Anatomy section 2
Terms
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- What makes up the skeletal system?
- all of the bones of the body plus the joints formed by their attachments to each other (~206)
- What makes up the axial skeleton?
- the skull, vertebral column, and anything else that is not part of the appendicular skeleton (80)
- What makes up the appendicular skeleton?
- The bones that make up the limbs plus girdles of attachment (126)
- What are the functions of the skeletal system?
- protection, support, movement, mineral reservoir, hemopoiesis, energy storage
- What makes up the Haversian systems?
- osteocytes, lamella, lacunae, canaliculi, Haversian canal
- What type of cells do you find in the skeletal system?
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-osteoprogenitor cells (mesenchyme)
-osteoblasts
-osteocytes
-osteoclasts - How do the osteoprogenitor cells function?
- bone cells are derived from these cells
- What does an osteoclast do?
- differentiates from endosteum and absorbs bone. They break down the wall of a cavity to enlarge it.
- What are the types of bone and how are they differentiated?
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according to space in between elements
-spongy(cancellous)
-compact - What are the part of a typical long bone?
- epiphyseal plate, diaphysis, epiphysis, articular cartilage, periosteum, endosteum, medullary cavity, red and yellow bone marrow
- what makes up the matrix of the skeletal system?
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-organic framework (33%) - collagen fibers/ground substance
-inorganic salts (67%) - calcium/phosphate salts. - what are the types of bone ossification?
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-intramembranous
-endochondral (intracartilagenous) - which bones ossify intramembranously?
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-flat skull bones
-mandible
-part of clavicla - which bones ossify intracartilagenously?
- -all other bones including long bones
- where do all bones form from, regardless of how they ossify?
- the middle layer of embryonic cells (mesoderm)
- when does intramembranous ossification begin?
- eight weeks into development
- 1. Describe what happens during intramembranous ossification.
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-mesenchyme cells differentiate into osteoblasts and start to secrete matrix
-osteoblasts form spicules of matrix - 2. Describe what happens during intramembranous ossification.
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-spicules trap osteoblasts in lacuna
-activity slows
-trapped osteoblasts called osteocytes - 3. Describe what happens during intramembranous ossification.
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-bone growth proceeds outward from center
-spicules thicken into trabeculae (spongy bone)
-trabeculae connect (compact) - 1. Describe what happens during endochondral ossification.
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-bone formation preceded by cartilage model
-cartilage model pulled out to be replaced by bone - 2. Describe what happens during endochondral ossification.
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-mesenchyme cells form cartilage model
-perichondrium surrounds cartilage model - 3. Describe what happens during endochondral ossification.
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-osteoblasts differentiate on inner surface of perichondrium
-collar of compact bone surrounds cartilage of diaphysis - 4. Describe what happens during endochondral ossification.
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-chondrocytes and lacunae in diaphysis enlarge (reducing amount of matrix)
-calcium deposits in remaining matrix (calcified cartilage) - 5. Describe what happens during endochondral ossification.
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-Nutrients can't diffuse to chondrocytes
-chondrocyes die leaving hollow spaces - 6. Describe what happens during endochondral ossification.
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-blood vessels and osteoprogenitor cells enter matrix from periosteum
-osteoprogenitor cells differentiate into osteoblasts - 7. Describe what happens during endochondral ossification.
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-osteoblasts form trabeculae/bone matrix
-this form primary ossification center in diaphysis - 8. Describe what happens during endochondral ossification.
- -later, secondary ossification centers form in epiphyses
- How do long bones increase in lenght?
- by laying down new bone at epiphyseal plate
- where do cartilage cells lay down new cartilage?
- at side of plate toward epiphysis (during growing years)
- where is cartilage being replaced by bone?
- at side of plate toward diaphysis
- how do long bones increase in diameter?
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-osteoblasts lay down new bone from periosteum
-osteoclasts reabsorb bone from endosteum - what are the different possible shapes of bone?
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-long- arms, legs, hands, feet
-short- carpals, tarsals
-flat- skull
-irregular- everything else - describe diploe and where you find it.
- one layer of spongy bone sandwiched in between 2 layers of compact bone. found in skull, makes skull weigh less, but is still strong
- name the other types of bone and give examples
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-sesamoid (patella)
-sutural (lambdoidal suture) - not everyone has them - What affects growth of bones?
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-stress (gravity, function)
-vitamins (A, C, B12, D)
-minerals (Ca, P, Na, Mg)
-hormones (sex, parathyroid, calcitonin, thyroxine, GH) - where do you find paranasal sinuses?
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-frontal
-sphenoid
-ethmoid
-maxillary - what are paranasal sinuses?
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-air spaces in certain skull and face bones
-lined with ciliated columnar epithelium - what are the functions of the paranasal sinuses?
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-lighten skull
-warm air (vascular epith.)
-resonate sound (voice)
-protection (phagocytosis)
-produce mucus (moisture) - what are fontanels?
- large membranous areas between incompletely ossified skull bones which allow for flexibility and skull growth
- which fontanel is the biggest one and the last to complete ossification (~1-2 years old)
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anterior- frontal/parietal
bregmatic fontanel - Which fontanel finishes ossification around 2 months old?
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posterior - occipital/parietal
occipital fontanel - which fontanels are finished with ossification around 3 months of age?
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sphenoid - temporal/frontal/parietal/sphenoid
anteriolateral fontanels - which fontanels finish ossification at one year old?
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mastoid - parietal/occipital/temporal
posterolateral fontanels - How many bones make up the vertebral column?
- 26
- Name the curves in the vertebral column.
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-anterior cervical
-posterior thoracic
-anterior lumbar
-posterior sacral - which vertebral curves are primary?
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-posterior thoracic
-posterior sacral - what signifies the formation of the secondary curves?
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-anterior cervical - hold up head
-anterior lumbar - can stand up on own - what is the purpose of vertebral curves?
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-increase strength, resilience, flexibility of spine
-maintain balance, absorb shock, protect from fracture.