30 terms

Anatomy & Physiology Bones and Bone Markings

Name the major regions of the skeleton and describe their relative functions. (Ch. 6 Obj. 1)
*Axial Skeleton: forms long axis of body and includes bones of skull, vertebral column, and rib cage.
*Appendicular skeleton: consists of the bones of the upper and lower limbs and the girdles (shoulder bones and hip bones) that attach the limbs to the axial skeleton.
List and describe 5 major functions of bones. (Ch. 6 Obj. 2)
SUPPORT: supports body and cradles soft organs, PROTECTION: e.g. skull protects the brain, MOVEMENT: skeletal muscles attached to bones by tendons, use bones as levers
MINERAL & GROWTH FACTOR STORAGE: e.g. minerals like calcium and phosphate, and insulin-like growth factors, BLOOD CELL FORMATION: hematopoiesis (blood cell formation) in marrow cavities of certain bones.
Indicate the functional importance of bone markings. (Ch. 6 Obj. 3)
Projections, depressions, and openings serve as sites of muscle, ligament, and tendon attachment, joint surfaces, or conduits for blood vessels and nerves.
(Depressions and openings allowing blood vessels and nerves to pass)
MEATUS: canal-like passageway, SINUS: cavity within a bone, filled w/ air and lined w/ mucous membrane, FOSSA: shallow, basin-like depression in a bone, often serving as an articular surface, GROOVE: furrow, FISSURE: narrow, slit-like opening, FORAMEN: round or oval opening through a bone.
large rounded projection, may be roughened
(Projections that are sites of muscle and ligament attachment)
narrow ridge of bone, usually prominent
(Projections that are sites of muscle and ligament attachment)
very large, blunt, irregularly shaped process
(Projections that are sites of muscle and ligament attachment)
small rounded projection of process
(Projections that are sites of muscle and ligament attachment)
raised area on or above condyle
(Projections that are sites of muscle and ligament attachment)
sharp, slender, often pointed projection
(Projections that are sites of muscle and ligament attachment)
any bony prominence
(Projections that are sites of muscle and ligament attachment)
bony expansion carried on a narrow neck
(Projections that help to form joints)
smooth, nearly flat articular surface
(Projections that help to form joints)
rounded articular projection
(Projections that help to form joints)
armlike bar of bone
(Projections that help to form joints)
canal-like passageway
(Depressions and openings allowing blood vessels and nerves to pass)
cavity within a bone, filled w/ air and lined w/ mucous membrane
(Depressions and openings allowing blood vessels and nerves to pass)
shallow, basin-like depression in a bone, often serving as an articular surface
(Depressions and openings allowing blood vessels and nerves to pass)
(Depressions and openings allowing blood vessels and nerves to pass)
narrow, slit-like opening
(Depressions and openings allowing blood vessels and nerves to pass)
round or oval opening through a bone
(Depressions and openings allowing blood vessels and nerves to pass)
Describe the gross anatomy of a typical long bone and flat bone. Indicate the locations of red and yellow marrow, articualr cartilage, periosteum, and endosteum. (Ch. 6 Obj. 4)
Diaphysis contains medullary cavity (marrow). In adults medullary cavity contains fat and is called yellow bone marrow cavity (yellow marrow). Epiphyses outer is compact bone, inner is spongy bone. Epiphyseal line in adult ephiphyseal plate in children. Epiphyseal plate disc of hyaline cartilage that grows to lengthen bone. Membranes: external surface covered by periosteum is double membrane (glistening white), internal surfaces covered by endosteum containing osteogenic cells which differentiate into osteoblasts (bone-forming) or osteoclasts (bone-braking-down). Osteocytes are mature osteoblasts that don't secrete matrix.
Describe the histology of compact and spongy bone.
(Ch. 6 Obj. 5)
Compact bone is outer layer. Structural unit is osteon (Haversian system). Lamella is a matrix tube that fill spaces between osteons. Central/Haversian canal contain blood vessels and nerves that serve oseon's cells. Perforating/Volkmann's canals connect blood and nerve supply from periosteum to the central canal and medullary cavity. Osteocytes (mature osteoblasts) occupy lacunae at junctions of lamellae. Canaliculi are hairlike canals that connect lacunae are tiny canals that connect osteocytes in the lacuna. Spongy bone is made of trabeculae. Trabeculae are struts and plates (no osteons) of bone. Trabeculae house red marrow (hemopoietic tissue)in epiphyses of long bones, sternum, and ilium. Spongy bone contains yellow bone marrow (adipose)
Discuss the chemical composition of bone and the advantages conferred by the organic and inorganic components.
(Ch. 6 Obj. 6)
Osteocytes: mature osteoblasts that no longer secrete matrix but maintain metabolism. Osteoblasts secrete osteoid. Osteoclasts break down bone matrix. Osteoprogenitor differentiate into osteoblasts. Osteoid (1/3 of matrix) is ground substance and collagen fibers. Inorganic matter (2/3 of matrix) is made of hydroxypatites/mineral salts, which are mostly calcium phosphates in the form of tiny packed crystals.
Compare and contrast intramembranous ossification (dermal ossification) and endochondral ossification.
(Ch. 6 Obj. 7)
INTRAMEMBRANOUS OSSIFICATION: Osteoblasts differentiate w/in mesenchymal in dermis. Dermal bone examples: flat bones of skull, mandible, clavicle. Mesenchymal cells secrete osteoid, osteoid becomes calcified forming ossification center, mesenchymal cells differentiate into osteoblasts, osteoblasts differentiate into osteocytes. ENDOCHONDRAL OSSIFICATION: Most originates in hyaline cartilage. Begins at primary ossification center. Secondary ossification centers form in epiphyses. Articular cartilage: Thin layer original cartilage model forms at the joint that prevents bone to bone contact. Epiphyseal plate and line are the only other place that hyaline cartilage remains after secondary ossification is complete.
Describe the role of 5 hormones and 5 nutrients in the regulation of bone growth and maintenance.
(Ch. 6 Obj. 8)
GH is most important factor: protein and cell growth throughout the body. THYROXINE: thyroid hormone that affects cell metabolism and increases osteoblast activity. SEX HORMONES AT PUBERTY: increase rate of bone formation. CALCITONIN AND PARATHYROID HORMONE (Ca++ & PTH) PTH increases calcium concentration in blood & Calcitonin decreases concentration (homeostasis, negative feedback mechanism). Cortisol (stress homone from adrenal gland) anti-growth (decreases bone formation) and catabolic. ---- Calcium and phosphorus: form hydroxyapatite of matrix. Vitamin C affects collagen synthesis and and differentiation of osteoblasts, not enough and get scurvy. Vitamin A stimulates osteoblast activity. Vitamin D: form of vitamin D is calcitrol that acts to increase bone resorption and calcium by kidneys. Vitamin K and B12 help w/ synthesis of proteins in bone.
Compare the locations and remodeling functions of the osteoblasts, osteocytes, and osteoclasts. (Ch. 6 Obj. 9)
Bone remodeling (bone deposit and resorption) occur at the surface of the periosteum and endosteum packets of osteoblasts and osteocytes called remodeling units. Osteocytes and osteoblasts secrete matrix. Osteoclasts degrade bone matrix and release Ca++ into the blood.
Explain how hormones and physical stress regulate bone remodeling.
(Ch. 6 Obj. 10)
Falling Ca++ levels cause thryoid gland to release PTH, PTH causes osteoclasts to degrade matrix which releases Ca++ into blood. If too much Ca++, calcitonin secreted and stimulates calcium salt deposit into bone. Wolff's law says that a bone grows or remodels in response to the demands placed on it. If loading on a particular bone increases, the bone will remodel itself over time to become stronger to resist that sort of loading.
Contrast the disorders of bone remodeling seen in osteoporosis, osteomalacia, and Paget's disease.
(Ch. 6 Obj. 11)
OSTEOPOROSIS: bone resorption exceeds bone deposition. PAGET'S DISEASE: increase in number of osteoclasts and resorption of bone and the deposition of new bone by osteoblasts resulting in disorderly bone remodeling. OSTEOMALACIA: softening of bone due to decrease in mineral content (Rickets is childhood osteomalacia).
Describe the different types of fractures.
(Ch. 6 Obj. 12)
Comminuted: bone fragments in three or more pieces. Compression: bone is crushed. Spiral: ragged break occurs when excessive twisting forces are applied to bone. Epiphyseal: epiphysis seperates from the diaphysis along the epiphyseal plate. Depressed: broken bone portion is pressed inward. Greenstick: bone breaks incompletely. One side of the shaft brakes, the other side only bends.