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22 Cards in this Set
- Front
- Back
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What is the function of bones? |
they give form and support to the body, allow motion, and protect vital organs |
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Where does blood cell formation take place? |
Bone marrow |
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What are bones made of? |
organic matrix of collagen and other proteins, and ground substance which is crystals of minerals - mostly calcium and phosphate |
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What are the three types of bone cells? |
Osteoblasts, osteocytes, and osteoclasts |
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Osteoblasts |
synthesize a proteinacious substance called osteoid - which later becomes calcified |
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Osteoblasts become |
osteocytes trapped within the bone matrix and supplying new bone matrix molecules |
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Osteoclasts |
break down the bone structure during growth and repair |
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Compact bone |
is arranged in halversian systems consisting of concentric layers of bone around a central canal containing blood vessels and nerves |
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Spongy bone |
the crystals are arranged in bars or plates |
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How many bones are in the adult body |
206 - young children have more bones that fuse together as they get older - such as the skull bones and sacrum |
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Axial skeleton |
involves the skull, vertebral column, ribs and sternum |
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Appendicular skeleton |
involves the shoulder girdle and arms, and the pelvic girdle and legs |
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Bone remodeling starts |
with the osteoclasts breaking down existing bone structure - the osteoblasts move in and lay down a protein matrix - the matrix is then mineralized with calcium - the osteoblasts get trapped within the mineralized matrix |
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Joints |
are where two bones join together - they allow movement |
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Joints are classified by |
the way the bones are joined and the movement they facilitate |
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Synovial joints |
such as the shoulder, hip, knee, and elbow - have a synovial membrane that lines the inner surface of the joint cavity - articular cartilage covers the bone surfaces and synovial fluid fills the joint cavity and lubricates the joints |
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How many muscles are there? |
350 named muscles - most of them are paired for reciprocal movements |
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Motor units consist of |
a motor neuron in the anterior horn of the spinal column and the muscle fibers that are innervated by its axons |
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Type I muscle fibers |
are red and have more myoglobin so that they can continue to use oxygen - they are involved with slow, sustained movements, resisting fatigue - marathon runners |
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Type II muscle fibers |
are white and have fast contractions for rapid movements - they rely on anaerobic glycolysis - sprinters |
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What happens inside the muscle cell? |
Actin and myosin fibers slide past each other to cause muscle contraction - troponin and tropomyosin assist with the contractions - creatine and creatine kinase are involved in energy supply in the muscle through the pathway that creates ATP from ADP |
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Aging causes |
a loss of muscle bulk and strength |
