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6 functions of integumentary system
- protection - physical, chemical, biological
- temperature regulation - dilation of dermal vessels and sweat at ^ temperatures
- cutaneous sensations
- metabolic functions - vitamin D and collagenase
- blood reservoir - up to 5% of bodies blood volume
- excretion - nitrogenous wastes and salt in sweat
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why are serious burns life threatening
- fluid loss
- massive infection
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skin markings
- friction ridges - (fingerprints) epidermal ridges on deeper papillary ridges
- cleavage lines - separation lines of collagen bundles
- flexure lines - dermal folds at or near joints
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types of skin cancer
- basal cell carcinoma - least malignant, ^ common
- squamous cell carcinoma - common
- melanoma - dangerous
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degrees of burns
- 1st - epidermal damage only
- 2nd - blisters
- 3rd - entire thickness of skin damaged, no pain immediately because nerves are destroyed
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development of skin
- epidermis - < ectoderm
- dermis and hypodermis < mesoderm
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developmental aspects from birth to adult
- sebaceous gland activity ^
- accumulative environmental assaults show after 30
- scaling and dermititus ^ with aging
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skeletal cartilages
- hyaline - support, flexibility and resilience
- elastic - similar to hyaline but springier
- fibrocartilage - collagen fibers for great tensile strength
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functions of bones
- support
- protection
- movement
- storage
- blood cell formation
- triglyceride storage
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classification of bones by shape
- long - femur
- short - patella, carpals
- flat - most skull bones, sternum
- irregular - vertibrae
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bone cells and functions
- osteogenic - stem cells in periosteum and endosteum that give rise to osteoblasts
- osteoblasts - make bone
- osteocytes - mature bone cells
- osteoclasts - break down bone
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intramembranous ossification
- membrane bone develops from fibrous membrane
- forms flat bones (clavicle, cranial bones)
- 1. ossification centers appear in the fibrous connective tissue membrane
- 2. bone matrix (osteoid) is secreted within the fibrous membrane and calcifies
- 3. woven bone and periosteum form
- 4. lamellar bone replaces woven bone just deep to the periosteum. red marrow appears
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endochondral ossification
- bone forms from cartilage
- 1. bone collar forms around hyaline cartilage model
- 2. cartilage in the center of the diaphysis calcifies and then develops cavities
- 3. the periosteal bud invades the internal cavities and spongy bone begins to form
- 4. diaphysis elongates and a medullary cavity forms as ossification continues. secondary ossification centers appear in the epiphyses in prep for stage 5
- 5. epiphyses ossify. when complete, hyaline cartilage only remains at the epiphyseal plates and articular cartilages
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4 functional zones of long bone growth
- at the epiphyseal plate
- 1. proliferation
- 2. hypertrophic
- 3. calcification
- 4. ossification (osteogenic)
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low blood calcium lvls
- parathyroid glands release PTH
- osteoclasts degrade bone and release calcium
- increased blood calcium
-
^ blood calcium lvls
- parathyroid glands release calcitonin
- osteoblasts deposit calcium salts
- blood calcium lowers
-
steps of bone fracture repair
- 1. hematoma forms
- 2. fibrocartilaginous callus forms
- 3. bony callus formation
- 4. bone remodelling
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developmental aspects of skeletal system
- nearly all bones completely ossified by 25
- bone mass decreases starting in 4th decade
- rate of loss determined by genetics and environmental factors
- old age - resorption predominates
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7 bones of orbital cavity
- sphenoid
- ethmoid
- palatine
- zygomatic
- maxilla
- lacrimal
- frontal
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5 bones of nasal cavity
- ethmoid
- inferior nasal conchae
- vomer
- maxilla
- palatine
- (Every Infamous Villain Makes Pie)
-
paranasal sinuses
- frontal
- ethmoid
- maxilla
- sphenoid
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8 cranial bones
- 2 parietal
- 2 temporal
- occipital
- sphenoid
- frontal
- ethmoid
-
14 facial bones
- 2 zygomatic
- 2 lacrimal
- 2 nasal
- 2 palatine
- 2 inferior nasal conchae
- 2 maxilla
- vomer
- mandible
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3 arches of the foot
- medial longitudinal
- lateral longitudinal
- transverse
-
fontanelles
- unossified remnants of membrane between fetal skull bones
- anterior
- posterior
- mastoid
- sphenoid
-
fetal skull
- fontanelles
- mandible and frontal bones are unfused
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skeletal growth rates
- birth - cranium huge relative to face
- 9 mos. - cranium is half adult size
- mandible and maxilla is foreshortened but lengthens with age
- arms and legs grow faster than trunk leading to adult proportions
- thoracic and sacral curvatures there at birth
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developmental aspects of skeleton in old age
- intervertebral discs become thin, less hydrated and less elastic
- ^ risk of disc herniation
- loss of stature by several cm common by age 50
- costal cartilages ossify, causing thorax to become rigid
- all bones lose mass
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joints - definition
- articulation
- where 2 bones meet
-
functional classification of joints
- synarthroses - no movement
- amphiarthroses - little movement
- diarthroses - freely movable
-
structural classification of joints
- fibrous
- cartilaginous
- synovial
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fibrous joints
- most are synarthrotic
- sutures - skull
- syndesmoses - fibula/tibula
- gomphoses - teeth in sockets
-
cartilaginous joints
- bones united by cartilage
- sychondroses - epiphyseal plate, 1st rib/sternum
- symphysis - pubic symphysis, between vertebrae - amphiarthrotic
-
features of synovial joints
- 1 articular cartilage : hyaline cartilage
- 2 joint (synovial) cavity
- 3 articular (joint) cavity
- 4 synovial fluid
- 5 reinforcing ligaments - capsular, extracapsular, intracapsular
- 6 rich nerve and blood vessel supply
-
friction reducing structures associated with joints
-
stabilizing factors at joints
- shapes of articular surfaces (minor role)
- ligament number and location (limited role)
- muscle tone that keeps tendons that cross the joint taut
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types of synovial joints
- plane - intercarpal/tarsal - nonaxial, gliding
- hinge - elbow, interphalangeal - uniaxial
- ball and socket - shoulder, hip - multiaxial
- pivot - radio/ulnar, atlas/axis - uniaxial
- saddle - carpal/metacarpal joint of thumb - biaxial
- condyloid - metacarpal/phalangeal - biaxial
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