6.1-6.2 Skeletal System Flashcards
What are the five functions of the skeletal system?
1.body support
2.organ protection
3. Body movement
4. Mineral storage (Ca and P)
5. Blood cell production
Connective tissue is characterized by having widely distributed cells separated by nonliving material known as
Matrix
Types of connective tissues
Cartilage, tendons, ligaments, and bones
The fibrous protein ________ provides flexibility but resist pulling or compression. This makes it well-adapted for the attachment functions of tendons. And ligaments as well as the shock absorption of cartilage.
Collagen
The matrix ______ _______ consists of of a molecule called __________.
Ground substance, proteoglycans
What are water trapping proteins that help cartilage be smooth and resilient?
Proteoglycans
Bone matrix is usually______% organic and ______% inorganic material.
35,65
The organic material is usually ______ and ______.
Collagen, proteoglycans
The inorganic material consists of primarily a calcium phosphate crystal called
Hydroxyapatite
________ _______ lend flexible strength to the matrix, giving the matrix weight- bearing strength.
Collagen fibers
If mineral in a long bone is reduced ______ becomes the primary constituent and the bone is very ______.
Collagen, flexible
If the amount of ______ is reduced in the bone, the mineral component becomes the primary constituent and the bone is very ______.
Collagen, brittle
rare disorder caused by faulty genes that results in too little collagen formation, or poor quality collagen.
as a result, the bone matrix has decreased flexibility and is more easily broken than normal bone
Brittle bone disease / osteogenesis imperfecta
Three different types of bone cells
Osteocytes, osteoblasts, osteoclasts
Bone building cells
Osteoblasts
These cells have an extensive endemic reticulum and numerous ribosomes. They produce collagen and proteoglycans.
Osteoblasts
Bone cell that secretes high concentrations of Ca 2+ and phosphate ions, forming crystals called hydroxyapatite.
Osteoblasts
The _______ _______ act as templates that stimulate further hydroxyapatite formation and mineralization of the matrix.
hydroxyapatite crystals
Formation of new bone cells by osteoblasts is called
Ossification or osteogenesis
What occurs by appositional growth on the surface of previously existing material, either bone or cartilage?
Ossification
strong bands of fibrous connective tissue that holds bones together
ligaments
osteoblasts become ______ once the osteoblasts have secreted sufficient bone matrix
osteocytes
what accounts for 90-95 percent of bone cells and are very long-lived, with a life span of up to 25 years.
osteocytes
osteocyte cell bodies are housed within the bone matrix in spaces called
lacunae
osteocyte cell extensions are housed in narrow long spaces called
canaliculi
bone destroying cells that break down bones
osteoclasts
breakdown of bone is called
reabsorption
massive, multinucleated cells that develop from red bone marrow cells and also differentiate into specialized white blood cells
osteoclasts
multi step process of bone reabsorption carried out by mature osteoclasts
- first, the osteoclasts must access the bone matrix
- osteoclasts contact the bone surface, they form attachment structures
- theses create a sealed compartment under the osteoclast
- next, the osteoclasts develop a ruffle border
a specialized reabsorption-specific area of the membrane
ruffle border
mature bone is called
lamellar bone
lamellar bone is organized into thin, concentric sheets or layers called
lamellae
osteoclasts create an ____ environment within the sealed compartment , which causes the breakdown of the bone matrix
acidic
osteocytes, within their lacunae, are arranged in layers sandwiched between
lamellae
spongy bone has ____ bone matrix and _____ space than compact bone
less , more
what consists of interconnecting rods or plates of bone called trabeculae
spongy bone
interconnecting rods or plates of bone
trabeculae
aka cortical bone, is the solid, outer layer surrounding each bone.
compact bone
compact bone has ____ matrix and is denser with ____ pores than spongy bone
more, fewer
the functional unit of compact one is an
osteon
composed of concentric rings of matrix, which surround a central tunnel and contains osteocytes
osteon
in cross section, an osteon resembles a circular target; the bull’s eye the target is the
central canal