TEST 3 for A&P(joints/articulations and muscle)

Comprehensive vocabulary flashcards covering the anatomy, histology, cellular mechanisms, hormonal regulation, fracture healing, pathologies, and joint classifications of the skeletal and articular systems.

Articulation

The junction or site where two or more bones meet, functioning to hold the skeleton together while conferring mobility.

Synarthroses

The functional classification designating immovable joints, exemplified by cranial sutures.

Amphiarthroses

The functional classification designating slightly movable joints, exemplified by intervertebral discs and the pubic symphysis.

Diarthroses

The functional classification designating freely movable joints, characteristically found in the limbs.

Fibrous Joints

A structural category where articulating bones are united by dense connective tissue fibers without an intervening joint cavity.

Sutures

Immovable cranial junctions composed of interlocking bone margins bound tightly by short connective tissue fibers.

Synostoses

Completely ossified, fused bony boundaries formed when fibrous cranial sutures ossify during middle age.

Syndesmoses

Fibrous junctions where articulating bones are held together exclusively by ligaments or fibrous bands, such as the distal tibiofibular connection.

Gomphoses

Peg-in-socket fibrous articulations that anchor each tooth within its bony alveolar socket via the periodontal ligament.

Cartilaginous Joints

A structural category where articulating bones are joined directly by cartilage and lack a fluid-filled joint cavity.

Synchondroses

Immovable cartilaginous unions united by a plate or bar of hyaline cartilage, such as epiphyseal growth plates and the joint between the first rib and manubrium.

Symphyses

Amphiarthrotic cartilaginous articulations where hyaline-coated bone surfaces are fused to an intervening pad of fibrocartilage.

Synovial Joints

A structural category characterized by fluid-filled articular cavities separating bones, allowing extensive mobility.

Gliding (Planar) Joints

Synovial articulations with essentially flat surfaces permitting only nonaxial slipping or sliding motions, such as intercarpal joints.

Hinge Joints

Uniaxial synovial articulations that permit angular movement in a single plane, as seen at the elbow.

Pivot Joints

Uniaxial synovial articulations that permit rotation around a central longitudinal axis, such as the proximal radioulnar joint.

Condyloid (Ellipsoidal) Joints

Biaxial synovial articulations where an oval convex surface nests into an elliptical depression, permitting angular motion in two planes.

Saddle Joints

Biaxial synovial articulations featuring complementary concave and convex surfaces, notably situated at the base of the thumb.

Ball-and-Socket Joints

Multiaxial synovial articulations where a spherical head fits into a cup-like depression, providing the greatest range of movement.

Knee Joint

The largest and most complex articulation of the body, functioning as three interconnected joints within a single joint cavity.

Seven Major Ligaments of the Knee Joint

Structures that stabilize the knee: the patellar ligament (anterior), two popliteal ligaments (posterior), anterior and posterior cruciate ligaments (intracapsular), tibial collateral ligament (medial), and fibular collateral ligament (lateral), complemented by the medial and lateral menisci.

Menisci

C-shaped fibrocartilage pads positioned between the femoral condyles and tibial plateau to cushion, stabilize, and distribute lateral load.

Unhappy Triad

A severe knee trauma marked by concurrent tearing of the tibial collateral ligament, medial meniscus, and anterior cruciate ligament.

Knee Locking

A mechanical stabilization occurring when standing with fully extended legs, jamming the lateral meniscus tightly between the tibia and femur.

Glenohumeral Joint

A loose ball-and-socket articulation where stability is sacrificed to maximize multiaxial range of motion.

Rotator Cuff

A dynamic stabilizing musculotendinous sleeve reinforcing the shoulder joint, comprised of the supraspinatus, infraspinatus, subscapularis, and teres minor.

Shoulder Dislocation Vulnerability

The anatomical orientation in which the humeral head is displaced most readily from the glenoid cavity, predominantly occurring anteriorly and inferiorly.

Anulus Fibrosus

The tough, outer fibrocartilage ring that binds an intervertebral disc to adjacent vertebral bodies.

Nucleus Pulposus

The elastic, gelatinous central core of an intervertebral disc that provides vertical shock absorption.

Slipped Disc

A spinal condition wherein the outer fibrocartilaginous ring bulges into the vertebral canal without complete rupture of the core.

Herniated Disc

A spinal pathology in which the gelatinous core ruptures through the outer fibrous ring, exerting direct pressure on spinal nerves or the spinal cord.

Sprain

A joint trauma resulting from the tearing of supporting ligaments.

Strain

A joint impairment resulting from excessive stretching of reinforcing ligaments without tearing.

Joint Immobilization

A condition that reduces synovial fluid circulation and can trigger arthritic symptoms, clinically counteracted with continuous passive motion therapy.

Gliding Movement

A motion wherein one flat bone surface slips or slides over another without appreciable angular or rotational change.

Flexion

An angular movement in the sagittal plane that decreases the angle between articulating bones.

Extension

An angular movement in the sagittal plane that increases the angle between articulating bones, reversing flexion.

Hyperextension

An angular movement extending a joint beyond its anatomical reference position.

Dorsiflexion

An angular movement of the ankle that lifts the superior surface of the foot upward toward the shin.

Plantar Flexion

An angular movement of the ankle that depresses the foot downward, pointing the toes.

Abduction

An angular movement that displaces a limb away from the body's midline along the frontal plane.

Adduction

An angular movement that brings a limb toward the body's midline along the frontal plane.

Circumduction

A composite movement combining flexion, abduction, extension, and adduction such that the distal end of a limb describes a cone in space.

Rotation

The pivoting motion of a bone turning around its own longitudinal axis.

Supination

A rotational forearm movement where the radius and ulna lie parallel, orienting the palm anteriorly or superiorly.

Pronation

A rotational forearm movement where the distal radius crosses over the ulna, orienting the palm posteriorly or inferiorly.

Inversion

A specialized foot motion that turns the sole medially toward the midline.

Eversion

A specialized foot motion that turns the sole laterally away from the midline.

Protraction

A nonangular anterior movement along a horizontal plane, such as jutting the mandible forward.

Retraction

A nonangular posterior movement along a horizontal plane, returning an anteriorly displaced body part to anatomical position.

Elevation

A motion that lifts a body part superiorly along the frontal plane, such as closing the jaw.

Depression

A motion that moves a body part inferiorly along the frontal plane, such as opening the jaw.

Opposition

A specialized movement permitted by the thumb's saddle joint that brings the thumb pad into contact with the fingertips of the same hand.

Psalm 1

Contrasts the two distinct paths of life: the narrow, uphill path of the blessed who delight in God's law versus the broad path of the ungodly that leads to destruction.

Psalm 51

David's prayer of confession and heartfelt repentance, pleading for God's mercy, forgiveness, and inward spiritual cleansing to create a clean heart.

Hebrews 12:1–2

Compares the life of faith to running an endurance race, urging believers to throw off every encumbering weight and sin while fixing their eyes on Jesus.

1 John 1:9

The biblical promise functioning as a 'spiritual shower,' assuring that if we confess our sins, God is faithful and just to forgive us and cleanse us from all unrighteousness.

Mark 1:35

Demonstrates the priority of personal prayer, highlighting Jesus rising very early in the morning while it was still dark to pray in solitary fellowship with the Father.

Characteristics of Muscle Tissue

Four specialized physiological properties comprising excitability (responsiveness), contractility (shortening), extensibility (stretching), and elasticity (recoiling to resting length).

Functions of the Muscular System

Crucial roles in producing body movement, maintaining posture, stabilizing joints, and generating heat during activity.

Skeletal Muscle Tissue

Voluntary, striated muscle fibers attached to bones and skin that facilitate locomotion, facial expression, and body posture.

Cardiac Muscle Tissue

Involuntary, striated muscle found exclusively in the heart wall, composed of branching cells controlled by pacemaker potentials and autonomic input.

Smooth Muscle Tissue

Involuntary, non-striated, spindle-shaped cells located in the walls of hollow visceral organs, airways, and blood vessels.

Epimysium

An external overcoat of dense regular connective tissue surrounding an entire skeletal muscle.

Perimysium

A collagenous connective tissue sheath that gathers skeletal muscle fibers into discrete bundles known as fascicles.

Endomysium

A delicate sheath of fine areolar connective tissue surrounding each individual muscle fiber.

Muscular Fascia

A connective tissue sheet situated external to the epimysium that binds muscles together and partitions them into functional compartments.

Satellite Cells

Myogenic stem cells located beneath the basal lamina capable of undergoing mitosis to repair damaged muscle fibers.

Tendon

A ropelike cord of dense regular connective tissue that anchors a muscle directly to the periosteum of bone.

Aponeurosis

A broad, sheetlike tendon providing a wide anchoring attachment between a muscle and adjacent bones or fascia.

Sarcolemma

The specialized plasma membrane enclosing an individual muscle fiber.

Sarcoplasm

The cytoplasm of a muscle fiber containing rich reserves of glycogen and oxygen-binding pigments.

Myoglobin

An oxygen-binding, iron-containing red protein in the sarcoplasm providing an intracellular oxygen reserve.

Glycosomes

Granules of stored glycogen distributed throughout the sarcoplasm that yield glucose fuel during contraction.

Myofibrils

Densely packed, rodlike contractile organelles occupying ~80% of muscle cell volume and displaying repeating striations.

Sarcomere

The smallest functional contractile unit of a muscle fiber, spanning from one Z disc to the next.

Thick Filaments

Contractile myofilaments composed of bundled myosin molecules with outward-projecting globular heads that bind actin and hydrolyze ATP.

Thin Filaments

Contractile myofilaments composed of helical F-actin chains bearing active myosin-binding sites, regulated by troponin and tropomyosin.

Tropomyosin

A rod-shaped regulatory protein that spirals around the actin core, physically blocking myosin-binding sites in resting muscle.

Troponin

A three-polypeptide regulatory complex that binds calcium ions, shifting the blocking protein away from active actin sites.

Titin

A giant elastic protein filament that extends from the Z disc to the thick filament, providing extensibility and passive recoil.

A Band

The dark, anisotropic central band of a sarcomere spanning the entire length of thick filaments.

I Band

The light, isotropic region of a sarcomere containing only thin and elastic filaments, bisected by a Z disc.

H Zone

The lighter midregion of the A band where thick filaments do not overlap thin filaments in a relaxed muscle.

M Line

A central structural protein meshwork holding adjacent thick filaments together at the sarcomere midline.

Sarcoplasmic Reticulum

A specialized network of smooth endoplasmic reticulum tubules surrounding myofibrils that sequesters and releases intracellular calcium.

Terminal Cisternae

Enlarged, perpendicular end-sacs of the sarcoplasmic reticulum that store calcium and form triads with transverse tubules.

T Tubules

Deep, hollow invaginations of the sarcolemma that conduct electrical action potentials deep into the muscle fiber interior.

Triad

A three-part membranous complex consisting of a central transverse tubule flanked on each side by terminal cisternae of the sarcoplasmic reticulum.

Neuromuscular Junction

The specialized synapse where the axon terminal of a somatic motor neuron meets the motor end plate of a muscle fiber.

Acetylcholine

The chemical neurotransmitter released from motor neuron axon terminals that initiates sarcolemma depolarization.

Acetylcholinesterase

The synaptic cleft enzyme that degrades acetylcholine to terminate excitation and prevent continuous, uncontrolled contraction.

Excitation-Contraction Coupling

The sequence of physiological steps converting an electrical action potential on the sarcolemma into the mechanical sliding of myofilaments.

Cross-Bridge Cycle

The recurring cycle involving myosin head attachment to actin, power stroke, ATP-driven detachment, and cocking for the next cycle.

Power Stroke

The mechanical step in contraction where the myosin head pivots and bends upon releasing ADP and inorganic phosphate, pulling actin toward the M line.

Motor Unit

A functional unit consisting of a single somatic motor neuron and all the muscle fibers it innervates.

Muscle Twitch

The mechanical response of a muscle to a single threshold stimulus, divided into latent, contraction, and relaxation phases.

Temporal (Wave) Summation

An increase in contractile tension produced when a second stimulus arrives before the muscle fiber completely relaxes.

Unfused (Incomplete) Tetanus

A sustained, quivering contraction produced by increasing stimulation frequency with only partial relaxation between stimuli.

Fused (Complete) Tetanus

A smooth, maximal sustained contraction that occurs at high stimulation frequencies with zero intervening relaxation.