Intro to dermatology Flashcards
Properties of the skin
-largest organ in the body -contains adnexal structures (added on to larger organs) e.g. nails, hairs, glands, sensory structures
Layers of the skin
epidermis dermis subcutaneous tissue
what is subcutaneous tissue also known as?
hypodermis
Properties of subcutaneous tissue
-Fat energy store -Insulation -Fibrous bands which anchor the skin to the underlying fascia
What is the dermis Made up of?
-Made up of collagen and elastin matrix with mucopolysaccharide -Main cells: fibroblasts, dermal dendritis cells and macrophages Contains: -Sebacous glands -Errector pili muscles -Hair follicles -Arteries -Veins -Sweat gland -Arteries
what are the layers of the dermis
From bottom to top: -Basale -spinosum -granulosom -Lucidum -corneum
Function of the basale
• Cells divide by mitosis • Some of the new cells become part of the more superficial layers • Contains melanocytes
Function of the spinousum
• Keratin accumulates • Lamellar bodies accumulate
Function of the granulosum
• Cells die • Lamellar bodie release lipids • Keratohyalin s and protein form a hard envelope
function of the lucidum
• Dead cells found between layers of keratohyalin
function of the corneum
• Cells containing keratin found within a hard protein envelope • These cells contain keratin • These cells are surrounded by lipid.
What do melanocytes do?
Melanocytes make melanosomes which are excreted and phagocytosed into keratinocytes.
what do largenhans cells do
Langerhans cells- process antigens and move to the lymph nodes to induce an immune response
Label the nail
From top to bottom:
- Hyponychium
- Nail plate
- Lateral nallifold
- Nail bed
- Lunula
- Cuticle
- Proximal nallifold
- Nail matrix
Explain the hair cycle
Anagen
- Active growing phase
- 80-90% of hair is in this phase
Catagen
- 2-3 week phase
- Growth stops
- Follicles shrink
- 1/3% of all hairs
Telogen
- resting phase for 1-4 months
- up to 10% of hairs on scalp
What are the main functions of the skin
Thermoregulation : Insulation, heat transfer
Immune system : Innate and adaptive
Barrier:
Protects against mechanical, chemical, UV light, microorganisms
Keeps in water, electrolytes and macromolecules
Sensation: Temperature, touch, pain
Vitamin D synthesis : converts 7-dehydrocholesterol into cholecalciferol
Intrapersonal communication: physical appearance, smell, self-identity
when is skin disease important
- Disfigurement
- Discomfort
- Disability
- Depression
- Death
Aetiology of skin disease
Internal :
- Systemic illness
- Autoimmune
- Genetics
- Drugs
- Infection
External:
- UV light
- Temperature
- chemical
- infection
Examples of skin disease caused by temp
e.g. Frost bite
Chill blains
Skin necrosis
Cold Urticaria
Cold urticaria
Macula
Small circumscribed area
Patch
Larger circumscribed area
Pustule
small pus filled area
Abcess
large pus filled area
