A&P Exam 2

Muscle

The largest structure in the organization of muscle tissue.

Fascicle

A bundle of muscle fibers.

Muscle Fiber

The individual cells that make up muscle tissue.

Myofibrils

Structures within muscle fibers made of repeating units called sarcomeres.

Sarcomeres

The basic unit of contraction in muscle fibers.

Actin

The thin myofilament found in sarcomeres.

Myosin

The thick myofilament found in sarcomeres.

Support

One of the functions of the skeletal system, providing a framework for the body.

Protection

Function of the skeletal system that safeguards vital organs.

Movement

The ability of the skeletal system to serve as levers for muscles.

Mineral storage

Function of the skeletal system that involves storing minerals like calcium and phosphorus.

Blood cell production

Red and white blood cells are produced in bone marrow.

Fat storage

Yellow marrow stores fat within the skeletal system.

Collagen

A protein providing tensile strength to bone and cartilage.

Calcium

Mineral that provides rigidity and strength in bone.

Phosphate

Works with calcium to form hydroxyapatite crystals in bone.

Ground substance

Gel-like material in the connective tissue matrix containing proteoglycans.

Compact Bone

Dense bone that forms the outer layer of bones.

Osteons

Structures in compact bone consisting of concentric rings of bone tissue.

Cancellous Bone

Also known as spongy bone; has a porous structure.

Trabeculae

Bony structures in cancellous bone that provide strength without weight.

Intramembranous Ossification

Bone develops directly from mesenchymal tissue, forming flat bones.

Endochondral Ossification

Bone replaces a hyaline cartilage model, typical in long bone development.

Epiphyseal plate

Location where growth occurs in children.

Remodeling

Continual process involving the balance between osteoblasts and osteoclasts.

Hematoma

Blood clot formed during the initial phase of bone repair.

Epiphysis

The ends of long bones where growth occurs.

Diaphysis

The shaft or central part of a long bone.

Metaphysis

Area between epiphysis and diaphysis where growth happens.

Medullary Cavity

The hollow space within the diaphysis that contains marrow.

Periosteum

Membrane covering the bone, except at joints.

Endosteum

Lining of the medullary cavity.

Articular Cartilage

Smooth cartilage at the ends of bones that reduces friction.

Fibrous Joints

Joints with no movement, like sutures in the skull.

Cartilaginous Joints

Joints with limited movement, such as intervertebral discs.

Synovial Joints

Freely movable joints like the knee or elbow.

Flexion

Decreasing the angle between bones.

Extension

Increasing the angle between bones.

Abduction

Moving a limb away from the body.

Adduction

Moving a limb toward the body.

Rotation

Turning a body part on its axis.

Circumduction

Circular movement of a limb.

Osteoporosis

Condition resulting from decreased bone mass with age.

Arthritis

Condition caused by loss of cartilage in joints.

Muscle Fiber

The basic structural unit of muscle tissue.

Myofibrils

Bundles of structures within muscle fibers that contain actin and myosin.

Sarcomere

The functional unit of muscle contraction, containing actin and myosin.

Resting Membrane Potential

The electrical charge difference across a cell membrane when at rest.

Action Potential

A rapid change in membrane potential leading to muscle contraction.

Acetylcholine (ACh)

The neurotransmitter released at the neuromuscular junction.

Calcium Release

Triggered by action potential, allowing muscle contraction to occur.

Contraction

The process where calcium binds to troponin, allowing myosin to interact with actin.

Relaxation

Process where calcium is pumped back, blocking actin sites and resulting in muscle relaxation.

Twitch

A single contraction of a muscle fiber.

Tetanus

A sustained muscle contraction resulting from rapid stimulation.

Recruitment

Increasing the number of active motor units to enhance muscle strength.

Summation

Increased force from stimuli before muscle relaxation occurs.

Aerobic Respiration

Requires oxygen and produces more ATP.

Anaerobic Respiration

Does not require oxygen and produces less ATP.

Isometric Contraction

Muscle tension increases without changing muscle length.

Isotonic Contraction

Muscle changes length to move a load.

Fast-Twitch Muscles

Quick, powerful contractions with rapid fatigue.

Slow-Twitch Muscles

Endurance-focused fibers that are slow to fatigue.

Excitation-Contraction Coupling

Process that leads to muscle contraction through calcium release.

ATP

Adenosine triphosphate, the primary energy carrier in cells.

Oxidative phosphorylation

Produces ATP using oxygen via the electron transport chain.

Glycolysis

The breakdown of glucose into pyruvate, producing 2 ATP.

Krebs Cycle

Process that processes pyruvate into ATP and electron carriers.

Electron Transport Chain

Uses NADH and FADH2 to generate ATP through oxidative phosphorylation.