Advertisement Upgrade to remove ads

Exoskeleton

Protects organism form the outside, includes clams and snails, calcium containing shells.

Endoskeleton

Internal support structure includes bones, cartilage, and plates.

Hydrostatic skeleton

Simplest type of skeleton, fluid constrained by flexible tissue, includes jellyfish and worms.

Functions of bones

Support and protection, supply of calcium and other minerals, aid in movement, blood cell formation.

Osteoblasts

Bone forming cells that secrete matrix.

Osteoclasts

Cells that degrade matrix at bone surface, release calcium and phosphorus into blood.

Osteocyte

A former osteoblast embedded in the matrix it produced.

Osteons

Set of concentric rings of osteocytes, contains circulatory vessels and nerves.

Spongy bone

Hard bone with many large spaces, red bone marrow fills the spaces.

Compact bone

Bones that consist of closely packed osteons.

Cartilage

More flexible than bone, lacks blood supply, slow to heal, high water content.

Chondrocytes

Cells in cartilage that secrete collagen and elastin.

Axial skeleton

Consists of skull, vertebral column, and rib cage.

Appendicular Skeleton

Appendages (limbs) and bones that support them, pectoral and pelvic girdles.

Yellow bone marrow

In the center of longbones, replenishes red bone marrow.

Red bone marrow

Located at the ends of longbones and flatbones. Blood cell formation.

Synovial joint

Consists of moveable bones joined by a fluid-filled capsule of fibrous connective tissue.

Sarcomere

One of many repeated units of a myofibril.

Myofibril

Runs the length of a muscle cell, contractile bundle that consists of thin and thick filaments.

Myosin

Thick filament of the myofibril.

Actin

Thin filament of the myofibril.

Muscle fiber

Made up of many myofibrils.

Muscles

Consists of many bundles of muscle fiber.

Sliding filament model

A muscle fiber contracts when thin filaments slide within thick filaments. The sarcomere shortens. Heads of myosin interact with actin forming a cross-bridge.

Neuromuscular junction

Synapse between a motor neuron and a muscle cell.

Muscle movement process

Motor neuron conveys message to muscle cell to contract.
Motor neurons release neurotransmitters.
Receptors on muscle bind to neurotransmitter.
Neurotransmitters to endoplasmic reticulum to release calcium (Ca2+).
Calcium binds to protein on actin and allows interaction with myosin.
Sarcomeres shorten.

Slow twitch fibers

Small cells.
Long duration contractions.
Capillaries have good supply of oxygen.
Many mitochondria.
For endurance.

Fast twitch fibers

Larger cells.
Short duration contractions.
Powerful contractions.
Short term use for strength.

Less myoglobin

Causes whitish appearance of muscles.

More myoglobin

Causes darker appearance of muscles.

Please allow access to your computer’s microphone to use Voice Recording.

Having trouble? Click here for help.

We can’t access your microphone!

Click the icon above to update your browser permissions above and try again

Example:

Reload the page to try again!

Reload

Press Cmd-0 to reset your zoom

Press Ctrl-0 to reset your zoom

It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.

Please upgrade Flash or install Chrome
to use Voice Recording.

For more help, see our troubleshooting page.

Your microphone is muted

For help fixing this issue, see this FAQ.

Star this term

You can study starred terms together

NEW! Voice Recording

Create Set