Integumentary System Flashcards
What is the integumentary system?
Organ system consisting of the skin, hair, nails, and exocrine glands
What does the integumentary system do?
-Protects the body from chemicals, disease, UV light, physical damage
-Produces sweat, oil, wax
-Waterproofing
-Supplying triglycerides
-Synthesis of vitamin D
What is the epidermis?
-Outer layer of the skin
-Consists of keratinized stratified squamous epithelium
-Avascular, must be nourished by tissue fluids from the dermis
What is the dermis?
-Second layer of the skin
-Thick layer of fibro-elastic connective tissue
-Highly vascular
-Contains receptor organs
What is subcutaneous tissue?
Layers of loose connective tissue containing various amounts of adipose tissue
What is the epidermal strata?
-Five distinct layers of cells attached to basement membrane
-Best defined in thick skin
-Consists of keratinocytes
What is a keratinocyte?
Cell that manufactures and stores keratin
What is keratin?
An intracellular fibrous protein that gives hair, nails, and skin their hardness and water resistance
What is a melanocyte?
Cell that produces melanin
What is melanin?
Gives hair and skin its colour, and helps protect the living cells of the epidermis from UV damage
What are the two layers of the dermis?
Papillary dermis
Reticular dermis
Describe the anatomy of the papillary dermis:
-Loose areolar connective tissue comprised of collagen + elastin fibres to form a loose mesh
-Projects into the stratum basale of the epidermis
-Contains: fibroblasts, adipocytes, phagocytes, lymphatic capillaries, nerve fibres, touch receptors (meissner corpuscles)
Describe the anatomy of the reticular dermis:
-Thicker than papillary
-Dense irregular connective tissue
-Well vascularized
-Elastin enables movement
-Collagen binds water to keep skin hydrated
What is the hypodermis?
-Directly below the dermis
-Well vascularized
-Loose connective & adipose tissue
What does adipose tissue in the hypodermis do?
-Energy reserve
-Insulation
-Cushion
What is hair?
-Keratinous filament grows in the epidermis in a hair follicle
-In the follicle is a hair papilla lined with stratum germinativum which produces the hair
-Hair bulb surrounds the papilla containing capillaries and nerve endings from the dermis
What are the functions of hair?
-Protection
-Sensory input
-Thermoregulation
-Communication
-Specialized hairs defend the body by trapping dust particles
What are sebaceous glands?
-Exocrine gland attached to hair follicle
-Produces sebum
What is sebum?
-Fatty/oily substance that coats the hair and skin
-Natural lubrication
-Prevents moisture loss and brittleness
-Inactive during childhood
-Secretion is stimulated by hormones
What are sweat glands?
-Exocrine sudoriferous glands produce sweat to cool the body
-Secretions are excreted by exocytosis
What are eccrine sweat glands?
-Produce hypotonic sweat for thermoregulation
-Found all over skin (esp. palms, soles, forehead)
-Sweat is mostly water, some salt, antibodies, metabolic waste, dermicidin, an antimicrobial peptide
What are apocrine sweat glands?
-Hair follicles in densely hairy areas (e.g., armpits)
-Larger than eccrine
-Sweat includes organic compounds that make the sweat thicker and more odorous
What are nails?
-Formed on the nail bed
-Composed of densely packed dead keratinocytes
-Forms at the nail root, a matrix of proliferating cells from the stratum basale that allows the nail to grow continuously
Vitamin D synthesis:
-Epidermal skin layer synthesizes vit D when exposed to UV
-D3 (cholecalciferol) is synthesized from a derivative of cholesterol
-Liver converts D3 to calcidiol, then converted to calcitriol in the kidneys
What is eczema?
-Allergic reaction manifested as dry, red, itchy skin
-Can include swelling, flaking, bleeding
-Managed with moisturizers, corticosteroid creams, immunosuppressants
What is acne?
-Skin disturbance in areas rich in sebaceous glands
-Common during puberty
-Overproduction of sebum and keratin can block hair follicles
-Results from infection by propionibacterium and staphylococcus
What is basal cell carcinoma?
-Cancer that affects the mitotically active stem cells in the stratum basale of the epidermis
-Most common skin cancer
-Head, neck, arms, back
-Starts in the stratum basale and spreads
What is squamous cell carcinoma?
-Affects the keratinocytes of the stratum spinosum
-Presents as lesions on the scalp, ears, and hands
-2nd most common skin cancer
-More aggressive than basal cell
-Can metastasize
What is melanoma?
-Uncontrolled growth of melanocytes
-Develops from a mole
-Highly metastatic
-Appears as asymmetrical brown and black patches with uneven borders and a raised surface
What does ABCDE stand for when it comes to melanoma?
Asymmetry
Borders (irregular)
Colour (varied shades of brown or black)
Diameter (larger than 6mm)
Evolving (shape changes)
What is depicted in this image?
Epidermis-thick skin
What is depicted in this image?
Dermis (reticular layer)-thick skin
What is depicted in this image?
Dermal papillae-thick skin
What is depicted in this image?
Eccrine sweat glands-thick skin
What is depicted in this image?
Epidermis-thin skin
What is depicted in this image?
Dermal papillae-thin skin
What is depicted in this image?
Eccrine sweat glands-thin skin
What is depicted in this image?
Hair follicle-thin skin
What is depicted in this image?
From inner to outer: hair shaft, internal root sheath, external root sheath, glassy membrane
Combining forms meaning skin:
cutane/o, derm/o, dermat/o
Combining forms meaning nail:
onych/o, ungu/o
Combining forms meaning hair:
pil/o, trich/o
What is alopecia?
Absence of hair from areas where it normally grows
What is nevus?
Pigmented lesion in or on the skin (mole)
What is an allergy test?
Allergy-causing substances placed on the skin and reactions are noted
What are bacterial and fungal tests?
Samples from skin lesions are taken to determine the presence of bacterial infection or fungal growth
What is a skin biopsy?
Samples of skin lesions removed and sent to pathology for examination
