Bones and Skeletal Tissue Flashcards
What does the skeletal system include?
- Bones
- Cartilages, ligaments, and other connective tissues
What are the 5 primary functions of the skeletal system?
- Support
- Storage of minerals and lipids
- Blood cell production
- Protection
- Leverage
What are the three parts that makes up the structure of a long bone?
- Diaphysis (shaft)
- Epiphysis (wide part at each end)
- Metaphysis
What is the diaphysis in the bone?
The wall of compact bone. Has a central space called medullary cavity (marrow cavity)
What is the epiphysis in the bone?
Mostly spongy bone
What is the metaphysis in the bone?
Where diaphysis and epiphysis meet
What are the 4 characteristics of bone?
- Dense matrix
- Osteocytes (bone cells) within lacunae organized around blood cells
- Canaliculi
- Periosteum
What are canaliculi?
Narrow passageways that allow for exchange of nutrients, wastes, and gases
What does periosteum do?
Covers outer surfaces of bones except at joints
What is the makeup of bone matrix?
2/3 calcium phosphate and 1/3 collagen fibers
What does calcium phosphate form crystals of?
Hydroxyapatite
What are the four types of bone cells?
- Osteogenic cells
- Osteoblasts
- Osteocytes
- Osteoclasts
What do osteogenic cells do?
- Divide to produce osteoblasts
- Assist in fracture repair
What do osteoblasts do?
Produce new bone matrix during osteogenesis (ossification)
Osteoblasts surrounded by bone matrix become __________________
Osteocytes
What are osteocytes’s two major functions?
- Maintain protein and mineral content of matrix
- Help repair damaged bone
What do osteoclasts do?
- Absorbs and removes bone matrix
- Secretes acids and protein-digesting enzymes
________ is the functional unit of compact bone
Osteon
What are the three components of the Osteon?
- Central canal
- Perforating canals
- Lamellae
What are the three layers of lamellae?
- Concentric lamellae
- Interstitial lamellae
- Circumferential lamellae
______________ lacks osteons
Spongy bone
______________ fills spaces between trabeculae and forms blood cells
Red bone marrow
________ bone marrow stores fat
Yellow
___________ is the membrane that covers the outside of bones and increases the strength of attachments
Periosteum
The endosteum is the cellular layer that lines the ___________
Medullary cavity
What are the two PARTS of bone development?
- Ossification (osteogenesis)
- Calcification
What are the two forms of ossification?
- Endochondral ossification
- Intramembranous ossification
Endochondral or intramembranous ossification: which way do most bones form?
Endochondral
Instramembranous ossification produces dermal bones such as __________ and ___________
- Mandible (lower jaw)
- Clavicles (collarbones)
Interstitial growth is growth in _______
Length
Appositional growth is growth in _______
Width
What three types of bone cells are involved in bone remodeling?
- Osteocytes
- Osteoblasts
- Osteoclasts
If removal is faster than replacement, bones __(1)___. If deposition predominates, bones ____(2)____.
1) Weaken
2) Strengthen
What two minerals are required in the diet?
Calcium and Phosphorous
What is the purpose of calcitriol and vitamin D3?
Allows calcium and phosphate ion absorption in digestive tract
Bones store 99% of the body’s what?
Calcium
This hormone increase blood calcium ion levels by:
- Stimulating osteoclast activity (indirectly)
- Increasing intestinal absorption
- Decreasing calcium excretion by kidney
Parathyroid hormone (PTH)
What are the two types of bone fractures?
Open (compound) or closed (simple)
______________ is inadequate ossification (reduction of bone mass)
Osteopenia
______________ is the severe loss of bone mass
Osteoporosis
