Ch. 13 Flashcards
What are the functions of the muscular system?
Moves the entire organism, movement of materials within the organism
What are muscle cells called?
Muscle fibers
What are the three muscle types?
Skeletal, smooth, and cardiac
Smooth muscle
Shaped like cylinders with pointed ends, have one nucleus, are arranged in parallel lines, have no striations, and are located in the walls of hollow internal organs and blood vessels and causes these walls to contract
Smooth muscle contractions
Involuntary, contracts slower than skeletal muscle, can sustain prolonged contractions, and does not fatigue easily
Cardiac muscle
Forms the heart wall
Cardiac muscle fibers
Uninucleated, striated, and tubular; branched, interlock at intercalated disks, contain gap junctions and permit contractions to spread through the heart wall
Cardiac muscle contractions
Contraction is rhythmic, occurs without nervous stimulation, is involuntary, relaxes completely between contractions, which prevent fatigue
Skeletal muscle fibers
Tubular, multinucleated, and striated; make up skeletal muscles, very long, voluntarily controlled
What are the functions of skeletal muscles?
Support, movements of bones and other body structures, and maintenance of a constant body temperature, movement of fluids in the cardiovascular system and lymphatic systems, and protection of the internal organs and the stabilization of joints
Fascicle
Bundle of skeletal muscle fibers, each fiber is surrounded by connective tissue
Fascia
Connective tissue that covers muscles and extends to become tis tendon
Bursae
Small, fluid-filled sacs which can often be found between tendons and bones
Agonist (prime mover)
The muscle that does most of the work
Synergist
Assists the agonist
Antagonist
The muscle that acts opposite the agonist
Sacrolemma
Plasma membrane of a muscle fiber that forms T-tubules
Sacroplasm
Cytoplasm of a muscle fiber that contains the organelles, including myofibrils
Sarcoplasmic reticulum
The smooth endoplasmic reticulum of a muscle fiber that stores Ca2+
T (transverse) tubules
Penetrate the cells; come close to portions of the sarcoplasmic reticulum
Myofibril
A bundle of myofilaments that contracts
Myoglobin
A red pigment that stores oxygen for muscle contraction
striations
