Test #2 Flashcards
In skeletal muscle crossbride cycling, ATP
Allows myosin to release actin and reset to the energized position
Which type of muscle fiber is least resistant to fatigue?
Fast gly
When an acetylcholinesterase (AChE) antagonist is in the synapse
There will be more acetylcholine in the synapse
Rigor mortis is because of
ATP, which is necessary for the removal of Ca from the sarcomere, is not being formed
Which of the following statements regarding the shortening of a skeletal-muscle fiber is not true? When a skeletal-muscle fiber shortens,
the actin and myosin myofilaments shorten
Which neurotransmitter system is implicated in Parkinson’s disease?
Dopamine
The tension in a skeletal muscle can be increased by
Temporal summation of a muscle fiber
Motor unit summation
An inhibitory postsynaptic potential (IPSP)
Is produced by an increased membrane permeability to K
What will happen to the concentration of a neurotransmitter in a synaptic cleft when the frequency of action potentials increases in the presynaptic neuron?
It increases
The EPSPs from two different synapses occur at the same time and cause a larger depolarization than either one alone could cause. This is an example of
Spatial summation in neurons
Which of the following is a parasympathetic nervous system function?
Increase smooth muscle contraction in the digestive tract
The binding of a neurotransmitter to its receptor at an inhibitory synapse can lead to the ____ of ____ channels
Opening; potassium
Predict the response of the smooth muscle of the uterus to sympathetic nervous system stimulation.
Inhibition and relaxation
Exocytosis of a neurotransmitter into the synaptic cleft is triggered by an influx of _____ (to the presynaptic cell) in response to the arrival of an action potential in the axon terminal.
Ca+2
When a skeletal muscle has been working for an extended period of time (more than 15 minutes, but less than 40), the primary source of ATP is
Metabolism of blood glucose
The transverse (T) tubules in a skeletal muscle fiber
Provide a means of transmitting an action potential in the muscle sarcolemma to the central portions of the muscle fiber
The neurotransmitter used in communication between a sympathetic motor neuron and a cardiac muscle cell is:
Norepinephrine
Which of the following is a biogenic amine that is NOT classified as a catecholamine?
Serotonin
Place the following steps of crossbridge formation in the correct order
i. AP reaches T-tubules
ii. Tropomyosin moves to reveal active sites
iii. Ca2+ is released from the SR
iv. Crossbridge forms
v. Ca+2 binds to troponin
3,1,5,2,4
Which of the following statements about acetylcholine is correct?
Acetylcholine binds to cholinergic receptors
Acetylcholine binds to nicotinic and muscarinic receptors
An EPSP in a membrane
Is often a direct result of the opening of chemical-gated Na+ channels in the membrane
“Motor-Unit” refers to
a single motor neuron plus all of the skeletal muscle fibers it innervates
a marathon runner’s legs would likely contain extremely well-trained ____ fibers?
Slow ox
A myofibril is
Composed of actin and myosin
Composed of proteins
The way in which the nervous system can detect the intensity of a stimulus is
The frequency of action potentials
During a skeletal muscle fiber twitch, Ca is pumped back into the sarcoplasmic reticulum primarily during the _____ phase.
Relaxation
Which of the following neurotransmitters is lipid-soluble and is contained in chocolate?
Anadamide
The response of a single skeletal much cell to a single action potential is termed:
A twitch
Calcium is released from the sarcoplasmic reticulum and then travels to the sarcomere via _____ and it is taken back up into the SR via _____
Diffusion; primary active transport
Which of the following neurotransmitters bind to adrenergic receptors?
a. Adrenaline
b. Epinephrine
c. Norepinephrine
No Question
Freebee
____ is an amino acid neurotransmitter at excitatory synapses whereas ____ is an amino acid neurotransmitter at inhibitory synapses.
Aspartate; glycine
The neurotransmitter released from postganglionic neurons in the parasympathetic nervous system is
Acetylcholine
Endorphins and enkephalins bind to which of the following receptors
Opiod
The release of a phosphate from the myosin molecule directly results in which of the following?
Release of the crossbridge
Put the following sources of energy from skeletal muscle contraction in the order in which they would be utilized;
i. ATP bound to myosin thick filaments
ii. Blood glucose
iii. Creatine phosphate
iv. Fatty acid metabolism
v. Stored glycogen
2,3,1,4,5
The binding of calcium to troponin will directly cause which of the following
The movement of tropomyosin, exposing the actin active sites
Aerobic, or low-intensity, muscle training eventually results in
More capillaries
More myoglobin
What is the effect of parasympathetic postganglionic acetylcholine?
Not enough information to determine
The preganglionic synapses in the sympathetic nervous system are
Excitatory and cholinergic
In a resting state, _____ covers the actin active site
Tropomyosin
Students who suffer from test anxiety often have some of the following symptoms: increased heart rate, dilated pupils, and a dry mouth. What branch of the autonomic nervous system would cause these symptoms?
Sympathetic
The time between the occurrence of an AP in skeletal muscle and the onset of tension is called what?
Latent period
What are the three types of muscle fibers that are found in skeletal muscles?
Slow ox, fast ox, fast gly
What is a change in the postsynaptic potential that brings membrane potential closer to threshold called?
Excitatory postsynaptic potential
Convergence in neuron physiology refers to which of the following?
The communication of several neurons to one postsynaptic cell
Multi-unit smooth muscle has gap junctions and all cells act as a single functional unit
False
Muscles used for delicate, finely controlled movements have smaller, more numerous motor units than more coarsely controlled muscles
True
During skeletal muscles contraction, the I band and H zone shorten but the A band stays the same
True
The neurotransmitter used primarily for reward and reinforcement in the CNS is GABA.
False
