HLT31507 CERTIFICATE III IN NUTRITION
& DIETETIC ASSISTANCE
Week 03
SKIN & BODY MEMBRANES
delivered by:
Mary-Louise Dieckmann
Body Membranes
Functions:
• Lining cavities
• Protects organs
• Covers body surfaces
• Lubricates body surfaces
Classifications of Body
Membranes
Two Classifications:
• Epithelial Membranes
– Cutaneous membrane
– Mucous membrane
– Serous membrane
• Connective Membranes
Cutaneous Membrane
• Cutaneous membrane = the skin
– Dry membrane
– Outermost protective boundary
• Superficial Epidermis
– Keratinized stratified squamous epithelium
• Dermis (underneath)
– Dense connective tissue
Mucous Membranes
• Lines all body cavities open to exterior body
surface
• Adapted for absorption or secretion
Serous Membranes
Lines body cavities that
are closed to the
exterior of the body
Always occurs in pairs
Serous layers separated by
serous fluid
Connective Membranes
• Synovial membranes
that cushion or protect
their structures
• Contain no epithelial
cells
• Line fibrous capsules –
synovial joints, bursae
and tendon sheaths
The Integumentary System
• Skin (cutaneous membrane)
• Skin derivatives:
– Sweat glands
– Oil glands
– Hair
– Nails
Functions of the Skin
• Protects deeper tissue from:
– Mechanical, chemical, bacterial and thermal
damage
– Ultraviolet radiation
– Desiccation
• Aids in heat regulation
• Aides in excretion of urea and uric acid
• Synthesizes Vitamin D
Structure of the Skin
• Epidermis – outer layer
– Stratified squamous epithelium. Avascular and
most cells are keratinocytes
– Four or five layers (four mostly, five on palms of
hands and soles of feed)
• Dermis – underlying layer
– Dense connective Tissue
• Hypodermis – not part of the skin
– Anchors skin to underlying organs, mostly
comprised of adipose tissue
Epidermis
•
•
•
•
Stratum basale
Stratum spinosum
Stratum granulosum
Stratum lucidum
(only in thick skin)
• Stratum corneum
Melanin
•
•
•
•
Pigment produced by melanocytes
Yellow, to brown to black
Mostly found in stratum basale
Amount of melanin produced depends on
genetics and exposure to sunlight
Dermis
Two layers:
Papillary layer
– Projections known as dermal papillae
– Pain receptors
– Capillary loops
Reticular layer
– Blood vessels
– Nerve receptors
– Glands
Skin Structure
Colour Determinants
• Melanin
– Yellow, brown or black pigments
• Carotene
– Orange-yellow pigment (from vegetables)
• Haemoglobin
– Red colouring from blood cells in dermis
– Oxygen content determines extent of red
colouring
Skin Derivatives
Sebaceous glands:
– Produce oil – lubricates the skin and kills bacteria
– Most glands have ducts that empty into hair
follicles
– Glands activated at puberty
Skin Derivatives
Sweat Glands
– Widely distributed across the body
– Two types:
• Eccrine – open via duct to pore on skin surface
• Apocrine – duct empties into hair follicles
Sweat
• Composition:
– Mostly water and some metabolic waste
– Fatty acids and proteins in apocrine glands
• Function:
– Helps dissipate excess heat and excrete waste
products
– Acidic nature inhibits the growth of bacteria
• Odour is from bacteria on skin
Homeostatic Imbalances of the
Skin
• Infections:
– Athletes foot (fungal infection)
– Boils and carbuncles (bacterial infection)
– Cold Sores (virus)
– Contact dermatitis (allergic reaction)
– Impetigo (bacterial infection)
– Psoriasis (cause unknown, can be triggered by
trauma, infection or stress)
Homeostatic Imbalances of the
Skin
• Burns
– Tissue damage and cell death caused by heat,
electricity, chemicals or UV radiation
– Associated dangers include:
• Dehydration
• Electrolyte imbalance
• Circulatory shock
Homeostatic Imbalances of
the Skin
Skin Cancer
• Two types – benign (encapsulated) and
malignant (metastasized)
• Most common type of cancer
Homeostatic Imbalances of
the Skin
Basal cell carcinoma (BCC)
– Least malignant and most common type
– Arises from stratus basale
Squamous cell carcinoma (SCC)
– Arises from stratum spinosum and metastasizes to lymph nodes –
early removal allows good chance of a cure
Melanoma
– Most deadly of skin cancer – cancer of melanocytes
– Metastasizes rapidly to lymph and blood vessels
– Detected using ABCD rule
Homeostatic Imbalances of
the Skin
ABCD Rule:
A – Asymmetry (two sides of pigmented mole do not
match)
B – Border irregularity (borders of mole are not
smooth)
C – Colour (different colours in pigmented area)
D – Diameter (sport is larger than 6mm in diameter)