Week7 Integumentary Flashcards
Integumentary System
2 parts
1.Skin:
• largest organ of the body
• Cutaneous membrane
2. Associated structures ‘appendages or accessory structures’
• Hair, nails, glands
2 primary layers of skin
- Epidermis
• Outermost portion
Comprised entirely of stratified squamous epithelial cells
• Contains no blood vessels ‘avascular’ - Dermis
• true skin’
• Connective tissue
• Contains blood vessels, nerves & glands
• Underneath and supporting the dermis is the subcutaneous layer.
Epidermis
Skin color changes
• Pink flush indicates increased blood volume or increased blood oxygen
• Cyanosis-bluish gray color indicates low blood oxygen level
• Vitiligo-patchy light skin areas resulting from acquired loss of epidermal melanocytes
> Increased skin pigmentation caused by hormonal changes in pregnant women
> Freckles small, flat macules common normal skin pigment variation
Dermis ( true skin)
Subcutaneous layer
Accessory structure of skin
Help protect the skin and give it more functions
1. Glands- Sebaceous oil gland
Sudorferous glands
2. Hair
3. Nails
Sebaceous glands
Subdoriferous
(Sweat gland)
Modified sudoriferous glands
Lanugo
Hair
Lanugo: Soft hair of fetus and newborn
Arrector pili
Arrector pili -involuntary smooth muscle, produces
“goose bumps” and causes hair to stand up straight
• Stimulates secretion of sebum (when contracted)
Nails
• Hardened keratin formed by epidermis over terminal ends of fingers and toes
• nail plate: sits on nail bed of epithelial tissue
• Root lies in a groove and is hidden by cuticle
• Lunula: Crescent-shaped area nearest root
• Function: Protection; assists with grasping objects;
• Nail bed may change color with change in blood flow
General health can affect nail appearance:
> abnormal colour, thickness, shape or texture
Functions of the Integumentary System
Four major functions:
- Protection: first line of defence
- Protection against dehydration (drying)
- Regulation of body temperature
- Collection of sensory information
Protection
a) Intact Barrier; Against infection by microbes
b) Surface cells are constantly shedding which removes pathogens.
C)Against ultraviolet rays from sun
d)
Against cuts and tears
e)
Sweat has some antimicrobial characteristics
• Protects against bacterial toxins.
• Protects against some harmful environmental chemicals.
- Protection against Dehydration
Skin prevents excess water loss by evaporation; it forms a boundary that encloses body fluids & limits water loss **
Keratin & Sebum help to waterproof the skin and keep it moist & supple
- Thermoregulation: Regulation of Body Temperature
- Thermoregulation: Regulation of Body Temperature
• Skin can release almost 3000 calories of body heat per day
> Mechanisms of temperature regulation:
a) Regulation of sweat secretion
b) Regulation of flow of blood close to the body surface
c) Shivering; contraction of arrector pili muscle
- Collection of Sensory Information
• Chief sensory organs of the body
> many nerve endings & special receptors that detect changes to its environment
a) Free nerve endings
• detect pain and temperature changes
b) Sensory receptors
• To light touch and deep pressure
c) Thermoreceptors
• Detect heat and cold
Many reflexes start with the sensory messages from the skin.
> The skin works with the brain and spinal cord
Other activities of skin
Absorption of substances e.g. medications
Excretion (minimal amount)
• Water (sweat)
• Electrolytes (sweat)
• Wastes (nitrogen containing waste)
Manufacture of vitamin D (for development & maintenance of bone tissue) under the effects of ultraviolet radiation from sunlight
Observations of the Skin
Color
Color
• Factors influencing skin color include:
1. Melanin: The degree of brown pigment in the skin
• indicates increase/excess (tanning, endocrine disorder) or absent (albinism, vitiligo,)
2. Hemoglobin: quantity of blood in the surface blood vessels.
• Pallor
• Flushing
• Cyanosis
3. Carotenoderma: yellow/orange skin discoloration
• Carotenemia: excess carotene in blood
• Skin pigment obtained from vegetables (orange/yellow)
4. Bile pigments: yellowish skin due to excess of bile pigments ‘bilirubin’
• Jaundice
reflecting impaired hepatic function, gallbladder problems, and/or excess hemolysis
Jaundice may be symptom of following:
- A tumour pressing on the bile duct, or a stone within the duct.
- Virus; Inflammation of the liver e.g. hepatitis
- Blood diseases in which red blood cells are rapidly destroyed.
- Immaturity of the liver; e.g.newborn, unable to process bilirubin
What color is associated with cyanosis? What color is associated with jaundice?
Blue grey
Yellow
Repair integument
Wound Healing
• Occurs only in areas with actively dividing cells
• Begins after blood has clotted, with an inflammatory response
• Stem cells produce new tissue cells and blood vessels
• Collagen is produced by fibroblasts to close the wound
• Larger injuries require extensive growth.
• Scar/cicatrix
• Keloids
Factors That Affect Healing
1. Nutrition
2. Blood supply
3. Infection
4. Age
Effects of aging on the skin
Stem cells, fibroblasts, and melanocytes are less active resulting
• impaired healing
• less hair; thinner on scalp, less on body
• Reduced connective tissue, (collagen)
• decreased pigmentation, — hair becomes gray
2. Localized areas of extra pigmentation ‘liver spots
3. Dermis becomes thinner, and skin may become transparent and lose its elasticity.
4. Hair texture changes, becomes drier
5. Sweat production and skin circulation decrease, impacting thermoregulation.
б.
Less fat in the skin also impacts thermoregulation
Toe nails may discolor & become abnormally thick
8. Fingernails may flake, become brittle or develop ridges
9. Skin cancer susceptibility increased
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