Chapter 6-Bones and Skeletal Tissue
For this assignment, please read the chapter and answer the questions below. Please type your answers in red or blue color.
Please note that points may be deducted if answers are not submitted in these colors.
Type your answer in the spaces provided below:
Describe each of the following functions of the Skeletal System
i. support- To provide structural support for the entire body.
ii. protection- surrounds soft tissue, fused bones of the skull protect the brain.
iii. body movement- Skeletal muscles, which attach to bones by tendons, use bones as levers to move the body and its parts.
iv. blood cell formation- most blood cell formation occurs in the red marrow cavities of certain bones.
v. mineral storage- where minerals are stored and lipids. They are released in to the bloodstream when needed. Bone is a reservoir for calcium and phosphate.
Long Bone Structure:
The ends of bones that form joints with adjacent bones are called the _epiphyses_.
The ends of these bones are covered with __articular cartilages_ (hyaline cartilage).
The epiphyseal plate is the site of bone __growth____.
The shaft of the bone is called the _diaphysis.
The diaphysis contains a hollow chamber called the _Medullary_ cavity that is lined with
_endosteum____ and filled with __yellow marrow_____.
Bone Marrow – Two Types:
What is the function of red marrow? To produce red and white blood cells and platelets.
Where is it found? It found in flat bones such as the pelvis, sternum, cranium, ribs and vertebrae.
What is the function of yellow marrow? To store fats
Where is it found? It is found in spongy bone and the shaft of long bones. Is located in the medullary cavity.
A tough layer of vascular connective tissue, called the __periosteum__, covers the bone and is continuous with ligaments and tendons.
Bone cells –
There are 4 types of bone tissue cells. Describe their function in living bone tissue.
a. Osteogenic cells – are mitotically active stem cells found in the membranous periosteum and endosteum. When stimulated these cells differentiate into osteoblast of bone lining cells.
b. Osteoblasts – actively mitotic bone forming cells that secrete bone matrix. To form new bone tissue.
c. Osteocytes – to help maintain bone as living tissue
d. Osteoclasts – to absorb and remove unwanted tissue
Microscopic Structure: The Osteon
Bone cells called _osteocytes_ are located within spaces called _lacunae___ that lie
in concentric circles around __central____ canals that contain blood vessels and nerves.
Osteocytes pass nutrients and wastes back and forth in grooves in the matrix called canalculi__.
The intercellular material consists of collagen and inorganic calcium salts. Collagen makes the
bone strong_, while the calcium salts make the bone _hard____.
Describe spongy bone structure: it looks like a poorly organized tissue. Its composed of small trabeculae of bones and lots of open space.
Where is spongy bone found? It is found at the ends of bones and joints.
Describe compact bone: Is smooth and homogenous. Is the heaviest hard type of bone. Supports our body and muscles as we walk or just move throughout the day.
In compact bone, osteocytes and intercellular material are organized into units called
___osteons__ that are cemented together.
Central canals contain blood vessels and nerve fibers, and extend in what direction through bone? It runs longitudinally through the bone.
Perforating canals connect the blood and nerve supply of the periosteum to what other structures? Central canals and medullary cavity
Describe how the structure called a lamella forms compact bone. It is a matrix tube that forms the growth rings, and contains the minerals that make the bones hard and gives structure.
Where is compact bone found? Compact bone is found on the outer shell of all bones and also the shafts in long bones.