Bone Tissue Flashcards
What type of tissue is Osseous Tissue?
Connective
What type of tissue are Blood Vessels?
Muscle, Epithelium, and Connective
What type of tissue is cartilage?
connective (hyaline)
What type of tissue are nerves?
nervous
What type of tissue is adipose?
connective (used for energy storage)
Functions of bone tissue?
- support
- movement
- blood cell formation (yellow bone marrow= energy storage)
- energy metabolism
- protection
- energy/ mineral storage
Endosteum
-thin membrane lining the marrow cavity of long bones
Periosteum
- tough membrane covering long bone but not cartilage
- made up of fibrous layer (DICT) and osteogenic layer (bone cells and blood vessels that nourish and repair)
What is the metaphysis also known as?
growth plate region
Why can the long bone be hollow, but still be strong?
because there is a point of no stress in which the tension and compression on opposite sides cancel out and therefore less bone is needed internally
-if the bone was completely compact bone, it would be too heavy
What is Diploe?
internal spongy bone of flat bones
What is osteoporosis?
- when the rate of resorption is greater than the rate of deposition, meaning that bone is breaking down faster than it is forming
- occurs in women after menopause due to the reduction of estrogen
What makes up the organic component of bone? The inorganic mineral salts?
Organic (35%) -cells and fibres (primarily collagen) -organic substances Inorganic Mineral Salts (65%) -calcium phosphate (resists compression)
How often is spongy bone replaced? Compact bone?
- spongy bone: 3-4 years
- compact bone: 10 years
Why are bones remodeled?
- to maintain a constant concentration of calcium and phosphate
- in response to mechanical stress
What cells are undifferentiated?
osteoprogenitor/ osteogenic cells
Where are osteoprogenitor/ osteogenic cells found?
in the inner layer of periosteum and endosteum
Function of osteoprogenitor cells?
to divide and replace themselves and become osteoblasts
Function of osteoblasts?
- bone forming cells
- form matrix and collagen fibres
- can not divide
- initiate calcification
Function of osteocytes?
- mature cells
- exchange nutrients and waste in blood
- do not secrete matrix or divide
Function of osteoclasts?
- bone degrading cells
- giant cell, many nuclei, crawls along bone surface
- breaks down bone tissue
- secretes concentrated HCl and releases lysosomal enzymes
What is the function unit of compact bone?
Osteon/ Haversian system
Why do collagen fibres run in opposite ways along the layers of lamellae?
to increase the resistance to twisting forces
What is the only way a bone can increase in length?
when new bone is deposited at the epiphyseal plate
When does the epiphyseal plate close?
between the ages of 18 and 21
What happens in the proliferation zone regarding bone growth?
cartilage cells undergo mitosis
What happens in the hypertrophic zone regarding bone growth?
older cartilage cells enlarge
What happens in the calcification zone regarding bone growth?
matrix becomes calcified, cartilage cells die, matrix begins deteriorating
What happens in the ossification zone regarding bone growth?
new bone formation is occurring
