Chapter 1: Structure and Function of Body Systems

Vocabulary flashcards covering key structural and physiological terms from Chapter 1.

Axial Skeleton

The division of the skeletal system that consists of the skull, ribcage, and vertebrae.

Appendicular Skeleton

The division of the skeletal system that includes all bones outside the axial skeleton, such as the scapula, humerus, pelvis, and femur.

Synovial Joints

Primary movement joints in the body containing a joint capsule with synovial fluid and hyaline cartilage on the bone ends.

Vertebral Column

The spine structure made up of $7$ cervical, $12$ thoracic, and $5$ lumbar vertebrae, along with the sacrum and coccyx.

Tendons

Structures composed of connective tissue that attach muscle to bone.

Ligaments

Structures composed of connective tissue that attach bone to bone.

Epimysium

The outermost layer of fascia surrounding the entire muscle.

Perimysium

The layer of fascia that surrounds one bundle of muscle fibers (a fascicle).

Endomysium

The layer of fascia that surrounds an individual muscle fiber.

Fascicle

A bundle of muscle fibers (cells) grouped together by fiber type.

Motor Unit

A single nerve and all the muscle fibers it innervates, causing all associated fibers to contract simultaneously.

Sarcomere

The smallest contractile unit of muscle, composed of actin and myosin filaments.

A Band

The region of a sarcomere that spans the entire length of myosin, which never changes length during muscle contraction.

I Band

The region of a sarcomere that contains actin but no myosin, which shortens during muscle contraction.

H Zone

The region of a sarcomere that contains myosin but no actin, which shortens during muscle contraction.

Z Disc

The boundary walls of a sarcomere that move closer together during muscle contraction and farther apart during muscle relaxation.

Sliding Filament Theory

The mechanism of muscle contraction within a sarcomere where myosin heads pull on actin filaments via a power stroke powered by ATP hydrolysis.

Type I Muscle Fibers

Oxidative skeletal muscle fibers primarily recruited for aerobic training.

Type IIa Muscle Fibers

Mixed skeletal muscle fibers containing both aerobic and glycolytic characteristics.

Type IIx Muscle Fibers

Glycolytic skeletal muscle fibers utilized during high-intensity efforts, such as a $1\text{--}5$ Rep Max.

Muscle Spindle

A sensory receptor that detects muscle stretch and responds by triggering a reflexive muscle contraction.

Golgi Tendon Organ (GTO)

A sensory receptor that senses muscle contraction and tendon strain, responding by causing muscle inhibition or relaxation.

SA Node

The primary pacemaker of the heart located in the cardiac conduction system.

AV Node

The region in the cardiac conduction system where the electrical impulse is delayed before reaching the ventricles.

Bradycardia

A resting heart rate condition characterized by fewer than $60\text{ BPM}$.

Tachycardia

A resting heart rate condition characterized by more than $100\text{ BPM}$.

P Wave

The deflection on an electrocardiogram (ECG) representing atrial depolarization.

QRS Complex

The waveform on an electrocardiogram (ECG) representing ventricular depolarization and atrial repolarization.

T Wave

The deflection on an electrocardiogram (ECG) representing ventricular repolarization.

Alveoli

The microscopic structures within the lungs where gas exchange takes place.