muscle and neurons Flashcards
80% of the lactic acid produced by skeletal muscle is converted to pyruvic acid by the ________.
kidneys
A myofilament that runs throughout the core of a thick filament and anchors it to a Z disc is called a(n) ________.
elastic filament
Aerobic respiration produces approximately ________ more ATPs per glucose molecule than glycolysis does.
36
Athletes who train at high altitudes increase their red blood cell count, which increases their oxygen supply during exercise. Increased oxygen supply results in ________.
longer aerobic respiration
Cardiac muscle has very little capacity for regeneration because it lacks ________.
satellite cells
During muscle contraction, a single myosin head consumes ATP at a rate of about ________ ATP per second.
5
How many muscle fibers stimulate one somatic motor neuron?
0
If one nerve stimulus arrives at a muscle fiber so soon that the fiber has only partially relaxed from the previous twitch, the most likely result will be ________.
incomplete tetanus
If the potassium leak channels were suddenly blocked in a resting neuron, what would happen to its resting membrane potential?
It would become more positive.
In order for muscle to continue contracting during anaerobic fermentation, which of the following is essential?
Myokinase
In skeletal muscle, the term that describes the alternating light and dark bands is ________.
striations
Loss of muscle mass from lack of activity is called ________.
atrophy
Michael Jordan was arguably the best player in professional basketball history. Scientifically, one would expect him to have highly developed ________ fibers.
white
Place the following events in synaptic transmission at a cholinergic synapse in order: A - A postsynaptic potential is produced; B - Voltage gated calcium channels open and calcium enters the cell; C - ACh is released and diffuses across the synaptic cleft; D - A nerve signal arrives at a synaptic knob; E - Ligand gated sodium channels open and sodium enters the cell.
D, B, C, E, A
Shortening a muscle while it maintains constant tension is called ________.
an isotonic contraction
Skeletal muscle is called ________, because it is usually subject to conscious control.
voluntary
The absence or inhibition of acetylcholinesterase at a synapse would lead to ________.
tetanus
The minimum stimulus needed to cause muscle contraction is called the ________.
threshold
The process of engaging more motor units to increase the strength of a muscle contraction is called ________.
recruitment
The protein that acts as a calcium receptor in skeletal muscle is ________.
troponin
The sarcolemma of a resting muscle fiber is most permeable to ________.
potassium
To stimulate muscle contraction, acetylcholine is released from the ________ into the synaptic cleft.
synaptic vesicles
What happens when acetylcholine stimulates its receptors in the neuromuscular junction?
The permeability of the sarcolemma to Na+ increases
When a skeletal muscle lengthens, its ________ helps resist excessive stretching and subsequent injury to the muscle.
collagen
Where is dystrophin, the protein that is defective in muscular dystrophy, normally found?
Between the outermost myofilaments and the sarcolemma of a muscle fiber
Where would you expect to find numerous gap junctions in muscular tissue?
The intercalated discs of cardiac muscle
Which fibers are primarily responsible for producing lactic acid?
Type IIB fast glycolytic fibers
Which muscle type depends solely on the sarcoplasmic reticulum as its calcium source?
skeletal muscle
Which muscle(s) can contract without the need for nervous stimulation?
Smooth and cardiac muscle
Which of the following contains overlapping thick and thin filaments?
a band
Which of the following has the largest mitochondria?
cardiac muscle
Which of the following is an accurate comparison of skeletal muscle to smooth muscle?
Smooth muscle contracts and relaxes more slowly.
Which of the following is not a purpose of the excess postexercise oxygen consumption (EPOC) in muscle?
To neutralize carbon dioxide buildup
Which of the following is predominately made up of myosin?
the thick filament
Which of the following is true concerning isotonic eccentric contraction?
The muscle lengthens but tension remains constant.
Which of the following is not a characteristic of a muscle cell?
plasticity
Which of the following marks the boundaries of a sarcomere?
Z discs
Which of the following would be caused by a contraction of smooth muscle?
goose bumps
Which statement best describes the goal of medications used to treat myasthenia gravis?
To inhibit the function of cholinesterase
Why is the contraction strength of smooth muscle relatively independent of its resting length?
It does not have sarcomeres
