Physiology: Functions of Skin Flashcards
(19 cards)
Functions of Skin (6)
Barrier function Metabolism and detoxification Thermoregulation Immune defence Communication Sensory functions
Consequence of failure
Barrier
- fluid loss –> dehydration
- protein loss –> hypoalbuminaemia
- Infection
Thermoregulation
- heat loss –> hypothermia
Immune defence
- spread of infection
metabolic
-disordered thyroxine metabolism
Communication
- inability to display healthy skin
Sensation
- pain sensation working –> pain
barrier function
Two way barrier; epidermis
Physical
- friction, mechanical trauma
- UV radiation
Chemical
-Irritants, allergens, toxins
pathogens
- Bacteria, viruses, fungi
Role of melanocytes
Produce melanin pigment.
Basal cells have. a superior cap of melanin pigment.
Melanin absorbs UV rays to protect DNA in cells nuclei
metabolism and detoxification
Skin is metabolically active
- Vit D metabolism
- Thyroid hormone metabolism
- Defence against chemicals, drugs, pollutants and sunlight
Vitamin D metabolism
- Vit D Sources
- Dietary Vitamin D
- UV light acts in skin- synthesised vitamin - Liver: 25 hydroxy-vitamin D
- Kidney
- 1,25 dihydroxy- vitamin D3
- Broken down Via D
- increases calcium absorption from bowel
- promotes mineralization of bone
Thermoregulation
Protects against being too hot or too cold
Warm/ cold sensitive thermoreceptors
- behavioural changes
- Control sweating/ shivering
Immune defence
Protection against infection
Sunlight responses
Allergic reactions
Langerhans and T cells important
Epidermis and dermis intact
Communication
Visual
Odour
Sociosexual behaviours
‘Stigma’: Situation of an individual who is disqualified from full social acceptance
Sensory functions
touch, pressure, vibration
Pain and itch
heat and cold
Nerve endings and receptors in skin
Merkels receptors
Slowly adapting
Meissners Corpuscles
Rapidly adapting
Ruffini’s corpuscles
Slowly adapting
Pacinian Corpuscle
Rapidly adapting
Constitutive barriers to skin infection
Physical barrier
Physiological Factors
Sebaceous Glands
Commensal Organisms
Physical barrier
tightly packed, highly keratinised, multi-layered cells
constantly undergo renewal and replacement
Physically limit colonisation by microorganism
Physiological factors
Low pH 5.5. (most pathogens are very sensitive to acidic environment)
Low oxygen tension
Sebaceous Glands
Secrete hydrophobic oils 9further repel water and micro-organisms
Lysozyme- destroys structural integrity of bacterial cell walls
Ammonia: anti-bacterial properties
Antimicrobial peptides e.g. defensives
Commensal organisms
Compete with invading organisms
