By: Julio, Rana, Anna Lee, Daisy, Haley, and Carlos

SKELETAL PHYSIOLOGY 101

THE 4 TYPES OF BONES…• Long bones- have extended longitudinal axes and expanded and

often uniquely shaped articular ends. Ex. The femur and the humerus

• Short bones- they are box shaped structures, they are about as broad as they are long. The tarsal and carpals are some examples of these types of bones.

• Flat bones- generally broad and thin with a flattened and or curved surface, certain bones like the shoulder blades, ribs and breastbones are some examples of these.

• Irregular bones- normally clustered in groups and come in various sizes and shapes, spinal and facial bones are examples of these bones, sesamoid bones are singly bones that are found close to the joints. (2)

6 MAJOR STRUCTURES OF A TYPICAL LONG BONE

• Diaphysis- it’s the main shaft like portion, it’s a hollow cylindrical shape and the thick compact bone that composes it, it provides strong support without cumbersome weight.

• Epiphyses- is the end of a long bone, provides generous space near joints for muscle attachments and also gives stability to joints.

• Articular cartilage- thin layer of hyaline cartilage that covers articular or joint surfaces of epiphyses

• Periosteum- it’s a dense white fibrous membrane that covers bone except at joint surfaces, most of this penetrate the underlying bone and this is important because it contains blood vessels that become incorporated into bones during their initial growth.

• Medullary- a tube like hollow space in the diaphysis of a ling bone, in adults it’s filled with connective tissue rich in fat called yellow marrow.

• Endosteum- a thin epithelial membrane that lines the medullary cavity of long bones (2)

THE MAJOR CONSTITUENTS OF BONE AS A TISSUE AND HOW STRUCTURAL ORGANIZATION

CONTRIBUTES TO FUNCTION

The major constituents of bone tissues are separated into different parts like the inorganic salts part of the bone matrix consist of hydroxyapatite (crystals of calcium and phosphate for bone hardness) and magnesium and sodium is also found in the bones, another part of the bone tissue is measuring the bone mineral density and the organic matrix which is composed of collagenous fibers and amorphous mixture of protein and polysaccharides called (ground substance). The structural organization adds overall strength and gives the bone a degree of resilience. (2)

DISCUSS EACH OF THE MAJOR COMPONENTS OF A HAVERSIAN SYSTEM

• Lamellae: cylinder shaped layers of calcified matrix

• Lacunae: small spaces containing tissue fluid in which bone cells lie stuck between the hard layers of the lamellae

• Canaliculi: Small canals radiating in all directions from the lacunae and connecting to each other and into larger canals

• Haversian canal: nutrients and oxygen move through canaliculi to the lacunae and their bone cells (2)

DESCRIBE THE FUNCTION OF THE THREE MAJOR TYPES OF CELLS FOUND IN BONES

• Osteoblasts: bone forming cells; small cells that secrete a specialized organic matrix called osteoid

• Osteoclasts: bone reabsorbing cells; multinucleate cells that are responsible for the active erosion of bone minerals

• Osteocytes: mature bone cells; nondividing osteoblasts that have become surrounded by matrix and now lie within the lacunae (2)

DISCUSS THE FIVE HOMEOSTATIC FUNCTIONS OF BONES

• SUPPORT: Bones are the supporting framework of the body

• Protection: the bony boxes or cages protect the delicate organs that lie within

• Movement: bones combines with their joints create levers

• Mineral storage: bones store the majority of calcium, phosphorus, and other minerals

• Hematopoiesis: also known as blood cell formation is a vital process that the red bone marrow carries out (2)

COMPARE AND CONTRAST THE DEVELOPMENT OF INTRAMEMBRANOUS AND ENDOCHONDRAL

BONE

• intramembranous bone- process by which most flat bones are formed within connective tissue membranes.

• endochondral bone- process by which bones are formed by replacement of cartilage models.

• They are similar because both of them are formations of things. (2)

DESCRIBE STEPS INVOLVED IN BONE FRACTURE REPAIR

• Fracture

• Formation of fracture hematoma

• Formation of internal and external callus

• Bone remodeling complete

• Vascular damage occurring immediately after a fracture results in a hemorrhage and the pooling of blood at the point of injury. The resulting blood clot is called a fracture hematoma. As the hematoma is resorbed, the formation of specialized callus tissue occurs. It serves to bind the broken ends of the fracture on both the outside surface and along the marrow cavity internally. The rapidly growing callus tissue effectively “collars” the broken ends and stabilizes the fracture so that the healing can proceed. If the fracture is properly aligned and immobilized and if complications do not develop, callus tissue will be actively “modeled” and eventually replaced with normal bone as the injury heals comepletely. (2)

COMPARE THE BASIC STRUCTURAL UNITS OF BONE AND CARTILAGE.

Bone Structure:

The ends of a long bone are called the epiphyses (singular, epiphysis), which are covered by a layer of hyaline cartilage called the articular cartilage and articulate with other bones. The internal area of the epiphyses contains red bone marrow where erythrocytes (red blood cells), leukocytes (white blood cells), and thrombocytes (platelets) are produced. The shaft of a bone is called the diaphysis. The diaphysis contains an internal medullary cavity that is lined by the endosteum and usually filled with yellow marrow, where fat is stored. Except for the articular cartilage, a bone is covered by a tough outer membrane called the periosteum., (2)

Cartilage Structure:

There are three major types of cartilage in the body: 1) hyaline cartilage, 2) fibrocartilage, and 3) elastic cartilage. Elastic cartilage exists in the epiglottis and the eustachian tube. Fibrocartilage, often exists temporarily at fracture sites. However, fibrocartilage is permanently present in three major locations in the body: 1) the intervertebral disks of the spine, 2) as a covering of the mandibular condyle in the temporomandibular joint, and 3) in the meniscus of the knee. The third type of cartilage, hyaline cartilage, is most prominently found in diarthroidal joints covering long bones. In addition, hyaline cartilage forms the growth plate by which long bones grow during childhood. The structure and mechanical behavior of hyaline cartilage in diathroidal joints, is typically called articular cartilage, and the meniscus of the knee. (2)

IDENTIFY THE THREE SPECIALIZED TYPES OF CARTILAGE

• Hyaline- most common type of cartilage, is a mixture of ground substance (rich in chondroitin sulfate and unique gel like polysaccharide) and collagenous fibers, it covers articular the surfaces of bones, forms costal cartilages, forms the cartilage rings in the trachea, bronchi, and the tip of the nose. (Ex: trachea)

• Elastic- external ear, epiglottis, Eustachian, and tubes that connect the middle ear and nasal cavity, large numbers of easily stained elastic fibers confer the elasticity and resiliency typical in this type of cartilage, elastic cartilage has a yellowish color and has a greater opacity than hyaline cartilage

• Fibrocartilage- sustains great weight when covering the articulating surfaces of bone or when serving as a shock absorbing pad between articulating bones in the spine (2)

COMPARE THE MECHANISM OF GROWTH IN BONE AND CARTILAGE

• Growth in bone- bones grow in diameter by the combined action of osteoblasts and osteoclasts

• Osteoclasts enlarge the diameter of the medullary cavity by eating away the bone of its walls

• Osteoblasts from the periosteum build new bone around the outside of the bone

• Growth of cartilage- occurs in 2 ways, interstitial and appositional

• Interstitial- cartilage cells within the substance of the tissue mass divide and begin to secrete additional matrix

• Appositional- occurs when the chondrocytes in the deep layer of the perichondrium begin to divide and secrete additional matrix, the new matrix is then deposited on the surface of the cartilage, causing it to increase in size. (2)

COMPARE THE CLASSIFICATION OF JOINTS ACCORDING TO BOTH STRUCTURE AND

FUNCTION• Joints are classified into 3 major categories by a structural or

functional scheme.

• Structural- named by the type of connective tissue that joins the bones together (fibrous or cartilaginous joints) or by the presences of a fluid-filled joint capsule (synovial joints)

• Functional- joints are divided into 3 classes by the degree of movement that they permit: synathroses (immovable), amphiarthroses (slightly moveable): diathroses (freely movement) (2)

IDENTIFY THE TYPES OF MOVEMENT AT SYNOVIAL JOINTS AND GIVE EXAMPLES OF

SPECIFIC JOINTS WHERE EACH OCCURS

• Ball-&-socket joint: This joint allows for freedom of rotation as well as back-and-forth movement in all planes. It allows for the most freedom in movement of any other joint. EX: shoulder and hip joint (2)

• Condyloid joint: They cannot rotate. A condyle is a curved process that fits into a fossa on another bone for its articulation. You also find this type of joint at the mandible-to-temporal bone joint. EX: joint between radius and carpal bones (2)

• Plane (or Gliding) joint: Although these joints appear to offer a lot of flexibility in movement direction, they do not offer a great distance in movement. But they can move in many directions and they can rotate. EX: between carpal and tarsal bones (2)

• Hinge joint: Hinge joints offer ease in movement, but only provide for movement in one plane (no twisting, no sliding side-to-side). Keep in mind that although a good example of a hinge joint is at your elbow, there are two bones in your forearm that interact at the elbow joint. Only one of them, the ulna, makes a hinge joint. When you are in the anatomical position and you bend your elbow as if bringing your palm to your shoulder, that is the movement of the hinge joint. EX: elbow joint (2)

• Pivot joint: This joint is one where one bone spins around on another bone. Although only one direction of spin has been diagrammed above, the spinning can occur in either direction. This type of joint is in our elbow (for the twisting motion) and is between our first two cervical vertebrae. EX: joint between first and second cervical vertebrae (2)

• Saddle joint: In the saddle joint, both of the bones that meet have odd shapes, but they are totally complementary to one another. So in the saddle joint, each bone has both concavities and convexities, but they fit nicely. EX: Thumb joint between first metacarpal and carpal bone (2)

CANCER TREATMENT MAY GENERATE A NEED FOR A BONE MARROW TRANSPLANT.

OSTEOPOROSIS IS A CONDITION CHARACTERIZED BY AN EXCESSIVE LOSS OF CALCIUM IN BONE. THESE 2 CONDITIONS ARE

DISRUPTIONS OR FAILURES OF 2 BONE FUNCTIONS. IDENTIFY THESE 2 FUNCTIONS AND

EXPLAIN WHAT THEIR NORMAL FUNCTION SHOULD BE.

• Hematopoiesis: This bone function is responsible for the formation of blood cells. This function is carried out by the myeloid tissue or bone marrow.

• Mineral Storage: Normally this bone function is responsible for maintaining the homeostatic level of blood calcium. If there is too much calcium in the blood, calcium is stored in the bones. If there is too little calcium in the blood calcium is removed from the blood. (4)

EXPLAIN WHY A BONE FRACTURE ALONG THE EPIPHYSEAL PLATE MAY HAVE SERIOUS

IMPLICATIONS AMONG CHILDREN AND YOUNG ADULTS.

• The epiphyseal plate plays a major role in the elongation of long bones in Infants and adolescents, in adults who have stopped growing the plate is replaced by an epiphyseal line. A fracture along the epiphyseal plate in a child or adolescent could result in impeded growth and growth defects. In later life arthritis would be apparent in the joint where the fracture happened. (1)

DURING THE AGING PROCESS, ADULTS FACE THE ISSUE OF A CHANGING SKELETAL FRAMEWORK. DESCRIBE THESE CHANGES AND EXPLAIN HOW THESE SKELETAL FRAMEWORK CHANGES AFFECT THE HEALTH OF OLDER ADULTS.

• the frame work changes because; the body cannot support no longer that much weight. It affects the body by there are no more cartilage in the joints and some people start having arthritis. (1)