Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
77 Cards in this Set
- Front
- Back
|
Skeletal System
|
The entire framework of bones and their cartilage, along with ligaments and tendons.
|
|
|
Osteology
|
The study of bone structure and the treatment of bone disorders.
|
|
|
List the several tissues which compose a bone
|
Bone or osseous tissue, cartilage, dense connective tissues, epithelium, adipose tissue, and nervous tissue.
|
|
|
Support
|
Skeleton serves as the structural framework the body by supporting soft tissues and providing attachment points for the tendons of most skeletal muscles.
|
|
|
Portection
|
Portects the most important internal organs from injury.
|
|
|
Assistance in movement
|
Most skeletal muscles attach to bones, when they contract they pull on bones to produce movement
|
|
|
Mineral homeostasis (storage & release)
|
Bone tissue stores several minerals especially calcium and phosphorus which contribute to the strength of bone. Store 99% of the HB calcium and on demand releases minerals into the blood to maintain critical mineral balances and to distribute the minerals to other parts of the HB
|
|
|
Blood cell production
|
Within certain bones, a connective tissue called red bone marrow produces: red blood cells, white blood cells, and platelets in a process called hemopoiesis.
|
|
|
Triglyceride Storage
|
Yellow bone marrow consists mainly of adipose cell, which store triglycerides which are a potential chemical energy reserve.
|
|
|
Long Bone (LB): has greater length than width.
1) Diaphysis 2) Epiphyses |
1) The bone's shaft or body, the long and cylindrical, main portion of the bone.
2) The proximal and distal ends of the bone |
|
|
LB
3) Metaphyses |
3) the regions between the diaphysis and the epiphyses which in a growing bone contain an epiphyseal growth plate, a layer of hyaline cartilage that allows the diaphysis of the bone to grow in length, and is replaced by bone at ages 18-21, and the resulting bony structure is the epiphyseal line.
|
|
|
LB
4) articular cartilage |
4) a thin layer of hyaline cartilage covering the part of the epiphysis where the bone forms an articulation (joint) with another bone. Reduces friction and absorbs shock at freely movable joints.
|
|
|
LB
5) Perisoteum |
5) Surrounds the external bone surface wherever it is not covered by articular cartilage and is composed of an outer fibrous layer of dense irregular connective tissue and an inner osteogenic layer that consists of cells. Some of these cells enable growth in thickness, but not in length. It also protects the bone, assists in fracture repair, helps nourish bone tissue, and seres as an attachment point for ligaments and tendons.
|
|
|
Perforating (sharpey's) fibers
|
the underlying bone to which the periosteum is attached by thick bundles of collagen fibers that extend from the periosteum into the extracellular bone matrix.
|
|
|
LB
6) Medullary Cavity or marrow cavity |
a hollow, cylindrical space within the diaphysis that contains fatty yellow bone marrow in adults.
|
|
|
LB
7) Endosteum |
A thin membrane that lines the internal bone surface facing the medullary cavity and contains a single layer of cells and a small amount of connective tissue.
|
|
|
1) Osteogenic cells
|
unspecialized stem cells derived from mesenchyme, the tissue from which almost all connective tissues are formed. They are the only bone cells to undergo cell division, and the resulting cells develop into osteoblasts; they are found in the periosteum, endosteum and in the canals within bone that contain blood vessels.
|
|
|
2) Osteoblasts
|
bone-building cells. They synthesize and secrete collagen fibers and other organic components needed to build the extra-cellular matrix ECM of bone tissue, and they initiate calcification. These cells surround themselves with ECM and become trapped in their secretions and become osteocytes.
|
|
|
3) Osteocytes
|
Mature bone cells, are the main cells in bone tissue and maintain its daily metabolism, such as the exchange of nutrients and wastes with the blood. These cells do not undergo cell division.
|
|
|
4) Osteoclasts
|
Huge cells derived from the fusion of as many as 50 monocytes and are concentrated in the endosteum. It's PM is deeply folded into a ruffled border where the cell releases powerful lysosomal enzymes and acids that digest the proteins and mineral components of the underlying bone matrix.
|
|
|
Resorption
|
The breakdown of bone extracellular matrix, is part of the normal development, maintenance and repair of bone.
|
|
|
Chemical Components of Bone
|
Not solid, but has many small spaces between its cells and ECM components. 80% is compact bone and 20% is spongy bone.
|
|
|
Compact Bone Tissue (CBT)
|
Contains few spaces and is the strongest form of bone tissue. It is found beneath the periosteum of all bones and makes up the bulk of the diaphyses of long bones, and it provides protection and support and resists the stresses produced by weight and movement.
|
|
|
CBT
Perforating or Volkmann's Canals |
Site where the penetration of compact bone is achieved by blood vessels, lymphatic vessels, and nerves from the periosteum.
|
|
|
CBT
Central of Haversian canals |
Connects with the vessels and nerves of the perforating canals and runs longitudinally through the bone.
|
|
|
CBT
Concentric lamellae |
Around the central canals, rings of calcified ECM much like the rings of a tree trunk
|
|
|
CBT
Lacunae |
The small spaces between the lamellae which contain osteocytes.
|
|
|
CBT
Canaliculi |
Small channels which radiate in all directions from the lacunae and are filled with extra cellular fluid or ECF
|
|
|
CBT
Osteons or Haversian Systems |
The arranged structural units which are the components of bone tissue
|
|
|
CBT
Interstitial Lamellae |
The are between osteons which also have lacunae with osteocytes and canaliculil
|
|
|
Spongy Bone tissue SBT
|
Unlike CBT, does not contain osteons. The name only applies to the appearance of the bone. It consists of lamellae arranged in a lattice of thin columns called trabeculae.
|
|
|
SBT contd.
|
Makes up most of the interior bone tissue of short flat and irregularly shaped bones, and most of the epiphyses of long bones. It forms a narrow rim around the medullary cavity of the diaphysis of long bones, where it is covered by endosteum. It is always covered by a layer of compact bone for protection.
|
|
|
Periosteal Arteries
|
accompanies by nerves, enters the diaphysis through many perforating canals and supply the periosteum and outer part of the compact bone.
|
|
|
Nutrient artery
|
Near the center of the diaphysis, it passes through a hole in compact bone called the nutrient foramen. Once inside, it divides into proximal and distal branches that supply both the inner part of compact bone tissue of the diaphysis and the spongy bone tissue and red marrow as far the epiphyseal plates or lines.
|
|
|
Metaphyseal Arteries
|
Enter the metaphyses of a long bone and, together with the nutrient artery, supply the red bone marrow and bone tissue of the metaphyses.
|
|
|
Epiphyseal Arteries
|
Enter the epiphyses of a long bone and supply the red bone marrow and bone tissue of the epiphyses.
|
|
|
Nutrient Veins
|
Accompany the nutrient artery and exit in the diaphysis, thus carry blood away from long bones.
|
|
|
Epiphyseal and Metaphyseal veins
|
Are numerous and accompany their respective arteries and exit in the epiphyses.
|
|
|
Periosteal veins
|
Accompany their respective arteries and exit in the periosteum.
|
|
|
Nerve supply of a bone
|
Nerves accompany the blood vessels that supply bones. The periosteum is rich in sensory nerves, some of which carry pain sensations.
|
|
|
Ossification
|
The process by which bone forms. Occurs in four situations: initial formation in embryo; growth during infancy, childhood and adolescence; the remodeling of bone throughout life; and the repair of fractures throughout life
|
|
|
Intramembranous ossification (IMO)
|
The simpler of the two methods of bone formation in which the flat bones of the skull and mandible are formed
|
|
|
IMO
Step 1: Development of the ossification center |
At site where bone will develop, specific chemical messages cause the mesenchymal cells to cluster together and differentiate, first into osteogenic cells and then into osteoblasts. Ossification center is the cluster site.
|
|
|
IMO
Step 2: Calcification |
The secretion of EXM stops, and the cells, now called osteocytes lie in lacunae and extend their narrow cytoplasmic processes into canaliculi that radiate in all directions.
|
|
|
IMO
Step 3: Formation of trabeculae |
What the ECM develops into which fuses with itself to form spongy bone.
|
|
|
IMO
Step 4: Development of the periosteum |
In conjunction with the formation of trabeculae, the mesenchyme condenses at the periphery of the bone and develops into the periosteum. Eventually a thin layer of Compact Bone replaces the surface layers of the spongy bone, but spongy bone remains in the center.
|
|
|
Endochondral Ossification ECO
|
Term for the replacement of cartilage by bone. Most bones in the body are formed this way.
|
|
|
ECO Step 1: Development of the cartilage model
|
At site where the bone will form, specific chemical messages cause the mesenchymal cells to crowd togetherin the shape of the future bone, and then develop into chondroblasts which secrete cartilage ECM, producing a model which consists of hyaline cartilage. A covering called perichondrium develops around the model.
|
|
|
ECO Step 2: Growth of the cartilage model
|
Once chondroblasts become deeply buried in the cartilage ECM they are called chondrocytes. The cartilage model grows by continual cell division of chondrocytes accompanies by further secretion of the cartilage ECM.
|
|
|
Intersitial Growth
|
Occurs in step 2 of ECO; means growth from within and results in an increase in length.
|
|
|
Appositional Growth
|
Occurs in step 2 of ECO, cartilage model grows by addition of more ECM material to the periphery of the model by new chondroblasts that develop from the perichondrium.
|
|
|
Epiphyseal Growth Plate EGP
|
A layer of hyaline cartilage in the metaphysis of a growing bone that consists of four zones.
|
|
|
EGP
1) Zone of resting cartilage |
1) The layer nearest the epiphysis and consists of small, scattered chondrocytes, it anchors the epiphyseal plate to the epiphysis of the bone.
|
|
|
EGP
2) Zone of proliferating cartilage |
Slightly larger chondrocytes in this zone are arranged like stacks of coins, they undergo interstitial growth as they divide and secrete ECM. They divide to replace those that die at the diaphyseal side of the epiphyseal plate.
|
|
|
EGP
3) Zone of hypertrophic cartilage |
3) This layer consists of large and maturing chondrocytes arranged in columns.
|
|
|
EGP
4) Zone of calcified cartilage |
The final zone of the epiphyseal plate is only a few cells thick and consists mostly of chondrocytes that are dead because the ECM around them has calcified. Osteocytes dissolve the calcified cartilage and osteoblasts and capillaries from the diaphysis invade the area.
|
|
|
EGP Growth in Length
|
This provides the only means by which the diaphysis can increase in length. The thickness of the plate remains constant but the bone on the diaphyseal side increases in length.
|
|
|
Epiphyseal Line
|
The bony structure that remains after the epiphyseal plate fades whose appearance signifies that the bone has stopped growing in length. The clavicle is the last bone to stop growing
|
|
|
Growth in thickness
|
This occurs by appositional growth. At the bone surface, cells in the periosteum differentiate into osteoblasts, which secrete bone ECM.
|
|
|
Bone remodeling
|
The ongoing replacement of old bone tissue by new bone tissue, which involves bone resorption, the removal of minerals and collagen fibers from bone by osteoclasts, and bone deposition which is the addition of minerals and collagen fibers to bone by osteoblasts.
|
|
|
Factors affecting bone growth and bone remodeling
|
Normal bone metabolism depends upon minerals such as calcium are phosphorus, vitamins like Vitamin A stimulate the activity of osteoblasts, and hormones the most important of which are the insulin-like growth factors (IGF's)
|
|
|
Fracture
|
Any break in a bone, which is named according due to its severity, its shape or position or even the physician who first described them.
|
|
|
Open (Compound) Fracture
|
Occurs when the broken ends of the bone protrude through the skin.
|
|
|
Closed (simple) fracture
|
One which does not break the skin
|
|
|
Comminuted Fracture
|
When the bone is splintered, crushed, or broken into pieces, and smaller bone fragments lie between the two main fragments. The most difficult to treat
|
|
|
Greenstick fracture
|
A partial fracture in which one side of the bone is broken and the other side bends, occurs only in children whose bones are not yet fully ossified and contain more organic material than inorganic material
|
|
|
Impacted fracture
|
One end of the fractured bone is forcefully driven into the interior of the other
|
|
|
Pott's Fracture
|
A fracture of the distal end of the lateral leg bone (fibula) with serious injury of the distal tibial articulation.
|
|
|
Colles' fracture
|
a fracture of the distal end of the lateral forearm bone in which the distal fragment is displaced posteriorly.
|
|
|
Stress Fracture
|
A series of microscopic fissures in bone that forms without any evidence of injury to other tissues and result from repeated, strenuous activities
|
|
|
Parathyroid Hormone or PTH
|
regulates the exchange of calcium ions, and is secreted by the parathyroid glands. This hormone increases calcium ion levels and operates via a negative feedback system
|
|
|
Calcitrol
|
the active form of Vitamin D, a hormone that promotes absorption of calcium from foods in the gastrointestinal tract into the blood. The formation of this hormone is stimulated by PTH
|
|
|
Calcitonin (CT)
|
A hormone which works to decrease blood calcium ion levels. It inhibits the activity of osteoclasts, speeds blood calcium ion uptake by bone and accelerates its deposition into bones.
|
|
|
Exercise and bone tissue
|
Bones of athletes which are repetitively and highly stressed become notably stronger and thicker. People of all ages can and should strengthen their bones by engaging in weight-bearing exercise.
|
|
|
Aging and Bone tissue
|
In old age, loss of bone through resorption occurs more rapidly than bone gain. Effects are more adverse in females.
|
|
|
demineralization
|
this is what the loss of bone mass results from, the loss of calcium and other minerals from bone ecm.
|
|
|
Brittleness
|
Results from a decreased rate of protein synthesis. Collagen fibers give bone its tensile strength, the loss of tensile strength causes the bones to become very brittle and susceptible to fracture.
|
