A&P EXAM 2

Caniliculi

(canal) are tiny interconnecting channels within the bon connective tissue that extend from each lacuna, travel through the lamellae, and connect to other lacunae and the central canal. Houses the osteocyte cytoplasmic projections that permit intercellular contact and communication. Nutrients, minerals, gases, and waste are transported through the cytoplasmic extensions within these passageways, allowing their exchange between the blood vessels of the central canal and the osteocytes.

Central canal

(haversian) a cylindrical channel that lies in the center of the osteon and runs parallel to it, extending through the central canal are the blood vessels and the nerves that supply the bone,

1. Briefly describe the process of endochondral ossification and explain the importance of chondrocytes to this process.

(within cartilage) It begins with a hyaline cartilage model and produces most bones of the skeleton like those of the upper and lower limbs, the pelvis, the vertebrae, and the ends of the clavicle. Long bone development is an example of this process. -1. The fetal hyaline cartilage model develops. (8-12 weeks pregnant) -2. Cartilage calcifies and a periosteal bone collar form. (fetal period) -3. The primary ossification center forms in the diaphysis. (fetal period) -4. Secondary ossification centers form in the epiphyses. (newborn-child) -5. Bone replaces almost all cartilage, except the articular cartilage and epiphyseal cartilage. (child) -6. Lengthwise growth continues until the epiphyseal plates ossify and form epiphyseal lines. (late teens to adult)

1. List the general steps of bone repair.

-1. A fracture hematoma forms - -2. A fibrocartilaginous (soft) callus forms - -3. A hard (bony) callus forms. -4. The bone is remodeled.

Longitudinal growth (interstitial) is an increase in the length that occurs withing the internal regions of the cartilage

-1. Chondrocytes housed within lacunae are stimulated to undergo mitotic cell division. -2. Following cell division, two cells occupy a single lacuna, now being called chondroblasts. -3. As chondroblasts begin to synthesize and secrete new cartilage matrix, they are pushed apart. Each cell now resides in its own lacuna and is call chondrocyte, -4. The cartilage continues to grow in the internal regions as chondrocytes continue to produce more matrix.

1. Describe the functions of the skeletal system. The skeletal system basic functions:

-provide structural support and serve as framework for the entire body (support and protect) -bones serve as attachment sites for skeletal muscles, other soft tissues, and organs (levers for movement) -process of blood cell production (hemopoiesis) -stores reserve of the mineral's calcium and phosphate, storage and release (storage of mineral and energy reserves)

1. Describe the functional classification of joints based on degree of movement allowed: synarthrosis, amphiarthrosis, and diarthrosis.

1. Synarthrosis: (joined together) these are immovable joints that include fibrous joints and one type of cartilaginous joint is synarthroses. 2. Amphiarthrosis: These are slightly movable joints. One type of fibrous joint and one type of cartilaginous joint are amphiarthrosis. 3. Diarthrosis: These are freely movable joints. It includes all synovial joints are diarthroses.

General characteristics of vertebrae

7 cervical 12 thoracic 5 lumbar 1 sacrum (5 fused vertebrae) 1 coccyx (3-5 fused vertebrae)

Appositional growth is an increase in width along the cartilages occurs outside edge, or periphery.

A bone increases in diameter as a new bone is added to the external surface. Continues throughout the person lifetime. -1. Undifferentiated stem cells at the internal edge of the perichondrium begin to divide. (note the perichondrium contains mesenchymal cells as well as these stem cells) -2. New undifferentiated stem cells and committed cells that differentiate into chondroblasts are formed, these chondroblast are located at the periphery of the old cartilage, where they begin to produce and secrete new cartilage matrix. -3. The chondroblasts as a result of matrix formation, push apart and become chondrocytes, with each occupying its own lacuna. The cartilage continues to grow at the periphery as chondrocytes continue to produce more matrix.

Which general bone marking classifications function as a passageway for nerves and blood vessels, as a site for articulation between bones, or as a point for attachment of tendons and ligaments?

A.) Depressions which is hosts the grooves and opening and spaces

1. Compare and contrast the axial and appendicular divisions of the skeleton.

A.) The axial skeleton consists of the 80 bones of the skull, vertebrae, sternum, and breastbone. B.) The appendicular skeleton is composed of the remaining 126 bones of the upper and lower limbs, shoulders, and hips.

Explain the functional advantages the female skeleton provides for childbirth.

A.) The female pelvic is structured for pregnancy and childbirth, and as a result, is generally wider and shallower than the male pelvis. B.) Female pelvis is generally lighter and less robust than its male equivalent due to greater muscle mass and body weight found in average male.

Openings and spaces

Canal- passageway through a bone Fissure- narrow, slit-like opening through a bone Foramen (pl., foramina)- rounded passageway through the bone Meatus- passageway through the bone Sinus- cavity or hollow space in a bone

Articulating surfaces

Condyle- large, smooth, rounded, oval structures Facet- small, flat, shallow surfaces Head- prominent, rounded epiphysis Trochlea- smooth, grooved, pulleylike process

1. Compare longitudinal and appositional bone growth. Where does each type of growth occur within the bone?

During early embryonic development both longitudinal (interstitial) and appositional growth occur simultaneously. Longitudinal declines rapidly as the cartilage matures because the cartilage becomes semirigid and is no longer able to expand. Further growth can only occur at the periphery of the tissue, so later growth is primarily appositional. Once the cartilage is fully mature, new cartilage growth typically stops. Only occurs after an injury, yet it is still limited due to lack of blood vessels in the tissue.

1. Briefly describe the process of intramembranous ossification. (Bone growth within the membrane)

Intramembranous ossification is also called dermal ossification because the mesenchyme that is the source of these bones is in the area of the future dermis. This process produces the flat bones of the skull (frontal bone) some of the facial bones (zygomatic bone, maxilla), the mandible (lower jaw), and the central part of the clavicle (collarbone). -Begins when the mesenchyme becomes thickened and condensed with a dense supply of blood capillaries.... The following steps continue: -1. Ossification centers form within thickened regions of mesenchyme beginning at the eighth week of development. -2. Osteoid undergoes calcification -3. Woven bone and its surrounding periosteum form -4. Lamellar bone replaces woven bone, as compact bone and spongy bone form.

Ligaments

Ligaments are specific fibrous connective tissue which generally functions as making attachment between the bones at any joint. In synovial joint like knee joint it associated with articular capsule and connects the femur to the tibia bone (shin bone) and provides stability.

1. Explain the differences between red and yellow bone marrow.

Red bone marrow - myeloid tissue, is hemopoietic (blood cell-forming), contains reticular connective tissue, developing blood cells, and adipocytes. Children's red marrow is located inside the spongy bone of most of the body as well as medullary cavity in long bones. Changes as children mature. Adults have red bone marrow in selected portions of the axial skeleton (flat bones of the skull, vertebrae, the ribs, the sternum, and the ossa coxae/hip bones, also in the proximal epiphyses of each humerus and femur. Yellow bone marrow - fatty appearing substance, within the medullary cavity of long bones and inner core of most epiphyses is the progressive decrease in developing blood cells and an increase in adipocytes.

Bursae

Synovial Bursae are small fluid filled pouches present around the tendon, ligaments and muscles of synovial joints to provide protection from injuries.

Tendons

Tendon connects the muscle to bone, in knee joint (synovial joint) quadriceps tendon attaches the femur with patella and tibia bone of the lower leg.

Where is the compact bone located? Where is the spongy bone located

The external surface of the bone. Parallel to the spongy bone. The interior surface of the bone. Parallel to the compact bone.

1. Explain the importance of an osteon to the function of compact bone and why compact bone is found in the diaphysis of a long bone.

The osteon (the microscopic structural unit of compact bone) is important to the function of the compact bone due to it being the basic functional and structural unit of the mature compact bone. Osteons are oriented parallel to the diaphysis of the long bone. The compact bone (dense and hard) is found in the diaphysis of a long bone to provide support and protection

Second-class levers

The resistance in the second-class lever is between the fulcrum and the applied effort. A common example of this type of level is lifting the handles of a wheelbarrow, allowing it to pivot on its wheel at the opposite end and lift a load in the middle. The load weight is the resistance, and the upward lift on the handle is the effort. A small force can balance a larger weight in this type of lever, because the effort is always farther from the fulcrum than the resistance. Second-class levers are rare in the body, body one example occurs when the foot is depressed (plantar flexed) so that a person can stand on tiptoe. The contraction of the calf muscle causes a pull superiorly by the calcaneal tendon attached to the heel (calcaneus).

Articular cartilage

a. All articulating bone surfaces in a synovial joint are covered by a thin layer of hyaline cartilage called articular cartilage. This cartilage has numerous functions: It reduces friction in the joint during movement, acts as a spongy cushion to absorb compression placed on the joint, and prevents damage to the articulating ends of the bones.

1. Identify the different structural classifications of synovial joints and describe the movements that can occur at each. Identify specific joints within each category.

a. Plane - joints between the intercarpal and intertarsal bones. b. Hinge - elbow joint, knee joint. c. Pivot - atlantoaxial joint. d. Condylar - knuckles e. Saddle - between the trapezium of the carpal bone and the first metacarpal, allow to grasp. f. Ball and Socket - shoulder joint, hip joint

Endosteum

a. an incomplete layer of cells that covers the internal surfaces of the bone within the medullary cavity (marrow cavity). Contains osteoprogenitor cells, osteoblasts, and osteoclasts.

Lacunae

a. are the small spaces that each house an osteocyte.

Synovial fluid-

a. is a viscous, oily substance located within a synovial joint. It has three functions: 1. Synovial fluid lubricates the articular cartilage on the surface of articulating bones. 2. Synovial fluid nourishes the articular cartilage's chondrocyles. The relatively small volume of synovial fluid must be circulated continually to provide nutrients to and remove waste from these cells. 3. Synovial fluid acts as a shock absorber, distributing stresses and force evenly across the articular surfaces when the pressure in the joint suddenly increases.

Osteocytes

are mature bone cells found in small spaces between adjacent concentric lamellae, these cells maintain the bone matrix.

multiaxial (triaxial)

bone moves in multiple planes or axes. a. Ball-and-socket joint - round head of one bone rests within cup-shaped depression in another bone. (glenohumeral {shoulder} joints, hip joint)

Epiphyses

expanded, knobby region that is at each end of a long bone. Is composed of an outer layer of compact bone and the inner has extensive region of spongy bone (resist stress that is applied from many directions). Proximal - end of the bone closest to the body trunk. Distal - the farthest from the trunk. Covering the joint surface is a thin layer of hyaline cartilage called articular cartilage, reduces friction and absorbs shock in movable joints.

-Long bones

greater in length than width. Upper limbs (arm, forearm, palm, fingers) lower limbs (thigh, leg, sole of the foot, toes) femur

Epiphyseal plates/lines

growth plate, in the growing bone, a thin layer of hyaline cartilage that provides for continued lengthwise growth of the bone. In adults a thing, defined area of compact bone is called the epiphyseal lines.

a. Lamellae - (plate or leaf)

i. Concentric - rings of the bone connective tissue that surround the central canal and form the bulk of the osteon. The numbers vary among each osteon. Each contains collagen fibers oriented at an angle in one direction, adjacent lamellae contain fibers oriented at 90-degree angles different from both the previous and next lamellae, this alternating pattern of collagen fiber direction gives bone part of its strength and resilience. ii. Interstitial - are either the components of compact bone that are between osteons or the leftover parts of osteons that have been partially resorbed (look like a bite has been taken out of them). Are incomplete and typically have no central canal. iii. Circumferential - are rings of bone immediately internal to the periosteum of the bone (external circumferential lamellae) or

a. Fibrous - primary function is to hold two bones together. They are immobile or slightly mobile. Dense regular connective tissue holds together the ends of the bones and bone parts. No joint cavity.

i. Sutures ii. Gomphoses iii. Syndesmoses

a. Cartilaginous - their primary function is to resist compression and tension stress and act as resilient shock absorbers. They are immobile or slightly mobile. Pad of cartilage is wedged between the ends of bones, no joint cavity.

i. Synchondroses ii. Symphyses

uniaxial

if the bone moves in just one plane or axis. a. plane joint - flattened or slightly curved faces slide across one another. (intercarpal joints, intertarsal joints) b. hinge joint - convex feature of bone fits into concave depression of another bone. (elbow joint, knee joint, IP {interphalangeal} joints) c. pivot joint - bone with a rounded surface fits into a ring formed by a ligament and another bone. (Atlantoaxial joint)

biaxial

if the bone moves in two planes. a. condylar joint - oval articular surface on one bone closely interfaces with a depressed oval surface on another bone. (MP {metacarpophalangeal or metatarsophalangeal} joints) b. saddle joint - saddle-shaped articular surface on one bone closely interfaces with a saddle-shaped surface on another bone. (articulation between a carpal bone {the trapezium} and the first metacarpal.

Parathyroid hormone (PTH)

increases blood calcium levels by encouraging bone resorption by osteoclasts. It is secreted and released by the parathyroid glands in response to reduced blood calcium levels. Is the final enzymatic step converting calcidiol to calcitriol (stimulates absorption of calcium ions from the small intestine into the blood) in the kidney occurring more readily with the presence of PTH. The removal of calcium from bone, the decrease in loss of calcium in the kidney and the increase in in calcium absorption from the gastrointestinal tract result in elevating blood calcium and returning it to normal ranges. -stimulus - low blood calcium levels, - receptor - parathyroid glands detect low blood calcium levels. - control center - parathyroid glands release parathyroid hormone. - effectors - Bone - PTH and calcitriol act to increase activity of osteoclast. Kidney - PTH and calcitriol act to decrease calcium excreted in urine. Small intestines - calcitriol increases absorption of calcium from small intestines. - Homeostasis restored - blood calcium levels rise and return to a normal homeostatic range.

Organic

is made of osteoid, which is produced by osteoblasts. An osteoid is composed of both collagen and a semisolid ground substance of proteoglycans (including chondroitin sulfate) and glycoproteins that suspends and supports the collagen fibers. The give bones tensile strength by resisting stretching and twisting and contribute to its overall flexibility.

Third-class levers

is noted when the effort is applied between the resistance and the fulcrum, as when picking up a small object with a pair of forceps. Third-class levers are the most common lever in the body. A third-class lever is found at the elbow where the fulcrum is the joint between the humerus and ulna, the effort is applied by the biceps brachii muscle, and the resistance is provided by any weight in the hand or by the weight of the forearm itself. The mandible acts as a third-class lever when you bite with your incisors on a piece of food. The temporomandibular joint is the fulcrum, and the temporalis muscle exerts the effort, whereas the resistance is the item of food being bitten.

Marrow cavity

medullary cavity, hollow cylindrical space within the diaphysis. In children this contains the red bone marrow that is later replaced by yellow bone marrow in adults.

· Knee joint

o patellar ligament o quadriceps tendon o fibular collateral ligament o tibial collateral ligament o lateral meniscus o medial meniscus o posterior cruciate ligament o anterior cruciate ligament

· Hip joint

o pubofemoral ligament o iliofemoral ligament o ischiofemoral ligament

· Shoulder joint - glenohumeral joint

o rotator cuff muscles o coracoclavicular ligament o acromioclavicular ligament o coracoacromial ligament

· Elbow joint - humeroulnar/humeroradial joint

o ulnar collateral ligament o anular ligament o radial collateral ligament

Calcitonin

promotes calcium deposition in bone and inhibits osteoclast activity. Is another hormone that aids in regulating blood calcium levels; however, it has a less significant role than either PTH or calcitriol. It is released from the thyroid gland (the parafollicular cells) in response to high blood calcium levels, it is also secreted in response to stress from exercise. Calcitonin inhibits osteoclast activity, it stimulates the kidneys to increase the loss of calcium in the urine, with the result of reduction in blood calcium levels. -When blood calcium levels are low parathyroid hormone and calcitriol stimulate bone to release calcium in the blood. -When blood calcium levels are high the thyroid gland secretes calcitonin to stimulate bone deposition and increase calcium excretion from the kidneys.

nonaxial

slipping movement only, no axis around which movement can occur (gliding joints, between the ulna and radius).

Osteon

small, cylindrical structures (harversian systems). Basic functional and structural unit of the mature compact bone. Are oriented parallel to the diaphysis od the long bone. When viewed it has the appearance of a bulls-eye target. Components of the osteon: the central canal, concentric lamellae, osteocytes, lacunae, canaliculi.

Articular capsule

surrounds the joint and promotes an extensive range of motion. It contains an articular disc, which is a thick pad of fibrocartilage separating the articulating bones and extending horizontally to divide the synovial cavity into two separate chambers. As. A result, the TMJ is really two synovial joints-one between the temporal bone and the articular disc, and the second between the articular disc and the mandible.

Diaphysis

the shaft of the long bone. It is elongated and cylindrical and provides leverage and major weight support.

Synovial

their primary function is movement; all are freely moveable. Ends of bons covered with articular cartilage, joint cavity separates the articulating bones, joint enclosed by articular capsule, lined with synovial membrane, contains synovial fluid.

1. Describe the effects growth hormone, testosterone, and estrogen have on bone growth and explain why older women are at a higher risk for osteoporosis than older men.

-Growth Hormone - stimulates the liver to produce the hormone IGF, which causes cartilage proliferation at epiphyseal plate and resulting bone elongation. - Testosterone/Estrogen - stimulate osteoblasts, promotes epiphyseal plate growth and closure. -Older women are at greater risk for osteoporosis because women have less bone mass than men, women being losing bone mass earlier and faster in life(ages 35 and up), postmenopausal women no longer produce significant amounts of estrogen, which appears to protect against osteoporosis by stimulating bone growth.

1. Explain why as a joint becomes more stable, it becomes less mobile, and vice versa.

A.) The more fiber/cartilage= more support/stability and more resistance to movement. Joints can be mobile or stable, but not both simultaneously. The most mobile joints are the most easily injured. B.) Articulating bones in fibrous joints are connected by dense regular connective tissue, fibrous joints have no joint cavity. C.) Articulating bones in cartilaginous joints also lack joint cavity but are usually connected by either hyaline cartilage or fibrocartilage D.) Articulating bones in synovial joints contain joint cavities with synovial fluid allowing free movement. -When the mobility of a joint increases, the stability decreases. If the joint mobility of a joint decreases, then the stability increases. The structure of the joint determines its mobility.

1. Describe the structural features of the paranasal sinuses

A.) The paranasal sinuses are air-filled chambers within the frontal, ethmoid, and sphenoid bones and the maxillae.

1. Define and differentiate between true, false, and floating ribs.

A.) The ribs are elongated, curved, flattened bones that originate on or between the thoracic vertebrae and end in the anterior wall of the thorax. Both males and females have 12 pairs of ribs. Ribs 1-7 are called true ribs. True ribs articulate directly and individually to the sternum by separate cartilaginous extensions called costal cartilages. The smallest true rib is the first. B.) Ribs 8-12 are called false ribs because their costal cartilages do not articulate directly to the sternum. The costal cartilages of ribs 8-10 fuse to the costal cartilage of rib 7 and thus indirectly articulate with the sternum. The last two pairs of false ribs (ribs 11 and 12) are called the floating ribs because they have no articulation with the sternum.

1. Compare and contrast the skull of a fetus or infant with that of an adult and explain the functional importance of fontanels.

A.) The shape and structure of cranial elements differ between infants and adults, causing variations in their proportions and size. The most significant growth in the skull occurs before age 5, when the brain is still growing and exerting pressure against the developing skull bones' internal surface. Brain growth is 90-95% complete by age 5, at which time cranial bone growth is close to completion, and the cranial sutures are almost fully developed. Note: that early in life the skull grows at a much faster rate than does the rest of the body. Thus, a young child's cranium is relatively larger compared to the rest of the body than that of an adult. B.) Fetus (anterior fontanel for birth) C.) Adult (hyaline cartilage becomes compact and spongy bone

Describe the curvatures of the vertebral column. Differentiate between primary and secondary curves

A.) There are 4 spinal curvatures: Cervical, thoracic, lumbar, and sacral curvatures. B.)The primary curves are the thoracic and sacral curvatures, and they are present at birth. These curvatures arch posteriorly and result in the vertebral column being C-shaped. C.)The secondary curves are cervical and lumbar curvatures, and they appear after birth. These curvatures arch anteriorly and are also known a compensation curves because they help shift the trunk weight over the legs. The cervical curvature appears when the child is first able to hold up its head without support (usually around 3-4 months of age). The lumbar curvature appears when the child is learning to stand and walk (typically by the first year of life). These curvatures become accentuated as the child becomes more adept at walking. The sacral curvature is less pronounced in females than in males, allows for a greater pelvic outlet to accommodate the passage of an infant through the birth canal.

Identify the regional and functional differences between the cervical, thoracic, & lumbar vertebrae

A.) Vertebrae at birth but fuse during childhood and adolescence to form the sacrum and the coccyx. The 24 non-fused vertebrae are grouped into three regions - cervical (neck), thoracic (middle back) and lumbar (lower back). There are seven cervical vertebrae, 12 thoracic vertebrae and five lumbar vertebrae, all of which possess unique characteristics that differentiate them from the other regions.Common Characteristicsbefore exploring the differences among the vertebral regions, it's important to understand that from the top of the spine to the bottom, vertebrae do, in fact, share some consistent characteristics. The most obvious is the fact that all are composed of bone. Another common characteristic is general function - the vertebrae are there, primarily, to support the body and protect the spinal cord. In addition, the vertebrae are separated by cartilaginous cushions called intervertebral discs. The one exception is at the very top of the spine, where the first cervical vertebra (the atlas) pivots on a flange that sticks up from the second cervical vertebra (the axis).Differences among Vertical RegionsThe major differences among the three spinal regions lies in shape and secondary function. Here is a brief description of the characteristics unique to each region:Cervical - smaller bones support the weight of the head and are flexible to allow a wide range of head movement; also, the axis is the only vertebra with no vertebral bodyThoracic - larger bones than in the cervical region; more rigid to provide a framework for the ribcage and the torso in order to protect the inner organs Lumbar - largest bones in the spine; support most of the weight of the upper body and allow for bending, twisting and hip flexion

First class levers

A.) has a fulcrum in the middle, between the effort (force) and the resistance. An example a first-class level is a pair of scissors. The effort is applied to the handle of the scissors while the resistance is at the cutting end of the scissors. The fulcrum (pivot for movement) is along the middle of the scissors, between the handle and the cutting ends. In the body, and example of first-class lever is the atlanto-occipital joint of the neck, where the muscles on the posterior side of the neck (effort) pull inferiorly on the nuchal lines of the skull and oppose the tendency of the head (resistance) to tip anteriorly.

Depressions

Alveolus (pl., alveoli)- deep pit or socket in the maxillae or mandible Fossa (pl., fossae)- flatten or shallow depression Sulcus- narrow grove

Tendon sheaths

An elongated bursa called a tendon sheath wraps around a tendon where there may be excessive friction. Tendons sheaths are especially common in the confined spaces of the wrist and ankle.

BONE FORMATION

Bone formation - begins with osteoblasts secrete osteoid. Calcification (mineralization) occurs when the hydroxyapatite crystals deposit in the bone matrix, initiated when the concentration of calcium ions and phosphate ions reach critical levels and precipitate out of solution forming hydroxyapatite crystals to deposit in and around collagen fibers.

BONE RESORPTION

Bone resorption - process when bone matrix is destroyed by substances released from osteoclasts into the extracellular space adjacent to the bone. Proteolytic enzymes released lysosomes within the osteoclasts chemically digest the organic components (collagen fibers and proteoglycans) of the matrix. While hydrochloric ac ids (HCl) dissolves the mineral parts (calcium and phosphate). The liberated calcium and phosphate ions enter the blood. Occurs when blood calcium levels are low.

1. Describe the function of vitamin D and explain the connection between the integumentary system and the skeletal system.

Calcitriol is and active form of vitamin D. -1. The precursor molecule is converted to vitamin D3 (cholecalciferol) either from ultraviolent light or dietary supplement which is released in the blood. -2. Vitamin D3 is converted to calcidiol in the liver (when an -OH group is added) as it passes through the blood vessels of the liver. -3. Calcidiol is converted to calcitriol in the kidney (when another -OH group is added) and is the active form of vitamin D3, the presence of parathyroid hormone increases the rate of this final enzymatic step in the kidney. Thus, the greater amounts of calcitriol are formed when parathyroid hormone is present.

Differentiate between the structure and function of compact bone and spongy bone.

Compact bones - also called dense or cortical bone, relatively rigid connective bone tissue that appears white, smooth, and solid. 80% of total bone bass Spongy bones - also called cancellous or trabecular bone, is located internally inside compact bone, appears porous. Makes up 20% of total bone mass.

1. Explain what happens to bone when the composition of either the organic or inorganic matrix changes.

Correct proportions of organic and inorganic substances of the bone matrix allow it to function properly. A loss of organic compounds (loss of protein or abnormal protein) results in brittle bones. Account for bones tensile strength by resisting stretching and twisting and contribute to its overall flexibility A loss of inorganic compounds (insufficient calcium) results in soft bones. Account for the bone's rigidity or relative flexibility of bone that provides compressional strength

Projections for tendon and ligament attachment

Crest- narrow, prominent, ridge-like projection Epicondyle- projection adjacent to a condyle Line- low ridge Process- and marked bony prominence Ramus (pl., rami)- angular extension of a bone relative to the rest of the structure Spine- pointed, slender process Trochanter- massive, rough projection found only on the femur Tubercle- small, round projection Tuberosity- large, rough projection

Tarsals

It is the ankle bone and is formed of typically seven bones. Tarsal bones are arranged in three rowsProximal or rural row: Tibia tarsal(medial) and fibular tarsal(lateral)Inter- tarsal or middle row: Central tarsalDistal or meta- tarsal row-First tarsal (medial), second tarsal, third tarsal and fourth the bones of proximal row joins with the distal extremities of the tibia and fibular bones of the leg.- ankle joint Proximal joint is formed by the proximal row bones - tibia and fibular tarsal and the fibula and tibia bones. Thus they together forms the ankle joint. It is formed by the distal row bones and the metatarsals. - taros metatarsal joint 5 metatarsals and 1st, 2nd, 3rd and 4th tarsal bones. Tarsal tunnel is a fibro-osseous found from medial malleolus to medial calcaneus.

Carpals

It is the wrist bone and is formed of typically eight bones and is arranged in two transverse joints. 1. They are arranged in two transverse rows - proximal and distal rows. 2. proximal row - radial, intermediate, ulnar, accessory 3. distal row - first, second, third, fourth The bones are almost convexo-concave in the proximal face and they joins with the distal extremities of the forearm bones. - radiocarpal joint Proximal joint is formed by the proximal row bones - radial, intermediate, ulnar and accessory carpal bones and the forearm bones - radius and ulna. And the joint that exists between them are the radiocarpal synovial joint. It is formed with the metacarpals by the distal row. - carpometacarpal joint 5 metacarpals and trapezium, trapezoid, magnum and uniform bones. Flexor retinaculum covers the palmar sided groove and thus forms the carpal tunnel.

1. Identify and define the following components of spongy bone

Spongy bones contain no osteons. a. Trabeculae -open lattice of narrow rods and plates of bone, bone marrow (when present) and blood vessels, these blood vessels are connected to blood vessels found in the Volkman's (perforating canals) and haversian canal (central canal). b. Canaliculi - tiny interconnecting channels that connect to the adjacent cavities to receive their blood supply, (unlike in the compact bone that connect to the central canal (haversian canal). c. Lacunae - small spaces that each house an osteocyte. d. Osteocytes - mature bone calls found in small spaces between adjacent concentric lamellae. Maintaining the bone matrix. e. Concentric lamellae - rings of the bone, concentric layers of bone matrix, are like tubes of different sizes fitting inside each other, usually surrounding the central canal in the osteon but spongy bones do not contain osteons.

1. Explain the importance of trabeculae to the function of spongy bone and why spongy bone is found in the epiphyses of long bone.

The trabeculae often form meshwork of crisscrossing bars and plates of small bone pieces. This structure provides great resistance to stresses applied in many directions by distributing the stress throughout the entire framework

Osteoblast (germ)

are formed from osteoprogenitor stem cells. Are positioned side by side on both surfaces, active osteoblasts exhibit a somewhat cuboidal shape and have abundant rough endoplasmic reticulum and Golgi apparatus. Perform the important function of synthesizing and secreting the initial semisolid organic form of bone matrix (osteoid). Osteoid later calcifies as a result of salt crystal deposition (hydroxyapatite), due to this mineral deposition on osteoid, osteoblasts become entrapped inside the they produce and secrete and thereafter differentiate into osteocytes.

Osteoclasts (broken)

are large, multi-nuclear, phagocytic cells. Derived from fused bone marrow cells similar to those that are produce monocytes. They exhibit a ruffled border, where they contact the bone, increasing their surface area to the bone. An osteoclast is often located within or adjacent to a depression or pit on the bone surface called resorption lacuna. Are involved in a process called bone resorption.

Osteocytes (hollow)

are mature bone cells derived from osteoblasts that have lost their bone forming ability when enveloped by calcified osteoid. They maintain the bone matrix and detect mechanical stress on a bone, if stress is detected osteoblast are signaled and it may result in the deposition of new bone matrix at the surface.

Osteoprogenitor

are stem cells derived from mesenchyme. They divide through process of cellular division; another stem cell is produced along with a 'committed cell' that matures to become an osteoblast. Located within both the periosteum and the endosteum.

-short bones

have a length nearly equal to their width. (carpal/wrist bones, tarsals/bones in the foot), Sesamoid bones (patella/kneecap)

-irregular bones

have elaborate, complex shapes. the vertebrae, the ossa coxae (hip bones), several bones inside the skull (the ethmoid, sphenoid, and sutural bones)

-flat bones

have flat thin surfaces and may be slightly curved. Provides extensive surface for muscle attachments. Flat bones form the roof of the skull, the scapulae (shoulder blades), the sternum (breastbone), and the ribs.

Inorganic

made up of salt crystals that are primarily calcium phosphate. Calcium phosphate and calcium hydroxide interact to form crystals of hydroxyapatite. Also incorporate other salts (calcium carbonate) and ions (sodium, magnesium, sulfate, and fluoride) during the process of calcification. They deposit around the long axis of collagen fibers in the extracellular matrix, they harden the matrix and account for the rigidity or relative flexibility of bone that provides compressional strength.

Joint cavity/synovial cavity

only synovial joints house joint cavity (or articular cavity), is a space that permits separation of the articulating bones. The articular cartilage and synovial fluid within the joint cavity together reduce friction as bones move at a synovial joint.

Adipose tissue

or fat, is an anatomical term for loose connective tissue composed of adipocytes. Main function is to store energy in the form of fat, although it also cushions and insulates the body.

Periosteum

tough sheath, covers the outer surface of the bone except for the areas covered buy articular cartilage. Is anchored by numerous collagen fibers called perforating fibers. Consist of two layers: The outer layer is dense irregular connective tissue it protects the bone from surrounding structures, anchors blood vessels, and nerves to the surface of the bones, and serves as an attachment site for ligaments and tendons. The inner layer is cellular layer including osteoprogenitor cells, osteoblasts, and osteoclasts.