Biological Foundations of Kinesiology

These flashcards cover essential vocabulary related to the musculoskeletal system and muscle physiology, providing definitions and explanations for key terms discussed in the lecture.

Skeletal System

The structure and framework of the body composed of bones.

Synovial Joint

A freely movable joint characterized by a fluid-filled cavity.

Collagen

A protein that provides toughness and flexibility to bone.

Phosphate

An inorganic component of bone that makes up 17% of its composition.

Muscle Fiber

A cylindrical cell that makes up skeletal muscle, containing myofilaments.

Endomysium

The connective tissue surrounding individual muscle fibers.

Motor Unit

A motor neuron and all the muscle fibers it innervates.

Cross-Bridge Cycle

The process through which muscle contraction occurs involving myosin and actin.

Calcium Ions

Essential for muscle contraction, they bind to troponin and facilitate the exposure of binding sites on actin.

Eccentric Contraction

A type of muscle contraction where the muscle lengthens while producing force.

Types of Bone

Cortical (compact) bone is dense and forms the outer layer, while trabecular (spongy) bone is less dense and found inside bones, providing flexibility and structural support.

Mechanical Functions of Bone

Bones provide weight bearing and support, protect internal organs, and serve as linkages for muscle attachment, enabling movement.

Physiological Functions of Bone

Bones store essential minerals such as calcium and phosphorus, produce blood cells in the marrow, and play a role in the immune response.

Composition of Bone

Bone consists of 25% water, 33% organic compounds (mostly collagen), and 39% calcium.

Significance of Mineral Content in Bones

Bones store crucial minerals: 99% of the body's calcium, 99% of phosphate, and significant portions of potassium (4%), sodium (35%), magnesium (50%), and carbonate (80%).

Bone Architecture Key Elements

Includes Hollow Shafts (resist bending/twisting), Expanded Ends (provide large surface area), and areas of Compact and Spongy Bone (balance rigidity and shock absorption).

Mechanical Components of Bone

Bones derive toughness and flexibility from collagen and organic compounds, while rigidity comes from calcium and minerals.

Bone Shape & Function

Flat bones protect vital organs (e.g., skull); short bones absorb shock (e.g., carpals); long bones provide leverage for movement (e.g., femur); irregular shapes reflect a balance of functions (e.g., vertebrae).

Types of Joints

Fibrous (Immovable), Cartilaginous (Semi-movable), Synovial (Freely movable).

Ligaments

Tissues mostly made of collagen that provide stability to joints, resist forces separating bones, and form the inner layer of the joint capsule, helping in the production of fluid and removal of cell debris.

Skeletal Muscles

Muscles that cross joints, facilitating movement and serving as secondary stabilizers through contractions and reflexes.

Endomysium

Connective tissue surrounding individual muscle fibers.

Fascicle

Bundles of muscle fibers surrounded by perimysium.

Epimysium

Connective tissue that surrounds the entire muscle, also known as deep fascia.

Sarcolemma

Cell membrane of muscle fiber.

Myofibrils

Individual contractile units containing myofilaments.

Z Disc

Boundary lines of sarcomeres.

Sarcoplasmic Reticulum (SR)

Storage site for calcium ions.

Thick Filament

Composed of myosin.

Thin Filament

Composed of actin, troponin, and tropomyosin.

ACh (Acetylcholine)

A neurotransmitter that binds to receptors to initiate the contraction process.

Troponin and Tropomyosin

Regulatory proteins on thin filaments that control access to myosin binding sites on actin.

Types of Motor Control

Fine Control refers to hand muscles with fewer fibers per motor unit, while Powerful Control involves larger muscles with more fibers per motor unit.

Cortical Bone

The dense outer layer of bone that provides strength and protection.

Trabecular Bone

Less dense bone found inside bones, providing structural support and flexibility.

Osteocytes

Mature bone cells responsible for maintaining bone tissue.

Osteoblasts

Bone-forming cells involved in the mineralization of the bone.

Osteoclasts

Bone-resorbing cells that break down bone tissue.

Calcium Phosphate

The primary mineral responsible for bone strength and rigidity.

Lamellae

Thin layers of bone tissue that form the microstructure of bone.

Haversian Canals

Channels that contain blood vessels and nerves within bone.

Synovial Joints

Freely movable joints characterized by a fluid-filled cavity, allowing a wide range of motion.

Synovial Fluid

Viscous fluid that lubricates and nourishes cartilage in synovial joints.

Ligaments

Connective tissues that connect bones and provide stability to joints.

Musculotendinous Unit

The functional unit composed of muscle, tendon, ligament, and bone, essential for movement.

Cardiac Muscle

Involuntary muscle found in the heart, responsible for pumping blood.

Skeletal Muscle

Voluntary muscle responsible for body movement and posture.

Smooth Muscle

Involuntary muscle found in internal organs, facilitating functions like digestion.

Z Disc

The boundary lines that define each sarcomere, crucial for muscle contraction.

Cross-Bridge Cycle

The process involving myosin binding to actin, leading to muscle contraction.

EMG Activation

The use of electromyography to measure electrical activity in muscles.

Concentric Contraction

Muscle shortens while generating force, as in lifting weights.

Isometric Contraction

Muscle maintains its length while developing tension, crucial for stabilizing positions.

Eccentric Contraction

Muscle lengthens while under tension, important for muscle development and injury prevention.