Chapter 7 Flashcards
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More info on functions of skeleton
Electrolyte balance
Acid-base balance
Blood formation
1) . The skeleton stores calcium and phosphate ions and releases them into the tissue fluid and blood as needed.
2) . Bone tissue buffers the blood against excessive PH changes by absorbing or releasing alkaline phosphate and carbonate salts.
3) . Red bone marrow is the major producer of blood vessels.
Functions of the skeleton
Support Protection Movement Electrolyte balance Acid-base balance Blood formation
Bones and osseous tissue
Connective tissue in which the matrix is hardened by the deposition of calcium phosphate
Contains blood, bone marrow, cartilage, adipose, neurons and fibrous CT
Four categories of bones
Flat- thin, curved plates
Long- serve as rigid levers that r acted upon by skeletal muscles to produce movement.
Short- bones equal in length and width that produce limited gliding movements.
Irregular bones- bones that don’t fit in any other category.
General anatomy of long bones
- Compact bone
- Marrow cavity
- Spongy bone
- Outer shell of dense white bone tissue.
- Space enclosed by compact bone which contains bone and marrow.
- Loosely organized bone tissue filling the central space of the ends of the bone and the middle of the non-long bones.
Features of long bones
- Diaphysis
- Epiphysis
- Articular cartilage
- The shaft that provides leverage.
- The head at each end of the bone that strengthens the joint and provides added surface area for attachment.
- A layer of hyaline cartilage that covers the joint surface where one bone meet another.
Linings of the bone
- Periosteum
- Some collagen fibers
- Endosteum
- And outer layer of collagen and inner layer of bone forming cells.
- Some of the collagen fibers are continuous with tendons binding muscle to bone.
- Layer of connective tissue that lines the Marrow cavity, covers the surfaces of spongy bone and lines the canal system.
Ephiphyseal plate
Hyaline cartilage in children separating the marrow spaces of the epiphysis and diaphysis, a zone where bones grow in length.
Anatomy of a flat bone
- Two layers of compact bone enclosing a middle of spongy bone.
- The spongy bone may absorb impact of a blow to the cranium even if the outer compact bone is fractured.
Histology of osseous tissue
Four principal types of bone cells
- Osteogenic cells
- Osteoblasts
- Osteocytes
- Osteoclasts
Osteogenic cells
Stem cells in the endosteum and periosteum that multiply continually and give rise to osteoblasts.
Osteoblasts
Bone forming cells that synthesize the organic matter of the bone matrix which is hardened by mineral deposition.
Osteocytes
Former osteoblasts that have become trapped in Lacunae in the matrix they deposited.
Lacunae are interconnected by canaliculi which allows cells to pass nutrients, chemical signals and wastes to one another.
Osteoclasts
Bone dissolving cells found on the bone surface.
They develop from bone Marrow stem cells.
They reside in pits that they have etched into the bone surface.
The matrix dry weight
One third organic and two thirds inorganic matter
The matrix organic matter includes
Collagen and other molecules
The matrix inorganic matter includes
85% hydroxyapatite, a calcium phosphate salt and 10% calcium carbonate with lesser amounts of other matter
What two things is bone a composite of and what does it do?
Collagen which gives it flexibility with tensile strength and
hydroxyapatite giving the strength to support the weight of the body.
Compact bone histology
What is an osteon?
It is a cylinder of tissue surrounding a central canal.
VAN
Van stands for veins, arteries and nerves. (red, blue, yellow)
They always travel together in a van
What are osteons made of?
- Concentric lamellae- which is rings of matrix.
- Central canal- which is passageway containing the nerve, artery and vein.
- Perforating canals- which are passageways that join central canals.
- Where do blood vessels enter the bone tissue?
2. Where do the inner most osteocytes receive nutrients from?
- Through nutrient foramina on the surface which opens into the perforating canals.
- The blood vessels and they pass them along through gap junctions and canaliculi, which are little canals.
What are some facts about spongy bone?
- The bone consists of a lattice of bone called spicules and trabeculae.
- Lamellae but no central canals because no Osteocyte is far from Marrow.
- Spongy bone imparts strength to a bone while adding minimum weight.
- The trabeculae are arranged along the bones lines of stress.
What is bone marrow?
It is the soft tissue that occupies the marrow cavity and the spaces in the spongy bone.