Bone Tissue

articulation

joint

Ligament

Connects bone to bone

Tendon

Connects muscle to bone

skeletal muscle tissue

Voluntary muscle pulls on bones and causes body movements.

costal cartilage

the cartilages that connect the sternum and the ends of the ribs

intervertebral discs

fibrocartilage pads that separate and cushion the vertebrae

negative feedback

A primary mechanism of homeostasis, whereby a change in a physiological variable that is being monitored triggers a response that counteracts the initial fluctuation.

Homeostasis

A tendency to maintain a balanced or constant internal state; the regulation of any aspect of body chemistry, such as blood glucose, around a particular level

Calcitonin

Secreted by thyroid glad to take calcium out of blood.; stimulates osteoblasts to store it in bone; lowers blood calcium levels

Osteoblasts

bone forming cells

osteoclast

Bone-destroying cells

deposition

the process in which material is laid down

Resorption

the process of removing or digesting old bone tissue

hematopoiesis

blood cell formation

long bone

longer than they are wide; femur

short bone

similar length and width; e.g. carpals and tarsals

irregular bones

oddly-shaped bones; e.g. bones of the vertebrae and face

sesamoid bones

round bones found near joints (e.g., the patella)

flat bones

These bones are thin, flat, and curved. They form the ribs, breastbone, and skull.

Functions of the skeletal system

support, protection, movement, storage, blood cell production

axial skeleton

Portion of the skeletal system that consists of the skull, rib cage, and vertebral column

appendicular skeleton

bones of limbs

calcium homeostasis feedback loop

Negative feedback loop;

too high: thyroid releases calcitonin-stimulates calcium salt deposits-calcium levels fall

too low: PTH released-osteoclasts degrade matrix and release-calcium levels rise

skeletal cartilage

avascular and not innervated

Bone strcuture

organs made of skeletal, nervous, and connective tissues

compact bone

Hard, dense bone tissue that is beneath the outer membrane of a bone

spongy bone

Layer of bone tissue having many small spaces and found just inside the layer of compact bone.

articular cartilage

covers the surfaces of bones where they come together to form joints

epiphysial line

remnant of growth plate

red bone marrow

found in spongy bone; site of hematopoiesis

Endosteum

membranous lining of the hollow cavity of the bone

proximal epiphysis

metaphysis

where diaphysis and epiphysis meet

diaphysis

shaft of a long bone

distal epiphysis

medullary cavity

cavity within the shaft of the long bones filled with bone marrow

yellow bone marrow

stores fat

nutrient artery

large artery that enters compact bone near the middle of the diaphysis

growth is regulated by

growth hormone, thyroid hormone, sex hormone

Periosteum

A dense fibrous membrane covering the surface of bones and serving as an attachment for tendons and muscles.

osteogenic stem cells

develop into osteoblast

Osteocytes

mature bone cells

osteon

structural unit of compact bone

central canal (haversian canal)

canal that houses blood vessels located at the center of the osteon

canailculi

microscopic channels in the bone that provides blood supply

lamellae

Concentric rings made up of groups of hollow tubes of bone matrix

circumferential lamellae

fill outer region of dense bone

perforating canals

Perpendicular to the central canal

Carry blood vessels into bone and marrow

lacunae

small cavities in bone that contain osteocytes

trabeculae

supporting bundles of bony fibers in cancellous (spongy) bone

osteoblast

bone-forming cell

bone remodeling

spongy bone replaced 3-4 years; compact replaced 10

organic components

bone cells and osteoid

inorganic compounds

do not contain carbon

fracture

any break in the calcified bone tissue

fracture repair

Step 1: Fracture hematoma forms

Step 2: Fibrocartilage (soft) callus forms

Step 3: Hard (bony) callus forms

Step 4: Bone remodeled

osteomalacia

softening of the bone

Osteoporosis

A condition in which the body's bones become weak and break easily.

Paget's disease

too much spongy bone; leads to deform