Term
| What does the skeletal system consist of? |
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Definition
| The skeletal system consist of the bones, ligaments, cartilages, and other connective tissues. |
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Term
| What are the five primary functions of the skeletal system? |
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Definition
The five primary functions are;
1. Support - the skeletal system provides structural support for entire body.
2. Storage of Minerals- the bones of the skeleton store energy reserves as lipids in areas filled with yellow bone marrow, and act as a mineral reserve.
3. Blood Cell Production - rbcs, wbcs, and other blood elements are produced in red bone marrow.
4. Protection - many soft tissues and organs are surrounded by skeletal structures.
5. Leverage - many bones function as levers that can change the magnitude and direction of the forces generated by skeletal muscles. |
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Term
| How many bones are there in the adult skeleton, and what are the six categories they are divided into? |
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Definition
There are 206 major bones in the adult skeleton.
The six categories are;
1. Sutural bones (wormian bones) - small, flat, irregularly shaped bones between the flat bones of the skull.
2. Irregular bones - complex shapes with short, flat, notched, or ridged surfaces.
3. Short bones - small and boxy (carpal/wrist bones, and tarsal/ankle bones).
4. Flat bones - thin, parallel surfaces (form skull, sternum, ribs, and the scapulae)
5. Long bones - long and slender (arm, forearm, thigh, leg, palms, soles, fingers, and toes)
6. Sesamoid bones - small, flat, and shaped somewhat like a sesame seed |
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Term
Where are the sesamoid bones located? |
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Definition
| sesamoid bones develop inside the tendons and are mostly located near joints at the knees, hands, and the feet. |
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Term
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Definition
| Osseous tissue - is a supporting connective tissue, that contains specialized cells and a matrix consisting of extracellular protein fibers and a ground substance. |
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Term
| Explain the matrix of bone! |
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Definition
| The matrix of bone tissue is solid and sturdy, due to the deposition of calcium salts around the protein fibers. It is also very dense and contains deposits of calcium salts. The matrix contains bone cells/osteocytes within pockets called lacunae, which are organized around blood vessels that branch through the bony matrix. |
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Term
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Definition
| Canaliculi is narrow passageways through the matrix, extend between the lacunae and nearby blood vessels, forming a branching network for the exchange of nutrients, waste products, and gases. |
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Term
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Definition
Osteocytes are mature bone cells that make up most of the cell population, each occupies a lacunae.
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Term
| One major function of osteocytes. |
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Definition
| 1. Osteocytes maintain the protein and mineral content of the surrounding matrix- which is not a static process, as there is continual turnover of matrix components. Osteocytes secrete chemicals that dissolve the adjacent matrix, and the minerals released enter the circulation, they then rebuild the matrix, stimulating the deposition of new hydroxyapatite crystals. The turnover rate varies from bone to bone. |
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Term
| The second major function of osteocytes. |
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Definition
| Osteocytes participate in the repair of damaged bone. If released from their lacunae, osteocytes can convert to a less specialized type of cell, such as as osteoblast or an osteoprogenitor cell. |
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Term
| What's the difference between osteoblasts and osteoclasts? |
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Definition
Osteoblasts produces new bone matrix the process is ossification/osteogenesis, they make and release proteins and other organic components of the matrix.
Osteoclasts are cells that remove and recycle bone matrix. |
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Term
| This is important in the regulation of calcium and phosphate concentrations in body fluids, what is this term? |
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Definition
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Term
| Is exercising good for the bones or is it a breakdown point for them? |
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Definition
| Exercising is very good and healthy for the bones. People who exercise regularly or participate in weight training bones become stronger. |
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Term
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Definition
| Periosteum is a membrane with a fibrous outer layer and a cellular inner layer, it isolates the bone from surrounding tissues, provides a route for the circulartory and nervous supply, and also participates in bone growth and repair. |
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Term
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Definition
| Endosteum is an incomplete cellular layer that lines the medullary cavity. The endosteum consists of a simple flattened layer of osteoprogenitor cells that covers the bone matrix without any intervening connective tissue fibers. |
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Term
| Compare the structures and functions of compact bone and spongy bone. |
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Definition
| The compact bone consists of osteons with little space between them, it lies over spongy bone and makes up most of the diaphysis. It functions to protect, support, and resist stress. The spongy bone consists of trabeculae with numerous red marrow - filled spaces, it makes up most of the structure of short, flat, and irregular bones and is also found at the epiphyses of long bones. It functions in storing marrow and providing some support |
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Term
| There are two major forms of ossification, what are they? |
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Definition
The two major forms of ossification are endochondral and intramembranous ossification.
Endrochondral ossification - bone replaces existing cartilage.
Intramembranous ossification - bone develops directly from mesenchyme or fibrous connective tissue. |
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Term
| In endochondral ossification the original source of osteoblasts is what? |
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Definition
| Cells of the inner layer of the perichondrium differentiate into osteoblasts, and a cartilage model is gradually replaced by bone. |
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Term
| What is remodeling and how does it work? |
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Definition
The process in which organic and mineral components of the bone matrix are continously being recycled and renewed.
Bone remodeling can leave the bone as a whole, change the shape, internal architecture, or mineral content of the bone. |
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Term
| The hormones that are involved in stimulating and inhibiting the release of calcium ions from bone matrix are? |
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Definition
| Parathyroid hormone (PTH) influences osteoclast activity to cause a release of stored calcium ions from bone, under the influence of calcitonin-osteoclast activity is inhibited, while osteoblasts continue to lock calcium ions in the bone matrix. |
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Term
| What's the difference between an external callus and internal callus? |
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Definition
External callus or enlarged collar of cartilage and bone, forms and encircles the bone at the level of the fracture.
Internal callus organizes within the medullary cavity and between the broken ends of the shaft. |
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Term
| The largest and heaviest bone in the body is what type of bone? |
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Definition
| The femur (thigh bone) is the largest and heaviest bone in the body. |
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Term
| Osteoporosis is more common in older women than in older men, why? |
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Definition
| Because in women the sex hormones estrogen play an important role in movng calcium into bones. After menapause, the level of these hormones decreases dramactically the result of this in older women have difficulty replacing the calcium in bones that is being lost due to normal aging. In men, the level of sex hormones androgens does not decrease until much later in life. |
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Term
| Define osteogenesis imperfecta (OI) |
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Definition
| An inherited genetic disorder characterized by extreme fragility of the bones; also known as brittle bone disease. |
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Term
| Define: bone mineral density test (BMD) |
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Definition
| A test to predict the risk of bone fractures by measuring how much calcium and other types of minerals are present in the patient's bones. |
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