LESSON 2: The Skeletal System

Femur

or thighbone, is the longest and strongest bone of the human skeleton

Stapes

in the middle ear, is the smallest and lightest bone of the human skeleton

Skeleton

supports the body, protects internal organs, provides for movement, stores mineral reserves, and provides site for blood cell formation

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___ bones in the adult human skeleton

Axial Skeleton

supports the central axis of the body. Consists of the skull, the vertebral column, sternum, and the rib cage

Spinal Column

protects the spinal cord

Intervertebral Disk

serve as shock absorbers between each vertebrae

Ribs

composed of 24 bones ; 7 pairs of true and 5 pairs of false ribs (2 of which are floating ribs) ; responsible for Hematopoiesis or the production of blood

Blood Platelets

also known as thrombocytes ; it’s functions for blood clotting process ; essential for preventing bleeding and for repairing damaged blood vessels

Appendicular Skeleton

consists of the extremities of the body e.g. shoulder girdle, arm bones, pelvic girdle, and leg bones

Shoulder Girdle

comprised of 4 bones ; 2 clavicles (collar bones) ; 2 scapulas (shoulder bones)

Arm

comprised of 3 bones ; Humerus (upper arm) ; Radius & Ulna (lower arm bones)

Wrist Bones

comprised of 8 carpals

Hand Bones

comprised of 5 metacarpals (palm bones)

Finger Bones

comprised of 14 phalanges (fingers and thumbs)

Pelvic Girdle

structure to which the leg bones are attached

Femur

thigh bone ; upper leg bones

Patella (knee cap), Tibia (shin bone), and Fibula

lower leg bones

Bones

solid network of living cells and protein fibers that are surrounded by deposits of calcium salts ; a living tissue composed mainly of mineral salts - calcium and phosphorus

Periosteum

tough layer of connective tissue surrounding the bone

Compact Bone

(also known as cortical bone) forms the hard, dense outer layer of bones which functions to primarily to provide strength and protection to bones

Spongy Bone

houses the bone marrow, allow for RBCs formation or erythropoiesis, and allow bones to be less dense and more light ; it also allows flexibility

Haversian System

a network of tubes that contain blood vessels and nerves

Bone Marrow

a soft tissue within bone cavities

Yellow Marrow

made up primarily of fat cells usually found in round bones

Red Marrow

produces red blood cells, some kinds of white blood cells, and cell fragments called platelets

Cartilage

a type of connective tissue scattered in a network of protein fibers - tough collagen and flexible elastin

Ossification

the process of bone formation where cartilage is replaced by bone

Osteoblasts

creates bone

Osteocytes

maintain the cellular activities of bone

Osteoclasts

break down bone

Joint

a place where one bone attaches to another bone ; permit bones to move without damaging each other

Immovable Joints Synarthrosis

allow no movement ; the bones are interlocked and held together by connective tissue, or they are fused ; the places where the bones in the skull meet are examples of immovable joints

Slightly Movable Joints

permit a small amount of restricted movement ; the bones are separated from each other ; the joints between the two bones of the lower leg and the joints between adjacent vertebrae are examples of this

Freely Movable Joints

permit movement in one or more directions ; grouped according to the shapes of the surfaces of the adjacent bones

Ball-and-socket joints

permit circular movement

Hinge joints

permit back and forth motion

Pivot joints

allow one bone to rotate around another

Saddle joints

permit one bone to slide in two directions

Ligaments

attached to membranes that surround bones and hold the bones together

Synovial Fluid

produced by the cells in the other layer of the joint capsule ; forms the thin film within the bone surfaces of a joint ; this lubricating film enables the ends of the bones to slip past each other smoothly

Inflammation

the body’s response when a tissue is damaged

Kyphosis

abnormal rounding of the spine that occurs in the upper and middle part of the back

Rickets

bone softening disease that causes severe bowing of the legs, poor growth and sometimes causes muscle pain and weakness

Arthritis

inflammation, swelling, redness of a joint

Osteoporosis

bone tissue becomes brittle, thin, and spongy

Bone Tumor

abnormal growth of cells within the bone that may be non cancerous or cancerous

Scoliosis

causes the spine to curve to the left or right side

Sprains

an injury that happens when the ligaments get overstretched or torn

Fractures

commonly occur when a person has fallen, an object has been dropped on them, or the bone has been twisted

Greenstick Fracture

an incomplete, bending break in a bone, where the bone cracks but does not break completely into separate pieces

Transverse Fracture

a type of bone break where the fracture line runs straight across the bone shaft, perpendicular (at a 90-degree angle) to the bone's longitudinal axis

Comminuted Fracture

a severe type of broken bone where the bone is shattered, splintered, or broken into more than two pieces

Spiral Fracture

a type of complete bone break that occurs when a long bone (such as the tibia, femur, or humerus) is twisted forcefully, causing a fracture line that wraps around the bone, resembling a corkscrew or spiral staircase.

Compound Fracture

a severe bone break where the fractured bone pierces through the skin or an accompanying wound exposes the bone to the outside environment