Chapter 5 Flashcards
The Integumentary System
- Skin
Accounts for 10-15% of body weight; Making it the [LARGEST ORGAN] In the body
Cutaneous Membrane {Skin}
-Two Components:
- Epidermis: (Superficial) *Keratinized Stratified Squamous Epithelium
- Dermis: (Deep) to Epidermis and the Basement Membrane; *Loose Connective Tissue & Dense Irregular Connective Tissue
Accessory Structures
- Sweat glands, Sebaceous Glands, Hair, & Nails
Sensory Receptors of the Skin
-The skin contains both Sensory Receptors and [Arrector Pili Muscles];
(Small bands of Smooth Muscle)
Epidermis
- Avascular;
- Relies on diffusion of oxygen & nutrients;
- 50% of Epidermal Cells are too far to maintain life. The layers are entirely made up of Dead Cells;
Hypodermis
- *Superficial Fascia or Subcutaneous Fat; *
- Deep to Dermis
- [NOT] part of the skin
- Made of Loose Connective Tissue & Adipose Tissue
Cellulite
- Dimpled appearance due to Collagen bands forming around the Adipose Tissue in the Hypodermis;
- Thighs, hips, and gluteal are areas effected most; Influenced by: genetics, gender, amount & distribution of Adipose Tissue, and age
- Is normal to have
- Healthy diet and Regular exercise help eliminate this
Functions of the Integumentary System
- Protection- [Pathogens]-> Fungi, Viruses, Bacteria
- Stratified Squamous, Keratinized Epithelium-> Durable and Flexible; Protecting the body from mechanical trauma, such as Stretching, Pressure, or Abrasion
- Continuous Barrier
- Destroy’s pathogens
Functions of the Integumentary System;
[Glands]
- Secrete antimicrobial substances;
~Sebaceous glands secretes gives the skin surface a slight acidic pH, [Acid Mantle]-> Inhibits growth of many and many pathogens;
~Absorption of UV light
~Skin secretes hydrophilic lipid-base chemicals
Functions of the Integumentary System
- Sensation- Perceive changes in Internal or External surroundings;
~ Skin has sensory receptors or cellular structures that detect changes in Internal or External environment;
~ Receptors detect potentially harmful stimuli, such as heat-cold-pain, that leads to tissue damage
Functions of the Integumentary System
- Thermoregulation- Negative feedback loops for stable Internal temperature;
* 98.6-97.5*
Example :
*Muscle activity in Metabolism
Body Temperature
- When it (Rises above normal), can be caused by extremes of weather or abnormal conditions; Causing fever
Sensory Receptors [Thermoreceptors]
- Control center in Hypothalamus of brain acts as a thermostat or thermoregulatory center; Receives input from thermoreceptors —> Process in which then responds to Sensory Inputs
Control Center Stimulating Sweating
-Sweat glands release sweat; Heats when it evaporates, cooling the mechanism
Control Center Stimulating Cutaneous Vasodilation
- Dermal blood vessels widen, [Dilate]
Body Temperature Returning to Normal Range & Cooling Mechanism
- Thermoreceptors no longer sense temperature above normal range, stopping the signaling the Hypothalamus;
- Thermoreceptors detect body temperature drop below normal range; Relaying to thermoregulatory center in the Hypothalamus
Hypothalamus
- Blood vessels in the Dermis narrow, [Vasconstrict] —>Reduces blood flow;
(Smaller) - Limits the heat lost;
Vasoconstriction
- Redirects the blood flow to deeper tissue; Helping conserve heat
Example:
Goosebumps, shivering, & teeth chattering
Functions of the Integumentary System
[Excretion]
- Excretion- Process where waste products and toxins are eliminated;
Example:
Kidneys; Skin makes a small contribution as well
Skin’s role in Vitamin D Synthesis
- Precursor: cholecalciferol when the epidermis is exposed to UV radiation;
- Cholecalciferol: released into blood; Modified to form [Calcitroil]-> active form of Vitamin D
Vitamin D
- Required for calcium ion absorption;
- Calcium Ion: Critical for nerve function, muscle contraction, building & maintaining of bone tissue;
Epidermis
Most Superficial Layer
- Keratinocytes: makes up 95% of Epidermis; Makes Epidermis stronger and less susceptible to mechanical trauma;
1. Manufacture Karatin-> tough fibrous protein
2. Linked together by desmosomes
Epidermal Strata Layers: 4-5 layers
- Stratum Basale layer: (single layer) of (stem cells) (resting) on the (basement membrane); The most Metabolically and Mitotically active Strata
- Involved in Vitamin D Synthesis
Epidermal Strata Layers: 2nd layer [Stratum Spinosum]
- Thickest layer;
- Metabolically and Mitotically active
Epidermal Strata Layers: 3rd layer [Stratum Granulosome]
- Keratin bundles or a Lipid Base substance;
- Waterproofing due to its hydrophobic nature;
- Leads to Isolation and the death of cells in this layer
Epidermal Strata Layers: 4th layer [ Stratum Lucidum]
- Clear, dead Keratinocytes;
- Found [ONLY] in [Thick Skin]
Epidermal Strata Layers: 5th layer [Stratum Corneum]
- Outermost layer of Epidermis;*
- Several layers of dead flattened keratinocytes;
- Sloughed off or Exfoliated mechanically; Shed skin—> Dust
Strata Epidermis Tip to Remembering
“Brilliant Studying Gives Loads of Confidence”: B= Basale S=Spinosum G=Granulosom L=Lucidum C=Corneum
Keratinocyte Life Cycle
- Location & Function of the Epidermis subject to physical and environmental stress;
- Stratum Cornea constantly sheds dead cells;
- Dead keratinocytes are replaced by [Mitosis] in the Stratum Basale and Spinosum
- Keratinocytes divide and push cells more into superficial layers
Keratinocyte Life Cycle…
- Keratinocytes (begin life) in the (Stratum Basale) or (Spinosum);
- (Passes) through (each) (Epidermal layer);
- Sheds from Stratum Corneum;
- (Migration) takes (40-50 days) to (complete);
Dendrite Langerhans Cells
- In Stratum Spinosum;
- Phagocytes of Immune System
Markel Cells
- Oval shaped
- Sensory receptors
- Detect light touch & discriminates shapes and textures
- Specialized for touch; (fingertips, lips, base of hair)
Melanocytes
- In Stratum Basale
- Produces [Melanin]-> Skin Pigment
Thick & Thin Skin
- Body differentiates to match it’s certain function;
- Palms of hand & Sole of foot (Greater Chance here) of mechanical stress;
Thick Skin
- Paper Towel texture*
- Does [NOT] have Hair Follicles
- Contains many Sweat Glands
Thin Skin
- Paper thin texture*
- Stratum Lucidum is missing
- Hairs, Sweat glands, and Sebaceous glands are present
Callus
- Additional layer of Stratum Corneum
- Repetitive pressure
Dermis
- Highly Vascular
- Deep to Epidermis
Functions:
Provides blood supply
Contains sensory receptors
Anchors epidermis
1st layer of Dermis
Papillary Layer- thinner and most superficial layer of the two;
- Stratum Basale-> Basement Membrane
- Special Collagen fibers; Anchors epidermis to dermis
2nd layer of Dermis
Dermal Papillae- tiny projections at the surface;
- Contains [Capillaries]-> tiny blood vessels; In loops extending up in the superficial part of Dermal Papillae
- Allows oxygen & nutrients to diffuse ECF into the Dermis; Then into the Avascular Epidermis
Tactile (Meissner) Corpuscles:
- In Dermal Papillae;
- Sensory receptors
- Responds to light touch
- More numerous where Sensation is the Function
Reticular Layer
- Bottom of Dermis*
- Rich in Proteoglycans that draw water
- Keeps skin firm & hydrated
- Cleavage lines & Flexure lines*
Lamellated (Pacinian) Corpuscles:
-Sensory receptors
- Respond to changes in pressure & vibration associated with Skin
Located : Blood vessels, Sweat glands, Hairs, Sebaceous glands, and Adipose tissue
Skin Markings
-Small (visible lines) in Epidermis created by (Interaction) between (Dermis & Epidermis)
Dermal Ridges
- Area where (Dermal Papillae) are more (prominent) (due to) presence of (thick Collagen bundles)
- Indent overlying Epidermis to create Epidermal Ridges; Occurs in loops, arches, & whorls-> Enhances the gripping ability of both hands & feet
- Sweat pores open, leaving a thin film or fingerprint on things touched
Tension (Cleavage) Lines
- Indentations in Epidermis
Flexure Lines
- Deep creases
Skin Wrinkles
- Age
- Decrease in Collagen fibers, elastic fibers, proteoglycans, & adipose tissue in the Dermis
- Reduces the skins firmness, hydration, and recoil ability after stretching; Around eyes, Forehead, & Mouth
3 ways to minimize Wrinkled Skin :
- Botox- smoother skin appearance
- Fillers- adipose tissue, collagen, and proteoglycans
- Topical Creams- reduce wrinkle appearance
Melanin
Various amounts of orange-red pigment [TO] black protein pigment;
- Produced by Melanocytes in Stratum Basale of Epidermis
- Composed of the amino acid [Tyrosine]-> tyrosine chemically binds by enzyme [Tyrosinase]; Reactions occur within a special vehicle known as [Melanosome]
*Protecting DNA from Mutations, included by UV Radiation *
Melanocytes
- In contact with Keratinocytes of the [Stratum Basale]-> Living layer & the Spinosum;
Melanosomes
- Migrate and is released by Exocytosis; Absorbed of Keratinocytes
Melanin …
- Transported to the [Superficial Side]-> Top, Umbrella
of the nucleus; - [MUST] be made continuously to maintain a consistent skin color as it degrades after days
- Increases with exposure to natural/artificial UV Radiation; UV light causes DNA damage in Melanocytes
- People of all skin pigmentations can develop sunburn & are at risk for skin cancers*
Secondary Function of Melanin
- Reduce Synthesis of Vitamin D*
- less calcium ion absorption
- Exposure to high amounts of UV prevents excess Vitamin D (Africa)
- Less exposure of UV allows individuals to develop lighter skin, allowing enough for Vitamin D Synthesis
- (Skin color) (depends) on the (number) of (Melanocytes); Fewer are located on the Palms of hand & Sole of feet
- (Skin tone) is (due to) the (difference) in the (amount) of (Tyrosinase & Melanin Type-Color)
Variations of Pigmentation
-Freckle: Increased Pigmentation; SPOT
-Mole or Nevus: Increased Area of Pigmentation; (# of cells)
Due to proliferation, there is no increase in Melanin production (enzyme)
-Albanism: Melanocytes fail (Albino)
Tanning
- $5 billion a years spent
- Salons promotes notion of “healthy tan”*—> NO SUCH THING
- UVA & UVB are associated with Sunburning, leading salons to claim UVA rays are safe
1st Minor Pigment effect Skin Pigmentation :
- Carotene: yellow-orange pigment
(egg yolks or orange vegetables)
- Lipid soluble in Stratum Corneum
- Slight yellow-orange color in parts
2nd Minor Pigment effect Skin Pigmentation :
- Hemoglobin:
- Found in Red Blood cells
- Iron containing Protein
- Transports oxygen
- Oxygen binds to Iron in an Oxidation Reaction; Same type of reaction causing Iron to rust
- Hemoglobin effect is an indirect result of blood flow in Dermis
Color Change
Associated with amount of blood flow in the Dermis
Erythemia : increases, making the skin more reddish
-Color change can be a response to exercise;
Conditions that cause Erythemia: Trauma, Fever, Infection
Pallor: decreases, resulting in the loss of normal pinkish hue; Most visible in pale skinned individuals
- Normal response when the body is trying to conserve heat;
- Can occur in the Endocrine System
Hair
- Provides protection preventing substances & organisms from entering the eyes and nose;
- Protects scalp from UV radiation & mechanical trauma
- Associated with a small sensory neuron; Role in detecting change in environment
Hair Pili
-Small filaments that protrude from the skins surface over the entire body [EXCEPT] regions with thick skin, lips & parts of external genetalia
2 Main Parts of Hair
- Shaft- portion of hair that protects from skin’s surface; made up of dead keratinized cells
- Root- embedded in Dermis;
- Indented at the base by protection of blood vessels from [Hair Papillae]
- Root & Hair Papillae are known as [Hair Bulb]
- Many Epithelial cells in root are alive, due to not completing the keratinization process
Both Shaft & Root are made up of?
Stratified Squamous Keratinized Cells
Matrix
- Base of the Root; Actively divides
- Root is embedded in the Hair Follicle
- Infolding of the Epidermis, -> [Epithelial Root Sheath]-> extends into dermis or hypodermis
3 Visible Regions of Matrix
- Inner Medulla- Soft core; Composed of Soft Keratin
- Middle Cortex- Layers of Keratinocytes; Contains Hard Keratin; Provides strength to strand
- Outermost Cuticle- Single overlapping layer of Keratinocytes; Contains Hard Keratin
Dermal Root Sheath
Surrounding Epithelial Root
- Smooth muscle known as, [Arrector Pili Muscles]
- Contraction causes hair to stand, [Piloerection] giving skin “goosebumps”
Hair Growth
1-1.5 cm per month AVG; Varies between Individuals
- GROWTH STAGE: Mitosis occurs in Matrix: Can take a month or six years-> depends on location
- RESTING STAGE: Matrix ends as cell’s die; Follicle shortens & the hair is pushed to the surface where it is dormant for at least a month or two; Falls out by new hair pushing it out & the new hair is now in growth stage
Types of Hair & Texture
-Lanugo: thin, non pigmented hair; Covers entire body of a fetus, it is then replaced with 1-2 hair types after it has fell out: 1. Terminal Hair or 2. Vellus Hair
Terminal Hair
- Thick, coarse, & pigmented hair
- Surrounds the eyes and the scalp
*Replaces lots of Vellus hair after puberty; Varies by gender with more hair replacement *
Vellus Hair
-Thinner, non pigmented hair
Development of Hair Color
-Determined by the Melanin produced in the Matrix by, [Melanocytes];
Blonde hair= Little Melanin
Black hair= Lot of Melanin
Red hair= Reddish pigment, containing Iron
*Melanocytes produce less Melanin with aging, resulting in hair becoming gray or white
Nails
-Stratified Squamous Epithelium filled with Hard Keratin
Nail Plate
-Most visible component of nail; Sits on top of an underlying Epidermal nail
Nail Body
-Visible portion; Nail plate
Nail Root
-Portion of plate that lies under skin
What is a Nail?
-Folded region of skin surround & reinforce the nail plate;
3 Types: Proximal nail fold, Medial & Lateral nail fold, & Distal of Free Edge of nail plate
Proximal Nail Fold
- Distal edge of this fold is, [Eponychium]-> Cuticle;
- Consists of [ONLY] Stratum Corneum
Medial & Lateral Nail Fold
-On Medial & Lateral edges of Nail Plate
Distal of Free Edge of Nail Plate
-Attached to the underlying nail bed, [Hyponychium]
Where does Nail Growth occur?
-Nail Matrix; Actively dividing cells push the neighboring Keratinocytes distally
Nails [DO NOT] contain Melanocytes. Why?
-Due to them mostly being translucent [EXCEPT] at the region, [Lunula]->half-moon shaped region of the proximal nail plate, representing an accumulation of Keratin;
Primary Function of the Nail
-Protection of underlying tissue; Distal tip of Fingers & Toes
Two Glands the Skin Contains ?
- Sweat (Sudoriferous) Glands- Produce Sweat
2. Sebaceous Glands- Produce Oily Sebum
1st Type of Sweat Glands
[Eccrine]
- Most prevalent type
- Coiled tubular glands found in Dermis
- Sweat containing water, waste products, & electrolytes
- Exits from duct through a [Sweat Pore] onto the Epidermal Surface
2nd Type of Sweat Glands:
[Apocrine]
- Large glands into a hair follicle
- Secretions can become [Odoriferous]-> smelly, once skin bacteria metabolizes their contents
- Influenced by sex hormones; Active after puberty
3rd Type of Sweat Glands:
[Ceruminous]
-Release a thick secretion called, [Cerumen]-> car wax
into hair follicles
-Cerumen traps incoming particles; Also lubricant
4th Type of Sweat Glands:
[Mammary]
-Highly specialized sweat glands that produce a sweat product, Milk
Sebaceous Gland
- Branched of secreting cells called Acini
- Coverage to form a central duct that empties into a hair follicle or a small pore
Found everywhere on body [EXCEPT] palms & soles Greatest number is found on the face & scalp
Sebum
- Waxy, oily mixture of mostly Lipids (fats)
- Secretory cells accumulate around the Sebum until the cell ruptures
- Contains cellular fragments & debris
- Coats hair
- Inhibits growth of or kills certain bacteria *
Acne
-Plugged Hair Follicle containing oil and dead skin cells
Acne Vulgaris
-Affects 96% of adolescents & young adults
Cause: accumulation of sebum and dead cells; [Comedone]-> blackhead
becomes infected by Propionibacterium acne, resulting in Inflammation and formation of a [Pustule]-> pimple
*Can be severe & can cause scarring *
Wound
-Disruption in the skin’s integrity
Includes:
Lacerations, Burns, Skin Cancers
Burn
- Wound caused by heat, extreme cold, electricity, chemicals and/or radiation
- Grouped into 3 classes according to the extent and depth of damage
1st class of a Burn: [1st Degree]
- Superficial, One layer
- Only damages the Epidermis
- Skin may develop [Erythemia]
2nd class of a Burn: [Second degree]
- Partial thickness burn
- Involves the Epidermis & part of or all of Dermis (2 layer)
- Results in Pain, Blistering, and Scarring
3rd class of a Burn: [Third Degree]
- Full thickness burn
- 3 layer
- Most damaging wound
- Involves the Epidermis, Dermis, & Hypodermis
- Not painfull at first due to nerves being destroyed
Rule of Nines
- Body is divided into 11 areas, representing 9% of total body area
- Useful tool for grading extent of burn
Skin Cancer
- Mutation in DNA that includes a cell to lose control of cell cycle;
- Unchecked by cell division, leading to the formation of a large population
- Cancerous tumors can metastasize, in which the cells spread through the blood or lymphatic system
1st Type of Affecting Skin Cancer:
[Basale Cell Carcinoma]
- Most common of all cancer types
- Appears as a nodule with a central crater
2nd Type of Affecting Skin Cancer:
[Squamous Cell Carcinoma]
- Second most common
- Cancer of Keratinocytes of Stratum Spinosum
- Scaly plaques may ulcerated & bleed ( normally found on head or neck)
- Tumors more likely to metastasize, which leads to them being surgically removed
3rd Type of Affecting Skin Cancer:
[Malignant Melanoma]
- Cancer of Melanocytes
- Early detection is Critical due to the metastasize tendency
- “Arms” of Melanocytes access Dermal blood vessels; Enables cells to spread to other tissues
- Treated with surgical removal & possible other options such as radiation or chemotherapy
- Prognosis depends on size of tumor, and depth into the Dermis
Cancer Distinguished by ABCDE:
A=Asymmetrical Shape; Two Un-matching Sides B=Border Irregularity; C=Color; Blue-Black or Variety D=Diameter; Larger than 6mm E=Evolving; Changing Shape
