Understanding Muscle Fiber and Skin Structure

Muscle Fiber

Elongated cells that make up skeletal muscle tissue

Striation

Light and dark stripes in which skeletal muscle fibers are grouped

Fascicle

Dense bundles in which skeletal muscle fibers are grouped

Voluntary Muscle

Muscle that are consciously controlled

Involuntary Muscle

Smooth muscles that cannot be consciously controlled

Myofibril

Thread-like structures found in skeletal muscle fiber

Myosin

Thick filaments that make up myofibril

Actin

Thin filaments that make up myofibril

Z Line

Structure to which actin filaments are anchored

Sarcomere

The region from one Z line to the nerve

Tendon

Fibrous connective tissue that attaches muscles to bone

Flexor

Muscle that bends a joint

Extensor

Muscle that straightens a joint

Muscle Fatigue

Physiological inability of a muscle to contract

Oxygen Debt

Temporary lack of oxygen availability

Skin Structure

Epidermis

Outer layer of the skin

Keratin

Protein that gives skin its rough, leather, texture and its waterproof quality

Melanin

Brown pigment that determines skin tone, hair tone

Dermis

Inner layer of the skin

Exocrine Glands

Glands that release secretions through ducts

Sweat Glands

Release excess water, salts, and urea

Oil Glands

Found on the surface of the skin and the shafts of hairs, preventing excess water loss and softening the skin and hair

Sebum

Fatty substance