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