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48 Cards in this Set

  • Front
  • Back
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?
-osteoprogenitor cells (mesenchyme)
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?
according to space in between elements
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?
-organic framework (33%) - collagen fibers/ground substance
-inorganic salts (67%) - calcium/phosphate salts.
what are the types of bone ossification?
-endochondral (intracartilagenous)
which bones ossify intramembranously?
-flat skull bones
-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.
-mesenchyme cells differentiate into osteoblasts and start to secrete matrix
-osteoblasts form spicules of matrix
2. Describe what happens during intramembranous ossification.
-spicules trap osteoblasts in lacuna
-activity slows
-trapped osteoblasts called osteocytes
3. Describe what happens during intramembranous ossification.
-bone growth proceeds outward from center
-spicules thicken into trabeculae (spongy bone)
-trabeculae connect (compact)
1. Describe what happens during endochondral ossification.
-bone formation preceded by cartilage model
-cartilage model pulled out to be replaced by bone
2. Describe what happens during endochondral ossification.
-mesenchyme cells form cartilage model
-perichondrium surrounds cartilage model
3. Describe what happens during endochondral ossification.
-osteoblasts differentiate on inner surface of perichondrium
-collar of compact bone surrounds cartilage of diaphysis
4. Describe what happens during endochondral ossification.
-chondrocytes and lacunae in diaphysis enlarge (reducing amount of matrix)
-calcium deposits in remaining matrix (calcified cartilage)
5. Describe what happens during endochondral ossification.
-Nutrients can't diffuse to chondrocytes
-chondrocyes die leaving hollow spaces
6. Describe what happens during endochondral ossification.
-blood vessels and osteoprogenitor cells enter matrix from periosteum
-osteoprogenitor cells differentiate into osteoblasts
7. Describe what happens during endochondral ossification.
-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?
-osteoblasts lay down new bone from periosteum
-osteoclasts reabsorb bone from endosteum
what are the different possible shapes of bone?
-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
-sesamoid (patella)
-sutural (lambdoidal suture) - not everyone has them
What affects growth of bones?
-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?
what are paranasal sinuses?
-air spaces in certain skull and face bones
-lined with ciliated columnar epithelium
what are the functions of the paranasal sinuses?
-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)
anterior- frontal/parietal
bregmatic fontanel
Which fontanel finishes ossification around 2 months old?
posterior - occipital/parietal
occipital fontanel
which fontanels are finished with ossification around 3 months of age?
sphenoid - temporal/frontal/parietal/sphenoid
anteriolateral fontanels
which fontanels finish ossification at one year old?
mastoid - parietal/occipital/temporal
posterolateral fontanels
How many bones make up the vertebral column?
Name the curves in the vertebral column.
-anterior cervical
-posterior thoracic
-anterior lumbar
-posterior sacral
which vertebral curves are primary?
-posterior thoracic
-posterior sacral
what signifies the formation of the secondary curves?
-anterior cervical - hold up head
-anterior lumbar - can stand up on own
what is the purpose of vertebral curves?
-increase strength, resilience, flexibility of spine
-maintain balance, absorb shock, protect from fracture.