3/28/20141 Chapter 6 (Integument). 3/28/20142 Introduction to the Integumentary System Integument =...
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Transcript of 3/28/20141 Chapter 6 (Integument). 3/28/20142 Introduction to the Integumentary System Integument =...
04/10/23 1
Chapter 6
(Integument)
04/10/23 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
04/10/23 3
Cutaneous Membrane Structure
• The skin is called the cutaneous membrane
• Two primary layers
– Epidermis
– Dermis
04/10/23 4
EPIDERMIS• FEATURES
– Outer, Thinner Layer of Skin– Tissue Type
• Membranous Epithelium– (Stratified Squamous Epithelium‑Keratinized)
04/10/23 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)
04/10/23 6
3 CELL TYPES: MELANOCYTES
• MELANOCYTES - Produce Melanin
•Functions of Melanin–Responsible for Color of Skin, Hair, and Eyes
–Filters UV Light
04/10/23 7
04/10/23 8
3 CELL TYPES: LANGERHANS• LANGERHAN'S CELLS
– Provide Defense against Foreign Invaders (Work with the Immune System)
04/10/23 9
EPIDERMAL CELL LAYERS
• 5 Layers
04/10/23 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
04/10/23 11
CELL LAYERS ‑ STRATUM LUCIDUM
• 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)
04/10/23 12
CELL LAYERS ‑ STRATUM GRANULOSUM
• STRATUM GRANULOSUM– "Granular Layer": Cells
in this Layer are Filled with Granules (Keratin Precursor)
– Keratinization Begins in this Layer
04/10/23 13
CELL LAYERS ‑ STRATUM SPINOSUM
• 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)
04/10/23 14
CELL LAYERS ‑ STRATUM BASALE
• STRATUM BASALE– "Base Layer": The
Innermost Layer of Epidermis
– Mitosis Occurs in this Layer
04/10/23 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
04/10/23 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
04/10/23 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
04/10/23 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
04/10/23 19
DERMIS• FEATURES
– Inner, Thicker Layer of Skin– Tissue Type: Connective Tissue– Called "True Skin" (Thicker and Gives
Strength to Skin)
04/10/23 20
STRUCTURES PRESENT IN THE DERMIS
• SENSORY
RECEPTORS
(Skin Functions as a
Sense Organ)– Specialized Nerve
Endings for • Hot
• Cold
• Pressure
• Pain
• Touch
04/10/23 21
04/10/23 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"
04/10/23 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)
04/10/23 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
04/10/23 25
Dermis is composed of 2 layers
• Papillary layers – dermal papillae
show through making fingerprints
04/10/23 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
04/10/23 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.
04/10/23 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.
04/10/23 29
Dermal Growth and Repair-Reticular Layer
• Elastic Fibers:– If overstretched
and torn, forms stretch marks.
04/10/23 30
Tattoo pigment is usually black and is inert and non- polarizable; however, red tattoo pigment often contains
cinnabar (which has mercury in it).
Epidermis
Dermis
Tattoo Pigment
04/10/23 31
Subcutaneous Layer
• Subcutaneous Layer– Hypodermis– superficial fascia)– Tissue type: connective
• loose areolar• adipose
04/10/23 32
SKIN LAYERS-ReviewPrimary 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)
04/10/23 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)
04/10/23 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)
04/10/23 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)
04/10/23 36
THE SKIN’S FUNCTIONS: Sensations
• SENSATION– Skin Functions as a
Sense Organ for the Sensations of Hot, Cold, Pressure, Pain, and Touch - D/T Sensory Receptors in the Dermis
04/10/23 37
THE SKIN’S FUNCTIONS: Movement
– 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
Watch:
Ehler’s Danlos syndrome
Characterized by stretchy skin and loose joints
MOVEMENT WITHOUT INJURY
Collagen
04/10/23 38
Mutations in amino acid sequence causes defects in collagenthat can cause problems in these areas:
Collagen & Aging
04/10/23 39
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
04/10/23 40
THE SKIN’S FUNCTIONS: Excretion
• EXCRETION– Skin Functions as an
Excretory Organ D/T Sweat Glands Located in the Dermis
04/10/23 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)
04/10/23 42
THE SKIN’S FUNCTIONS: Immunity
• IMMUNITY– Skin Works With the
Immune System to Defend Against Microorganisms D/T Langerhans Cells in the Epidermis and Phagocytes
04/10/23 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
04/10/23 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.
04/10/23 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.
04/10/23 46
THE SKIN’S FUNCTIONS: Temperature Control
• HOMEOSTATIC CONTROL OF BODY TEMPERATURE– MECHANISM
INVOLVED WHEN BODY TEMPERATURE INCREASES
04/10/23 47
THE SKIN’S FUNCTIONS: Temperature Control
– HOMEOSTATIC CONTROL OF BODY TEMPERATURE
• MECHANISM INVOLVED WHEN BODY TEMPERATURE DECREASES
04/10/23 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.
04/10/23 49
Burns-1st degree
• 1st degree– causes minor discomfort– some reddening– typical sunburn– Peeling– no blistering.
04/10/23 50
Burns-2nd degree
• 2nd degree– involves the deep
epidermal layers– and some dermal
layers– may damage sweat
glands, etc– blistering– swelling– scarring.
04/10/23 51
Burns-3rd degree
• 3rd degree burns– full-thickness
burns– complete
destruction of dermis and epidermis
– no pain due to destruction of nerve endings
04/10/23 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.
04/10/23 53
Rule of Nines
04/10/23 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
04/10/23 55
Appendages: Hair-Germinal Matrix
– 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.
04/10/23 56
Appendages: Hair-Papilla, Root, Shaft
• HAIR PAPILLA– 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
04/10/23 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
04/10/23 58
Appendages: Hair-Sebaceous Glands
• 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
04/10/23 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
04/10/23 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
04/10/23 61
Appendages: Skin Glands
• Sebaceous glands – Oil glands; sebum (oil) has antifungal and antibacterial properties
04/10/23 62
Appendages: Skin Glands
• Ceruminous glands – specially modified sweat glands; found in external ear canals; produce cerumen (wax)