Integumentary System Flashcards
Functions of the Integumentary System (6)
- Barrier: both physical and chemical
- Immunologic: antigen processing to appropriate effector cells in the lymphatic system
- Homeostasis: in regards to temperature/water loss
- Convey sensory information
- Endocrine: secretes hormones, cytokines, growth factors. Production and activation of Vit D
- Excretion: sweat
Two main layers of the skin
and 1 non layer of skin
- Epidermis: stratified squamous keratinized epithelium. Avascular. Consists of keratinocytes (skin cells)
- Dermis: 2 layers- loose connective tissue followed by dense irregular connective tissue
- Hypodermis: not a layer of skin-layer of subcutaneous tissue
Layers of the Epidermis (5)
Stratified squamous keratinized epithelium
- Stratum Corneum: most superficial-dead keratinized cells
- Stratum Lucidum: THICK SKIN ONLY
- Stratum Granulosom: cells that are about to die
- Stratum Spinosum: maturing and slowly dying cells
- Stratum Basale: can differentiate (stem cells)
Avascular
Function of Keratinocytes
specialized epidermal cell
- Most important-90%
- Specialized apoptosis to keep cells stable
Keratin: tough protein
Function of Melanocytes
specialized epidermal cell
Produce melanin (pigment)
Function of Langerhans
Specialized epidermal cell
Dentritic-antigen presenting cells
Merkel Cells
Specialized epidermal cells
Sensory
Dermis functions/contents
- Gives strength and elasticity to skin
- Contains: epidermal appendages, nerve corpuscles, and glands
- Contains smooth muscle that move hairs
Dermis Papillary layer
- Loose connective tissue (more cells)
- Contains blood vessels
- Predominantly type 1 and type III collagen fibers
- Elastic fibers are threadlike and form an irregular network
- Relatively thin and contains Meisner corpuscles
Dermis Reticular layer
Think network
- Much thicker than the papillary layer
- Dense irregular connective tissue (less cells)
- Mostly type 1 collagen
Dermal Papillae
Fingerlike connective tissue protrusions
Fingerprints
Eccrine Sweat Glands
- Connect to the surface of the skin by a coiled duct
- Deep in the dermis
- Most numerous on the palms and soles
Apocrine Sweat Glands
Merocrine
- Anchored deep in the dermis
- Open into hair follicles
- Located in armpits/ genital area
More viscous
Sebaceous Glands
- Most open into hair follicles
- Must numerous on face/scalp
- Can also be in hairless places (lips)
Ceruminous Glands
- Modified sweat glands
- Located in the ear canal
What is the function of arrector pili muscle?
Pull hair shaft into upright position
Hair Texture
- Straight: round
- Wavy: oval
- Curly: elliptical (kidney bean)
Hair Colour
Dark: melanin like that found in skin
Blonde/Red: melanin contains sulfur/iron
Gray: lose enzyme thats produces melanin
White: air bubbles
What do the nails come from?
Stratum Corneum (heavily cornified)
Where do nails come from?
Stratum corneum
Lanula: white part
Free Nerve Endings
- Most numerous-terminate in the stratum granulosom
- Pain and temperature
- Surround most hair follicles
Merkel’s Corpuscle
- Detect touch sensations
- Most abundant in fingertips
- Cytoplasm contains neurosecretory granules
- Express antigenic markers of both epidermal and neural type
Pacinian Corpuscle
- Detect pressure and vibration
- Deep dermis and hypodermis
- Capsule structure with myelinated nerve surrounding
Meisner’s Corpuscle
- Detect fine vibration low frequency stimuli
- Consist of flattened schwann cells that form several irregular lamellae
Q tip like
Ruffini’s
- Detect stretch and torque
- Fluid filled space that have thin connective tissue capsule
