Muscles, Tendons, Ligaments and Fascia

Practice vocabulary flashcards covering the types, structures, functions, and nomenclature of the muscular system and its associated connective tissues based on lecture notes.

Muscles

Structures consisting predominantly of contractile cells that produce movements of various parts of the body by contraction.

Skeletal Muscle

A type of voluntary and striated muscle that makes up about $40\%$ of the total body mass; functions include producing movement, generating body heat, and maintaining posture.

Origin

The attachment of a skeletal muscle that is usually the more fixed and proximal attachment.

Insertion

The attachment of a skeletal muscle that is the more movable and distal attachment.

Epimysium

A thin layer of connective tissue that encloses the skeletal muscle.

Perimysium

The connective tissue that surrounds smaller bundles of muscle fibers.

Endomysium

The connective tissue that encloses each individual muscle fiber.

Circular Muscles

Normally sphincter muscles that appear circular in shape and surround openings, such as the Obicularis Oris (mouth) and Obicularis Oculi (eyes).

Convergent Muscles

Also known as triangular muscles, these have an origin wider than the point of insertion to allow for maximum force production, such as the Pectoralis Major.

Parallel Muscles

Also called strap muscles, these have fibers running parallel to each other; they are typically long with good endurance but low strength, such as the sartorius and Sternocleidomast oid.

Fusiform

Muscle fibers that are similar to parallel fibers but possess a spindle shape, such as the Brachioradialis.

Pennate Muscles

Muscles containing a large number of fibers per unit, making them very strong but easily tired.

Unipennate

Pennate muscles with fibers arranged to insert in a diagonal direction onto the tendon, such as the Lumbricals and Extensor Digitorum.

Bipennate

Muscles with two rows of fibers facing in opposite diagonal directions with a central tendon, like a feather; allows greater power but less range of motion, such as the Rectus Femoris.

Multipennate

Muscles with multiple rows of diagonal fibers and a central tendon that branches into two or more tendons, such as the Deltoid muscle.

Spiral

Muscle fibers oriented in a spiral manner, such as the latissimus dorsi.

Rectus

A term in muscle nomenclature indicating a straight orientation, where muscle fasciculi run straight.

Oblique

A term in muscle nomenclature indicating fibers that lie oblique to the longitudinal axis of the structure.

Abductor

A muscle that functions to move a structure away from the midline.

Adductor

A muscle that functions to move a structure toward the midline.

Masseter

A chewing muscle described as 'a chewer'.

Smooth Muscle

Involuntary and nonstriated muscle arranged in circular and longitudinal layers in visceral organ walls; innervated by the autonomic nervous system.

Peristaltic waves

Rhythmic contractions of smooth muscle in the walls of the GI tract, uterine tubes, ureters, and other organs.

Cardiac Muscle

Involuntary and striated muscle that forms the myocardium; it contracts spontaneously and is innervated by the autonomic nervous system.

Tendon

A fibrous connective tissue that attaches muscle to bone, cartilage, or structures like the eyeball.

Ligaments

Fibrous bands that connect bones to bones or cartilage, or folds of peritoneum that support visceral structures.

Aponeurosis

Flat fibrous sheets or expanded broad tendons that serve as the means of origin or insertion for a flat muscle.

Retinaculum

A fibrous band in the region of joints that holds a structure in place and prevents the bow-stringing of tendons.

Raphe

The line of union of symmetrical structures by a fibrous or tendinous band, such as the pharyngeal or scrotal raphes.

Bursae

Flattened sacs of synovial membrane containing synovial fluid to minimize friction; found where tendons rub against bone, ligaments, or other tendons.

Synovial tendon sheaths

Tubular sacs filled with synovial fluid that wrap around tendons to reduce friction where they pass under ligaments or through osseofibrous tunnels.

Fascia

A fibrous sheet that envelops the body under the skin and invests muscles; may limit the spread of pus and extravasated fluids like blood or urine.

Superficial fascia

Loose connective tissue between the dermis and deep fascia consisting of a fatty superficial layer and a membranous deep layer; contains nerves, vessels, and fat.

Deep fascia

A sheet of fibrous tissue that invests and supports muscles as an elastic sheath; provides muscle attachments and forms retinacula and fibrous sheaths.

Muscular atrophy

A decrease in muscle size resulting from a decrease in the size of individual fibers and a progressive loss of myofibrils.

Disuse atrophy

Muscular atrophy resulting specifically from a lack of muscle use, common in bedridden patients.

Muscular Hypertrophy

An increase and growth of muscle cells.