66 terms

Skeletal System Part 1

the study of the form and structure of an animal body and its parts
the study of the functions of the animal body and its parts
The animal's left
The animal's right
toward the head
toward the tail
toward the tip of the nose. Used to describe positions and directions only on the head
toward the top when an animal is standing on all four legs; toward the backbone
toward the bottom surface of an animal when it is standing on all fo legs; toward the belly
toward the median plane (center line) of the body
away from the median plane of the body
toward the center of the body or a body part
toward the surface of a body or a body part
used only for extremities; a position or direction toward the body proper (trunk)
used only for extremities; a position or direction away from the body proper
the caudal surface of the forelimb distal to the carpus
the caudal surface of the forelimb distal to the tarsus
the maintenance of equilibrium or balance in the body
The tendency for molecules to move from an area of higher concentration to an area of lower concentration
Facilitated Diffusion
the diffusion of molecules across the cell membrane with the aid of carrier proteins. No energy or ATP is required.
the passive movement of water through a semipermeable membrane from a dilute solution to a more concentrated one
Active Transport
the active movement of molecules by specific carrier proteins; molecules may move against a concentration gradient; energy required in the form of ATP
is a high energy molecule produced in the mitochondria of cells
the study of bone
- is the second hardest natural substance in the body - the hardest substance is tooth enamel
- A vital living tissue with the ability to heal itself
- Composed of cells embedded in a hard matrix. Soft material becomes hard bone as calcium and phosphate are added
Osteoblasts - Bone Cels
build bone. Osteoblasts secrete the matrix and supply the calcium and phosphate to harden the bone
Ossification - Bone Cells
the formation and hardening of bone
mature bone cells trapped in the hard matrix. an osteocyte can revert back into an osteoblast
Osteocytes are former osteoblasts that exist in spaces in the ossified matrix called
receive their blood supply and communicate through little channels called
responsible for eating excess bone away. Necessary for remodeling of bone. Also allow the body to withdraw calcium from bone to raise calcium levels in the blood
Bone Formation
two mechanisms: endochondral ossification and intramembranous ossification
Endochondral Ossification
Most common. Cartilage in the fetus replaced by bone
Intramebranous Ossification
Occurs only in the bones that form parts of the skull. Bone forms from fibrous membranes that cover the brain in the developing fetus
shaft of a long bone. In the developing fetus when cartilage is being replaced by bone, the diaphsis is the primary growth center
the ends of a long bone. In the fetus - secondary growth centers
Epipyseal or growth plates (physis)
areas between the diaphysis and the epiphysis where new bone is formed. Cartilage plates in very young animals that allow the bones to lengthen as the animal grows. When the plates ossify, the bone stops growing in length.
Volkman's Canals
tiny blood vessels from the periosteum pass through the bone at right angles in passageways through the bone called Volkmann's canals. Source for most of the blood supply to the bone cells. Blood vessels in Volkmann's canals join with blood vessels in Haversian canals
Haversian Canals
run lengthwise in the bone; contain blood vessels, lymph vessels and nerves that supply the osteocytes in the Haversian systems
Nutrient Foramina
Large channels in some larger bones, esp. long bones, that provide passageway for large blood vessels. These larger vessels primarily carry blood into and out of bone marrow. On a radiograph a nutrient foramina can look like a crack in the bone cortex
Two Main Types Of Bone
cancellous bone and compact bone
Cancellous Bone
spongy bone; tiny spicules of bone with marrow in between. Helps make the bone lighter but still strong.
Compact Bone
heavy, dense, and strong. In the diaphyses of long bones and forms the outside layer of all bones. Compact bone is composed of tiny, tightly compacted cylinders of bone called haversian systems
Haversian Systems
concentric layers of dense bone arranged around a central canal; run lengthwise in the shafts of long bones
the fibrous membrane that covers the outside of bone EXCEPT for their articular ( joint ) surfaces. (The inner surface of the periosteum contains osteoblasts that allow bone to increase in diameter and are involved in the healing of bone fractures.)
just like the periosteum but lines the hollow interior of bones
Long Bones
femur, humerus, tibia, radius, ulna
Short Bones
carpal and tarsal bones
Flat Bones
scapula, pelvis, some skull bones
Irregular Bones
vertebrae, some skull bones, sesamoid bones. Sesamoid bones are found in some tendons
Red Bone Marrow
Ø Hematopoietic tissue ( produces blood cells )
Ø Major marrow in young animals
Ø Only a small percentage of the marrow in adult animals
Ø In the adult, red bone marrow is in the ends of some long bones and in bones of the pelvis and sternum ( cancellous bone
Yellow Bone Marrow
Ø Adipose tissue ( fat )
Ø Most common type of bone marrow in adults
Ø Not very hematopoietic
Ø Found in the shafts of long bones
Ø Can revert to red bone marrow if body needs to produce more blood cells
Articular Surfaces
- joint surfaces
- a smooth area of compact bone where bones come into contact with one another to form joints. Each articular surface is covered by a thin layer of hyaline cartilage. There is no periosteum covering articular cartilage
a large round, cylindrical articular surface. The major condyles are located on the distal end of the femur and the humerus and on the occipital bone of the skull
a spherical articular surface on the proximal end of the femur, the humerus, and ribs. The head of the humerus and femur form the ball portion of the shoulder and hip ball-and-socket joints
a flat articular surface where joint movement would be a rocking motion. Examples include carpal and tarsal bones; vertebrae; and some long bones such as radius and ulna
Lumps and bumps on bones. Examples of processes include articular surfaces such as condyles and heads; and sites for muscle attachments such as vertebral spinous processes, the spine of the scapula, the greater trochanter of the femur, the tubercle of the humerus, etc
a hole in bone. Examples include nutrient foramina and the two large obturator foramina of the pelvis
a depressed or sunken area on the surface of a bone. Usually occupied by muscles or tendons
Support - Functions of Bone
provides attachment sites for muscles; support for the soft tissues of the body
surrounds many delicate organs and tissues. Example - the bones of the skull protect the brain
attachment of muscles to bone via tendons allows the muscles to move the joints
stores most of our calcium and other minerals
a hormone from the thyroid gland that helps to prevent hypercalcemia by depositing excess calcium from the blood into bone
hormone from the parathyroid gland prevents hypocalcemia by withdrawing calcium from bone
Blood cell formation - hematopoiesis
occurs in bone marrow