Lecture Exam 2 Flashcards
Describe the functions of the skeletal system
-Support - Provides framework for the attachment of soft tissues and organs
-Storage of minerals and lipids - calcium is the most abundant mineral. Calcium salts. energy in the form of lipids in the yellow marrow.
-Blood cell production - red, white, and other blood cell and elements are produced in the red bone marrow.
-Protection - skeletal structures surround many soft tissues and organs.
-Leverage - the movement that function as levers
Classify bones according to their shapes, give examples for each
sutural, flat, irregular, long, short, and sesamoid bones
Describe the bone structure of long bones and flat bones
Long bone: shaft - diaphysis; ends - epiphysis; connection of the two - metaphysis; compact bone; spongy bone; medullary cavity
Flat bone (parietal bone): cortex - compact bone; diploë - spongy bone
Identify the components of bone matrix
1/3 collagen fibers and 2/3 calcium salts
Identify the cell types in bones, and list their major functions
-Osteogenic cells - stem cells whose divisions produce osteoblasts (grandmother cells)
-Osteoblast - immature bone cell that secretes organic components of matrix
-Osteocyte - mature bone cell that maintains the bone matrix
-Osteoclast - multinucleate cell that secretes acids and enzymes to dissolve bone matrix
Compare the bone structure of compact bone and spongy bone
Compact bone consists of osteons with little space between them. Compact bone lies over spongy bone and makes up most of the diaphysis. It functions to protects, support, and resist stress.
Spongy bone consists of trabeculae with numerous red marrow-filled spaces. functions in storing marrow and providing some support.
Identify the major parts of an osteon (from bone list)
osteon (Haversian system)
central (Haversian) canal
lamellae (concentric, interstitial, circumferential)
osteocytes
lacunae
canaliculi
perforating (Volkmann’s) canal
Describe the structure of the periosteum and know its functions
The periosteum is a membrane with fibrous outer layer and a cellular inner layer. Tendon fibers interwoven in the periosteum and into the bone matrix. Perferforating fibers is the fibers that interweave in the periosteum and is cemented in the bone matrix keeping a tight hold.
Functions - Isolates the bone from surrounding tissues; provides a route for the blood vessels and nerves; and takes part in bone growth and repair
Describe the structure of the endosteum and know its functions
Endosteum is an incomplete cellular layer containing osteoblasts, osteogenic cells and osteoclasts; that lines the medullary cavity, the central canals, and the perforating canals.
Functions - Active during bone growth, repair, and remodeling. Where the osteoclasts and osteoblasts can remove or deposit matrix components
Define ossification and calcification, and be able to differentiate between the two.
Ossification - is the formation of bone. All ossification includes calcification.
Calcification - is the deposition of calcium salts – which takes place during ossification. Not all calcification is during ossification. When veins calcify for instance.
Explain the steps of endochondral ossification
Begins with the formation of a hyaline cartilage model.
1) as the cartilage enlarges, chondrocytes near the center of the shaft increase greatly in size. The matrix is reduced to a series of small struts that soon begin to calcify. the enlarged chondrocytes then die and disintegrate, leaving cavities within the cartilage.
2)blood vessels grow around the edges of the cartilage, and the cells of the perichondrium convert to osteoblasts. The shaft of the cartilage then becomes ensheathed in a superficial layer of bone.
3) Primary ossification center. Blood vessels penetrate the cartilage and invade the central region. Fibroblasts migrating with the blood vessels differentiate into osteoblasts and begin producing spongy bone at a primary ossification center. Bone formation then spreads along the shaft towards both ends of the former cartilage.
4)Remodeling occurs as growth continues, creating a medullary cavity. The osseous tissue of the shaft becomes thicker, and the cartilage near each epiphysis is replaced by shafts of bone. Further growth involves increases in length and diameter.
5) Secondary ossification center. Capillaries and osteoblasts migrate into the epiphysis, creating secondary ossification centers.
6)The epiphysis eventually become filled with spongy bone. The metaphysis, a relatively narrow cartilaginous region called the epiphyseal cartilage, or epiphyseal plate, now separates the epiphysis from the diaphysis. On the shaft side of the metaphysis, osteoblasts continuously invade the cartilage and replace it with bone. new cartilage is produced at the same rate on the epiphyseal side.
7) At puberty, the rate of epiphyseal cartilage production slows and the rate of osteoblast activity accelerates. As a result, the epiphyseal cartilage gets narrower and narrower, until it ultimately disappears. The event is called epiphyseal closure. The former location of the epiphyseal cartilage becomes the epiphyseal line.
Explain the steps of intramembranous ossification
Begins when osteoblasts differentiate within a mesenchymal or fibrous connective tissue.
Describe the remodeling and homeostatic mechanisms of the skeletal system
Bone remodeling - is the continuously recycling and renewal of the organic and mineral components of the bone matrix
Homeostatic Mechanisms - The skeletal system helps maintain mineral homeostasis by regulating the level of calcium and other minerals in the blood by storing or releasing them from bones as needed. With PTH and Calcitriol with a negative feedback loop with PTH released during calcium levels too low and Calcitriol released when calcium ions levels are too high.
PTH increases the blood calcium ion levels by indirectly stimulating the osteoclast activity, increasing the amount of calcium ion absorbed in the intestines and decreasing the amount of calcium ions excreted by the kidneys.
Calcitonin is released from the thyroid as the calcium ion levels increased the blood. which restricts osteoclasts, increases kidneys excretion, and lessens intestinal absorption.
List the nutritional needs and effects on bone
The bones depends on a combination of nutritional factors:
-Minerals - Normal bone growth and maintenance cannot take place without a constant dietary source of calcium and phosphorus. magnesium, fluoride, iron, and manganese is also required.
-Calcitriol and Vitamin D3 - Hormone calcitriol, which is synthesized in the kidneys is essential form normal calcium and phosphate ion absorption. Calcitriol is synthesized from a steroid, cholecalciferol (produced in skin or absorbed from diet).
-Vitamin C - must be in the diet. key in enzymatic reactions in collagen synthesis, also stimulates osteoblast differentiation. Deficiency causes scurvy, which is a loss of bone mass and strength.
-Vitamin A, K, and B12 - A stimulates osteoblast activity (important in children). K and B12 for synthesis of proteins in normal bone
Understand the relationship between calcitonin, calcitriol, and PTH in regards to maintaining blood calcium levels.
The parathyroid glands produce the parathryroid hormone (PTH). PTH increases the blood calcium ion levels by indirectly stimulating the osteoclast activity, increasing the amount of calcium ion absorbed in the intestines and decreasing the amount of calcium ions excreted by the kidneys.
Calcitriol is in the kidneys and it increases calcium and phosphate ion absorption by the intestines of the digestive tract.
Calcitonin is released from the thyroid as the calcium ion levels increased the blood. which restricts osteoclasts, increases kidneys excretion, and lessens intestinal absorption.
Describe the hormones that impact bone growth
Growth hormone is produced in the pituitary gland. Which stimulates osteoblast activity and the synthesis of bone matrix.
Thyroxine is produced in the thyroid gland. With the growth hormone, stimulates osteoblast activity and the synthesis of bone matrix.
Describe the steps in bone fracture and repair
1) fracture hematoma formation
2)Callus formation. the cells of the intact edosteum and periosteum undergo rapid cycles of cell division, and the daughter cells migrate into the fracture zone. An internal callus as a network of spongy bone unites the inner edges of the fracture. An external callus of cartilage and bone encircles and stabilizes the outer edges of the fracture.
3) Spongy bone formation. As the repair continues, osteoblasts replace the central cartilage of the external callus with spongy bone, which then unites the broken ends. Fragments of dead bone and the areas of bone closest to the break are resorbed and replaced. The ends of the fracture are now held firmly in place and can withstand normal stresses from muscle contractions.
4)Compact bone formation. A swelling initially marks the location of the fracture. Over time, this region will be remodeled by osteoblasts and osteoclasts, and little evidence of the fracture will remain. The repair may be “good as new” or the bone may be slightly thicker and stronger than normal at the fracture site. Under comparable stresses, a second fracture will generally occur at a different site.
Know the major types of fractures
Transverse factures - break along its long axis
Displaced and nondisplaced fracture - abnormal arrangement vs normal alignment.
Compression fracture- force on vertebra where it compresses the bone
Spiral fractures - twisting stresses that spread along the length of the bone
Epiphyseal fractures- break across the epiphyseal cartilage.
Comminuted fractures - shattered affected area into multitude of bony fragments
Greenstick fracture - break on one side and bend on the other (common in children)
Colles fracture - result of reaching out to cushion a fall
Pott’s fracture- occurs at the ankles and effects both bones of the leg
Define osteopenia and osteoporosis
Osteopenia is the normal part of the aging process of the bone becoming thinner and weaker.
Osteoporosis - When reduction of the bone mass is sufficient to compromise normal function.
Classify the major types of joints by function
Synarthrosis: These types of joints are immobile or allow limited mobility. This category includes fibrous joints such as suture joints (found in the cranium) and gomphosis joints (found between teeth and sockets of the maxilla and mandible).
Amphiarthrosis: These joints allow a small amount of mobility. Most joints in this category include cartilaginous joints such as those found between vertebrae and the pubic symphysis.
Diarthrosis: These are the freely-movable synovial joints. Synovial joints are further classified based on the different types of movement they provide
Classify the major types of joints by structure
Synarthrosis Fibrous - Suture (skull sutures bound by a dense fibrous connective tissue) and Gomphosis (fibrous connection between a tooth and its socket)
Synarthrosis Cartilaginous - Synchondrosis (a rigid, cartilaginous bridge between two articulating bones).
Synarthrosis Bony - Synostosis (totally rigid, immovable joint created when two bones fuse and the boundary between them disappears).
Amphiarthrosis Fibrous - Syndesmosis (when bones are connected by a ligament).
Amphiarthrosis Cartilaginous - Symphysis (When the articulating bones are connected by a wedge or pad of fibrocartilage).
Diarthrosis Synovial (Allows a wider range of motion, usually located at the ends of long bones).
Describe the basic structure of a synovial joint, and describe common accessory structures.
Basic structure is fibrous joint capsule, synovial membrane, articular cartilages, and joint cavity (contains synovial fluid).
While common accessory structures is bursa, fat pad and cartilages, ligaments, and tendons
functions of the fibrous joint capsule
One of the two membranes which is on the outside and incapsulates the synovial fluid
Functions of synovial membrane
One of the two membranes which is on the inside of the two and incapsulates the synovial fluid. incomplete epithelial layer that secrete the synovial fliud
