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Anatomy L3 (LJ)
College leve connective tissue, skin
Term | Definition |
---|---|
3 basic components of connective tissue | Specialized cells, non-cellular matrix (ground substance), extra cellular fibers produced by the cells themselves: Collagen based (provides strength and flexibility, elastin based ( provide elasticity), Reticular fibers (provide structural softness. |
Loose connective tissue | FILLS SPACE BETWEEN ORGANS: adipose ( cushion, insulator, storage medium, reticular ( fibrous mesh - lymph nodes and bone marrow), areolar (fibrous mesh- fascia and underlies epithelia. |
Dense regular connective tissue | Dense collagen fiber network: fibers run parallel = tensile support, FOUND IN TENDONS AND LIGAMENTS AND APENEUROSES (not elastic but strong), poorly vascularized. |
Dense irregular connective tissue | Fibers make for a chaotic meshwork, CAPABLE OF MULTIDIRECTIONAL TENSION, wrapped at bones (periosteum) and organ ( peritoneum) |
Elastic connective tissues | Fiber directions mostly straight, very stretchy (ex: interspinous ligaments) IN VERTEBRAE AND PENIS |
Supporting connective tissues | Bone and cartilage |
Fluid-based connective tissues | Blood and lymph |
Skin as an organ system | Cutaneous membrane + hair + nails + exocrine glands ( excrete various substance on the surfaces of skin by way of duct) makes up 15% of body weight, about 0.5-4.0 mm thick. |
Function of skin | 1. Protection from abrasion/chemicals/pathogens/UV-light. 2. Prevention of water loss and temp. regulation. 3. Synthesis of vitamin D. 4. Sensory reception. 5. Communication of emotions. 6. Storage of fat. 7. Excretion of water, electrolytes, drugs. |
4 types of proteins | COLLAGEN- digestible, KERATIN- indigestible protein, MELANIN- skin pigment, CAROTENE- skin pigment |
Skin color | Blood: pink tinge to un-pigmented skin, Carotene: red/ orange tinge, Melanin: in epidermis, black/yellow/ brown pigments absorb UV light, protects deeper cell and dermis, UV light triggers melanin synthesis ( tanning ). |
Rosacea | Sebaceous gland hyperplasia |
Cyanosis | Oxygen deficit mean a blue-gray tinge. |
Papillary layer of the dermis (top) | Dermal papillae, distorts overlying basement membrane/ epidermis (fingerprints), contain capillary loops (blood vessels), contain sensory receptors (Meisner's corpuscles), most skin pathologies concerns dermal papillae |
Reticular layer of the dermis (bottom) | Dense irregular connective tissues fibers; supports various blood vessels, lymph, nerve endings and glands. |
Nails | Hyponychium: anterior boundary = free edge, Eponychium (cuticle): =statum corneum, Lunula: white are under the cuticle, Nail root: fold of epithelium - point of growth. COMPOSITES OF DERMIS + EPIDERMIS |
Hair follicle | Is a complex organ. Pocket of epidermal cells that extends into dermis. Follicle is lubricated by sebaceous gland. Dermal papilla @ bottom of follicle, receives nutrition from capillary loop. Hair shaft has a soft inner medulla + a hard outer cortex. |
2 types of hair | Vellus (peach-fuzz) covers most of the body. Terminal ( all others) head, body, eyebrows and eyelashes. |
Alopecia: androgenetica | Male pattern baldness; dihydrotestosterone |
Alopecia: universalis | Auto immune alopecia; complete hairlessness |
Hirsutism | Women who have hair growing like men, like the bearded lady. (Pneumonic: her-suit-ism; women in a suit looks like a man and has hair growth like a man). |
Hypertrichosis (congenital) | Over production of hair both in men and women, but harder to notice in men because men are expected to be substantially more hairy than women. |
Goose bumps | Arrector pilli ( smooth muscle reflex) hair stands up. |
Merocrine sweat glands (Eccrine) | Merocrine type secretion. Common in palms, soles, most of body. Simple watery secretion used to control body temp.. Electrolytes, urea, amino acids, ammonia, lactic acid, 500 ml/hr(active)-500 ml/day (sedentary). |
Apocrine sweat glands | Apocrine type secretion. Limited distribution: axilla + anogenital regions. ACTIVATED AT PUBERTY, OFTEN ODOROUS. Phermones: emotions, sex-status, relatedness? |
Mammary glands (milk) | Evolved from apocrine glands on body wall. Mixed: apocrine/merocrine mechanism. Salt, calcium, phosphate, lipids, protein. |
Ceruminous glands (ear wax) | Evolved from apocrine sweat glands in ear canal. Mixed: apocrine/holocrine mechanism. |
Sebaceous glands (oil: sebum) | Holocrine type of secretion. Waterproof and moisturizes. Provides resistance to bacteria/ fungal growth location: head, chest, back (w/ hair-follicles). Boils/ acne=blocked glands/follicles. |
Ulcer (sore) | Localized shedding of the epithelium |
Decubitis Ulcer | Bed-ridden/pressure=chronic lack of blood supply. Kills cells and causes sores |
Wrinkles | Collagen/elastic fibers damaged by chemicals/UV. Shredded collagen/ elastic fibers: stretch-marks |
Excessive UV exposure | Damage to dermis and epidermis=wrinkles and cancer. |
Folliculitis | Bacteria in hair follicle causes inflammation. |
Seborrheic dermatitis (dandruff) | Inflammation of over-active sebaceous glands. |
Melanoma | Aggressive malignant tumor. Associate w/ UV light exposure. Tanning beds 75% more likely. (Asymmetry, Border, Color, Diameter, Evolving) |
Endocrine glands | Duct-less, secretions release cell products directly into intercellular fluid and/or blood supply. (ex: Gut derivatives: pancreas, thyroid, thymus) |
Exocrine glands | Ducted glands, secretions released from epithelial surface into small ducts that empty to the lumen of the GI tract or skin surface (sweat, tears, saliva). |