CODY MON Exam 3

why is a skeletal muscle striated and smooth muscle non-striated

this is due to the organization of sarcomeres

a lever is defined as which of the following

a rigid structure that moves on a fixed point called the fulcrum

which of the following describes the relative concentrations of sodium ions inside and outside the neuron

sodium is more concentrated outside the cell

a skeletal muscle cell is depolarized when

Na+ enters the cell

Long-distance runners would be expected to have a higher percentage of which muscle fiber type(s)?

type I

the resting membrane potential is depended on which of the following

I. different distribution of ions across the axon membrane

II. the opening of voltage-gated channels

III. the active transport of ions across the membrane through Na+/K+-ATPase

I and III only

all of the following pertain to depolarization except ----- (Hint: Remember what happens during the depolarization phase of an action potential)

increased potassium permeability through the membrane

while characterizing the effects of medical marijuana, researchers have discovered a new type of channel that contains a binding site for the active ingredient, THC, on the outside of the cell. This new receptor could be classified as -----

a ligand gated channel

the two major contractile proteins in a muscle cell include

actin and mysoin

someone that is able to run a relatively fast marathon likely has a high percentage of which type of muscle fiber

type I

fiber recruitment ----

all of the above are true

type IIa muscles have all of the following characteristics except for

high endurance capacity

compare the functioning of tropomyosin to troponin in skeletal muscle contraction

one portion of troponin binds Ca2+, moving tropomyosin out of the way for actin and myosin to form a cross-bridge

the muscles that are most directly involved in bringing about a movement are called which of the following

agonist

what is occurring at the phase 2 of the action potential below

depolarization

what happens at the peak phase of the action potential

voltage-gated K+ channels are opening

which of the following statements is true regarding muscle atrophy

atrophy is caused by consistent inactivation of muscle fibers

based on your knowledge of the concentration gradients of sodium, potassium, chloride, and calcium, predict the direction these ions will move across the membrane through open channels

sodium, chloride, and calcium enter the cell. potassium exits the cell

predict what will happen to skeletal muscle over time in inactive people. (Hint: what ultimately happens after prolong inactivity)

skeletal muscle fibers turn into fat and connective tissue

release of acetylocholine into the synaptic cleft is dependent on the presence of what ion

calcium

according to the length-tension relationship of skeletal muscle

tension is highest with moderate actin-myosin filament overlap

what kind of system is primarily used to generate energy during weight training

anaerobic system

the disassociation of the myosin cross-bridge is directly activated by which of the following

the attachment of ATP to myosin heads

hypothesize how the addition of tetrodotoxin (TTX), which specifically blocks voltage-gated Na+ channels, would affect neurons. (Hint: Remember what voltage gated Na+ channels are utilized for?)

TTX would decrease formation of the action potential

skeletal muscle is the main muscle type responsible for the following functions except

Both A and C

how do excitatory post-synaptic potentials (EPSPs) differ from inhibitory post-synaptic potentials (IPSPs)

EPSPs have a depolarizing effect on membrane potential

describe the role of actin in skeletal muscle tension development

actin will bind to myosin, causing myosin to ratchet, causing cross-bridges to form, and tension development

usain bolt is able to run the 100-meter dash in under 10 seconds. At the tail end of his run, where is ATP being derived from

creatine phosphate and ADP

which statement best demonstrates the role of ATP in skeletal muscle contraction

ATP causes the myosin head to enter a high-energy state when hydrolyzed

when an action potential moves down an excitable membrane, this process is called

propagation

repeated activation of a channel over a short period of time will cause a greater change in membrane potential. This is called

temporal summation

in the aftermath of a snowstorm, Jimmy is outside shoveling all the snow on the driveway using a shovel. The next day, he notices his muscles are incredibly sore, and it doesnt go away until approximately two days later. What are possible explanations of this

microtears in the muscle

at high levels of muscular activity, when oxygen is used faster than it can be replaced, pyruvic acid is broken down without oxygen through glycolysis which accumulates which of the following

lactic acid

synaptic potentials that do not depolarize membrane potential enough to reach threshold are known as

subthreshold potentials

compare to action potentials, graded potentials

result in weaker changes in membrane potential the further from the point of origin they extend

membrane potential is created by

the uneven distribution of ions across the membrane

what triggers the opening of the activation gates on voltage-gated sodium channels

when threshold is reached

which of the following best illustrates what happens when a neurotransmitter binds to its receptor on the postsynaptic membrane

there is an increase in conductance of Na+ in the postsynaptic membrane

which of the following describes the relative concentrations of potassium ions inside and outside the neuron

potassium is more concentrated inside the cell

which of the following muscle fiber type are incorrectly paired with the characteristic of that fiber

type II fibers - predominately use aerobic energy pathways

an isometric muscle action is a muscle action in which the muscle

does not change length because the contractile force is equal to the resistive force

define a muscle motor unit

a single neuron plus all the muscle fibers it innervates

predict what would happen if a patient suffers from hyponatremia (low blood Na+)

the action potential would not form properly - the peak would be too low

acetylocholinesterase is an important molecule at the neuromuscular junction because it

actively degrades acetylcholine

all of the following are true regarding anaerobic training except

it regenerated ATP at a faster rate than the oxidative system

resting membrane potential is characterized by all of the following except ----- (Hint: Remember what happens during the resting membrane potential)

high chloride permeability

which of the following describes graded potentials

all of these statements describe graded potentials

a concentric contraction

shorten a muscle during contraction

which of the following is true during the relative refractory period

a larger than normal stimulus is required to generate an action potential

a cross-bridge occurs when

the myosin head binds to actin