Download Skeletal System Notes-Skeletal Tissue Skeletal Tissue Types of

Skeletal System Notes-Skeletal Tissue
Skeletal Tissue
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Types of Bones
-Long bones; Examples:
-Short bones; Examples:
-Flat bones; Examples:
-Irregular bones; Examples:
-Sesamoid bones- irregular bones that appear singularly Ex:
Parts of a long bone
-main part of bone,
made up of compact bone
-ends of long bone,
made up of cancellous bone
-At development, epiphysis is separated from diaphysis
by a
thick layer of cartilage called the epiphyseal plate (this is
where mitosis occurs)
-hyaline cartilage that
covers epiphysis
-fibrous connective
tissue that covers entire bone except at articulates (places
covered by articular cartilage)
-hollow tube in
diaphysis, in adults it’s filled with yellow marrow which is fat
Endosteum- lines
medullary cavity of long bones
Microscopic Anatomy
- Compact Bone
-Osteocytes are found in lacunae, lacunae are arranged in circles called lamellae, lamellae are formed around a
Haversian canal, canaliculi connect all lacunae and act as a transportation system
-Cancellous Bone
-Doesn’t have a Haversian system, instead they have trabeculae (hallow spaces) where bone cells are found.
Red bone marrow is found here, thus being the site for hematopoesis (red blood cell production).
Bone Cells
-build up bone
-break bone down
-mature osteoblasts that no longer have a function
Regulation of blood calcium
- Your blood stores 98% of all body calcium. Calcium levels must be maintained for proper bone formation, blood
clotting, nerve impulses and cardiac and skeletal muscle contraction.
-Controlled by the two hormones:
and
is the main hormone involved
- Regulation: When blood calcium is low, hormone is stimulated, activating osteoclasts. Bone will be broken down and
calcium will enter blood. When blood calcium levels are too high, PTH will be supressed, reducing amount of calcium
that enters blood stream. Calcitonin- activated by high levels of blood calcium, stimulates osteoblast activity and
suppresses osteoclast activity.
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Development of Bone
-bone formation
-The skeleton will begin as hyaline cartilage but then turns into bone (for all bones except flat bones which form from
membranes). Cartilage is covered by bones (osteoblasts) and then the cartilage is eaten away, forming a hallow
medullary cavity.
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Repair of bone fracture
- Blood at injury site will form a clot. A special type of callus tissue will form, binding the bones together. The tissue is
then replaced by bone.
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Bone Markings
 Angle-corner
 Body-main part of bone
 Condyle-rounded bump
 Crest- raised ridge, usually a place for muscle
attachment
 Epicondyle- bump near condyl (muscle
attachment)
 Facet- flat surface that forms a joint w/ a flat
bone
 Fissure-long, thin hole for blood vessels and
nerves
 Foramen- round hole
 Fossa-depression, receives articulating bone
 Head-distinct epiphysis on long bone
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Line- more faint than crest
Margin-edge of flat bone
Meatus-tubelike opening or channel
Neck-narrow portion, usually at end of head
Notch-V like margin at edge of flat area
Process- raised area of projection
Ramus-curved portion of bone
Sinus-cavity within a bone
Spine-raised more than a crest
Sulcus-elongated depression
Trochanter- large bump for muscle attachment
(largest of the bumps)
Tuberosity-oblong raised bump for muscle
attachment