Anatomy and Physiology Ch.6 The Muscular System
While doing "jumping jacks" during an exercise class, your arms and legs move laterally away from the midline of your body. This motion is called_______
Abduction
What is released by axon terminals into the synaptic cleft to stimulate a muscle to contract?
Acetylcholine
Which of the following is NOT a function of the muscular system?
Blood cell formation
What mineral is released within the muscle cells to trigger contraction?
Calcium
Figure 6.2: The epimysium is represented by ______
Label A
Figure 6.2: The endomysium that wraps individual muscle fibers is indicated by _____
Label B
Figure 6.2: The perimysium wraps a fascicle of muscle cells and is represented by _____
Label C
Figure 6.2: The muscle fiber (cell) is indicated by ____
Label D
What metabolic waste accumulates in muscle with excessive exertion?
Lactic acid
Which type of muscle tissue contracts most quickly upon stimulation?
Skeletal
The sarcoplasmic reticulum wraps like a sleeve around the myofibril and stores and releases calcium
TRUE
What is acetylcholine?
The neurotransmitter that stimulates skeletal muscle to contract
Jason injured his hamstring muscle group during football practice. He will be unable to perform ______
Thigh extension and knee flexión
What changes occur in the sarcomere during muscle contraction?
Z discs move closer together
Which facial muscle is considered the "smiling" muscle since it raises the corners of the mouth?
Zygomaticus
What initiates an actin potential on a muscle cell?
acetylcholine binding to receptors on the sarcolemma within the neuromuscular junction
What enzyme breaks down acetylcholine into acetic acid and choline to prevent continued contraction of the muscle fiber?
acetylcholinesterase
A myosin head binds to which molecule to form a cross bridge?
actin
What is the unstoppable electrical current that travels down the length of the entire surface of a sarcolemma?
action potential
Which movement is opposite to abduction?
adduction
Which method of regenerating ATP during muscle contraction can produce lactic acid?
anaerobic glycolysis
What causes the release of calcium from the terminal cisternae of the sarcoplasmic reticulum within a muscle cell?
arrival of an action potential
What condition results if muscles are not used, such as when immobilized In a cast for healing a broken bone?
atrophy
What causes the myosin head to disconnect from actin?
binding of ATP
Why are calcium ions necessary for skeletal muscle contraction?
calcium ions trigger the binding of myosin heads to actin filaments
The prime mover of arm abduction is the ______ muscle.
deltoid
Which connective tissue bundles muscle fibers into fascicles?
perimysium
Which of these muscles extends the knee?
rectus femoris
What causes the power stroke?
release of ADP and Pi
The plasma membrane of a skeletal muscle cell is called the _____
sarcolemma
What organelle wraps and surrounds the myofibril and stores calcium?
sarcoplasmic reticulum
A Sarcomere is ______
the contractile unit between two Z discs
Which of these muscles is the prime mover of elbow extension?
triceps brachii
The binding of calcium to which molecule causes the myosin binding sites to be exposed?
troponin
What is the function of creating phosphate?
Directly regenerates ATP from ADP within a muscle cell
Muscles will hypertrophy if they are not used continually
FALSE
Which layer of connective tissue surrounds each skeletal muscle fiber?
endomysium
Which of these characteristics applies only to cardiac muscle tissue?
intercalated discs
What is the main function of the quadriceps group?
knee extension
Which chemical is produced during vigorous exercise when the supply of oxygen is limited or inadequate?
lactic acid
