Chapter 5 skeletal
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Chapter 5 skeletal
What is the skeletal systems supporting connective tissue?
What is the skeletal systems dense connective tissue proper?
What is the function of the bones?
Support the body
Storage for minerals and lipids (98% calcium, marrow)
Blood cell production
Protection (ribs, skull, pelvis?
Leverage (change magnitude & direction of muscle)
What are bones?
What is bone tissue made of?
Supporitng connective tissue
What does the bone matrix consist of?
Calcuim salts on 2/3 collagen fibers
Strong solid matrix (withstand compression)
Name the cells of bone tissue?
What are osteoprogenitor cells? What is their function?
Mitosis & differentation (daughter cells) repair
What do daughter cells become?
What is the function of osteoblasts?
Produce new bone (secrete bone matrix)
Becomes mineralized, may respond to
Mechanical or hormonal stress to
What are osteocytes? What is their function?
Mature bone cells
Maintain the matrix (dynamic)
Controls release of calcium to the blood
& depositing of Ca++ salts in the matrix
What is a chamber, or cave within an osteocyte?
What are the layers in an osteocyte called?
Within the osteocyte, what are the channels called?
What is the purpose of the canaliculi?
Connects to blood supply inside or outside
Their are gap junctions between them
What is the function of the osteoclast cells?
Dissolve bone matrix
& release Ca++ to blood
At a young age which is more active osteoblasts or osteoclast cells?
What are the two types of bone matrix?
How does the spongy bone look? What is the function?
Open framework (struts)
What will trabeculae do in the spongy bone if stressed?
Align themselves to support the bone
What is the quaility of the compact bone? What is the function?
Dense & solid
Forms walls of bones
Thicker at high stress areas
What is a osteon?
Functional unit of mature compact bone
In an osteon, where are the osteocytes & matrix found?
In concentric circles around central canal
In an osteon where do the canaliculi interconnect?
Name and define the three parts of the long bone?
What does physis mean?
Name the layers of the bone?
What is the periosteum membrane? What is it's function?
Outside surrounds the bone
Necessary for bone growth and repair
Where is the marrow located?
Inside the endosteum
What is the endosteum? It's function?
Thin layer of connective tissue
Lines the surfaces of bony tissue
That forms the medullary cavity
Active in growth and repair
Which cells are present in the endosteum?
Replacing other tissue with bone tissue
What is the process of ossification in a human embryo 'skeleton'?
Fibrous connective tissue (mesenchymal cells)
& hyaline cartilage loosely shaped like bones
Undergo ossification to become bones
When does ossification begin?
6-7 week embryo (1/2 inch long)
Name the two ways ossification can occur?
Intramembranous (within a membrane)
Endochondral (within a cartilage)
What bones are the outcome of intramembranous ossification?
What is the process from beginning to end of intramembranous ossification?
Ossification centers begin in
Fibrous connective tissue
(meschymal cells differentiate into osteoblasts)
These center secrete matrix which undergoes
Calcification and center gets larger
The bone becomes spongy bone and then produces
The outer compact bone
What are fontanels?
Membrane left that is not ossified
Describe the endochondral ossification process?
Cavities form in the cartilage model by
A bone collar is formed around the shaft of the model by
Osteoblasts. Blood vessels penetrate the collar
& cartilage and enter the central cavity and bring osteoblasts
That produce spongy bone. The bone shaft becomes thicker
Capillaries enter epiphysis bringing osteoblasts
That create secondary ossification centers
How are most bones formed?
Through endochondral ossification
What is a chondrocyte?
The only cells found in cartilage
How are osteocytes important to bone maintenance?
They are continually removing &
Replacing calcuim salts
How much of the adult skeleton is demolished and rebuilt, or replaced each year?
What two bone cells remain active throughout our lives?
When does bone growth occur?
When osteoblasts are creating more
Matrix then osteoclast cells are removing
What is true for the bone cells of older individuals?
Osteoclast cell activity is
Higher than osteoblasts
What is osteoporosis?
The result of too little mineralization of bones
What is linked to osteoporosis?
Deficiency of mineral in youth
Loss of estrogen at menopause
Imbalance of activity of osteoblasts and osteoclasts