Skeletal System Teas Prep

long bones

bones that are longer than they are wide; function primarily in movement and supporting the body weight; rod shaped; extremities (epiphyses) are covered in articular cartilage and are wider than the shaft (diaphysis); most of bones of upper and lower limbs are this as well as collar bones

short bones

roundish or cube-shaped bones; have little to no role in movement; function in support and stability; ex: carpals, tarsals of wrist and ankle

flat bones

bones that are flattened, thin and usually curved; broad shape for protection and muscle attachment; ex: scapulae, sternum, ribs, ilia of pelvic girdle, and certain cranial bones

irregular bones

bones that have complex shapes with short, flat, notched or ridged surfaces; examples are vertebrae that form the spinal column and several bones in the skull; their form is suited for their specific function

sesamoid bones

bones that are found embedded in tendons where there is a considerable amount of mechanical stress; ex: kneecap

compact (cortical) bone

hard, dense bone tissue, usually found around the outer portion of bones as well as the shafts of long bones; consists of cylindrical structures of osteons (Haversian systems)

Osteon (Haversian system)

structural unit of compact bone; each consists of haversian canal that contains nerve fibers and blood vessels

Haversian canal

one of a network of tubes running through compact bone that contains blood vessels and nerves; connect though perforating canals (Volkmann's canals); surrounded by concentric layers of calcified lamellae with small spaces of lucanae

perforating canals (Volkmann's canals)

Connect the haversian canals with each other and the periosteum.

Small channels in bone that transmit blood vessels from the periosteum into the bone and that communicate with the Haversian canals; provide energy and nourishing elements for osteons.

lamellae

calcified concentric rings made up of groups of hollow tubes of bone matrix; surround haversian canals

lacunae

small cavities in bone that contain osteocytes; connected to others by canaliculi to allow oxygen and nutrients to reach the osteocytes and for wastes to be removed

trabeculae

supporting bundles of bony fibers in cancellous (spongy) bone; flattened interconnected plates of spongy bone

spongy (cancellous) bone

Bone tissue that consists of an irregular latticework of thin plates of bone called trabeculae; porous tissue; found inside short, flat, and irregular bones and in the epiphyses of long bone; not as strong or abundant as compact bone and does not contain osteons; no central canals but osteocytes reside in lacunae that are connected by canaliculi

red bone marrow

located within the spongy bone, is hemopoietic tissue that manufactures red blood cells, hemoglobin, white blood cells, and thrombocytes

osteoblasts

bone forming cells derived from osteoprogenitor cells; take calcium from blood and produce the matrix (including collagen fibers) that form bone; differentiate into mature bone cell when it is completely encased in matrix

osteocyte

mature bone cell formed from differentiation of osteoblasts; most abundant bone cells; maintain matrix by recycling calcium slats

osteoclasts

large multinucleate cells that are formed by fusion of monocytes (large WBC); reside on bone surfaces and secrete acid and digestive enzymes that break down and return calcium to blood

joint

A place in the body where two bones come together/connect; classified by material holding it together (structure) and range of motion (function)

fibrous joint

immoveable and held together by ligaments (fibrous connective tissue) only
types: suture, gomphosis, syndesmosis

cartilaginous joint

held together by cartilage
types: synchondrosis, symphysis

Synovial joint

most common type of joint; characterized by joint cavity filled with synovial fluid
types: pivot, hinge, saddle, gliding, condyloid, ball and socket

suture joint (fibrous)

type of fibrous joint; immovable - ex: skull

Gomphosis joint (fibrous)

type of fibrous joint immovable - ex: teeth/mandible

Syndesmosis joint (fibrous)

type of fibrous joint - slightly moveable - ex: distal tibiofibular joint

synchondrosis joint (cartilaginous)

type of cartilaginous joint- hyaline cartilage, nearly immovable - ex: first rib/sternum

symphysis joint (cartilaginous)

type of cartilaginous joint - fibrocartilage, slightly moveable - ex: intervertebral discs, pubic symphysis

pivot joint (synovial)

type of synovial joint; allows for rotation - ex: atlantoaxial joint

hinge joint (synovial)

type of synovial joint; allows movement in one plane (ex: knee)

saddle joint (synovial)

type of synovial joint; type of joint found at the base of each thumb; allows grasping and rotation; allows pivoting in 2 planes and axial rotation: ex: 1st metacarpal/trapezium

gliding joint (synovial)

type of synovial joint that allows one bone to slide over another; found in wrist and ankles (carpals)

condyloid joint (synovial)

type of synovial joint that does everything except rotating; allows pivoting in 2 planes but no axial rotation; ex: radiocarpal joint

ball and socket joint (synovial)

type of synovial joint that has the highest range of motion; ex: hip

synarthrosis joint

immovable joint - either fibrous or cartilaginous: ex: skull sutures, teeth/mandible (type of joint by function)

amphiarthrosis joint

slight range of motion, either fibrous or cartilaginous; ex: intervertebral discs, distal tibiofibular joint (type of joint by function)

diarthrosis joint

freely movable joint - always synovial; ex: wrist, knee, shoulder (type of joint by function)

bones

provide a resting ground for muscles (attachment points for muscles) and protection of vital organs and body; reservoir for calcium

ligaments

Connect bone to bone and help stabilize joints; composed of dense regular connective tissue consisting of bundles of collagen fibers and elastic fibers; more elastic than tendon; yellow due to protein elastin

tendons

Connect muscle to bone; composed of dense regular connective tissue consisting fo bundles of collagen fibers and elastic fibers; tougher than ligament

cartilage

A connective tissue that is more flexible than bone and that protects the ends of bones and keeps them from rubbing together; flexible yet resistant to stretching; not innervated and has no blood supply except for perichondrium that forms surfaces of nearly all cartilage

bone matrix

hard acellular matrix produced by bone cells composed of 35% collagen and 65% inorganic material

hydroxyapatite

type of calcium phosphate that makes up most of the inorganic matter in bone

fracture

caused when a force against the bone that is greater than the bone can sustain, causing it to splinter, fracture, or break

closed fracture

when bone breaks but does not puncture through the skin ad protrude through to the outside

open fracture

when bone breaks and punctures skin protruding to outside of the body

comminuted fracture

when bone breaks in multiple areas - often seen in trauma

greenstick fracture

when part of bone bends and does not fully break - often occurs in young children because their bones are more flexible, soft, and still developing

spiral fracture

when bone is twisted or rotated like a corkscrew

avulsion fracture

when a tendon or ligament is taxed and pulled to hard causing it to pull away and break the bone

oblique fracture

break of a bone at an angle cause by outside force coming at a right angle to the bone

transverse fracture

when the fracture is perpendicular to the shaft of the bone

pathological fracture

caused by disease making the bone so weak that it may break without warning simply by putting minimal pressure on it

perichondrium

Dense irregular connective tissue membrane covering cartilage

chondroblast

immature cartilage cell (responsible for matrix production)

Chondrocytes

mature cartilage cells that reside in lacunae

hyaline cartilage

Most common type of cartilage; consists of evenly distributed collagen fibers that explain its glassy appearance; it is found on the ends of long bones, ribs, and nose (found in locations that require strong support with some pliability)

fibrous cartilage

very tough form of cartilage found in the intervertebral disks of the spine and at the junctions where tendons attach to bone; has collagen arranged into thick fibers which allows it to withstand tension and compression; found in jaw, knee, and between vertebrae

elastic cartilage

cartilage with abundant elastic fibers; more flexible than hyaline cartilage due to presence of elastic fibers; found in epiglottis and external ear

calcitriol

A hormone produced from vitamin D that acts to increase absorption of calcium in intestine that will increase level of calcium in blood; stimulates osteoclasts to break down bone (moves calcium into blood)

calcitonin

peptide hormone secreted by parafollicular cells of thyroid gland when calcium is too high; inhibits activity of osteoclasts and stimulates activity of bone forming osteoblasts

parathyroid hormone (PTH)

peptide hormone produced and secreted by the parathyroid glands in response to low blood calcium levels; increases quantity and activity of osteoclasts