BIO 2010 Exam III Practice Key: Skeletal and Muscular Systems

Vocabulary practice flashcards covering bone physiology, joint anatomy and classifications, muscle organization, cellular respiration, and biomechanical lever systems from the BIO 2010 Exam III key.

Perforating canals

Passageways that connect the central canals of adjacent osteons in compact bone.

Collagen (in bone matrix)

Extracellular matrix protein component that provides bone with resilience, preventing it from becoming brittle.

Elbow joint

A complex joint that contains two distinct articulations: the humerus with the ulna and the humerus with the radius.

Symphysis

A type of cartilaginous joint in which the bones are connected by a pad of fibrocartilage, such as the intervertebral discs.

Red bone marrow

The specialized bone tissue where hematopoiesis (blood cell formation) takes place.

Fibrous joints

Joints held closely together by dense connective tissue containing many collagen fibers.

Oxygen debt

The extra oxygen consumed after strenuous exercise used to restore ATP, creatine phosphate, glucose, and oxygen stores.

Muscle contraction movement

Action producing movement at a synovial joint by pulling a skeletal muscle's insertion toward its origin.

Vitamin A (in bone development)

A micronutrient required for normal osteoblast and osteoclast activity; a deficiency slows or retards bone development.

Myoglobin

A pigmented protein located in muscle tissue that stores reserve oxygen.

Syndesmosis

A fibrous joint bound by ligaments or an interosseous membrane allowing slight twisting movement, classified functionally as amphiarthrotic.

Myosin head

The projecting portion of a thick filament that attaches to actin binding sites to form cross-bridges.

Rotator cuff

A reinforcing shoulder structure formed where the tendons of multiple shoulder muscles blend directly with the fibrous layer of the joint capsule.

Refractory period of cardiac muscle

An extended period of inexcitability that prevents cardiac muscle from undergoing wave summation and sustained tetanic contractions.

Diarthrotic joints

Freely movable joints; the functional classification encompassing all synovial joints.

Fast-twitch glycolytic (Type IIb) fibers

Skeletal muscle fibers characterized by low myoglobin content, a white appearance, rapid contraction speed, and rapid fatigue.

Endochondral bones

Bones, including the femur and humerus, that originate developmentally as hyaline cartilage models.

Epiphyseal plate

A temporary cartilaginous synchondrosis joint whose hyaline cartilage is replaced by bone once longitudinal growth ends.

Twitch

The contractile response of an individual muscle fiber to a single impulse.

Lamellae arrangement (compact vs. spongy bone)

The primary structural difference between compact and spongy bone, organized into osteons in compact bone and trabeculae in spongy bone.

Summation

The combining of individual muscle twitches from repeated, rapid stimuli before the fiber can fully relax, producing a sustained, stronger contraction.

Metaphysis

The flared, widening zone of a long bone positioned between the diaphysis and the epiphysis.

Bursa

A fluid-filled sac lined with synovial membrane that cushions and reduces friction as tendons move over bony prominences.

Blood calcium regulation

Tight endocrine maintenance by parathyroid hormone (PTH) and calcitonin necessary because calcium is essential for nerve impulse conduction and muscle contraction.

Periodontal ligament

A specialized fibrous connective tissue ligament anchoring the cone-shaped root of a tooth into its bony socket in a gomphosis.

Eccentric contraction

An isotonic contraction occurring when a muscle generates tension while actively lengthening, such as the quadriceps lowering the body into a chair.

Glycolysis

The anaerobic stage of cellular respiration that occurs within the cytoplasm of the cell.

Flexor muscles

Muscles whose contraction causes a joint angle to decrease.

Abduction

Movement of a limb or body part away from the midline of the body, such as lifting an arm laterally.

Compound (open) fracture

A break in a bone where the fractured end punctures through the skin, exposing the bone to the outside environment.

Visceral smooth muscle

Smooth muscle whose fibers act collectively as a single unit to generate coordinated rhythmic peristaltic waves, unlike multi-unit fibers which act independently.

I band

The light region within a sarcomere that consists solely of thin (actin) filaments.

Osteoblasts

Bone-building cells that deposit new extracellular matrix and subsequently mature into osteocytes.

Joint aging

Age-related degradation of joint function and flexibility caused largely by a diminishing capillary blood supply.

Antagonist

A muscle that opposes or yields to the movement of an agonist (prime mover), such as the biceps brachii relaxing during triceps extension.

Tendon

A cordlike extension of dense connective tissue that anchors a muscle directly to a bone.

Aponeurosis

A broad, flattened sheet of dense connective tissue serving as a wide attachment tendon.

Epimysium

A dense connective tissue sheath enclosing an entire skeletal muscle.

Perimysium

A connective tissue sheath that separates muscle tissue into individual bundles called fascicles.

Fascicle

A distinct bundle of skeletal muscle fibers bound together within a muscle by perimysium.

Sarcolemma

The outer cell membrane enveloping a skeletal muscle fiber.

Sarcoplasmic reticulum

A specialized network of membranous channels within a muscle fiber that stores and regulates calcium ions.

Transverse (T) tubule

A membranous invagination of the sarcolemma that conveys electrical impulses deep into the interior of a muscle cell.

Myofibril

A cylindrical contractile rod of thick and thin filaments running lengthwise along the inside of a muscle fiber.

Z line

A protein disc that anchors thin filaments and demarcates the lateral boundaries of a sarcomere.

Hematoma (fracture repair)

The initial stage of bone fracture healing characterized by the pooling and clotting of blood at the injury site.

Cartilaginous callus

The second repair stage in which phagocytes digest debris and fibrocartilage bridges the fracture gap.

Bony callus

The third repair stage wherein invading osteoblasts convert the fibrocartilaginous framework into a rigid, hard bony union.

Bone remodeling

The final stage of fracture repair where excess callus is resorbed and reconstructed close to the bone's original structural contour.

Ball-and-socket (spheroidal) joint

A synovial joint type featuring a hemispherical head fitted into a cup-like cavity (e.g., hip), conferring multiaxial motion and rotation.

Hinge joint

A uniaxial synovial joint type configured to permit angular movement in a single plane, such as the interphalangeal joints.

Plane (gliding) joint

A synovial joint with relatively flat articulating surfaces allowing sliding or nonaxial gliding movements, as seen between carpal bones.

Third-class lever

A lever mechanism in which the input effort lies positioned between the fulcrum and the resistance load, exemplified by the forearm during a biceps curl.