Skin and Temperature Regulation Flashcards
Define the Integumentary System
A group of organs working together, forming cutaneous membrane (skin)
Describe 3 Properties of the Skin
- Covers external surface of body
- Contains accessory structures
- 1.2-2.2 square meters- 4.5kg- skin, average adult
Name 3 Accessory Structures to the Skin
Hair
Sweat and oil glands
Nails
Name the 3 layers of the integumentary system
- Epidermis
- Dermis (mesoderm)
- Hypodermis- superficial fascia (mesoderm)
Describe the Epidermis
Epidermis (ectoderm)
Contains epithelial cells that are the thinnest outer layer of the skin.
Contains 4 main layers (5 in areas of greatest wear- i.e. soles of feet, palms and fingers
Non-vascularised
Describe the Dermis
- Below epidermis (bulk of skin)
- Tough and strong containing flexible and fibrous connective tissue
- Contains collagen and elastin 2-4mm thick at birth
- Contains structures (glands, hair follicles, blood supply and nerves
- Vascularized
- Sensation- heat, touch, pressure and pain
Describe the Hypodermis (Superficial Fascia)
- Subcutaneous (not strictly skin)
- Shares some protective functions- superficial tough tissue wrapping skeletal muscle
- Stores adipose tissue (fat)
- Anchors skin
- Provides insulation and calorie reservoir
Name the Cellular Skin Layers (Epidermis)
In order from bottom (newest cells) to top (oldest cells) Stratum Basale Stratum Spinosum Stratum Granulosum Stratum Lucidum Stratum Corneum BEAUTIFUL SOUTHERN GIRLS LOVE CHICKEN
Describe the Stratum Basale
- Deepest layer
- Lies next to dermis
- Mitosis cells (makes epidermal cells: keratinocytes)
- Daughter cells are pushed upward to become the more superficial layer (cells of the other strata)
Describe the Stratum Spinosum
- Connected to other cells by ‘spindles’
- Cells tightly connected to adjacent cells, helps resist tension
- Cells become flattened and start to die as they move upward
- 8 to 10 layers of cells
Describe the Stratum Granulosum
- Cells contain granules (lamellar granules) that release lipid (fat) rich secretion, helping waterproof the skin
Describe the Stratum Lucidum
- Only occurs in thick, hairless skin of the palms of hands and soles of feet
- 3-5 layers of cells
- Contain large amounts of keratin (tough fibrous protein)
Describe the Stratum Corneum
- Outermost layer of epidermis
- 20-30 layers of cells in the healthy adult
- Shingle-like dead cells are filled with keratin
- Protects from abrasion
- Contain lipids and proteins
- Outer layer sloughs off
- Basal layer replaces stratum corneum keratinocytes
What are the Types of Skin Cells?
Keratinocytes (90%)- produce keratin
Melanocytes (8%)- produce melanin pigment which is transferred to other cells
Langerhan Cells- from the bone marrow, involved in immunity
Merkel Cells- in the deepest layer, form touch receptor with sensory neuron
What are the Functions of the Skin?
- Protection
- Body Temperature Regulation
- Cutaneous Sensation
- Excretion
- Blood Reservoir
- Metabolic Functions
- Sensation
- Preventative
What is Skin Colour Determined By?
- Melanin
- Carotene
- Haemoglobin
Name the Properties of the Skin in a Term Baby
- Dermis 2-4mm thick
- Sweat gland mature 1 week
- Subcutaneous layer of lipid deposits- brown adipose (BAT) for energy and insulation
- Vernix caseosa protects, moisturises and facilitates colonisation
Name the Properties of the Skin in a Pre-Term Baby
- Dermis thinner
- Transparent and gelatinous
- Ruddy red connectivity between layers less
- Sweat glands mature 21-33 days (longer for extreme pre-term)
- +/- vernix caseosa
- Oedema
Name the Appendages to the Skin
- Cutaneous glands are all exocrine glands (contents released via a duct)
- Sebaceous glands
- Sweat gland
- Hair
- Hair follicles
- Nails
What are the Two Types of Sweat Glands
- Eccrine- open via duct to pore on skin surface
2. Apocrine- ducts empty into hair follicles
What is the Composition of Sweat?
Mostly Water
- Salts and vitamin C
- Some metabolic waste
- Fatty acids and proteins (apocrine only)
What is the Function of Sweat?
- Helps dissipate excess heat (by the evaporation of sweat from skin surface)
- Excretes waste products
Name Some Properties of Sweat Glands
Produce sweat
Widely distributed in skin
Name Some Properties of Sweat
- Acidic nature inhibits bacteria growth
- Odour is from associated bacteria
