Bio test 3- Top hat &quizzes
Cocaine had which of the following effects as a synapse?
- Blocks dopamine reuptake
Interneuron
- Relays information along the CNS pathway
The cause of multiple sclerosis is unknown, but it damages and destroys oligodendrocytes.
- The afferent pathway may not be processed correctly - Motor information may not reach the intended effectors - Action potential would travel slower or not at all
Three main types of neurons
- sensory(afferent) neuron - interneuron - Motor(efferent) neuron
Which of the following neuroglia cells help make the blood brain barrier?
Astrocytes
During the depolarization phase of neuronal action potential, voltage gated sodium channels are ___ and voltage gated potassium channels are_____
Open; closed
Neurons communicate strength of signal by changing the frequency of fired action potentials
TRUE
Your Aunt Selena is very considered about her wrinkles. Though you try assuring her that wrinkles are beautiful and are a sign of a life well lived, your aunt decides to get a botox treatment. How does botox work?
The botulinum neurotoxin from Claustridum botulinum is injected into skeletal muscle. Botulinum is endocytosed into the motor neuron and it cleaves the SNARE proteins. Because SNARE proteins have been destroyed, vesicles containing neurotransmitters can not dock and fuse, and no neurotransmitters are released. This then prevents muscle contraction and the skeletal muscle relaxes and softens, and wrinkles are minimized.
Which ion channel type opens in response to charges in membrane potential?
voltage-gated channels
6 types of neurogilia (glial cells) in nervous system
- Astrocytes - Microglia - Oligodendrocytes - Ependymal cells - Satellite cells - Schwann cells
Motor(efferent) neuron
- Communicates "efforts" to effector tissue
Grading potentials occurs in the dendrites and cell bodies of neurons. If the graded potential caused the membrane potential of the cell to approach threshold, it is considered a_____
- Depolarization
The neurotransmitter binds to its receptor on a postsynaptic neuron and causes the opening of a NA+ channel. sodium ions___ the neuron, resulting in an ___
- Enter; EPSP
Sensory(afferent) neuron
- Gathers info from internal and external env't and sends it to the CNS for processing
Grading potentials occur in the dendrites and cell bodies of neurons. If the grading potential causes the membrane potential of the cell to become more negative, it is considered a______
- Hyperpolarization
During the repolarization phase of a neuronal action potential, voltage-gated sodium channels are_______and voltage-gated potassium channels are___
- Inactivated; open
Statements about myelin
- Increases transmission speed of an action potential - Electrically insulates fibers - Sheaths are made of mostly lipids - Exclusively located on axons
Astrocytes
- Located: Central Nervous System - Function: Helps maintain proper extracellular env't; helps establish blood brain; guides migrating neurons during dev'
Ependymal cells:
- Located: Central Nervous System - Function: Lines the wall of the ventricles; help make cerebrospinal fluid
Microglia:
- Located: Central Nervous System - Function: Specialized white blood cells that help protect the brain and spinal cord from pathogens
Oligodendrocytes:
- Located: Central Nervous System - Function: Wraps myelin around the axons of neurons in the CNS
Satellite cells:
- Located: Peripheral Nervous System - Function: Wraps around the cell body of neurons in the peripheral nervous system and helps maintain proper extracellular env't
Schwann cells:
- Located: Peripheral Nervous System - Function: Wraps myelin around the axons of peripheral nervous system neurons
The depolarization phase of an action potential is due to the ___of voltage gated sodium channels
- Opening
The repolarization phase of an action potential is due to the ___of voltage gated K+ channels
- Opening
G protein receptors (GPCR) interact with G proteins in the plasma membrane when a external signal molecule binds to a GPCR it causes a comforter missional charge in the GPCR. This exchange when triggers the interaction between the GPCR and the nearby G protein what happens next
- The activated G protein opens an ion channel - Enzymes are activated - Second-messenger is produced
When the action potential arrives at the axon terminal, it causes opening of ______
- Voltage gated calcium channels
During a relative refractory period of an action potential
- another action potential can be fired, but it takes a greater stimulus for the membrane potential to reach threshold
work increase is spread of action potential propagation down the axon
- myelination - increased axon diameter
Two types of postsynaptic potentials are _____ postsynaptic potentials and _____ postsynaptic potentials.
-excitatory>in -inhibitory>away
The speed at which axons conduct/propagate action potentials down their axon vary dependingon the anatomy (structure) of each axon. The two main factors that influence speed of actionpotential propagation are:_____ and _____. Axons with myelinationand/or a large diameter conduct action potentials ______ quickly than axons without myelination and/or with a small axonal diameter. In the CNS, _______produce myelin whereas in the Peripheral Nervous System, myelin is produced by ______ spaces between myelin are called ______. When an action potential seemingly"jumps" from node to node, it is called ______ conduction.
-myelination -axonal diameter -more -oligodendrocytes -Schwann cells -nodes of ranvier -saltatory
Which of the following is/are true of myelination?
-the spaces between myelination are called "nodes of ranvier" -myelination protects and electrically insulates axons -myelination increases speed of action potential propogation
Arrange the steps in proper order from first (1) to last (5.)
1. Action potential is generated at the axon hillock and propagates down the axon to the axon terminal 2. Action potential arrives at axon terminal and causes opening of voltage-gated calcium channels 3. Calcium flows into the cell the the open voltage gated calcium channels 4. Calcium causes neurotransmitter-filled synaptic vesicles to dock and fuse with the plasma membrane thereby exocytosing the neurotransmitter 5. Neurotransmitter diffuses across the synapse and binds to ligand-receptors on the postsynaptic neuron
Rearrange the following items to describe the proper steps in an action potential, from start to finish.
1. The membrane potential of the neuron shifts from resting membrane potential to threshold. 2. Voltage-gated Na+ channels open. 3. Na+ rushes into the cell and the cell depolarizes. 4. Voltage-gated Na+ channels inactivate. Voltage-gated K+ channels open. 5. K+ ions flow out of the neuron and the neuron repolarizes. 6. Voltage-gated K+ channels stay open beyond the resting membrane potential and the neuron hyperpolarizes. 7. Pumps return the neuron back to resting membrane potential.
Let's say a presynaptic neuron releases into the synaptic cleft the neurotransmitter acetylcholine (ACh). The postsynaptic neuron may have either a Nicotinic ACh Receptor or a Muscarinic ACh Receptor on its plasma membrane to which acetylcholine can bind. Which of the following below matchs the mechanism of the Muscarinic ACh Receptor?
ACh binds to MAChR, which activated the G Protein, which travels intracellularly along the membrane and causes opening of the voltage gated K+ channels; Is a G Protein Coupled Receptor (GPCR); Usually creates a IPSP when ACh binds.
Let's say a presynaptic neuron releases into the synaptic cleft the neurotransmitter acetylcholine (ACh). The postsynaptic neuron may have either a Nicotinic ACh Receptor or a Muscarinic ACh Receptor on its plasma membrane to which acetylcholine can bind. Which of the following below matchs the mechanism of the Nicotinic ACh Receptor?
ACh binds to NAChR and causes opening of sodium channels (on receptor channel) and sodium flows into the cell; Is a Direct Ligand Gated Receptor; Creates an EPSP when ACh binds.
When a monoamine binds to the receptor, it activates a G protein. The G protein then...
Activates the enzyme Adenylate Cyclase, which converts ATP into cAMP. cAMP then goes on to produce a myriad of effects.
The kinetics of voltage-gated potassium channels mandate that they open and close in a proper order. Which of the following properly illustrates the kinetics of voltage-gated potassium channels.
At rest, voltage-gated potassium channels are closed. During the depolarization phase of the action potential, voltage-gated potassium channels are closed. At the peak of the action potential, voltage-gated potassium channels open. Because voltage-gated potassium channels are slow-acting, it takes a long time for them to close, so they stay open well into the hyperpolarization phase.
The kinetics of voltage-gated sodium channels mandate that they open/close/inactive in a proper order. Which of the following properly illustrates the kinetics of voltage-gated sodium channels.
At rest, voltage-gated sodium channels are closed. During the depolarization phase of the action potential, voltage-gated sodium channels are open. At the peak of the action potential, voltage-gated sodium channels inactivate. These channels MUST close again before reopening.
Postsynaptic potentials are:
Changes in membrane potential of the postsynaptic neuron in response to a neurotransmitter binding to a receptor on the postsynaptic neuron.
during the hyperpolarization phase of a neuronal action potential, voltage-gated sodium channels are____ and voltage-gated potassium channels are____
Closed; open
You are doing your Masters work in a neuroscience lab and are measuring the restingmembrane potential of a neuron (you have one recording electrode on the inside of the neuron,and one "grounded" in the extracellular fluid). The membrane potential slightly deviates frombaseline RMP. If the membrane potential becomes more positive, this is called________ and if the membrane potential becomes more negative, this is called _________
Depolarization & Hyperpolarization
Which of the following influences the speed of action potential propogation?
Diameter of an axon Myelination
Cerebrospinal fluid flows through the ventricles of the brain and supplies nutrients to the brain while also offering the brain buoyancy. Which of the following neuroglia cells help make cerebrospinal fluid?
Ependymal cells
Neurons communicate strength of signal by altering the amplitude of action potential deflection.
False
Voltage-gated Na+ channels and voltage-gated K+ channels do not exist within the axon terminal. Instead, the axon terminal has voltage-gated Cl- channels.
False
Muscarinic acetylcholine receptors are _________ receptors that cause the opening of ________.
G protein coupled; K+ channels
Binding of acetylcholine to nicotinic acetylcholine receptors results in ____
IPSPs
Multiple Sclerosis:
Is an autoimmune disease in which one's own immune system attacks the myelin sheaths, causing them to become sclerotic (hard) and then non-functional.
Ion channels are in bedded in the plasma membrane and when open allow current(ions) to flow(diffuse) across the plasma membrane----going in or out. Ion channels matched with the proper stimulus that causes each channel type to open Leak channel: Mechanically gated ion channel: Ligand gated ion channel: Voltage gated Ion Channel:
Leak channel: Always open Mechanically gated ion channel: Physical stimuli such as touch & pressure & temp ect. Ligand gated ion channel: Ligands (chemicals) binding to receptor Voltage gated Ion Channel: Changes in voltage/charge
These neurogilia are specialized white blood cells that reside in the nervous system and offer protection against pathogens that have gained access to neural tissue.
Microglia
These no Julia are specialized white blood cells that reside in the nervous system and offer protection against pathogens and that have gained access to natural tissue
Microglia
One of the ~100 billion neurons in your brain fires an action potential. During the repolarization phase of that action potential, while the voltage-gated sodium channels are still inactivated, your neuron decides it wants to fire another action potential. Can it do so? Why or why not?
No. The neuron is in absolute refractory period, so no additional action potentials can be fired.
The separation of charge across the plasma membrane is known as Membrane Potential. Our neurons are excitable cells, meaning, they respond to the environment by changing the distribution of ions across their plasma membrane, in other words, by changing their membrane potential. Neurons can therefore experience 3 different states of membrane potentials— Resting Membrane Potential: Graded Potentials: Action Potentials:
RMP: separation of charge across the plasma membrane when the cell is at rest. GP: Separation of charge across the membrane when small localized charges occur in the dendrites and cell body AP: Separation of charge across the membrane(in the axon) when the neuron is firing an acton potential.
The separation of charge across the plasma membrane is called membrane potential. because neurons are excitable, they respond to their environment by changing their membrane potential. The three states a member potential Resting membrane Potential: Graded Potential: Action Potential:
Resting membrane Potential: Separation of charge across the membrane while cell is at rest. Graded Potential: Separation of charge across the membrane when small, localized changes occur in the dendrites and cell body. Action Potential: Separation of charge across the membrane (specifically in the axon) When the neuron is firing an action potential
which of the following neuroglia functions to help maintain the proper extracellular environment so the neurons can properly function in the PNS.
Satellite cells
In this branch of the nervous system in active during times of stress and its commonly referred to as "fight or flight"
Sympathetic nervous system
For a given neuron, every action potential (AP) that gets fired is of the same amplitude
TRUE
The greater the stimulus, the more action potentials get fired per unit of time; the weaker the stimulus, the fewer action potentials get fired per unit of time
TRUE
An unknown neurotransmitter is released from a presynaptic vesicle and binds to receptors on the postsynaptic membrane. When the neurotransmitter binds, it causes Cl- channels to open and Cl- flows into the postsynaptic neuron. What happens to the postsynaptic membrane?
The inside of the cell becomes more negative
When a presynaptic neuron synapses on the axon of a postsynaptic neuron, it is called:
axoaxonic synapse
Postsynaptic neurons typically don't receive just one presynaptic input, rather, most neurons have anywhere from 1000-10000 different presynaptic inputs, many firing all at the same time. It is up to the postsynaptic neuron to add together all of the inputs (excitatory and inhibitory ) and decide whether or not to fire an action potential. This process is known as _______ and occurs at the axon hillock.
??summation>temporal??
In unmyelinated axons, action potentials seemingly jump from node to node, in a process called "saltatory conduction."
False
in the dentraits of the sensory neuron, opening of mechanically gated sodium channels results in the_______ of sodium and a resulting_____
Influx; depolarization
Two neurons synapse onto the dendrites of one neuron. One of these neurons is excitatory and causes EPSPs in the postsynaptic neuron and the other neuron is inhibitory and causes IPSPs in the postsynaptic neuron. If both presynaptic neurons fired at the same time, what would this cause in the postsynaptic neuron?
Ipsp/epsp cancellation
Types of summation seen at the postsynaptic neuron
Spatial summation temporal summation EPSP-IPSP cancellation
Anatomically speaking, there are three main types of neurons— unipolar: bipolar: multipolar neurons: Identify the locations of these neurons.
U: Sensory neurons B: Interneurons and special sense neurons M: motor neurons; most neurons of body
The ___division carries signals to the smooth muscle in the urinary tract.
Visceral motor
When a presynaptic neuron synapses on the cell body of a postsynaptic neuron, it is called:
axosomatic synapse
Which of the following structural classes of neurons have one dentite leading into a cell body and one long Axon coming off the cell body? these neurons are found in a special sense (taste receptors, olfactory receptors)
bipolar neurons
Monoamine oxidase (MAO)
degrades monoamine neurotransmitters
Summation occurs
in the axon hillock
An unknown neurotransmitter is released from a presynaptic vesicle and binds to receptors on the postsynaptic membrane. When the neurotransmitter binds, it causes Cl- channels to open and Cl- flows into the postsynaptic neuron. What is this change in the postsynaptic membrane potential officially called?
inhibitory postsynaptic potential
A neurotransmitter binds to it's receptor on a postsynaptic neuron and causes the opening of K+ channel. Potassium ions_____ the neuron, resulting in an____
leave; IPSP
Which ion channel type opens in response to chemicals binding to it?
ligand-gated channels
Motor neurons send information from the Central Nervous System to target organs and glands. Motor neurons can correctly be classified as which of the following?
multipolar neurons efferent neurons
during the depolarization phase of a neuronal action potential voltage gated sodium channels are _____ and voltage gated potassium channels are
open; closed
Which of the following is NOT a function of astrocytes
phagocytizes pathogens
Once a neurotransmitter binds to a ligand receptor on the postsynaptic neuron, it can cause changes/alterations in the membrane potential of the postsynaptic neuron. These changes are called______
postsynaptic potentials
Sensory neurons gather information from the external and internal environments, and send that information to the Central Nervous System for processing. Sensory neurons can also correctly be classifed as which of the following?
unipolar neurons & afferent neurons
