S10 Skin and Dermatology Flashcards
What are the three general layers of skin?
- Epidermis
- Dermis
- Hypodermis
What are the layers of the epidermis?
- Stratum Corneum
- Stratum Lucidum (only on palms and soles of feet)
- Stratum Granulosum
- Stratum Spinosum
- Stratum Basale
Is the epidermis vascular or avascular?
Avascular
What is the function of the epidermis?
Prevents water loss, prevents pathogen ingress, prevents underlying tissue loss, synthesis of keratin.
Describe the stratum corneum and where it is found.
Made up of squames (dead keratinocytes).
Always sheds.
Thickest on palms and soles of feet.
What is the stratum lucidum.
A transparent one cell wide layer only present on the palms and soles of feet.
Describe the stratum granulosum and what you find there.
Made up of stratified squamous epithelia.
Contains lamellar granules (make keratin fibres) and tonofibrils.
Describe the stratum spinosum and what you find there.
Made up of 3 layers of cuboidal epithelia held together by desmosomes.
First point at which you find Golgi bodies and where lamellar bodies/granules are produced.
Describe the stratum basale and what you find there.
Made up of columnar epithelial cells.
Where keratinocytes are renewed by cell division. As the cells differentiate they move away from the epidermis-dermis junction and towards the surface.
Contain melanocytes.
Make tonofilaments.
What are the layers of the dermis?
- Papillary dermis
2. Reticular dermis
How do the epidermis and dermis link together?
The epidermis/stratum basale joins the dermis in interdigitations called dermal papillae
What does the dermis contain?
- Sweat glands
- Hair follicles
- Arrector pili muscles
- Sensory structures
- Subeceous glands
What sort of connective tissue makes up the dermis?
Irregular dense connective tissue
What is the function of the dermis?
Helps give the skin structure and involved in thermoregulation
What is the hypodermis made up of?
Mainly adipose tissue and loose connective tissue
Where in men and women is the hypodermis thicker?
Men - thicker around the abdomen and shoulders
Women - thicker around the hips, buttocks and thighs
In both - thick on palms and soles of feet
What does the loose connective tissue of the hypodermis contain?
- Fibroblasts
- Macrophages
- Fibres
- Mast cells
What is the function of the hypodermis?
An energy store, shock absorber, insulator.
Also site of hormone production.
What are melanocytes?
Cells in the stratum basale (epidermis) that produce melanin.
Everyone has the same number of melanocytes but darker skinned people produce more melanin.
What are Langerhans cells?
Dendritic cells in the stratum basale (epidermis).
They present antigens to T-lymphocytes and cause an immune response (e.g. contact dermatitis).
What do keratinocytes produce?
The protein keratin
What are dead keratinocytes called?
Squames
In which layer of the epidermis does apoptosis of keratinocytes occur?
Stratum granulosum
What breaks down to allow squames to ‘move up’ the epidermis
Desmosomes
What are the skin associated structures?
- Hairs
- Sebaceous glands
- Arrector pili
- Sweat glands
- Nails
What are the 3 different types of hair and what are they like?
- Lanugo - baby hairs
- Vellus - short, thin, soft and light - replace lanugo
- Terminal - long, wide, dark and coarse - head and genitals
What are the functions of hair?
- Thermoregulation
- Sexual attraction (pheromones)
- Sensation (sensory nerve endings)
- Protection
Where do on your skin do you get no hair?
Palms of hands and soles of feet (palmar and plantar skin)
What to sebaceous glands do? And where do you find them?
Exocrine glands that secrete sebum, an oily waxy substance that lubricates and waterproofs skin.
Found near hair follicles
What type of glands are sweat glands?
Exocrine
What do arrector pili muscles do? And where are they found?
Smooth muscle fibres that are attached to the hair ‘bulb’ (base of hair follicle) in the papillary dermis. They cause hairs to stand up (thermoregulation or fight/flight response) and induces sebum release.
What are the 6 signs of inflammation?
- Rubor (redness)
- Tumor (swelling)
- Calor (heat)
- Dolor (pain)
- Functio laesa (loss of function)
- Pruritus (itching)
What factors should you consider when taking a dermatology history?
- Symptoms
- What factors exacerbate or relieve it?
- Past medical history
- Personal and family history of skin diseases
- Drug history
- Social, occupational, travel and sexual history
- Psychological impact of skin disease
What should you consider when doing a dermatological examination?
- Is there adequate exposure and lighting?
- Have you looked at the hair/scalp, mucous membranes and nails?
- The morphology of the disease - how do the lesions look and their distribution
- Touch the lesions (with consent)
- If appropriate, examine other systems e.g. joints, lymph nodes
What is eczema? What can cause it?
An itchy inflammation of the skin.
Can be caused by allergies, stress, heat/sweating, infection, etc.
What are the 9 main functions of skin?
- Protection and repair
- Thermoregulation
- Excretion of waste products
- Lubrication
- Storage (adipose tissue)
- Vitamin D synthesis
- Absorption
- Aesthetics
- Sensation
What is the dermatological term for a small lump (less than 5mm)?
Papule
What is the dermatological term for a larger lump (5-10mm)
Nodule
What is the dermatological term for redness?
Erythema
What is the dermatological term for scaling?
Scaling
What is the dermatological term for a small water blister?
Vesicle
What is the dermatological term for a larger water blister?
Bulla
What is the dermatological term for pus-filled vesicle
Pustule
What is the dermatological term for thread vein?
Telangiectasia
What is the dermatological term for hair loss/thinning?
Alopecia
What is the dermatological term for hairiness?
Hirsutism
What is the dermatological term for scratch marks?
Excoriations
What is the dermatological term for stretch marks?
Striae
What is the dermatological term for itching?
Pruritus
What is the dermatological term for thinning?
Atrophy
What is the dermatological term for a non-palpable area of discolouration?
Macule
What is the dermatological term for a large non-palpable area of discolouration (bigger than 2cm)?
Patch
What is the dermatological term for a palpable, flat topped area bigger than 2cm?
Plaque
What is the dermatological term for loss of epidermis (superficial)?
Erosion
What is the dermatological term for loss epidermis and dermis (deep)?
Ulcer
What is the dermatological term for thickening of the skin with exaggerated skin markings?
Lichenification