Study Guide for Lecture Exam 2: Chapters 9-13

Flashcards covering joint classifications, muscle anatomy, muscle actions, and microscopic organization of muscle tissue based on lecture notes for Chapters 9-13.

Joint

The point of contact between two bones, between bone and cartilage, or between bone and teeth.

Ligament

A strong band of connective tissue that connects bone to bone and helps stabilize joints.

Fibrous Joints

Joints where bones are held together by dense irregular connective tissue and there is no synovial cavity; examples include sutural, syndesmoses, and gomphoses.

Cartilaginous Joints

Joints where bones are held together by cartilage and lack a synovial cavity; examples include synchondroses and symphyses.

Synovial Joints

Joints characterized by the presence of a synovial (joint) cavity and an articular capsule, typically being diarthroses (freely movable).

Articular Cartilage

A layer of hyaline cartilage that covers the articulating surfaces of bones in a synovial joint to reduce friction and absorb shock.

Synovial Fluid

A viscous fluid secreted by the synovial membrane that lubricates joints, absorbs shock, and provides nutrients to articular cartilage.

Bursae

Sac-like structures situated in body tissues to alleviate friction in some joints; commonly found between skin and bone, or tendons and bone.

Tendon Sheaths

Tube-like bursae that wrap around certain tendons that experience considerable friction.

Gliding

A simple movement where nearly flat bone surfaces move back-and-forth and from side-to-side with respect to one another.

Circumduction

A sequence of flexion, abduction, extension, and adduction resulting in a circular movement of a distal body part.

Arthroplasty

The surgical repair or replacement of a joint, such as hip or knee replacements.

Origin

The attachment of a muscle's tendon to the stationary bone.

Insertion

The attachment of the muscle's other tendon to the movable bone.

Prime Mover (Agonist)

The muscle that contracts to cause an action.

Antagonist

The muscle that stretches and yields to the effects of the prime mover.

Synergist

A muscle that assists the prime mover by reducing unnecessary movement or adding extra force.

Fixator

A muscle that stabilizes the origin of the prime mover so it can act more efficiently.

Epicranius (Occipitofrontalis)

Muscle composed of the Frontalis, which raises eyebrows and wrinkles forehead, and the Occipitalis, which pulls the scalp posteriorly.

Buccinator

The muscle that compresses the cheek to allow for blowing, sucking, and whistling.

Platysma

Muscle that tenses the skin of the neck and pulls the lower lip inferiorly to produce a pouting expression.

Sternocleidomastoid

Neck muscle that flexes the neck when acting bilaterally and rotates the head to the opposite shoulder when acting unilaterally.

Erector Spinae

A group of muscles along the vertebral column that extend the waist when acting bilaterally and laterally flex it when acting unilaterally.

Respiratory Diaphragm

The prime mover of inspiration that flattens and moves inferiorly upon contraction to expand the thoracic cavity.

Serratus Anterior

The "boxer's muscle"; prime mover of scapula abduction (protraction) and upward rotation.

Latissimus Dorsi

The "swimmer's muscle"; responsible for extending, adducting, and medially rotating the arm.

Deltoid

The prime mover of arm abduction; also involved in flexion, extension, and rotation of the arm.

Quadriceps Femoris

A group of four muscles (Rectus femoris, Vastus lateralis, Vastus medialis, Vastus intermedius) that all extend the leg at the knee.

Hamstrings

A muscle group (Biceps femoris, Semitendinosus, Semimembranosus) that extends the thigh and flexes the leg at the knee.

Epimysium

The outermost layer of connective tissue surrounding the entire skeletal muscle organ.

Perimysium

Connective tissue that surrounds groups of 10 to 100 or more muscle fibers, separating them into fascicles.

Endomysium

The thin layer of connective tissue that penetrates the interior of each fascicle and separates individual muscle fibers.

Sarcolemma

The plasma membrane of a muscle fiber.

Sarcoplasmic Reticulum

A fluid-filled system of membranous sacs that encircles each myofibril and stores calcium ions for muscle contraction.

Sarcomere

The basic functional unit of a myofibril, extending from one Z-disc to the next.

Myosin

The contractile protein that makes up thick filaments; functions as a motor protein.

Actin

The main contractile protein component of thin filaments, containing myosin-binding sites.

Troponin and Tropomyosin

Regulatory proteins specifically located on thin filaments that help switch the muscle contraction process on and off.

Hypertrophy

An increase in the diameter of muscle fibers, typically resulting from forceful muscular activity.

Neuromuscular Junction (NMJ)

The synapse between a somatic motor neuron and a skeletal muscle fiber.

Motor Unit

Consists of one somatic motor neuron plus all the skeletal muscle fibers it stimulates.

Anatomical Snuff Box

A surface anatomy landmark found on the lateral aspect of the wrist.

Popliteal Fossa

The diamond-shaped depression on the posterior aspect of the knee.