall: 2 Layers
1) Outer: Dermal Root Sheath
2) Inner: Epithelial Root Sheath
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55. Appendages: Hair-Germinal Matrix
Cap-shaped Cluster of Cell at Bottom of Hair Follicle
Formed from stratum germinativum
Forms the Hair (Mitosis and Keratinzation)
Papilla’s (from dermis) capillaries nourish g. matrix-next slide.
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56. Appendages: Hair-Papilla, Root, Shaft
Dermis that Protrudes into the Germinal Matrix
Contains Blood Vessels
HAIR ROOT
Hidden Portion of the Hair (Lies in Hair Follicle)
HAIR SHAFT
Visible Portion of the Hair
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57. Appendages: Hair-Cortex & Medulla
CORTEX AND MEDULLA OF HAIR
Medulla: Inner Core of the Hair
Cortex: Outer Portion of the Hair (Cells Contain Melanin and Keratin)
Cuticle: Covers Cortex
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58. Appendages: Hair-Sebaceous Glands
Oil Glands; Part of Hair Follicle
Secrete Sebum Directly into Follicle
Functions of Sebum:
1) Lubricates Skin, Hair
2) Antifungal
Located in Dermis in All Areas Except Palms and Soles
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59. Appendages: Nails Nail body – visible part of the nail
Heavily keratinized cells.
Root – invisible part found behind cuticle
Cuticle – fold of skin
Lunula – moon shape,
Cells beneath are stratus germinativum that produce nail cells by mitosis.
Nail bed – cells supporting the nail
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60. Appendages: Skin Glands
Sweat Glands
most numerous skin glands
produces watery liquid in which waste materials such as ammonia and urea and salts are excreted
bacterial growth causes it to stink
Two types:
Eccrine
most common type
Apocrine
deep in the subcutaneous layer; armpit, areola, around anus
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61. Appendages: Skin Glands
Sebaceous glands – Oil glands; sebum (oil) has antifungal and antibacterial properties
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62. Appendages: Skin Glands
Ceruminous glands – specially modified sweat glands; found in external ear canals; produce cerumen (wax)
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