The Skeletal System Flashcards
Osteon
Functional unit of COMPACT bone
Osteocyte
Help regulate the balance of new bone formation and old bone degeneration, regulates calcium balance
Osteoblast
Build new bone, form new bones and add growth to existing bone tissue
Osteoclast
Collapse bone, dissolve old and damaged bone tissue so it can be replaced by new healthier cells created by osteoblasts
Lamellae
The ECM (extracellular matrix) around bone cells that gives compact bone its hardness and rigidity
Lacunae
Gaps or open spaces that house bone cells
5 Categories of Bone
Long
Short
Flat
Irregular
Sesamoid (round)
Long Bone
Cylindrical shape, longer than it is wide, found in arms, legs, fingers and toes, function as levers and move when muscles contract
Short Bone
cube-like shape, found in carpals (wrist) and tarsals (ankle), provide stability, support and limited motion
Flat Bone
Thin, could be curved, serve as points of attachment for muscles and protect internal organs, Examples: skull, ribs, sternum (chest bone) and scapulae (shoulder blade)
Irregular Bone
Not easily characterized by shape, does not fit into other categories, Examples: vertebrae and facial bones
Sesamoid (round) Bone
a small round bone (shaped like a sesame seed) form in tendons and protect them from compressive forces, vary in number and placement from person to person, found in tendons associated with feet, hands, and knees
Spongy Bone
Porous bone, found in the end of long bones, honeycomb shape
Trabeculae
Small, needle like projections of bone that comprise spongy bone
Compact Bone
The dense, hard outer layer of bone, provides strength and protection
Periosteum
Outermost layer of bone, contains nerves and blood vessels, provides oxygenated blood to bone and allows for feeling within the bone
Yellow Bone Marrow
Stores fat and stem cells that preserve fat for energy production, develop bone, cartilage, muscles and fat cells, located within bone
Red Bond Marrow
Generates red blood cells, white blood cells, and platelets, located within bone
Bone Marrow
Soft fatty tissue inside bone cavities, forms platelets, red and white blood cells, in the center of most bones and in the ends of spongy bones
Axial Skeleton
Bones that form the body’s central axis, examples: head, neck, chest, back
Appendicular Skeleton
Bones that attach (append) to your axial skeleton, examples: pelvis and limbs (arms, hands, feet, legs)
Facial bones
Underlie the facial structure, form nasal cavity and enclose the eyeballs, support teeth of upper and lower jaw
Brain case
The part of the skull that surrounds and protects the brain and houses ear structures
Cranium (skull)
Composed of 22 bones including facial bones and brain case, supports the face and protects the brain
Articulation
A joint, any place where adjacent bones or a bone and cartilage come together to form a connection
Synarthrosis
immobile or nearly immobile joint, strong union between bones, provide protection for internal organs
syn= with/together arthourn= to fasted by a joint
Diarthrosis
A freely movable joint, most body movements, mostly found in appendicular skeleton
di= 2 arthroun= to fasten by a joint
Amphiarthrosis
A joint that has limited mobility
Amphi= both arthroun= to fasten by a joint
Uniaxial
Movement in one anatomical plane
Example: elbow, knee
Biaxial
Movement in two anatomical planes
Example: metacarpophalangeal joint (knuckle) of the hand
Convex
Surface that is rounded or curved outward
Concave
Surface that curves inward
Antagonistic Muscle Pairs
Muscle pairs that contract and relax opposite one another, enables smooth and controlled movement
Example: bicep and tricep, hamstring and quadriceps
Fibrous Joint
Bones are connected by fibrous connective tissue, synarthrosis
Cartilaginous Joint
Bones are joined by hyaline cartilage or fibrocartilage, amphiarthrosis
Synovial Joint
The articulating surfaces of the bones are not fully connected, but rather come into contact with each other within a joint cavity filled with lubricating fluid, diarthrosis
Most common joint in the body
Multiaxial
Movement in all three anatomical planes
Example: shoulder and hip
Pivot Joint
Rounded portion of bone is enclosed within a ring formed partially by bone and partially by ligament, bone rotates within this ring, uniaxial diarthrosis joint
Hinge Joint
The round (convex) end of a bone fits into the end of a curved (concave) bone, uniaxial joint
Example: elbow, ankle, knee
Condyloid Joint
A shallow groove at the end of one bone fits into a rounded part of an adjacent bone, biaxial joint
Example: bending and spreading of the fingers
Saddle Joint
Both of the articulating surfaces for the bones have a saddle shape, fit together like a rider on a saddle, biaxial joint
Example: carpal and metacarpal at the base of the thumb
Plane Joint
AKA gliding joint, the articulating surfaces are flat(ish) and slide against each other, multiaxial joint
Example: carpals and tarsals, clavicle and scapula
Ball and Socket Joint
Rounded head of one bone fits into the concave articulation of another bone
multiaxial joint with the greatest range of motion
