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What are glands of the skin
Specialized exocrine glands found in dermis
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Types of glands
Sebaceous, Sudiferous, Cermunious, Mammary
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Sweat Glands 2 types
- Merocrine glands
- Apocrince glands
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Aprocrine
Almost always empty onto a hair follicle
Have a lipid component which increase bacteria to the area and that produces the smell. (Bromhidrosis)
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Eccrine
Almost never empty onto a hair follicle
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Sebaceous Glands
Oily Secretions called Sebum
flask shaped gland with duct that opens into hair follice.
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Ceruminous Glands
Only found in ear conal
- produce ear wax
- waterproofs the eardrum
- Bitterness repels mites and other pest
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Mammary Glands
modified apocrine seat gland
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Nails
tighly packed keratinzed cells
Lunula appears white due to thickened stratum basale in that area
Cuticle is stratum corneum
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Nail Growth
Nail root/matrix only part that is actively alive
occurs faster on dominate hand
occurs more during summer/fall
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Thin Skin
covers most of the body
thin epidermis that lacks stratum lucidum
lacks epidermal ridges
has fewer sweat glands and sensory receptors
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Thick Skin
only on palms and soles
lacks hair follicles and sebaceous glands
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Functions of the skin (5)
- barrier
- Vit D. synthesis
- Sensory function
- thermoregulation
- psychological/social function
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Skin Function Thermoregulation
Releasing of sweat onto the skin
adjusting blood flow to/from the body surface
Shivering and constriction of surface vessels
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Skin function- protection/barrier
- Physical
- tight cell junctions
- Chemical
- sweat slightly acidic in nature (microbial-factor)
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Skin Function --Excretion and Absorption
only minor role of the skin
400mL of water ecaporates from the skin daily
Lipid soluble substances can be absorbed
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Skin Function --Vit D synthesis
need the skin to produce calsatrione
sunlight activates the precursor to vit D
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Epidermal wound healing (Small abrasion or minor burn
- 1) Basal cells migrate across the wound
- 2) contact inhibition with other cells stops migration
- 3) epidermal growth factor stimulates cell division
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Deep Wound Healing (if injusry reaches the dermis)
1) imflam phase has clot unite wound edges and WBC arrive from dialtes and more permeable blood vessels
2) migratory phase begins the regroth of epithelial cells and the formation of scare tissue by the fobroblasts
3) proliferative phase is a completion of tissue formation
4) maturation pahse sees the scab fall off
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Skin Cancer (basal cell carcinoma)
rarely metastasize
arises from stratum basale and invades dermis
treated by surgical removal and radiation
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Skin cancer (Squamous Cell carcinoma)
may metastasize
arises from keratinocytes in the stratum spinosum
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Skin Cancer (Maligant melanoma)
metastaize rapidly
mostly deadly cancer
arises form melanocytes of a pre-existing mole
ABCDE (asymmetry, border irregular, color, diameter(over 6mm) elevation)
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Burns---1st degree
only the epidermis
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Burns--2nd degree
epidermis and part of dermis (blistered)
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burns--#rd Degree
epidermis, dermis and more is destroyed
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Skin Grafts -- Autograft
tissue from a different region of the patient
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Skin Grafts --- isograft
skin graft from idential twin
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Skin Grafts-- Homograft
graft from unrelated person (temporary)
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skin grafts--heterograft/xenograft
tissue from another species
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Functions of bones (6)
- 1) supporting and protecting soft tissue
- 2) attachment site for muscles making movement possible
- 3) storage of minerals, calcium, and phosphate
- 4) blood cell production in red bone marrow (hemopoiesis)
- 5)Energy storage in yellow bone marrow
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shapes of bones
- 1) long
- 2) flat
- 3) irregular
- 4) short
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Structure of Flat bone
2 layers of compact bone seperated by spongy bone
middle layer is spongy bones with no marrow cavity
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Structure of long bone --Shaft
Diaphysis
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Structure of Long Bone- ends
Epiphysis
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Structure of long bone-- growth plate region
metaphysis
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Structure of long bone--marrow cavity
Medullary Cavity
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Structure of long bone-lining of marrow cavity
Endosteum
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Structure of long bone---tough membrane convering bone but not the cartilage
Periosteum
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osteogenic cells
reside in endosteum, periosteum or central conals
arise from embryonic fibroblasts
only new source of steoblasts
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Osteoblasts
form and help mineralize organic matter of matrix
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Osteocytes
are osteoblasts that have become trapped in the matrix
signal osteoclasts and osteoblasts about mechanical stresses.
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Osteoclasts
break down bone
reside in pits called resorption bays
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Matrix of osseous tissue (Organic matter)
collagen, glycosaminogycans, proteoglycans and glycoproteins
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Matrix of Osseous Tissue (Inorganic Matter)
- 85% hydroxyapatite
- 10% calcium carbonate
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Osteon
Basic structural unit
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Perforating canals or Volkmann Canals
vascular canals perpendiculary joing centeral canals
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Red Bone Marrow
Hemopoietic-produces blood cells
Found in vertebrae, ribs, sternum, pelvic girdle and proximal heads of femur and humerous in adults.
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Yellow Bone Marrow
fatty marrow of long bones in adults
shock absorber
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Bone Formation
bones arise out of connective tissue
Most bones are derived from intramembranous
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Intramembranous Bone Formation
1) mesenchymal cells become osteoprogenitor cells then osteoblasts
2) Osteoblasts surround themsleves with matrix to become osteocytes
3) matrix calcifies into trabeculae with spaces holding red bone marrow
4) mesenchyme condenses as periosteum at the bone surface
5) superficial layers or spongy bone are replaced with compact bone
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Zones of Growth in Epiphyseal plate-zone of resting cartilage
anchors growth plate to bone
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Zones of Growth in Epiphyseal plate-Zone of Proliferating cartilage
rapid cell division (stacked coins)
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Zones of Growth in Epiphyseal plate-Zone of hypertrophic cartilage
cells enlarged and remain in columns
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Zones of Growth in Epiphyseal plate-Zone of calcified cartilage
thin zone, cells mostly dead since matrix calcified
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Achondroplastic Dwarfism
short stature but normal sized head and trunk
results of spontaneous mutation when DNA is replicated
only effects long bones
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