Chapter 7 Flashcards
The nervous system is divided into the what two parts?
Central Nervous System and Peripheral Nervous System
The central nervous system includes the ____ and _____.
Brain and spinal cord
The peripheral nervous system includes the _____ and ______.
Cranial and spinal nerves
The nervous system consists of what two kinds of cells?
Neurons and Supporting cells (glial cells)
Of the two cells in the nervous system, which one is a functional unit of the nervous system.
Neurons
Of the two cells in the nervous system, which one maintains homeostasis?
Glial cells
Of the two cells in the nervous system, which is 5 times more common than the other?
Glial cells
What gathers and transmits information by responding to stimuli, producing and sending electrochemical impulses, and releasing chemical messages?
Neurons
What contains a cell body, dendrites, and axons?
Neurons
In the neuron, what contains the nucleus?
Cell body
The ______ is the nutritional center and makes macromolecules.
Cell Body
Groups of cell bodies in the central nervous system are called what?
Nuclei
Groups of cell bodies in the peripheral nervous system are called what?
Ganglia
The _____ are what receive the information and convey it to the cell body.
Dendrites
The _____ are what conduct impulses away from the cell body.
Axons
The _____ is what moves soluble compounds toward the nerve endings via the rhythmic contraction of axon.
Axoplasmic flow
The _____ moves large and insoluble compounds bidirectionally along microtubules very fast.
Axonal transport
The _______ moves materials away from the cell body.
Anterograde transport
The anterograde transport moves materials away from the cell body using the molecular motor _____.
Kinesin
The _______ moves materials towards the cell body.
Retrograde transport
The retrograde transport moves materials toward the cell body using the molecular motor _____.
Dynein
Which transport can viruses and toxins enter the CNS?
Retrograde transport
The _______ neurons conduct impulses into the CNS.
Sensory/ Afferent
The _______ neurons carry impulses out of the CNS.
Motor/ Efferent
The _______ neurons integrate the nervous system activity, and is located entirely inside the CNS.
Association/ Interneurons
In the structural classification neuron ________, the cell body site along side of the single process. Example is a sensory neuron.
Pseudounipolar
In the structural classification neuron ______, there is one dendrite and one axon that arises from opposite ends of the cell body. Example is a retinal neuron.
Bipolar
In the structural classification neuron _____, there are many dendrites and one axon. Example is motor neurons.
Multipolar
What are the two supporting cells in the PNS?
Schwann and satellite cells
Of the two supporting cells in the PNS, which one myelinates the PNS axons?
Schwann cells
What are the four supporting cells in the CNS?
Oligodendrocytes, microglia, astrocytes, and ependymal cells
Of the supporting cells in the CNS, which one myelinates several CNS axons?
Oligodendrocytes
Of the supporting cells in the CNS, which one appears to be neural stem cells?
Ependymal cells
In the PNS, each Schwann cell myelinates _____ of 1 axon by wrapping round and round the axon.
1 mm
What is the purpose of the Schwann cells myelinating the axon?
Electrically insulates the axon
The uninsulated gap between adjacent Schwann cells are called the _______.
Node of Ranvier
Axon regeneration occurs much more readily in which of the two nervous systems?
PNS
Oligodendrocytes produce ____ that inhibit regrowth.
Proteins
Oligodendrocytes form glial scar tissue that blocks _______.
Regrowth
When an axon in the PNS is severed, the distal part of the axon _______.
Degenerates
When an axon in the PNS is severed, the Schwann cells survive and form _______.
Regeneration Tubes
When the Schwann cells survive the axon being severed, the regeneration tubs releases chemicals that ________.
Attract growing axon
Where does the regeneration tube of the Schwann cells guide regrowing axons?
To the synaptic site
What promotes fetal nerve growth, is required for survival of many adult neurons, and is important in regeneration?
Neurotrophins
What is the most common glial cell?
Astrocytes
Which supporting cell is involved in buffering K+ levels, recycling neurotransmitters, regulating adult neurogenesis, and releasing transmitters that regulate neuronal activity?
Astrocytes
The ______ allows only certain compounds to enter the brain.
Blood Brain Barrier
The blood brain barrier appears to be induced by _____.
Astrocytes
In the Resting Membrane Potential, at rest Na+/K+ pump and limited permeability keep _____ high outside the cell.
K+
In the Resting Membrane Potential, at rest ____ is very permeable and is high inside the cell. This is attracted by negative charges inside the cell.
K+
_______ can discharge their RMP quickly by rapid changes in permeability to ions, and neurons and muscles do this to generate and conduct impulses, therefore muscles and nerve cells are considered excitable.
Excitable Cells
Membrane potential is measured by placing 1 electrode _______ and 1 ______.
Inside the cell and outside the cell
______ occurs when membrane potential becomes more positive.
Depolarization
________ in the membrane potential becomes more negative than resting membrane potential.
Hyperpolarization
______ is when the membrane potential returns to resting membrane potential.
Repolarization
Membrane potential occurs by ion flow through ______. Some are normally opened and some closed.
Membrane channels
_____ leakage channels are always open in the membrane ion channels.
K+
Closed channels have ______ that can be opened.
Molecular gates
Voltage gated channels are opened by _______.
Depolarization.
Voltage gated _____ and ____channels are closed in resting cells.
K+ and Na+
The RMP is determined to be ____ in most neurons.
-70mV
A nucleus is a group of _____ in the CNS.
Somas
A _____ neuron has two processes, one at either end of the soma.
Bipolar
Each Schwann cell wraps only about ____ of axon, leaving gaps of exposed axon between the adjacent Schwann cells.
A millimeter
Another name for an association neuron is an ______.
Interneuron
An ______ is a wave of membrane potential change that sweeps along the axon from some to synapse.
Action Potential
The wave in an action potential is formed by rapid depolarization of the membrane by Na+ ____ and followed by rapid repolarization by K+ _____.
Influx; Efflux
The wave in an action potential is formed by rapid depolarization of the membrane by Na+ ____ and followed by rapid repolarization by K+ _____.
Influx; Efflux
In the mechanism of action potential, in _________ at threshold VG Na+ channels open, Na+ is driven inward by its electrochemical gradient, and causes rapid change in MP from -70 to +30 mV.
Depolarization
In the mechanism of action potential, in _____ VG Na+ channels close while VG K+ channels open, electrochemical gradient drives K+ outward, and repolarizes axon back to RMP.
Repolarization
Depolarization and repolarization occur via ______.
Diffusion
_______ and ______ do not require active transport, and after an action potential Na+/K+ pump extrudes Na+, recovers K+.
Depolarization and repolarization
When a membrane potential reaches threshold, an ______ is irreversibly fired.
Action potential
The reason there is an irreversibly fire back in the action potential is because positive feedback opens more and more _______ channels.
Na+
Shortly after the Na+ channels open, the Na+ channels close and become inactivated until _______.
Repolarization
The increased stimulus intensity causes more _______ to be fired. The size remains constant.
Action Potentials
______ refractory period is when the membrane cannot produce another action potential because Na+ channels are inactivated.
Absolute
_____ refractory period occurs when VG K+ channels are open, making it harder to depolarize to threshold.
Relative
______ refer to how axons properties affect its ability to conduct currents.
Cable Properties
Cable properties includes high resistance of ______. The resistance decreases as axons diameter increases.
Cytoplasm
In cable properties, the current leaks out through _____.
Ion channels
When conduction is an unmyelinated axon, an ______ reaches threshold and fires AP, its Na+ influx depolarizes adjacent regions to threshold.
Axon Hillock
When the conduction is a myelinated axon, ____ cant flow across the myelinated membrane, thus no AP’s occur under myelin and no current leaks which increases the current speed.
Ions
A _____ is a functional connection between a neuron (presynaptic) and another cell (postsynaptic).
Synapse
What are the two different kinds of synapses?
Chemical and electrical
Synaptic transmission at chemical synapses is vis ______.
Neurotransmitters
Which synapse is rare in the nervous system?
Electrical synapses
In an electrical synapse, depolarization flows from presynaptic into postsynaptic cell through channels called _______.
Gap junctions
The gap junctions in an electrical synapse are formed by ______ proteins that are found in smooth and cardiac muscles, brain, and glial cells.
Connexin
The synaptic cleft separates the ______ of the presynaptic from the postsynaptic cell.
Terminal Bouton
Neurotransmitters in the chemical synapse are located in the _______.
Synaptic Vesicles
The vesicles fuse with the terminal bouton membrane that release neurotransmitters by ____.
Exocytosis
The amount of neurotransmitters released in a chemical synapse depends upon the frequency of ________.
Action Potentials
The AP gets smaller as it travels down the membrane. T/F
False
All parts of the neuron membrane are capable of carrying action potentials.
False
The word “saltatory” comes from the Latin word “to climb” and refers to the depolarization phase of the action potential.
False
In a synaptic transmission, the AP’s travel down the axon to depolarize the ______.
Terminal Bouton
In a neurotransmitter release, action potentials reach the axon terminal and Ca2+ enters the axon terminal via ________.
Voltage Gated Channels
When neurotransmitters are release, the Ca2+ binds to sensor proteins in the ______.
Cytoplasm
Neurotransmitters are released from the vesicles into the ______.
Synapse
In the synaptic transmission, the neurotransmitter diffuses across the cleft and binds to receptor proteins on the _______ membrane, opening ligand or chemically regulated ion channels.
Postsynaptic
In the synaptic transmission, ______ channels cause EPSP’s.
Depolarizing
In the synaptic transmission, _____ channels cause IPSP’s.
Hyperpolarizing
If a membrane potential in the postsynaptic cell reaches threshold at the ______, a new action potential is generated.
Axon Hillock
What is the most widely occurring neurotransmitter?
Acetylcholine
Acetylcholine is found in the ____ and ____, and also occurs at all neuromuscular junctions.
Brain and ANS
Acetylcholine has ____ and ______ receptor subtypes that can be excitatory or inhibitory.
Nicotinic and Muscarinic
________ channels contain both a NT receptor site and an ion channel, and opens when ligand (NT) binds.
Ligand Gated
A nicotinic ACh Channel is formed by 5 ______ subunits.
Polypeptide
In a G-protein coupled channel, _____ receptors are not part of the ion channel.
NT
______ ACh channels are the binding of 1 ACh activates G-protein cascade which affects gated K+ channels.
Muscarinic
In the muscarinic ACh channel, the opening of channels causes ______.
Hyperpolarization
In the muscarinic ACh channel, the closing of channels causes ______.
Depolarization
______ inactivates ACh, by terminating its actions and is located in the cleft.
Acetylcholinesterase
_____ neurons use acetylcholine as NT.
Cholinergic
The large synapses on skeletal muscles are called _____.
Neuromuscular junctions
What blocks the ACh action at neuromuscular junctions?
Curare
Monoamine NT’s include serotonin, norepinephrine, epinephrine, and _____.
Dopamine
Serotonin is derived from _________.
Trytophan
Norepinephrine and epinephrine are derived from ______.
Tyrosine
Histamine is derived from an _______.
Amino acid
_______ is involved in regulation of mood, behavior, appetite, and cerebral circulation.
Serotonin
What are the two major dopamine systems in the brain?
Nigrostriatal and Mesolimbic
Nigrostriatal dopamine system originates in the __________ and is involved in motor control.
Substantia nigra
The mesolimbic dopamine system is involved in ____ and emotional reward.
Behavior
Of the two dopamine systems in the brain, which one is activated do to addictions?
Mesolimbic
Glutamic acid and aspartic acid are major _____ excitatory NT’s.
CNS
Glycine is an ______ NT.
Inhibitory
_______ is the most common NT in the brain.
GABA
Endorphins, enkephalins, and dynorphins are endogenous ____ NT’s.
Opioid
Neuropeptide ____ is the most common neuropeptide. It inhibits glutamate in the hippocampus, and has a powerful stimulator of appetite.
Y
______ are the only lipid NT’s.
Endocannabinoids
NO and CO are _____ NT’s.
Gaseous
_______ are graded in magnitude, have no threshold, cause depolarization, summate, and have no refractory period.
EPSP’s
_________ takes place when EPSP’s from different synapses occur in postsynaptic cells at the same time.
Spatial Summation
________ occurs because EPSP’s that occur closely in time can sum before they fade.
Temporal Summation
________ occurs when 1 neuron synapses onto an axon or bouton of another neuron, inhibiting release of it NT.
Presynaptic Inhibition
