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Questions and Answers
The basic functional units of the nervous system are individual cells called:
The basic functional units of the nervous system are individual cells called:
Supporting cells of the nervous system, called neuroglia, perform all of the following, EXCEPT:
Supporting cells of the nervous system, called neuroglia, perform all of the following, EXCEPT:
What is the term for the nervous system comprising all neurons outside the brain and spinal cord?
What is the term for the nervous system comprising all neurons outside the brain and spinal cord?
The autonomic nervous system provides regulation of each of the following, EXCEPT:
The autonomic nervous system provides regulation of each of the following, EXCEPT:
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Which of the following is NOT a basic function of the nervous system?
Which of the following is NOT a basic function of the nervous system?
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Neurons are classified on the basis of structure as each of the following, EXCEPT:
Neurons are classified on the basis of structure as each of the following, EXCEPT:
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The multipolar neuron consists of all of the following, EXCEPT:
The multipolar neuron consists of all of the following, EXCEPT:
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The axons of some neurons are wrapped in an insulating sheath made of:
The axons of some neurons are wrapped in an insulating sheath made of:
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The insulating sheath is interrupted at regular intervals, exposing the neural membrane. These interruptions are called __________ of Ranvier.
The insulating sheath is interrupted at regular intervals, exposing the neural membrane. These interruptions are called __________ of Ranvier.
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Neurons use _________________ to carry information from the cell body to the synaptic terminal.
Neurons use _________________ to carry information from the cell body to the synaptic terminal.
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An action potential is a change in membrane potential during __________ of a neuron.
An action potential is a change in membrane potential during __________ of a neuron.
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Where in a neuron is the highest density of voltage-gated sodium (Na+) channels found?
Where in a neuron is the highest density of voltage-gated sodium (Na+) channels found?
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Events that make initiation of an action potential less likely are:
Events that make initiation of an action potential less likely are:
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Which of the following is a CORRECT step in the generation of an action potential?
Which of the following is a CORRECT step in the generation of an action potential?
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From the time an action potential begins until the normal resting potential has stabilized, the membrane will not respond normally to additional depolarizing stimuli. This period is known as the:
From the time an action potential begins until the normal resting potential has stabilized, the membrane will not respond normally to additional depolarizing stimuli. This period is known as the:
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In a neural action potential, repolarization involves the loss of _________ ions.
In a neural action potential, repolarization involves the loss of _________ ions.
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The _________________ exchange pump slowly restores intracellular and extracellular ion distributions to pre-stimulation levels when the neuron is not active (i.e. at rest).
The _________________ exchange pump slowly restores intracellular and extracellular ion distributions to pre-stimulation levels when the neuron is not active (i.e. at rest).
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An action potential (impulse) is relayed along the axon of a neuron in a series of steps, with action potentials in one section of the axon bringing the adjacent region to _________________ and 'handing on' the impulse.
An action potential (impulse) is relayed along the axon of a neuron in a series of steps, with action potentials in one section of the axon bringing the adjacent region to _________________ and 'handing on' the impulse.
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Continuous propagation is the basic mechanism by which an action potential is propagated along a ____________________, appearing to move along the membrane in a series of tiny steps.
Continuous propagation is the basic mechanism by which an action potential is propagated along a ____________________, appearing to move along the membrane in a series of tiny steps.
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Where action potentials 'jump' along the axon in a series of steps this is known as:
Where action potentials 'jump' along the axon in a series of steps this is known as:
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Electrical impulses are passed from neurons to neurons or other cells at a specialized junction called a:
Electrical impulses are passed from neurons to neurons or other cells at a specialized junction called a:
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Electrical synapses are rare and occur when presynaptic and postsynaptic membranes are locked together tightly by:
Electrical synapses are rare and occur when presynaptic and postsynaptic membranes are locked together tightly by:
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In a chemical synapse, communication across the synaptic cleft requires the release of a _________________ from the presynaptic membrane.
In a chemical synapse, communication across the synaptic cleft requires the release of a _________________ from the presynaptic membrane.
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According to the 'lock-and-key' model, the same neurotransmitter may act on:
According to the 'lock-and-key' model, the same neurotransmitter may act on:
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Substances that can bind to a receptor are called ligands. Ligands that block or reduce neurotransmitter action are called:
Substances that can bind to a receptor are called ligands. Ligands that block or reduce neurotransmitter action are called:
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Neurotransmitters that may be either excitatory or inhibitory depending on the postsynaptic receptor are called ___________________ neurotransmitters.
Neurotransmitters that may be either excitatory or inhibitory depending on the postsynaptic receptor are called ___________________ neurotransmitters.
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ACh is the neurotransmitter of the neuromuscular junction, the specialised synapse between a motor neuron and a muscle, where it acts on the _________________ acetylcholine receptor.
ACh is the neurotransmitter of the neuromuscular junction, the specialised synapse between a motor neuron and a muscle, where it acts on the _________________ acetylcholine receptor.
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Which of the following is NOT an accurate event at the cholinergic synapse?
Which of the following is NOT an accurate event at the cholinergic synapse?
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When signals from another nerve terminal at the presynaptic membrane causes a decreased release of neurotransmitter, it is called:
When signals from another nerve terminal at the presynaptic membrane causes a decreased release of neurotransmitter, it is called:
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An excitatory postsynaptic potential (EPSP) is a _________________ caused by the arrival of a neurotransmitter at the postsynaptic membrane.
An excitatory postsynaptic potential (EPSP) is a _________________ caused by the arrival of a neurotransmitter at the postsynaptic membrane.
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Individual postsynaptic potentials can combine by the process of summation, which integrates the effects of:
Individual postsynaptic potentials can combine by the process of summation, which integrates the effects of:
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The addition of stimuli occurring in rapid succession (i.e from single source) is called:
The addition of stimuli occurring in rapid succession (i.e from single source) is called:
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A reflex arc contains each of the following, EXCEPT:
A reflex arc contains each of the following, EXCEPT:
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The region of the brain which performs higher functions and planning and execution of voluntary motor action is called the:
The region of the brain which performs higher functions and planning and execution of voluntary motor action is called the:
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The electroencephalogram provides a clinical assessment of overall brain function, and records each of the following, EXCEPT:
The electroencephalogram provides a clinical assessment of overall brain function, and records each of the following, EXCEPT:
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The __________________________ is an area of the brain responsible for maintenance of homeostasis by controlling behaviours essential to survival of the individual or species via hormones and the sympathetic nervous system.
The __________________________ is an area of the brain responsible for maintenance of homeostasis by controlling behaviours essential to survival of the individual or species via hormones and the sympathetic nervous system.
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Activation of the ________________________ branch of the autonomic nervous system causes 'rest-and-repose' responses, associated with relative inactivity and digestion.
Activation of the ________________________ branch of the autonomic nervous system causes 'rest-and-repose' responses, associated with relative inactivity and digestion.
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A number of organs have _____________________________ by both sympathetic and parasympathetic nerves, with opposite effects.
A number of organs have _____________________________ by both sympathetic and parasympathetic nerves, with opposite effects.
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The principal neurotransmitter of the sympathetic nervous system, which may act on alpha and beta receptors is:
The principal neurotransmitter of the sympathetic nervous system, which may act on alpha and beta receptors is:
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The principal neurotransmitter of the parasympathetic system is ______________________, acting on muscarinic receptors.
The principal neurotransmitter of the parasympathetic system is ______________________, acting on muscarinic receptors.
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Study Notes
Nervous System Basics
- The basic functional unit of the nervous system is a neuron.
- Supporting cells of the nervous system are called neuroglia, and they perform a range of functions, including protecting neurons, providing structural support, and regulating interstitial fluid.
- The nervous system is broadly divided into the central nervous system (CNS) and the peripheral nervous system (PNS).
- The CNS comprises the brain and spinal cord.
- The PNS comprises all neurons outside the brain and spinal cord.
- The PNS is further divided into the somatic, autonomic, and enteric nervous systems.
- The autonomic nervous system regulates smooth muscle, cardiac muscle, and glandular secretions.
- The basic functions of the nervous system include sensory, motor, and integrative functions.
Neuron Structure and Function
- Neurons are classified by structure as unipolar, bipolar, multipolar, and anaxonic.
- Multipolar neurons have a cell body (soma), multiple dendrites, and a single axon.
- The axon is often covered in a myelin sheath, which is interrupted at regular intervals called nodes of Ranvier.
- Neurons use electrical impulses to transmit information from the cell body to the synaptic terminal.
- An action potential is a rapid change in membrane potential during the excitation of a neuron.
- Voltage-gated sodium (Na+) channels are concentrated at the axon hillock.
- Events that make initiation of an action potential less likely are considered inhibitory.
- The generation of an action potential involves polarization to threshold, activation of sodium (Na+) channels and rapid depolarization, inactivation of sodium (Na+) channels and activation of potassium (K+) channels, and return to impermeability.
- The refractory period prevents the generation of additional action potentials during the repolarization process.
- Repolarization involves the loss of potassium (K+) ions.
- The sodium-potassium exchange pump restores intracellular and extracellular ion distributions to pre-stimulation levels.
- Action potentials are propagated along the axon in a series of steps, with the action potential in one section bringing the adjacent region to threshold.
- In myelinated axons, action potentials "jump" along the axon in a series of steps known as saltatory propagation.
- In unmyelinated axons, the action potential appears to move along the membrane in a series of tiny steps known as continuous propagation.
Synapses and Neurotransmission
- Synapses are specialized junctions where electrical impulses are passed from neurons to neurons or other cells.
- Electrical synapses occur when presynaptic and postsynaptic membranes are tightly locked together by gap junctions.
- In chemical synapses, communication across the synaptic cleft requires the release of a neurotransmitter from the presynaptic membrane.
- Neurotransmitters bind to receptors on the postsynaptic membrane based on the 'lock-and-key' model.
- Ligands that block or reduce neurotransmitter action are called antagonists.
- Certain neurotransmitters can be either excitatory or inhibitory depending on the postsynaptic receptor.
- Acetylcholine (ACh) is the neurotransmitter of the neuromuscular junction, where it acts on nicotinic acetylcholine receptors.
- Events at the cholinergic synapse include the arrival of an action potential at the synaptic terminal, the entry of calcium (Ca2+) ions that trigger the release of ACh, the binding of ACh to receptors and depolarization of the postsynaptic membrane, and the removal of ACh by acetylcholinesterase (AChE).
- Presynaptic inhibition occurs when signals from another nerve terminal at the presynaptic membrane cause a decreased release of neurotransmitter.
- Excitatory postsynaptic potentials (EPSPs) are graded depolarizations caused by the arrival of a neurotransmitter at the postsynaptic membrane.
- Postsynaptic potentials can combine by the process of summation, which integrates the effects of graded potentials.
- Temporal summation involves the addition of stimuli occurring in rapid succession from a single source.
- Spatial summation involves the addition of simultaneous stimuli from multiple sources.
Reflex Arcs and the Brain
- A reflex arc includes a receptor organ, an afferent neuron, a central synapse, an efferent neuron, and an effector organ.
- The brain region responsible for higher functions, planning, and execution of voluntary motor actions is called the cortex.
- The electroencephalogram (EEG) records brain activity in the form of alpha, beta, delta, and theta waves.
- The hypothalamus plays a crucial role in maintaining homeostasis by controlling behaviours essential for survival.
Autonomic Nervous System
- The autonomic nervous system regulates involuntary functions and is divided into sympathetic and parasympathetic branches.
- The parasympathetic branch is associated with "rest-and-repose" responses, while the sympathetic branch is associated with "fight-or-flight" responses.
- Many organs receive dual innervation by both sympathetic and parasympathetic nerves, with opposite effects.
- The principal neurotransmitter of the sympathetic nervous system is noradrenaline (norepinephrine), which acts on alpha and beta receptors.
- The principal neurotransmitter of the parasympathetic system is acetylcholine (ACh), acting on muscarinic receptors.
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