The Integumentary System Flashcards
What is the integument?
Outer covering of the body
(Skin,glands, hair, nails)
What are the functions of the integument?
Protection
Sensation
Vitamin D production
Temperature regulation
Excretion
What is the integument protecting against?
Abrasions
UV light
Microorganisms
Water loss
What are the layers of the skin?
Epidermis
Dermis
The subcutaneous layer (not really skin) (below the dermis)
What is the epidermis?
The surface epithelial layer
Prevents water loss and abrasion damage
What is the dermis?
An underlying dense connective tissue layer
Structural strength
What does the dermis do?
Carries out majority of the functions of the skin
What connective tissue fibres are present in the dermis?
Collagen/ elastin fibres
Fibroblast cells
What are the layers of the dermis?
Papillary layer (superficial)
Reticular layer (deeper)
What is contained within the papillary layer of the dermis?
Fine collagenous and elastin fibres
Blood vessels
What is contained within the reticular layer of the dermis?
Dense fibres
What is contained within the dermis?
Hair follicles
Sensory receptors
Sweat and sebaceous glands
Blood vessels
Lymphatic vessels
How does the dermis handle growth and repair?
Does NOT continuously shed and regenerate (only in the epidermis)
Wound healing: fibroblasts proliferate
Collagen fibres
Over stretched skin= damage to dermis
The epidermis is avascular. What does this mean?
Doesn’t have blood vessels
In the epidermis which layer is the cells generated?
Basal layer/ stratum basale
What process is responsible for the epidermis being waterproof?
Keratinisation
What are the cell types in the epidermis?
Basal cells (precursor of keratinocytes)
Keratinocytes (contains keratin) (90% of cells in skin)
Melanocytes (filter Uv lights) (pigment producing cell)
Langerhans cells
Merkel cells (sensory cells)
What are the cell layers in the epidermis?
Stratum germinativum (growth layer)
Stratum basal
Stratum spinous
Stratum granulocytes (granular layer)
Stratum lucidium (clear layer)
Stratum corneum
What cells are present in the stratum basal layer of the epidermis?
Basal cells
Merkel cells
Melanocytes
What cells are present in the stratum spinosum layer of the epidermis?
Keratinocytes
Keratin and lipid
Basal cells
Langerhans cells
What happens in the stratum granulosum cell layer in the epidermis?
Cells deposit keratin
Superficial cells begin to degenerate
What cells are present in the stratum lucidium layer of the epidermis?
Dead cells
More keratin
More lipid
What cells are present in the stratum corneum layer of the epidermis?
Dead cells filled with keratin (constantly shed)
What are the two types of sweat glands?
Eccrine sweat glands
Apocrine sweat glands
What are the characteristics of the eccrine sweat gland?
Open directly through sweat pores
Function throughout life
Secretes water with a few salts
Eliminates waste and cools body
What are the characteristics of the apocrine sweat glands?
Open into hair follicles
Limited distribution (armpits/ genitalia)
Begins to function at puberty
What are the characteristics of the sebaceous glands?
Open into hair follicles
Secrete sebum
Anti-fungal activity
What does skin colour depend on?
Pigments
Blood
Thickness of stratum corneum
What is melanin?
Group of pigments
What are the characteristics of melanin?
Produced by melanocytes
Protects from UV
Production affected by UV, hormones and genetics
Wher do we get different types of vitamin D from?
D3 from UV
D2 and D8 from diet
What is the process of vitamin D production?
UV light converts a form of cholesterol to cholecalciferol(D3) (a precursor for vitamin D)
Blood transports precursor to liver and kidneys (where vitaminD is produced)
What is vitamin D used for?
Absorption of calcium and phosphorus
