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64 Cards in this Set

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What are the Six Tissues that make up a bone?
bc dean - anagram
bone (osseous) tissue
cartilage tissue
dense connective tissue
adipose tissue
nervous tissue
Six Main Functions of the Skeletal System
SPAM BT - anagram
Assistance in Movement
Mineral Storage and Release
Blood Cell Production
Triglyceride storage
The skeleton serves as the structural framework for the body by supporting soft tissues and providing attachment points for the tendons of most skeletal muscles
The skeleton protects the most important internal organs from injury. For example, cranial bones protect the brain, vertebrae (backbones) protect the spinal cord, and the rib case protects the heart and lungs
Assistance in Movement
Most skeletal muscles attach to bones; when they contract, they pull on bone to produce movement
Mineral storage and release
Bone tissue stores several minerals, especially calcium and phosphorus, which contribute to the strength of bone. Bone tissue stores about 99% of total body calcium. On demand, bone releases minerals into the blood to maintain critical mineral balances and to distribute the minerals to other parts of the body.
Blood Cell Production
Within certain bones, a connective tissue called red bone marrow produces red blood cells, white blood cells, and platelets, a process called hemopoiesis. Red bone marrow consists of developing blood cells, adipocytes, fibroblasts, and microphages within a network of reticular fibers. It is present in developing bones of the fetus and in some adult bones, such as the hip bones (pelvic bones), ribs, sternum (breastbone), vertebrae (backbones), skull, and ends of the humerus (arm bone) and femur (thigh bone). In a newborn, all bone marrow is red and is involved in hemopoiesis. With increasing age, much of the bone marrow changes from red to yellow.
Triglyceride Storage
Yellow bone marrow consists mainly of adipose cells, which store triglycerides. The stored triglycerides are a potential chemical energy reserve.
Types of Bones
Long Bones
have greater length than width and consist of a shaft and a variable number of extremities (ends). They are slightly curved for strength. Long bones consist mostly of compact bone tissue, which is dense and has smaller spaces but they also contain considerable amounts of spongy bone tissue, which has larger spaces. Long bones include the humerus (arm bone), ulna and radius (forearm bones), femur (thigh bone), tibia and fibular (leg bones), phalanges (finger and toe bones).
Short Bones
are somewhat cube-shaped and nearly equal in length and width. They consist of spongy bone except at the surface, where there is a thin layer of compact bone. Examples of short bones are the carpal (wrist) bones and tarsal (ankle) bones
Flat bones
generally thin and composed of two nearly parallel plates of compact bone enclosing a layer of spongy bone. Flat bones afford considerable protection and provide extensive areas for muscle attachment. Flat bones include cranial (skull) bones, which protect the brain; the sternum (breastbone) and ribs which protect organs in the thorax; and the scapulae (shoulder blades).
Irregular Bones
have complex shapes and connot be grouped into any of the three categories just described. The yalso vary in amount of spongy and compact bone present. Such bones include the vertebrae (backbones), certain facial bones, and aforementioned calcaneus (heel bone)
Sesamoid Bones
develop in certain tendons where is considerable friction, compression, and physical stress. They are not always completely ossified and measure only a few millimeters in diameter except for the two patellae (kneecaps). Sesamoid bones vary in number from person to person
Sutural (Wormian) Bones
are small bones located within the sutures (joints) of certain cranial bones. The number of sutural bones varies greatly from person to person.
Anatomy of a Bone
articular cartilage
medullary cavity
is the bone's shaft, or body - the long, cylindrical, main portion of the bone
are the proximal and distal ends of the bone
are the regions between teh diaphysis and the epiphyses. In a growing bone, each metaphysis contains an epiphyseal plate - a layer of hyaline cartilage that allows the diaphysis of the bone to grow in length
Articular Cartilage
a thing layer of hyoline cartilage covering the part of the epiphysis where the bone forms an articulation joint with another bone. Articular cartilage reduces friction and absorbs shock at freely movable joints. Because articular cartilage lacks a perichondrium and lacks blood vessels, repair of damage is limited.
is a tough sheath that surrounds the bone surface wherever it is not covered by a layer of articular cartilage. It is composed of an outer fibrous layer of dense irregular connective tissue and in inner osteogenic layer that consists of cells. The periosteum protects the bone, assists in fracture repair, helps nourish tissue and serves as an attachmetn point for ligaments and tendons.
Medullary Cavity
is a hollow, cylindrical space in the diaphysis that contains fatty yellow bone marrow and numerous blood vessels in adults.
is a thin membrane that lines the medullary cavity. It contains a single layer of bone-forming cells and a small amount of connective tissue.
Bone Surface Markings
Spinous process
Depression and Opening
Narrow slit between adjacen parts of bones through which blood vessels or nerves pass
Example: Superior orbital fissure of the sphenoid bone
Depression and Opening
Opening through which blood vessels, nerves, or ligaments pass
Example: Optic foramen of the sphenoid bone
Depression and Opening
Shallow depression
Example: Coronoid fossa of the humerus
Depression and Opening
Furrow along a bone surface taht accommodates a blood vessel, nerve or tendon.
Example: Intertubercular sulcus of the humerus
Depression and Opening
Tubelike opening
Example: External and internal auditory meatus of the temporal bone
Processes that form joints
Large, round protuberance at the end of a bone
Example: Lateral condyle of the femur
Processes that form attachment points for connective tissue
Projection above a condyle
Example: Medial epicondyle of the femur
Process that form joints
Smooth flat articular surface
Example: Superior articular facet of a vertebra
Process that form joints
Rounded articular projection supported on the neck (constricted portion) of a bone
Example: head of the femur
Processes that form attachment points for connective tissue
Prominent ridge or elongated projection
Example: Iliac crest of the hip bone
Processes that form attachment points for connective tissues
Long, narrow ridge or border (less prominent than a crest)
Example: Linea aspera of the femur
Processes that form attachment points for connective tissues
Spinous process
Sharp, slender projection
Example: Spinous process of a vertebra.
Processes that form attachment points for connective tissue
Very large projection
Example: Great trochanter of the femur
Processes that form attachment points for connective tissue
Small, rounded projection
Example: Great tubercle of the humerus
Large, rounded usually roughened projection
Example: Ischial tuberosity of the hip bone
Four types of cells present in bone tissue
Osteogenic cells
Osteogenic Cells
are 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. They are found along the inner portion of the periosteum, in the endosteum and in the canals within bone that contain blood vessels
are bone building cells. They synthesize and secrete collagen fibers and other organic components needed to build the extracellular matrix of bone tissue, and they iniate calcification.
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. Like osteoblasts, osteocytes do not undergo cell division.
are huge cells derived from the fusion of as many as 50 monocytes (a type of white blood cell) and are concentrated at the endosteum. Here the cell releases powerful lysosomal enzymes and acids that digest the protein and mineral components of the underlying extracellular matrix of the bone. This is termed resorption.
Compact Bone Tissue
the type of bone tissue observed at the surfact of a bone, but it also can extend deeper into the bone tissue and makes up the bulk of the diaphysis of long bones. The surface layers of the compact bone form as thing concentric layers of bone called circumferential lamellae. in the deeper compact bone, the osteon, or haversian system is the basic structural unit. Resembling the growth rings of a tree, the osteon is a series of concentric lamellae.
Central Canal
a hollow where a network of blood vessels, lymphatics and nerves are located
spaces between the concentric lamellae which contain osteocytes
tiny channels filled with extracellular matrix
Spongy Bone Tissue
This tissue does not contain osteons. It is always located in the interior of a bone, protected by a covering of compact bone. It consists of lamellae that are arranged in an irregular lattice of thin columns of bone called trabeculae. Microscopic spaces between the trabeculae are filled with red bone marrow in some bones which produce blood cells and yellow bone marrow (adipose tissue) in other bones.
Bone Formation
Occurs in four principal situations (1) the initial formation of bones in an embryo and fetus (2) the growth of bones during infancy, childhood, and adolescence until their adult sizes are reached (3) the remodeling of bone (replacement of old bone by new bone tissue throughout life) and (4) the repair of fractures (breaks in bones) throughout life.
Two Methods of Bone Formation
Intramembranous Ossification
Endochondrial Osssification
Intramembranous Ossification
1. Development of the ossification center
2. Calcification
3. Formation of Trabeculae
4. Development of the Periosteum
Endochondrial Ossification
1. Development of the Cartilage Model
2. Growth of the Cartilage Model
3. Development of the primary ossification center
4. Development of the medullary cavity
5. Development of the secondary ossification centers
6. Formation of articular cartilage and epiphyseal plate
Bone Growth in Thickness
As new bone tissue is deposited on the outer surface of bone by osteoblasts, the bone tissue lining the medullary cavity is destroyed by osteoclasts in the endosteum.
Bone Growth in Thickness #1
Ridges in periosteum create groove for periosteal blood vessel
Bone Growth in Thickness #2
Periosteal ridges fuse forming and endosteum-lined tunnel
Bone Growth in Thickness #3
Osteoblasts in endosteum build new concentric lamellae inward toward center of tunnel, forming a new osteon.
Bone Growth in Thickness #4
Bone grows outward as osteoblasts in periosteum build new circumferential lamellae. Osteon formation repeats as new periosteal ridges fold over blood vessels.
Remodeling of Bone
the ongoing replacement of old bone tissue by new bone tissue. It involves bone resorption, the removal of minerals and collagen fibers from bone by osteoclasts, and bone deposition, the addition of minerals and collagen fibers to bone by osteoblasts.
literally a condition of porous bones; in large part due to depletion of calcium from the body - more calcium is lost in urine, feces, and sweat than is absorbed from teh diet.
Types of Bone Fractures
Open Fracture
Comminuted Fracture
Greenstick Fracture
Impacted Fracture
Pott's Fracture
Colles' Fracture
Steps Involved in Repair of Bone Fracture
1. Formation of Fracture Hematoma
2. Fibrocartilaginous Callus Formation
3. Bony Callus Formation
4. Bone Remodeling
Factors Affecting Bone Growth
1. Minerals
2. Vitamins
3. Hormones
Exercise and Bone Tissue
unstressed bones diminishes because of the loss of bone minerals and decreased numbers of collagen fibers. Weight bearing activities such as walking or moderate weight lifting, help build and retain bone mass.