Human Neuro Study Deck Test 1 Flashcards
The brain is made up of approximately how many neurons?
100 Billion
Neurons have a nucleus that contains _____?
Genes
Neurons have specialized projections called _____ and _____.
Dendrites and Axons
The _____ of a neuron bring information TO the cell body.
dendrites
The _____ of a neuron take information AWAY from the cell body.
axons
Through what kind of process do neurons communicate with each other?
Electrochemical
Neurons form specialized connections called “synapses” and produce special chemicals called _____ that are released at the synapse.
neurotransmitters
Approximately how many neurons do we have in the human brain?
1 Quadrillion
Is it true that we only use 10% of our brains?
No
How much does the adult human brain weigh?
Between 1300-1400 g or
Approximately 3 lbs
How long is a neuron?
Anywhere from less than a millimeter to about a meter (3 feet)
Name some of the levels that neuroscientists study.
Behavioral Level
System Level
Local Circuit Level
Single Neuron Level
Synapse Level
Membrane Level
Genetic Level
At what level of neuroscience do we study what causes people and animals to do the things they do?
Behavioral Level
At what level of neuroscience do we study the various parts of the nervous system like the visual or auditory system, which could also include investigations of what parts of the brain are connected to other parts?
System Level
At what level of neuroscience do we study the functions of groups of neurons (nerve cells)?
Local Circuit Level
At what level of neuroscience do we study what individual neurons do in relation to some “event,” or study what is contained within a particular neuron?
Single Neuron Level
At what level of neuroscience do we study what happens in the space between neurons?
Synapse Level
At what level of neuroscience do we study what happens at ion channels?
Membrane Level
At what level of neuroscience do we study the ____ basis of neuronal function?
Genetic Level
What contains the neuron’s nucleus and organelles, and is responsible for maintaining the cell’s health and metabolism?
Cell Body (Soma)
What are the tree-like extensions of a neuron that receive electrical signals from other neurons and convey this information to the cell body?
Dendrites
What is a long, thin fiber that transmits electrical signals away from the cell body to other neurons, muscles, or glands?
Axon
What is a fatty layer that wraps around the axon of some neurons, speeding up the transmission of electrical signals?
Myelin Sheath
What are gaps in the myelin sheath that allow for the rapid transmission of electrical signals along the axon?
Nodes of Ranvier
What are the endpoints of the axon where neurotransmitters are released to communicate with other neurons or muscles?
Axon Terminal (Terminal Buttons)
What are the chemical messengers that neurons use to communicate with each other across synapses?
Neurotransmitters
Based on functions, what type of neurons, also known as afferent neurons, are responsible for converting external stimuli from the environment into internal electrical impulses, transmitting sensory information from the skin, muscles, and sensory organs to the central nervous system?
Sensory Neurons
Based on functions, what type of neurons, also known as efferent neurons, convey impulses from the central nervous system to the muscles and glands, causing them to contract or secrete products, respectively, enabling bodily movements and responses to the environment?
Motor Neurons
Based on functions, what type of neurons are located within the central nervous system and connect sensory and motor neurons and carry out complex processing and integrative functions, are involved in reflexes, neuronal circuits, and the processing of information in the brain?
Interneurons
Based on location, what type of neuron resides within the brain and spinal cord and is responsible for processing and integrating sensory information, generating thoughts and emotions, and initiating motor responses?
Central Nervous System (CNS) Neurons
Based on location, what type of neurons are located outside the central nervous system and include sensory neurons that bring information into the CNS and motor neurons that carry commands from the CNS to muscles and glands in the body?
Peripheral Nervous System (PNS) Neurons
Based on structure, what neurons are characterized by having one axon and multiple dendrites extending from their cell body and are the most common type of neuron in the central nervous system and are typically involved in motor functions and interneuronal communication?
Multipolar Neurons
Based on structure, what neurons have two processes extending fro the cell body: one axon and one dendrite, and are primarily found in sensory organs, such as the retina of the eye and the olfactory system, and are involved in the transmission of sensory information?
Bipolar Neurons
Based on structure, what neurons have a single process that extends from the cell body and divides into two branches far from the cell body: one connected to dendrites that receive sensory information and another that transmits information to the central nervous system? They are primarily found in the peripheral nervous system and are involved in transmitting touch, pain, and temperature sensations.
Unipolar Neurons
Based on structure, what neurons lack a distinct axon and have dendrites that look similar to each other, and are found in the brain and retina where they play roles in interneuronal communication without producing action potentials? They mainly modulate the electrical activity of neighboring neurons.
Anaxonic Neurons
Based on structure, what neuron is this?
Anaxonic Neuron
Based on structure, what neuron is this?
Bipolar Neuron
Based on structure, what neuron is this?
Multipolar Neuron
Based on structure, what neuron is this?
Unipolar Neuron
What are the supporting cells of the central nervous system?
Glial Cells (Neuroglia, or “neural glue”)
What is a glial cell that provides support to neurons of the central nervous system, provides nutrients and other substances, and regulates the chemical composition of the extracellular fluid?
Astrocyte or “star cell”
What is a type of glial cell in the central nervous system that forms myelin sheaths, surrounds axons and insulates them, preventing messages from spreading between adjacent axons?
Oligodendrocyte
What is the smallest type of glial cell that acts as a phagocyte and protects the brain from invading microorganisms?
Microglia
What is a cell in the peripheral nervous system that is wrapped around a myelinated axon, providing one segment of its myelin sheath?
Schwann Cell
What is a semipermeable barrier between the blood and the brain produced by cells in the walls of the brain’s capillaries?
Blood-Brain Barrier
What is the electrical charge across a cell membrane; the difference in electrical potential inside and outside the cell?
Membrane Potential
What is the state of a neuron when it is not being altered by excitatory or inhibitory postsynaptic potentials at approximately -70 mV in the giant squid axon?
Resting Membrane Potential
What is the reduction (toward zero) of the membrane potential of a cell from its normal resting potential?
Depolarization
What is an increase in the membrane potential of a cell, relative to the normal resting potential?
Hyperpolarization
What is the brief electrical impulse that provides the basis for the conduction of information along an axon?
Action Potential
What is the value of the membrane potential that must be reached to produce an action potential?
Threshold of Excitation
In reference to membrane potential, what is the movement of molecules from regions of high concentration to regions of low concentration?
Diffusion
In reference to membrane potential, what is the attractive force between atomic particles charged with opposite signs or the repulsive force between two atomic particles charged with the same sign?
Electrostatic Pressure
What is an aqueous solution of a material that ionizes a soluble acid, base, or salt?
Electrolyte
What is a charged molecule?
Ion
Which ions are positively charged?
Cations
Which ions are negatively charged?
Anions
Knowing the _____ potential can help you predict which way the ion will move.
equilibrium
At rest, the membrane is permeable to _____, _____, and _____.
potassium, chloride, sodium
The Sodium-Potassium Pump uses energy in the form of _____ to move three sodium ions out of the cell and two potassium ions in. This moves the ions against their electrochemical gradients, which is why it requires energy. The pump functions to keep the ionic concentrations at proper levels inside and outside the cell.
ATP, or Adenosine Triphosphate. This is an energy-carrying molecule found in all living things.
What is a specialized protein molecule that permits specific ions to enter or leave the cell?
Ion channel
What is an ion channel that opens or closes according to the value of the membrane potential?
Voltage-dependent Ion Channel
What is the principle that once an action potential is triggered in an axon, it is propagated without decrement to the end of the fiber?
All-or-None Law
What is the principle that variations in the intensity of a stimulus or other information being transmitted in an axon are represented by variations in the rate at which that axon fires?
Rate Law
What is the conduction of action potentials by myelinated axons in which the action potential appears to jump from one node of Ranvier to the next?
Saltatory Conduction
What is the location on a receptor protein to which a ligand binds?
Binding Site
What is a chemical that binds with the binding site of a receptor?
Ligand
What is a small bud on the surface of a dendrite, with which a terminal button of another neuron forms a synapse?
Dendritic Spine
What is the membrane of a terminal button that lies adjacent to the postsynaptic membrane and through which the neurotransmitter is released?
Presynaptic Membrane
What is the cell membrane opposite the terminal button in a synapse, the membrane of the cell that receives the message?
Postsynaptic Membrane
What is the space between the presynaptic membrane and the postsynaptic membrane?
Synaptic Cleft
What is a small, hollow, beadlike structure found in the terminal buttons; that contains molecules of a neurotransmitter?
Synaptic Vesicle
What is a region of the interior of the presynaptic membrane of a synapse to which synaptic vesicles attach and release their neurotransmitter into the synaptic cleft?
Release Zone
When _____ _____ are conducted down an axon (and down all of its branches), something happens inside all of the terminal buttons. Several synaptic vesicles located just inside the presynaptic membrane fuse with the membrane and then break open, spilling their contents into the synaptic cleft.
Action Potentials
What is a receptor molecule in the postsynaptic membrane of a synapse that contains a binding site for a neurotransmitter?
Postsynaptic Receptor
What is an ion channel that opens when a molecule of a neurotransmitter binds with a postsynaptic receptor?
Neurotransmitter-dependent Ion Channel
What is a receptor that contains a binding site for a neurotransmitter and an ion channel that opens when a molecule of the neurotransmitter attaches to the binding site?
Ionotropic Receptor
What is a receptor that contains a binding site for a neurotransmitter; activates an enzyme that begins a series of events that opens an ion channel elsewhere in the membrane of the cell when a molecule of the neurotransmitter attaches to the binding site?
Metabotropic Receptor
What is a protein coupled to a metabotropic receptor; conveys messages to other molecules when a ligand binds with and activates the receptor?
G Protein
What is a chemical produced when a G protein activates an enzyme; carries a signal that results in the opening of the ion channel or causes other events to occur in the cell?
Second Messenger
What is an excitatory depolarization of the postsynaptic membrane of a synapse caused by the liberation of a neurotransmitter by the terminal button?
Excitatory Postsynaptic Potential (EPSP)
What is an inhibitory hyperpolarization of the postsynaptic membrane of a synapse caused by the liberation of a neurotransmitter by the terminal button?
Inhibitory Postsynaptic Potential (IPSP)
What is the reentry of a neurotransmitter just liberated by a terminal button back through its membrane, thus terminating the postsynaptic potential?
Reuptake
What is the destruction of a neurotransmitter by an enzyme after its release—for example, the destruction of acetylcholine by acetylcholinesterase?
Enzymatic Deactivation
What is a neurotransmitter found in the brain, spinal cord, and parts of the peripheral nervous system; responsible for muscular contraction?
Acetylcholine (ACh)
What is the enzyme that destroys acetylcholine soon after is is liberated by the terminal buttons, thus terminating the postsynaptic potential?
Acetylcholinesterase (AChE)
What is the process by which inhibitory and excitatory postsynaptic potentials summate and control the rate of firing of a neuron?
Neural Integration
Whose experiment in 1921 provided the first proof that nerve impulses are transmitted by chemical means and earned him a Nobel Prize? In this experiment two hearts, one with an intact vagus nerve, and one without, were bathed in saline. The vagus nerve of the first heart was stimulated electrically. Then he transferred the saline from heart 1 to heart 2, which slowed without the stimulation. This demonstrated the chemical substance’s effect.
Otto Loewi
What primary neurotransmitter is secreted by the efferent axons of the central nervous system. All muscular movement is accomplished by its release and it is involved in regulating REM sleep, perceptual learning, and memory.
Acetylcholine
What is a cofactor that supplies acetate for the synthesis of acetylcholine?
Acetyl-CoA
What is the enzyme that transfers the acetate ion from acetyl coenzyme A to choline, producing the neurotransmitter acetylcholine?
Choline acetyltransferase (ChAT)
What does the black widow spider produce that triggers the release of acetylcholine?
Venom