CHP 6 BONE TISSUE AND SKELETAL SYSTEM

SUTURAL BONES

Small, irregular bones Found between the flat bones of the skull

OSTEOCYTE

mature bone cell

EPIPHYSIS

wider section at each end of the bone

STAGES IN FRACTURE REPAIR

1. hematoma forms 2. fibro-cartilaginious callus forms, new blood vessels 3. bony callus forms 4. bone remodeling

FUNCTIONS OF THE SKELTAL SYSTEM

1.Support 2.Storage of minerals (calcium) & lipids (in the yellow marrow) 3.Blood cell production (in the red marrow) 4. Protection 5.Movement

BONE MARKINGS

BONE LANDMARKS Display projections, depressions, and openings that serve as sites of muscle, ligament, and tendon attachment, as joint surfaces, or as conduits for blood vessels •Tuberosity—rounded projection •Crest—narrow, prominent ridge •Trochanter—large, blunt, irregular surface •Line—narrow ridge of bone •Tubercle—small rounded projection •Epicondyle—raised area above a condyle •Spine—sharp, slender projection •Process—any bony prominence •Condyle—rounded articular projection •Ramus—armlike bar

OSTEOCLAST

Bone-destroying cells

YELLOW BONE MARROW

Contains adipose tissue; Triglycerides stored in the adipocytes of the tissue can serve as a source of energy

LONG BONES

Cylindrical in shape, being longer than it is wide. Arms (humerus, ulna, radius) Legs (femur, tibia, fibula) Fingers (metacarpals, phalanges) Toes (metatarsals, phalanges).

Main function of the skeletal and bones systems

Enable body movement

ANATOMY OF A LONG BONE

Diaphysis, epiphysis, epiphyseal plates, epiphyseal line

OSSEOUS TISSUE (BONE)

Hard, dense connective tissue Forms most of the adult skeleton Support structure of the body

MEDULLARY CAVITY

Hollow region in the diaphysis, filled with yellow marrow

CALCITONIN

Inhibits osteoclast activity and stimulates calcium uptake by bones

BONE DEPRESSIONS AND MARKINGS

Meatus •Canal-like passageway Sinus •Cavity within a bone Fossa •Shallow, basin-like depression Groove •Furrow Fissure •Narrow, slit-like opening Foramen •Round or oval opening through a bone

ENDOSTEUM

Membraneous cavity where bone growth, repair, and remodeling occur. •Incomplete cell layer •Lines the medullary cavity •Covers trabeculae of spongy bone

The body deposits calcium in the bones when blood levels get too high, and it releases calcium when blood levels drop too low (is this positive or negative feedback?!?).

NEGATIVE FEEDBACK LOOP Regulated with PTH, Vitamin D and Calcitonin

CALCIUM

Needed to make calcium phosphate and calcium carbonate, which forms hydroxyapatite crystals that give bone its hardness

IRREGULAR BONES

Odd shaped bone thats not easily classified Found in vertebrae, pelvic, and facial bones

CARTILAGE

Semi-rigid form of connective tissue, Provides flexibility and smooth surfaces for movement.

SESAMOID BONES

Small, round bones found near joints Shaped like a sesame seed Feet, hands, patella

SYNTHESIS OF VITAMIN D

Sunlight activates a precursor to vitamin D Enzymes in the liver and kidneys transform that molecule into calcitriol (most active form of vitamin D) Necessary vitamin for absorption of calcium from food in the gastrointestinal tract

PATHWAYS IN CALCIUM HOMEOSTASIS

The body regulates calcium homeostasis with two pathways; 1. Signaled to turn on when blood calcium levels drop below normal 2. Signaled to turn on when blood calcium levels are elevated.

Examples of how bones SUPPORT the body?

The cranium protects the brain. The vertebrae protects the spinal cord. the rib cage/sternum protects the heart/lungs.

CALCIFICATION

The deposition of calcium salts within a tissue

Bones support Movement which means?

They act as "Levers"

FLAT BONES

Thin, flat, slightly curved Sternum, scapulae, ribs, most skull bones Serve as points of attachment for muscles and protect internal organs.

TYPES OF FRACTURES

Transverse-Occurs straight across the long axis of the bone Oblique- Occurs at an angle that is not 90 degrees Spiral- Bone segments are pulled apart as a result of a twisting motion Comminuted- Several breaks result in many small pieces between two large segments Impacted- One fragment is driven into the other, usually as a result of compression Greenstick- A partial fracture in which only one side of the bone is broken Open (or compound)- A fracture in which at least one end of the broken bone tears through the skin; carries a high risk of infection Closed (or simple)- A fracture in which the skin remains intact

ARTICULAR CARTILAGE

a thin layer of cartilage that reduces friction and acts as a shock absorber.

PROJECTION

an area of a bone that projects above the surface of the bone

HOLE

an opening or groove in the bone that allows blood vessels and nerves to enter the bone.

OSTEOBLAST

build bone cells

COMPACT BONE

dense, hard layers of bone tissue that lie underneath the periosteum

HEMATOPOIESIS

formation of blood cells

OSSIFICATION

formation of bone

OSTEOGENESIS

formation of bone

OSTEOGENIC CELLS

give rise to osteoblasts which give rise to osteocytes

EPIPHYSEAL PLATE

growth plate

VITAMIN D

needed for calcium absorption

CANALICULI

pathways for nutrient & waste exchange

Red Bone Marrow

produces red and white blood cells and platelets

EPIPHYSEAL LINE

remnant of the epiphyseal plate, seen in adult bones

PTH

stimulates osteoclastic activity

VITAMIN K

supports bone mineralization and may have a synergistic role with vitamin D

CALCITRIOL

the active form of vitamin D (secreted by the kidneys) that promotes absorption of calcium from foods in the GI tract into the blood, helping to further increase blood calcium level

DIAPHYSIS

the tubular shaft that runs between the proximal and distal ends of the bone.

PAGETS DIESEASE

viral infection of bone that deforms (porous and curved) the skeleton due to the acceleration of bone loss

ARTICULATION

where two bones come together

SHORT BONES

wrist and ankle

PERIOSTEUM

•Isolates bone •Provides a route for circulatory & nervous supply •Participates in bone growth & repair