Musculoskeletal System and Neuromuscular System

What are the main components of the musculoskeletal system?

Bones, joints, muscles, and tendons.

How do muscles interact with bones?

Muscles pull against bones.

What is the role of joints in the skeleton?

Joints are the junction of bones.

What type of joint allows for full movement?

Synovial joints.

What are the two classifications of the skeletal system?

Axial skeleton and appendicular skeleton.

What is a tendon?

A tendon connects muscle to bone.

What happens at the neuromuscular junction?

A motor neuron innervates the muscle fiber.

What are the three types of muscle fibers?

Type I, Type IIa, and Type IIb.

What triggers muscle contraction at the sarcomere level?

Calcium is released from the sarcoplasmic reticulum.

What is sliding filament theory?

Myosin cross bridges pull on actin, causing muscle contraction.

What occurs during the relaxation phase of muscle contraction?

Stimulation of motor neuron stops and calcium is pumped back into the sarcoplasmic reticulum.

What is the function of proprioceptors?

To provide the CNS with information needed to maintain muscle tone and perform complex movements.

What do muscle spindles detect?

Changes in muscle length (senses stretch)

What defines the difference between type IIa and type IIx fibers?

Type IIa has greater aerobic capacity and is less fatiguable compared to type IIx.

What is the purpose of valves in the heart?

To prevent backflow of blood.

What role do hemoglobin molecules play in the cardiovascular system?

They transport oxygen and facilitate CO2 removal.

Musculoskeletal system

The system composed of bones, joints, muscles, and tendons.

Force transmission

Force is transmitted through pulling and rotation of muscles against bones.

Skeletal system

Composed of around 206 bones that provide leverage, support, and protection.

Axial skeleton

Part of the skeletal system that includes the skull, sternum, ribs, and vertebral column.

Appendicular skeleton

Part of the skeletal system that includes the shoulders, arms, wrist, hands, pelvic girdle, legs, ankles, and feet.

Joint

The junction where two bones meet.

Fibrous Joint

A type of joint with no movement.

Cartilaginous Joint

A type of joint that allows slight movement.

Synovial Joint

A type of joint that allows full movement.

Uni-axial Joint

A joint that rotates on one axis.

Biaxial Joint

A joint that rotates around two perpendicular axes.

Multi-axial Joint

A joint that rotates around three axes.

Hyaline cartilage

Cartilage found on articulating surfaces of bones.

Synovial fluid

Fluid found in a joint capsule that reduces friction.

Skeletal musculature

The composition of each skeletal muscle, including muscle tissue, connective tissue, nerves, and blood vessels.

Tendon

A structure connecting muscle to bone.

Epimysium

The connective tissue that surrounds an entire muscle.

Perimysium

The connective tissue that surrounds bundles of muscle fibers.

Endomysium

The connective tissue that surrounds individual muscle fibers.

Fasciculus

Bundles of muscle fibers surrounded by perimysium.

Neuromuscular junction

The site at which a motor neuron innervates a muscle fiber.

Motor unit

A motor neuron and all the muscle fibers it innervates.

Type I Muscle Fiber

Slow-twitch fiber; fatigue-resistant and has a high aerobic energy supply.

Type IIa Muscle Fiber

Fast-twitch fiber; has greater aerobic capacity and more capillaries.

Type IIb Muscle Fiber

Fast-twitch fiber; highly fatiguable with low aerobic capacity.

Sarcoplasm

The cytoplasm of a muscle fiber containing contractile components.

Myofibrils

Strands within muscle fibers containing myofilaments (myosin and actin).

Sarcomere

Structural unit of a myofibril, aligning myosin and actin.

T-tubule

A tubule that runs perpendicular to sarcoplasmic reticulum and terminates near the Z line.

Sliding filament theory

Theory explaining muscle contraction where myosin cross-bridges pull actin filaments inward.

Z line

The line in the sarcomere that marks the boundary between two adjacent sarcomeres.

I band

Region in the sarcomere containing only actin filaments.

H zone

A region in the sarcomere containing only myosin filaments.

Calcium ions (CA2+)

Released from the sarcoplasmic reticulum during muscle contraction.

Action potential

Electrical signal that triggers muscle contraction.

Muscle twitch

The brief contraction that occurs from a single action potential.

Tetanus

A sustained muscular contraction resulting from repeated stimulation.

Proprioceptors

Sensory receptors located in joints, muscles, and tendons that provide the CNS with information about body position.

Muscle spindles

Proprioceptors that sense stretch and detect changes in muscle length.

Golgi tendon organ

Proprioceptor located in tendons that senses tension.

Cardiovascular system

The system including the heart and blood vessels which circulates blood throughout the body.