Structure and Function of the Skin Flashcards
Describe skin
Largest organ in the body
Contains adnexal structures - hair, nails, glands and sensory structures
Important role in protection, homeostasis and transmission of sensations
What are the layers of the skin?
Skin - epidermis and dermis
Subcutaneous tissue below
Describe the process of cell development in the skin
- Stratum basale - cells divide by mitosis and some newly formed cells become superficial strata
- Stratum spinosum - keratin fibres and laminar bodies accumulate
- Stratum granulosum - keratohyalin and hard envelope form
- Stratum lucidum - dead cells lie within keratohyalin
- Stratum corneum - dead cells with hard protein envelope
Describe the nail anatomy
Hyponychium
Nail plate
Lateral nailfold
Nail bed
Lunula
Cuticle
Proximal nailfold
Nail matrix
What are the 3 stages of the hair cycle?
Anagen
Catagen
Telogen
What is the anagen phase?
Active growing phase
80-90% of hair
Where chemo effects
What is the catagen phase?
2-3 weeks phase growth stops/ follicles shrink
1-3% of hairs
What is the telogen phase?
Resting phase for 1-4 months
Up to 10% of hairs in a normal scalp
What are the functions of the skin?
Thermoregulation
Skin immune system
Barrier
Sensation
Vitamin D synthesis - UV light converts 7-dehydrocholesterol to cholecalciferol
Interpersonal communication
Describe the epidemiology of skin disease
22-30% of population affected
50% skin cancer/ lesions
25% require surgical procedure
Why is skin disease important?
Disfigurement, discomfort, disability, depression and death
What are some external causes of skin disease?
Temp., UV, chemical, infection and trauma
What are some internal causes of skin disease?
Systemic disease, genetics, drugs and infection
What are some cold injuries to skin?
Frostbite, chilblains, skin necrosis and cold urticaria
What is an example to trauma causing skin disease?
Dermatitis Artefacta - self induced trauma