The Skeletal System and Bone Physiology

Comprehensive vocabulary flashcards covering the skeletal system's functions, bone types, anatomy, histology, and physiology.

Bone

A connective tissue made of cells, gels, and fibers that accounts for approximately $18\%$ of total body weight.

Support

One of the main functions of the skeletal system where bones form a strong framework for the body and support soft parts like muscles and organs.

Hemopoiesis

The production of red blood cells, white blood cells, and platelets within the red bone marrow.

Triglyceride Storage

The storage of fat in yellow bone marrow, which the body can utilize for energy.

Neurocranium

Also known as the braincase; it is composed of cranial bones and functions to house and protect the brain.

Viscerocranium

The portion of the skull built by the facial bones that represents the skeleton of the face.

Sutures

Immovable fibrous joints that join the cranial bones together.

Temporal bone

A bone that forms portions of the sides and base of the skull, derived from the Latin 'os temporale' meaning the temple.

Parietal bone

A large, thin, four-sided cranial bone that makes up much of the top and sides of the skull; derived from 'paries' meaning wall.

Frontal bone

A cranial bone that surrounds and protects the anterior portion of the brain and comprises the forehead.

Occipital bone

A cranial bone that surrounds the back and base regions of the brain.

Ethmoid bone

A spongy, cuboid-shaped bone located at the top of the nasal cavity and between the two orbits.

Sphenoid bone

A butterfly-shaped cranial bone located in the middle of the skull between the frontal and temporal bones.

Mandible

The lower jawbone; it holds the lower teeth and is the only mobile bone in the human skull.

Vomer

A thin, flat bone that forms the inferior part of the bony nasal septum, dividing the nasal cavity into right and left halves.

Maxilla

The upper jawbone ($2$) which holds the upper teeth and forms the floor of the eye sockets and the majority of the hard palate.

Zygomatic Bones

Commonly known as the cheekbones ($2$); they form the prominences of the cheeks and the outer edges of the eye sockets.

Palatine Bones

L-shaped bones ($2$) located at the back of the nasal cavity that form the posterior one-third of the hard palate.

Hyoid bone

A small u-shaped bone located at the midline at the level of $C3$ that does not articulate with any other bone.

Vertebral Column

A series of vertebrae divided into $7$ Cervical, $12$ Thoracic, $5$ Lumbar, $5$ fused Sacrum, and $4$ fused coccyx.

True Ribs

The first seven pairs of ribs ($1-7$) that connect to the sternum.

False Ribs

Rib pairs $8-10$ within the rib cage.

Floating Ribs

The last two pairs of ribs ($11-12$) in the rib cage.

Sternum

Also called the breastbone; it is located at the midline anteriorly and articulates with the clavicles and costal cartilages.

Auditory Ossicles

Three tiny bones in the middle ear—the malleus (hammer), incus (anvil), and stapes (stirrup)—that transmit sound vibrations.

Clavicle

The collarbone; an S-shaped bone that connects the trunk with the appendicular skeleton of the upper limb.

Scapula

The shoulder blade; a flat, triangular upper limb bone that lies on the posterior surface of the thorax over ribs $2-7$.

Humerus

The arm bone; it is the only bone in the arm and the longest bone of the upper limb.

Carpal bones

Eight irregular bones that form the root of the hand, frequently termed the wrist.

Os coxa

The hip bone, made up of three bones that fuse during early adulthood: the ilium, ischium, and pubic bone.

Femur

The longest and strongest bone in the body, which extends from the hip to the knee.

Patella

Also known as the kneecap; it is the largest sesamoid bone in the human body and is invested within the patellar tendon.

Tibia

The shinbone; it is the larger bone of the leg, located medially to the fibula, and bears most of the body's weight.

Tarsal bones

A group of seven bones that form the ankle and instep.

Long Bones

Bones that are longer than wide with a cylindrical shape, featuring a diaphysis and two epiphyses.

Sesamoid Bones

Bones shaped like sesame seeds that develop embedded in tendons to reduce friction, such as at the ends of long bones.

Diaphysis

The shaft or long, central part of a bone, composed mainly of dense compact bone.

Epiphyses

The wider, rounded ends of a bone containing lightweight spongy bone.

Metaphysis

The 'bridge' area between the diaphysis and epiphysis containing the growth plate (Epiphyseal Plate) in growing individuals.

Periosteum

A protective membrane wrapping the outside of the bone (except joint areas) that contains cells for growth and healing.

Medullary Cavity

The inner hollow space inside the diaphysis that stores yellow bone marrow in adults.

Compact Bone

Also known as cortical or dense bone; it is strong, heavy, and made of structural units called osteons.

Spongy Bone

Also called cancellous or trabecular bone; it is light and porous, made of thin columns called trabeculae.

Osteons

The structural units of compact bone, also known as Haversian systems.

Osteoblasts

Bone-forming cells responsible for development, growth, maintenance, and repair.

Osteocytes

Mature bone cells that maintain daily cellular activities and the exchange of nutrients and waste.

Osteoclasts

Bone-destroying cells responsible for bone resorption during remodeling.

Hydroxyapatite

The predominant mineral salt of bone matrix that causes the bone to harden through calcification.

Intramembranous Ossification

A process where bone forms directly from mesenchyme without going through a cartilage stage.

Endochondral Ossification

Also known as intracartilaginous ossification; the formation of bone from hyaline cartilage.

Interstitial Growth

A type of bone growth that results in an increase in length or height.

Appositional Growth

A type of bone growth that results in an increase in width or diameter.