int Flashcards
Components of the Integumentary System
Functions of the Int System
- physical and immunological protection
- thermoregulation (sweat glands and insulation)
- sensation
- metabolic functions (Vit D synthesis and stores energy as subcutaneous fat)
Composition
Composed of all four tissue types:
- Epithelium
- Connective Tissue
- Muscle
- Nerve
Epithelium in Skin (2)
covers surface and forms boundary
Connective Tissue in Skin (2)
supports epithelium, provides strength and resiliency
Muscle in IS (2)
controls diameter of blood vessels, adjusts position of hairs
Nerve Tissue in IS (3)
controls smooth muscles, generates sensation, stimulates glands
Skin - size/weight
largest organ system of body:
- ~2 sq meters or 22 sq feet
- 15% body weight
- thickness from 0.5 mm to 4.0 mm
- average thickness 1 - 2 mm
Stratum Germinativum - aka? composed of? attached to?
- aka stratum basal (b/c it’s the basal layer, job is to continuously divide)
- large basal cells
- firmly attached to basal lamina (which is attached to CT)
basal cells
stem cells that divide to give rise to new keratinocytes (found in stratum germinativum/basal)
Stratum Spinosum - composed of?
- “spiny” layer
- composed of keratinocytes
- where cells are first called keratinocytes
Keratinocytes
- first called in stratum spinosum
- contain bundles of tonofilaments (intermediate filaments, attach to desmosomes)
- desmosomes attach keratinocytes together
- keratinocytes still capable of division
Stratum Granulosum - develop? synthesize? secrete? death?
- “granular” layer
- develop large numbers of keratin filaments
- synthesize keratohyalin granules
- secrete lipids that fill spaces between cells = forms a water repellent sealant
- cells alive here, but keratinocytes die once ready to leave
Stratum Lucidum - found where? large amounts of?
- “clear” layer (because there is so much keratin, once they become dehydrated they become less clear)
- found only in thick skin of finger tips, palms and soles of feet
- large amounts of keratin and thickened plasma membranes
Stratum Corneum - composition? properties?
- corne = hard or hoof like
- multiple layers of dead cells
- cells continuously shed and replaced
- water repellent barrier
- protects against abrasion and microbe invasion (more abrasive forces = more layers)
Thin vs. Thick Skin (layers - 3)
- stratum corneum much thinner (in thin)
- other layers less clear in thin
- papillae less well developed in thiin
Thin vs. Thick Skin (location and creation)
- thick: can be turned thin if no abrasive forces
- thin: found in axilla becasue less abrasive forces
- thin can be turned thick after being subjected to abrasive forces (blisters, callouses)
Melanocytes (constitute %, produce, contain, transfer)
- constitute 8% epithelial cells
- produce melanin pigment
- contain long, slender processes which insert between keratinocytes
- transfer melanin granules to keratinocytes
Langerhans Cell (arise in? migrate to? what kind of cell? funciton in?)
- arise in bone marrow
- migrate to epidermis
- phagocytic cells
- function in immune response
Merkel Cells (number? location? function?)
- least numerous cell type
- located only in basal layer
- function in touch sensation (delicate touch)
skin color due to a combination of?
- dermal blood supply
- variable quantities of three pigments - melanin (brown/black), pheomelanin( red/yellow), and carotene (yellow/orange)
Pale Skin (pink colour due to? dilation of blood vessels? lowered oxygenation..?)
- pink: hemoglobin in dermal blood vessels
- dilation of BV during inflammation increases red color
- lowered oxygenation of blood: hemoglobin darkens, skin appears blue (cyanosis)
DARk Skin (due to? # melanocytes? melanin synthesis?)
- increased amount of pigment
- # constant whether in dark light skin (depends on how active they are)
- rate of melanin synthesis and transfer is increased (which absorbs UV light, prevents DNA damage)
Functions of Melanin? (3)
- absorbs UV, prevents UV induced DNA damage
- pigment accumulates around cell nucleus
- melanocytes increase rate of synthesis in response to UV exposure - results in tanning
UV - induced Skin Damage to Epidermis?
- chromosomal damage
- causes skin cancer
UV induced skin damage to dermis?
- damage to fibroblasts
- alters composition of extracellular matrix
- premature wrinkling
dermis - what? components (2)?
- connective tissue layer beneath epidermis
- superficial papillary layer
- deep reticular layer
Papillary Layer - properties? type of tissue? purpose? nerve endings?
- thin
- consists of areolar CT
- papillae increase area of contact with epidermis
- nerve endings for: touch, temp sensation, pain, tickle/itch
Reticular Layer - properties? tissue type? composed of? function?
- thick
- consists of dense irregular CT
- many elastic fibres
- provides extensibility and elasticity to skin
