Anatomy & Physiology Skeletal System

Transcription

1 I. Functions of the Skeletal System A. the body Anatomy & Physiology Skeletal System B. of vital organs C. Provide for movement D. storage (calcium & phosphate) E. cell formation II. Bone Structure A. Microscopic anatomy 1. complex series of canals & that run through the dense bone matrix and supply to the osteocytes (bone cells) a. (Haversian canal) elongated cylinder that runs to the long axis of the bone. Arteries, veins, & nerves run through the osteons. b. rings or layers of bone matrix. c. space in the bony matrix where the osteocyte resides. d. small channels that connect lacuna (and neighboring osteocytes) to each other and provide a means for passing nutrients & wastes between cells. e. Matrix composition & 2. Types of bone tissue a. bone relatively solid part of bone. Make bones hard & strong. Usually found on the of the bone. b. bone network of bony struts that form a honeycomb of flat bony pieces. Allows bones to be lightweight. Found on the of the bones. 1

2 1) interlocking plates or struts. 2) (red or yellow) - fills the spaces between the trabeculae. B. Gross anatomy 1. expanded ends. Compact bone on the exterior. Spongy bone fills the interior. The joint surface of each epiphysis is covered with a layer of. 2. shaft of the bone. Composed of a thick layer of compact bone. a. hollow shaft of the diaphysis. It is filled with marrow. b. on a bone is normally applied along the axis of the diaphysis. 3. tissue that fills the spaces of spongy bone & medullary canals. a. tissue (blood cell forming). 1) found in the spongy bone & medullary canals of 2) found in the bones of. b. fat. Found in the medullary canals of the bones of. 4. cartilage cartilage that covers the ends of bones & provides a smooth articulating surface between the two bones of a joint. 5. fibrous, tough, vascular layer that covers the outer surface of a bone. a. Actively involved in bone &. b. Allows attachment surface for tendons & ligaments. 6. covers the internal bone surface of the medullary canal. Similar to periosteum. 2

3 C. Bone Development ( ) 1. Formation of bones from the hardening of cartilage models of the future bones. 2. the process of bone formation. Has 2 phases. a. ossification 1) Begins at the center of the of the hyaline bone around the month of development. 2) A bone collar forms around the diaphysis of the hyaline model. 3) Hyaline bone becomes ossified with. 4) Ossification proceeds from the center of the diaphysis toward the two epiphyses. 5) The hyaline bone continues to grow & elongate, thus preventing the ossification from reaching the epiphyses for years. b. ossification 1) Around, both of the epiphyses begin calcifying the cartilage from the inside outward. 2) Primary & secondary ossification usually finishes around years of age. 3) The junction of P & S ossification forms a gagged line called the. c. Hyaline cartilage remains at the ends of the bones as cartilage. D. Bone Remodeling 1. The continual breaking down of calcium salts by and the relaying of calcium salts by. 2. We recycle % to % of our bones every week to repair and strengthen the bones and to maintain calcium balance in our blood. 3

4 E. Hormonal effect on bone growth & remodeling 1. gland secretes the hormone, which stimulates & decreases blood calcium levels. Makes bones stronger. 2. secretes the hormone, which stimulates activity & increases blood calcium levels. This makes the bones weaker. 3. Anterior Pituitary secretes, which stimulates bone growth & elongation. F. Classification of bones 1. almost all bones of appendages 2. carpals & tarsals 3. ribs, scapula, cranial bones, sternum 4. vertebrae, coxal, facial 5. small bones with no bony attachments (E.g. patella) III. Skeletal System Disorders A. Bone Fractures 1. bone breaks cleanly, but does not penetrate the skin. 2. broken ends of the bone penetrate through the skin. 3. bone broken into many pieces & fragments. 4. bone is crushed inward. 5. broken bone ends forced into each other. 6. ragged break occurs when excessive twisting is applied to the bone. 7. bone breaks incompletely much like a green twig. 4

5 B. Skeletal Disorders 1. decreased osteoblast activity due to the body s inability to absorb calcium. Usually seen in the although exercise & proper calcium intake in middle years can delay the onset of this disorder. Factors that speed up the effects of osteoporosis are:. More often seen in. 2. Vit. deficiency causes soft bones due to a reduction in calcium. Causes legs and other skeletal disformities. 3. excessive GH secretion closure of the epiphyseal plates. Results in a. 4. excessive GH secretion closure of the epiphyseal plates. Results in. IV. Joints / Articulations A. General info 1. Joints are. 2. Three functional types: movable (synarthrosis); moveable (amphiarthrosis); moveable (diarthrosis) B. Synarthroses ( movable joints) 1. Occur between bones that come in close contact with each other. 2. A thin layer of fibrous connective tissue separates the bones. 3. Examples are: 5

6 C. Amphiarthroses ( moveable joints) 1. Joints are limited to a few degrees of movement. 2. Occur in areas where the bones are connected by disks of fibrocartilage or by thick ligaments. 3. Examples are: D. Diarthroses ( moveable joints) 1. Joints are able to move in directions and with degrees of movement. 2. Bones have a layer of (hyaline) cartilage at the ends & are held together by ligaments. 3. Articulating bones are separated by a fluid filled joint cavity the cavity that allows for substantial freedom of movement. 4. The articular capsule is a double layers capsule that surrounds the ends of the bones with a protective fibrous layer and a inner synovial membrane. 5. fluid is a slippery lubricant that fills the synovial joint. 6. Synovial joints that bear greater weight (E.g. knee) contain pads & fluid filled sacs ( ) also help to pad the joints from extrinsic wear. E. Types of freely moveable joints 1. most freely moveable type. Able to move in 3 planes. Ex: 2. - nearly flat surfaces are able to glide over one another in 2 planes. Ex: oval surface of one bone fits on the complementary concave surface of the other bone. Ex:. 4. convex surface of one bone fits into the concave surface of the other bone thus limiting them to 1 plane of movement. Ex:. 6

7 5. cylindrical surface of one bone rotates within a ring formed by the other bone. Movement limited to rotation. Ex:. 6. cones with both concave & convex shaped articular surfaces. Allows for a wide variety of movements. Only one example V. Joint Disorders A. chronic joint disorder due to the wearing down of the articular cartilage due to age. Often called arthritis. Accounts for % of all arthritis. B. arthritis autoimmune disease whereby the immune system attacks its own tissues and destroys the articular cartilage. Onset usually begins in the s and can eventually lead to disfigurement and crippling. C. the build up of crystals in the joints. The crystals are painful and can wear away at the articular cartilage. D. inflammation of a bursa due to injury or excessive friction in a joint. E. inflammation of the tendon sheaths of a joint due to overuse. 7