Bio Chapter 7 FINAL
Action potentials are all-or-none. Which of the following summarizes this principle? A) If a threshold stimulus is reached, the action potential will always be of the same strength. B) An action potential can vary in both strength and duration. C) Several stimuli will cause a stronger response. D) The effects of several stimuli are combined until the neuron fires.
A
An axon was stimulated with .075 volts and there was no response. Later it was stimulated with .15 volts and there was a response. What conclusions can you draw from this observation? A) The threshold stimulus was between .075 volts and .15 volts. B) Acetylcholinesterase levels were too high. C) None of the above can be concluded given this information. D) Summation was occurring.
A
During a neuron's resting potential, the cell _____. A) spends energy pumping materials around B) conserves energy to prepare for an action potential C) blocks its dendrites from receiving any new impulses D) transmits impulses down its axon
A
The electrical impulse transmitted by a neuron is caused by the movement of _____. A ions B electrons C molecules D free radicals
A
The most abundant cells in nervous tissue are _____. A) glia B) axons C) epithelia D) Neurons
A
What type of neuron would carry information to a gland in your body? A.motor B.interneuron C.sensory D.afferent
A
A neurotransmitter found in both the central nervous system and the peripheral nervous system.
Acetylcholine
Nerve impulse a signal is conducted along an axon.
Action potential
A long extension from the cell body of a neuron that carries an electrochemical message away from the cell body toward another neuron or effector.
Axon
Neurons with a myelin sheath carry impulses _____________ unmyelinated cells. A. slower than B. faster than C. at the same speed as
B
What would be the result if calcium could not enter the synaptic knob? A) Neurotransmitters would break down faster. B) Neurotransmitters would not be released. C) The cell could regenerate. D) The response would be inhibitory.
B
Which of the following carry impulses toward the cell body? A) glial cells B) dendrite C) axon D) Schwann cells
B
Which of the following is the cause of Alzheimer's disease? A) low levels of dopamine B) protein clusters in and between neurons C) pesticides accumulating in the CNS D) mercury contamination of drinking water
B
Which of the following is true of the refractory period? A) The nerve impulse can no longer increase in intensity. B) The neuron cannot be stimulated. C) The charge inside the neuron is becoming more positive. D) The action potential is approaching the synapse.
B
Which of the following most likely causes Parkinson's disease? A. excessive acetylcholine production B. low dopamine production C. high aluminum concentrations D. low serotonin levels
B
As an action potential begins in the axon of a neuron _____. A) the area outside of the cell gains sodium B) the area outside of the cell gains protein molecules C) the inside of the cell becomes more positively charged D) the inside of the cell becomes more negatively charged
C
By definition, a nerve consists of _____. A.a neuron and the support cells making up the myelin sheath B.a single dendrite, cell body, and axon C.several neurons bundled together D.the entire neuromuscular junction
C
If the inside of the neuron is negatively charged compared to the outside, the neuron is in the __________________. A retraction period B excitatory phase C resting state D action potential
C
When neurotransmitters cross a synapse and bind to the receptors on a neuron _____. A) an action potential is initiated B) an action potential is inhibited C) an action potential is either inhibited or inhibited D) None of the options is correct; neurotransmitters binding to receptors generally have little impact on action potentials.
C
Which of the following best describes how signals travel on neurons in the human body? A axon → cell body → dendrite B Either choice a or b depending on where the signal originates C dendrite → cell body → axon D cell body → axon → dendrite
C
Which of the following best describes the connection between two typical neurons? A) The axon of one neuron slots into another neuron like an electrical cord plugs into the wall. B) The axon of one neuron touches the surface of another neuron. C) The axon of one neuron hovers very close to another neuron. D) The axon of one neuron grips onto the axon of another neuron.
C
After a neurotransmitter binds to a receptor on a dendrite, which of the following is most likely to happen to the neurotransmitter? A) It will be taken in by the dendrite, passed down the axon, and released at the end of the axon. B) It will be absorbed by the dendrite and digested by the cell. C) It will remain in the synapse until an inhibitory neurotransmitter arrives. D) It will be broken down and eliminated in the synapse.
D
Which of the following is NOT a neurotransmitter? A. acetylcholine B. serotonin C. dopamine D. acetylcholinesterase
D
A muscle or a gland that brings about a response to a stimulus
Effector
Afferent neurons carry information away from the brain and spinal cord to an effector.
False
Multiple sclerosis is a disease involving insufficient production of norepinephrine by motor neurons.
False
Myasthenia gravis is a disease that involves the loss of dopamine receptors at neuromuscular junctions.
False
Parkinson's disease results from the loss of neurons that produce serotonin.
False
The myelin sheath slows down the conduction of electrical impulses in order to prevent short-circuiting between neurons.
False
The neuron sending the message across the synaptic cleft is called the postsynaptic neuron.
False
The resting potential of a neuron is typically 5 mV.
False
An associate neuron in the CNS between sensory and motor neurons.
Interneuron
A protein lined pore channel through a plasma membrane through which one type or a few types of ions can pass.
Ion Channel
A Neuron specialized to carry information away from the CNS to an effector, either a muscle or a gland.
Motor (efferent)
An insulating layer around axons that carry nerve impulses over relatively long distances that composed of multiple wrappings of the plasma membrane of certain glial cells.
Myelin Sheath
A bundle of parallel axons, dendrites, or both from many neurons
Nerve
Cells of the nervous system that support, insulate, and protect nerve cells also called glial cells are
Neuroglia
Nerve cells involved in intercellular communication.
Neurons
Chemical released from the axon tip that affects the activity of another cell by altering the electrical potential difference
Neurotransmitter
The type of nerve transmission along a myelinated axon in which a nerve impulse jumps from one node of ranvier to the next
Saltatory conduction
A type of glial cell in the PNS that forms the myelin sheath by wrapping around the axon many times
Schwann cell
A nerve cell specialized to conduct nerve impulses from the sensory receptors toward the central nervous system
Sensory neuron
A molecular mechanism in a plasma membrane that uses cellular energy in the form of ATP to pump ions against their concentration gradients
Sodium-potassium pump
A phenomenon that results when a muscle is stimulated to contract before it has time to completely relax from previous contraction
Summation
The site of communication between a neuron and another cell, such as another neuron or a muscle cell.
Synapse
The degree in which the voltage difference across the plasma membrane of a neuron
Threshold
Alzheimer's disease results from the loss of neurons that produce acetylcholine.
True
Electrical impulses cannot cross the synaptic cleft between adjacent neurons without a neurotransmitter.
True
Insufficient production and activity of the neurotransmitter serotonin is associated with depression.
True
The interval following an action potential during which a neuron cannot be stimulated to generate another action potential
refractory period
The separation of charge across the plasma membrane of a neuron when the neuron is not transmitting an action potential
resting potential
