Test 2: Integumentary System Flashcards
Structures that make up integumentary system
Skin and accessory structures
Epidermis purpose
Protects from trauma, chemicals Controls permeability, water loss Protection from pathogens Synthesizes vitamin D Sensory receptors Coordinates immune responses
Dermis layers, functions
Papillary layer
Nourishes and supports epidermis
Reticular layer Restricts spread of pathogens Stores lipid reserves Attaches skin to deeper tissues Sensory receptors of touch, pressure, pain, vibration, temperature Vessels for thermoregulation
Epidermis, general features
Superficial layer
Purple under stain
negatively charged, dermis is positively charged and pink
Keratinized stratified squamous epithelium
Together with dermis make up cutaneous membrane
Avascular
Layers of the epidermis
Thick vs thin skin
Thin skin has 4 layers vs 5 of thick skin
fewer cells
hands, lips are thick skin
Stratum corneum
Keratin layer, dead keratinocytes (no nuclei)
Stratum lucidum
Only found in thick skin
Stratum granulosum
Grainy appearance, where pigments are located
Stratum spinosum
Largest layer
hairs connecting cells look spine
Stratum basale
deepest layer
stem cells
4 Main cells of epidermis
Keratinocytes
Most abundant, large amounts of keratin
Melanocytes Specialized cells of stratum basale Pigment- melanin Everyone has the same number but the production level is different Absorbs UV 3% of cells in skin
Langerhans cells
Immune function, develop in bone marrow
Macrophages of the skin
Merkel cells Specialized cells of stratum basale 1% of cells in skin Found in hairless skin on merkel discs Sense pressure
Dermis, types of fibers
Collagen fibers
Very strong, resist stretching, provide flexibility
Elastic fibers
Permit stretching, recoils to original length
Limit the flexibility of collagen fibers to prevent damage to tissue
Dermis, layers
Outer papillary layer
areolar and adipose tissue
Smaller capillaries, lymphatics, sensory neurons
Dermal papillae projecting between epidermal ridges
Deep reticular layer
Dense irregular connective tissue and adipose
Larger blood vessels, lymph vessels, nerve fibers
Lines of cleavage, dermis
Collagen and elastic fibers are arranged in parallel bundles, result in lines of cleavage
resist force in specific direction
cuts parallel to lines of cleavage heal quicker
Hypodermis, features
Made of loose connective tissue areolar and adipose tissue Subcutaneous layer Regulates temperature and store energy site of subcutaneous injections
Types of hair
Lanugo
fine soft hair that covers a newborn
disappears
Vellus
white, thin, on most of body during childhood
Terminal hair
thick, strong, pigmented and fully matured
scalp, pubic region, face
Arrector pili
Involuntary smooth muscles causing hairs to stand up
Sebaceous glands
Lubricate the hair
Control bacteria
transformed keratinocytes with lots of lipids and oil droplets, coats hair and makes them more waterproof, secretes substances by rupturing
typical (hair) vs sebaceous follicles (skin surface)
Stem cells
regenerate skin
Feathers
epidermal growths
flight, communication, insulation
veined feathers cover exterior
downed feathers are underneath veined feathers
Nails,. pathology
made of matrix, nail plate, nail bed, skin
Lacuna is the moon shaped white part
pathology
absence of lacuna indicates vascular issues or high blood pressure
yellow nails indicates resp disorder, thyroid gland
blue indicates hypoxemia, cyanosis
pitted and distorted indicate psoriasis
concave indicates blood disorder
clubbing of nails indicates hypoxemia
protect fingers and toes, made of dead cells packed with keratin
Unguis
nail, claw, fang
Horns vs antlers
horns
not parts of skull, although fused to skull
covered in sheath of keratin
antlers can be shead
part of skull, emerge first as cartilage with bony replacing
covered with layer of fluffy skin called velvet
Sweat glands
merocrine secretion of watery solution, flush epidermal surface
Types of exocrine glands, description
Acocrine
limited distribution, complex composition, influenced by hormones
pinched off portion of cell
Merocrine
widespread, thin secretions, controlled primarily by nervous system
important in thermoregulation and excretion
Secretion through secretory vesicles, intact cell membrane, exocytosis
Holocrine
mature cell dies and becomes secretory product
Sensory receptors in skin
Merkel disks connected to merkel cell
Meissner corpuscles sense touch below basal level of epidermis
Pacinian corpuscle sense pressure at dermis
Free nerve endings
Thermoreceptors
Repair of skin
1: Blood clot and scab formation platelets clot blood mast cells trigger inflammation for wound healing, vasodilation 2: Cellular migration Epithelial cells form around wound At dermal layer, fibroblasts secrete ECM (collagen, etc) around would Macrophages eat bacteria, debris Forms granulation tissue 3: Epidermis covers granulation tissue Fibroblasts still secrete more matrix Macrophages also still work 4: Epidermis covers scar tissue scar tissue is built in patterns, weaker
Skin and aging
can’t sweat as well less adipose tissue not as much blood supply fewer melanocytes elderly get sunburn easier
