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82 Cards in this Set
- Front
- Back
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What is the function of nervous tissue? |
Nervous Tissues * Nervous tissue functions to conductmessages throughout the body. * When nerve cells are stimulated, an electricalsignal quickly travels through the nerve cell tothe nerve ending, triggering events |
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What elements of the body are included in nervous tissue? |
Includes nerve tissue and sense organs |
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What are the functions of the nervous system? |
Nervous system functions to: *Senses environment - receives information from both outside and inside the body *Processes the information it receives *Responds to information |
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What are the two parts of the nervous system and what is included in them? |
1. Central Nervous System *brain and spinal cord 2. Peripheral Nervous System (PNS) *Nervous tissue outside the brain and spinal cord *sense organs |
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What are the two types of nervous system cells and what are their functions? |
Two types of nervous tissue cells: 1. Neurons - the cells that are responsible for transmitting messages 2. Neuroglia cells - cells that support the neurons |
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What is the function of neurons? |
they are the cells that are responsible for transmitting messages |
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What is the function of neuroglia cells? |
they are the cells that support the neurons |
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Name the types of neuroglia cells and describe their functions. |
Neuroglia cells: *microglial - immune system cells, engulf bacteria and cellular debris *Astrocytes - provide nutrients to neurons *Oligodenrocytes and Schwann cells - form myelin sheaths |
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Picture of a neuron and neuroglial cell |
Picture of neuron |
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Name the three main parts of a neuron and describe the function of each one. |
Parts of a neuron: 1. Cell body - contains the nucleus, main body of the cell 2. Dendrites - projections from the cell body that carry messages TO the cell body 3. Axons - one large projection that carry messages AWAY from the cell body. |
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What are the neurons of the Peripheral Nervous System and what is the function of each? |
Neurons of the Peripheral Nervous System 1. Neurons in the PNS are either carrying messages to or from the CNS 2. Afferent = Sensory neurons = Neurons carrying messages TO the CNS. 3. Efferent = Motor neurons = Neurons carrying messages FROM the CNS. |
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What are afferent neurons and what do they do? |
Afferent neurons are sensory neurons. They carry messages to the CNS (away from the sensation - i.e. touching a burning candle) |
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What are efferent neurons? |
Efferent neurons are motor neurons. The carry messages from the CNS (tell a muscle to pull back after touching a hot candle) |
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Where are interneurons in the Central Nervous System located and what to they do? |
Interneurons are located between the sensory and motor neurons WITHIN the CNS. Interneurons integrate and interpret sensory signals. |
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Where are sensory neurons located? |
Sensory (or afferent neurons) neurons cell bodies are located in the dorsal root ganglion. |
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Picture of sensory neurons |
Find picture |
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Where are motor (efferent) neurons located? |
Motor (efferent) neuron cell bodies are located in the gray matter of the spinal cord. Their axons leave the CNS and go to the skeletal muscles. |
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The cell bodies of these neurons are located in the root ganglia. |
Sensory (afferent) neurons |
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These neuroglia cells provide nutrients to neurons. |
astrocytes |
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What are the projections of the neuron cell body that carry messages to the cell body? |
Dendrites |
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Which type of neuron (efferent or afferent) would alert the brain that you have touched a hot body? |
Afferent |
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What are myelinated neurons, where are they located and what is their function? |
Myelinated neurons * Neurons that have axons covered withneuroglial cells that contain the protein myelinare called myelinated neurons * Myelinated neurons are able to carry messagesfaster than non-myelinated neurons |
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What is a benefit of myelinated neurons over non-myelinated neurons? |
Myelinated neurons are able to carry messages faster than non-myelinated neurons. |
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What is the main function and benefit of myelinated sheaths? |
Functions of Myelin Sheaths * The main benefit of myelin sheaths is thatmyelinated neurons are able to carry messages faster than non-myelinated neurons * Myelin sheaths from Schwann cells also help regenerate injured PNS neuron axons |
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What are the two types of cells that myelinated neurons? |
*Schwann cells and Oligodendrocytes are wrapped around neuronal axons. |
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What are Schwann cells? |
Schwann cells are myelinated neurons that are found in the PNS. |
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What are oligodendrocytes? |
Oligodendrocytes are myelinated neurons that are found in the CNS. |
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What are Nodes of Ranvier? |
Nodes are Ranvier are spaces on the axon between glial cells (myelinated cells only?). |
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Picture of myelinated neurons |
Find picture |
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Picture of myelin sheath |
Find picture |
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What causes Multiple Sclerosis (MS)? |
Multiple Sclerosis (MS) * Caused by the destruction of the myelinsheath that surrounds axons found in theCNS *Can result in paralysis and loss ofsensation, including loss of vision |
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What is a nerve? |
Nerve contain neuron axons that are bundles together |
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What three structures does a nerve bundle contain? |
1. Axons 2. Blood vessels 3. Connective tissue |
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Picture of a nerve |
Find picture |
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An ion is an atom that has gained or lost a ____ |
electron |
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What are the two ways an ion can pass through a membrane? |
1. Facilitated diffusion 2. Active transport (not simple diffusion) |
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What is a nerve impulse? |
The Nerve Impulse Is an ElectrochemicalSignal *A nerve impulse, or action potential, involvessodium ions (Na+) and potassium ions (K+)that cross the cell membrane through the ionchannels * Each ion channel is designed to allow onlycertain ions to pass through |
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A nerve impulse is also an _______ _________ |
action potential |
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What two ions are involved in a nerve impulse? How do they cross the cell membrane? |
1. Sodium ions (Na+) 2. Potassium ions (K+) they cross the cell membrane through ion channels |
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True or false: Each ion channel is designed to allow only certain ions to pass through |
True |
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Does active transport go with or again the concentration gradient? |
Against |
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Does facilitated diffusion go with or against the concentration gradient? |
Facilitated diffusion goes with the concentration gradient |
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What is membrane potential? |
The difference in charge between the inside and outside of the neuron is the membrane potential. |
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What is important to remember about membrane resting potential? |
Resting Membrane Potential * A neuron that is not conducting a message issaid to be “Resting” * When a neuron is resting there is moresodium (Na+) outside the neuron cell andmore potassium (K+) inside the cell * The inside of the cell has a negative chargecompared to the outside the cell |
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When a neuron is in resting potential is it conducting messages? |
No. a neuron that is not conducting a message is said to be "resting" |
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When a neuron is resting is there more sodium (Na+) inside or outside the cell? |
When the neuron is resting there is more sodium (Na+) outside the neuron cell. |
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When a neuron is resting is there more potassium (K+) inside or outside the neuron cell? |
When a neuron is resting there is more potassium (K+) inside the cell. |
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When a neuron is resting is the inside our the outside of the cell ore negatively charged? |
Inside of the cell |
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What does the sodium potassium pump do? |
Sodium Potassium Pump * To maintain this resting membrane potentialthe neuron pumps Na+ out of the cell and K+into the cell. * The transport proteins take 3 Na+ ions out forevery 2 K+ ions into the cell = Na+/K+ pump * This is Active Transport – requiring ATP |
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What is action potential? |
Action Potential * An electrochemical signal conducted alongan axon. It is a wave of depolarizationfollowed by repolarization * Depolarization is caused by sodium ionsentering the axon * Repolarization is caused by potassiumions leaving axon |
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What is the first step of the action potential? |
1. The axon is depolarized when voltage gatedsodium ion channels open and Na+ comesrushing in, causing the inside of the neuron tobecome positively charged |
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During depolarization what ion comes rushing in and does the inside of the neuron become more negatively or positively charged? |
During depolarization,Na+ (sodium) comes rushing into the neuron cell and the inside becomes positively charged. Depolarization begins when the voltage gated sodium channels open. |
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What is the second step in the action potential? |
2. The axon is repolarized when voltage gatedpotassium ion channels open up and allow K+to go out of the axon * This returns the membrane potential to benegative on the inside of the neuron * The action potential travels down the axon |
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During repolarization, what ion leaves the inside of the neuron and why? |
During repolarization, K+ (potassium) leaves the cell when the voltage gated potassium ion channels open. This returns the neuron cell back to mostly negative on the inside. |
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What happens after Repolarization (the action potential)? |
After the action potential, the sodiumpotassium pump restores the originalconditions by pumping sodium (Na+) out ofthe cell and potassium (K+) back into the cell Copyright © 2009 Pearson Education, Inc. The Nerve Impulse Copyright © 2009 Pearson Education, Inc. Figure 7.5 (4 of 4) |
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Good chart of nerve impulse |
Biology book |
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What is the refractory period after the action potential? |
Action Potentials * The direction is always one way down theaxon. The sodium channels areinactivated for awhile after the actionpotential passes = refractory period. |
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Does an action potential always take place? |
No. It is an all or nothing response – if it is nota great enough stimulation the channelswon’t open. The level of the actionpotential is always the same. |
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When a neuron is resting, sodium ions have a greater concentration: a. inside the cell b. outside the cell c. concentration is the same |
b. outside the cell |
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When a neuron is depolarizing, which ions come into the neuron? a. calcium (Ca++) b. sodium ((Na+) c. potassium (K+) d. chlorine (Cl-) |
b. sodium (Na+) |
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When a neuron is depolarizing, the inside of the neuron cell becomes: a. positively charged b. negatively charged |
a. positively charged |
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How are messages passed from one nerve to the next or from the nerve to a muscle> |
Nerve Synapse The junction between two neurons orbetween a neuron and a muscle is called asynapse |
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What is a nerve synapse? |
The junction between two neurons or between a neuron and a muscle is called a synapse. |
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What are the three components of a synapse? |
Components of the Synapse 1. Presynaptic neuron is the transmittingneuron
2.Postsynaptic neuron is the receiving neuronor the muscle 3. And the gap in between them = synapticcleft |
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The the presynaptic neuron transmit or receive? |
Transmit |
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Presynaptic neurons contain synaptic vesicles that contain __________? |
neurotransmitters |
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Good picture of a synaptic transmission |
Textbook (figure 7.8) |
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What are the steps of transmission across the synaptic cleft? |
1. The action potential gets to the end of thepresynaptic axon 2. The action potential triggers Ca2+ to enterthe presynaptic axon terminal 3. The Ca2+ triggers synaptic vesicles locatedat the axon terminal to merge with theneural membrane 4. The synaptic vesicles release theneurotransmitters into the synaptic cleft 5. These neurotransmitters travel across thesynaptic cleft to the postsynaptic neuron(or the muscle) 6. Neurotransmitter binds to receptors on thepostsynaptic neuron (or muscle) 7. These receptors are ligand gated sodium ionchannels which allow Na+ to enter thepostsynaptic neuron (or muscle) and triggersan action potential in the postsynaptic neuron(or muscle contraction) 8. Once the neurotransmitters are released theyneed to be destroyed or contained quickly orthey will continue to stimulate the nerve Copyright © 2009 Pearson Education, Inc. Synapse PLAY Animation—The Synapse |
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What is acetylcholine? |
Acetylcholine 1* Acts in both the PNS and the CNS as aneurotransmitter * Causes voluntary muscles to contract * Acetylcholinesterase |
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What is myasthenia gravis? |
Myasthenia gravis is an autoimmunedisease that attacks the acetylcholinereceptors, resulting in reduced musclestrength |
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What is the function of a neurotransmitter? |
When a nerve impulse reaches the end of an axon, the message must jump across a small gap to the next cell. A chemical called a neurotransmitter is released from the axon's tip and diffuses across the gap to relay the message. |
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How do neurotransmitters work? |
1.When the nerve impulse reaches the end of the presynaptic neuron, the synaptic knob release packets of neurotransmitters in a tiny sac called a synaptic vesicle. 2. Calcium ions are released causing the membranes of the synaptic vesicles to fuse with the plasma membrane. 3. The neurotransmitter is dumped into the synaptic cleft 4. the neurotransmitter diffuses across the synaptic cleft and binds with receptors on the membrane of the post synaptic membrane. A receptor is a protein that recognizes a particular neurotransmitter. therefore only certain neurons can be affected by a given transmitter. ("Like a key in a lock") When the neurotransmitter binds with the receptor an ion channel is opened. *See textbook p. 119 |
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Where do neurotransmitters work? |
They are a chemical released from the synaptic knob into tiny synaptic vesicles. They merge with the plasma membrane and then enter the synaptic cleft. They then bind with receptors of the postsynaptic neuron. An ion channel is opened on the postsynaptic neuron. |
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What ions are involved with neurotransmitters and how do they work? |
Calcium ions are involved. *When the nerve impulse reaches the synaptic know, gates of calcium ion channels open. Calcium ions move into the knob, causing the membranes of the sync[tic vesicles to fuse with the plasma membrane. |
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What is the synaptic cleft? |
The gap between the cells (in relationship to the synapse vocabulary) |
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What is the synaptic knob? |
The end of the axon branch that is a small bulblike swelling. (*Note the neuron sending the message to the synaptic knob is the presynaptic neuron ("before the synapse) and the neuron receiving the message is the postsynaptic neuron ("after the synapse") |
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What is an excitatory synapse? |
The excitatory synapse is one where the binding of the neurotransmitter to the receptor opens sodium channels allowing sodium ions to enter and increasing chances if an action potential. |
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what is an inhibitory synapse? |
An inhibitory synapse is when the binding of the neurotransmitter opens different ion channels, which decreases the likelihood that an action potential will take place in the postsynaptic neuron (the cell's interior becomes more negatively charged than usual). |
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What is summation? |
The combined effects of the excitatory and inhibitory effects on a neuron at any given moment determines whether an action potential will take place. |
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Do neurotransmitters stay around after being released into the synapse? |
No, they are quickly removed so their effects are temporary (so they do not keep exciting or inhibiting responses). |
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What is acetylcholinesterase? |
Find answer |
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What are ligand gated channels? |
Find answer |
