Transcript Integumentary System AKA: Skin

Integumentary
System
A.K.A.: Skin
Chapter 6
Integumentary Overall Functions
1.
2.
3.
4.
5.
Protect Underlying tissues & organs
Excrete salts, water, & organic wastes
(excretory organ)
Maintain normal body temperature
Synthesize vitamin D in epidermis
Sensation of touch, pressure, pain, & temp.
Integumentary Overview

1.
2.
Main Structure:
Cutaneous
Membrane
1. Epidermis
2. Dermis
Subcutaneous layer

Accessory Structures
Hair Follicles
Exocrine Glands
 Sebaceous
 Sweat
Nails
Nerve Endings
Skin
Epidermal Layers:Stratified Squamous
1.
2.
3.
Stratum Germinativum – Stratum Basale
 Mitosis
Stratum Spinosum
 Some cells still divide
Stratum Granulosum
 Keratin (protein):

Day 1
Water resistant, durable (poor envmt for
bacteria) also nails, hooves, horns, quills

4.
5.
No more mitosis
Stratum Lucidum: palms & soles only
Stratum Corneum (superficial)
 Flattened, dead, keratinized cells
Day 14
Shed after
2 wks
Epidermal Layers
Eyelid
Palm & Sole
Epidermal Functions
1.
Vitamin D synthesis



2.
3.
Stratum spinosum & germinativum
 UV light + steroid precursor Vitamin D
Vitamin D Purpose:
 Needed for bones to absorb calcium
Ricketts: bone disease
 Epidemic in inner city
Protection/ Waterproof
Protective Senses
Skin Color: 2 Determinants
Hemoglobin: Good O2 reddish tint
1.
•
More red, inflamed
Less pale
Cyanosis: sustained decr. O2 blue
•
Caused by extreme cold or cardiopulm. dz.
•
•
2.
Skin Pigments
Carotene: (carrots)
2. Melanin:
•
Melanocytes (germinativum & dermis),
Melanocyte stimulating hormone (MSH)pituitary gland & Melatonin- pineal gland
• Albino: can’t produce melanin
1.
Cyanotic Foot
Melanocytes
Nerve Endings of Epidermis
1.
2.
3.
4.
Free Nerve Endings:
Pain & Temp.
(epidermis & dermis)
Merkel’s discs: static
L.T. (epidermis)
Meissner’s
Corpuscles: dynamic
L.T. (dermis)
Pacinian Corpuscles:
deep pressure &
vibration (deeper
tissue- subcutaneous)
Dermis: 2 layers
1.
Papillary Layer

Areolar connective tissue
 Rich in capillaries & nerves
 Dermal papillae: extensions
into epidermis
 Epidermal ridge (fingerprints)
2.
Reticular Layer

Dense irregular connective
tissue
 Support, attachment, & allows
flexibility
Other Dermal Components &
Functions
Accessory Organs: hair, sweat & sebaceous
glands
 Blood vessels
 Lymphatics: assists in tissue repair
 Nerve fibers:
Sensory receptors & nerve fibers
Controls blood flow & gland secretion rates

Dermis: Wrinkles & Stretch Marks

UV radiation & over stretched skin (pregnancy)
 Stretch
elastin beyond limits
 Wrinkles & stretch marks

Retin-A: vitamin A derivative
 Acne
treatment
 incr. blood flow to incr. dermal repair & decr.
wrinkles
Subcutaneous Layer: Hypodermis

Structure: loose connective tissue w/ abundant
adipocytes
 In
babies: more adipose WHY??
 Adults: fat located differently in male, female

Function: stabilizes skin, store energy, insulate
 Very
elastic
 Good for med injection
 Slow, steady infusion
 No vital organs & limited # capillaries
Accessory Structure: Hair Follicles


Hairs found everywhere except palms, soles,
lips, sides of fingers & toes
Hair Structure:
1. Shaft: size, shape, and color of hair
2. Root: encloses matrix
3. Hair Follicle:
 Papilla: areolar tissue w/ capillaries
 Matrix:



4.
5.
Medulla- division (inner layer)
Cortex- begin keratinizing
Cuticle- fully keratinized (outer layer)
Arrector pili muscle: smooth muscles
Nerve Root Plexus
Hair Follicle
Hair Types & Colors
Types:
1.
2.
3.
Vellus: fine, “peach fuzz” (most of body)
Terminal: heavy, colored (head, eyebrows)
Intermediate: in-between (legs & arms)
Colors:
1.
2.
3.
Determined by melanocytes at papilla
Genetic
Pigment production slows w/ age graying
Exocrine: Sebaceous Glands
1.
Sebaceous glands

Holocrine glands
 Associated with hair follicle: secrete sebum
 Sebum: prevents drying & inhibits bacterial growth
 Shampoo: removes natural oilstiff, dry hair
2.
Sebaceous Follicle

3.
Secretes directly to epidermis
 face, back, chest
 Acne: (caused by hormone changes)
 Glands blocked, secretions accumulate
inflammation bacterial infection
Ceruminous Gland: cerumen (earwax)to
protect inner ear
Sebaceous Follicle & Gland
Exocrine: Sweat Glands- 2 Types
1.
2.
Apocrine Sweat Glands
 Secrete through hair
 Armpits & groin
 1st secrete at puberty hormones
 Sexual state & identity
 + envmt for bacteria odor
Merocrine Sweat Glands
 Widespread (palms/ soles)
 Secrete to skin surface
 Function:
 Cooling effect
Apocrine

Protection: dilute chem, wash
away bacteria
Merocrine
Skin Local Control : Inflammation

Epidermis= great protection
 Thick,
keratinized cells
 Tight junctions b/w cells
 Sebaceous & sweat glands
 Avascular

Papillary layer= bacterial
heaven
 Once
bacteria enters papillary
layer inflamm response
 Mast cells initiate response
Skin Local Control: Regeneration
1.
Clot Formation:
1. Platelets & fibrin (scab)


2.
Isolates area
Creates network for new
cell migration
Division, Migration, &
Phagocytosis:
1. Stratum germinativum


2.
Divide & Migrate
Granulation tissue: fibrin
clot, fibroblasts, capillary
network
Macrophages

Phagocytosis
Regeneration (con’t)
3.
Scar tissue (lots of
collagen, little blood)
1.
Fibroblasts

4.
Contraction:
1.
Platelets & epithelial cells

5.
Damaged hair follicles,
sweat & sebaceous glands
replaced w/ scar tissue
Pull wound together
Clot dissolves
Aging Integumentary System
Temperature Control
1.
2.
3.
Sweat Glands
 Cooling effect
Muscles
 Mostly skeletal & arrector pili
Blood Flow
 Superficial: heat transfer
 Deeper: maintain heat
Application: Skin Cancer

Basal cell carcinoma: Most common
 Malignant
 Germinativum (basale) layer
 Common Cause: UV radiation
 Metastasis

rare
Squamous Cell Carcinoma: 2nd most common
 Malignant
 Common cause:
 Metastasis

UV radiation
rare
Melanoma: most dangerous & rare
 Malignant
 Cancerous
melanocytes
 Common cause: UV radiation
 High Metastasis rate

Diagnosis: ABCD
 Assymetry,
Border, Color, Diameter
Application: Burns & Skin Grafts

1.
Partial 2.
Thickness
3.
Full
Thickness
Depth of Burn
First degree
 Superficial epidermis
 Erythema, sunburn red, blisters, painful
 Heals in few days
Second degree
 Down to germinativum & dermis red, moist,
blisters, blanch with pressure
 Painful
 Accessory structures unaffected
 Minor if >15% body burned 3 weeks to heal
Third degree
 Down to subcutaneous white, brown, black, or
whit, dry
 Less painful WHY?
 Hard to heal if extensive through body skin graft
may be needed
Burns& Treatments
Estimation of Burns
•Rule of 9’s (p. 204)
Skin Grafts
 Split- Thickness
 Epidermis
Other Concerns:
1. Fluid & electrolyte balance
2. Thermoregulation
3. Infection
4. Contractures

Full-Thickness
 Epidermis
&
Dermis

Skin Flap
 All
3 layers
Rule of 9’s
Application: Decubitus Ulcer

Decubitus Ulcer= Pressure Sore
 Most
common: over bony areas (i.e. sacrum, heel)
 Cut off blood supply decrease nutrients & O2 to tissues
 Population most affected:
 Bed ridden
 Decreased sensation: diabetics (feet & hands), SCI
 Wheelchair bound
 Stages:
 I: reddening
 II: blister
 III: all 3 skin layers affected
Risk of
Infection  IV: all 3 layers of skin & underlying tissues (muscle/
tendons/ bones)
 Prevention: positioning every 2 hours, weight shifts in
wheelchair, cushioning/ supports
Decubitus Ulcers