Neuroscience 1 - The neuron Flashcards
1
Q
Central Nervous System (CNS)
A
- The brain and the spinal cord, encased in bone
2
Q
Peripheral Nervous System
A
- Remaining nerve tissue in the body, once the nerve fibers leave the bony protection.
3
Q
Glial cells
A
- Provide structural support, nourishment, and insulation needed for neurons
- Housekeeping
4
Q
Neurons
A
- A specialized cell that transmits nerve impulse
5
Q
Efferent Nerve Fibers
A
- Fibers that carry information outward from the central nervous system to the periphery of the body.
6
Q
Afferent Nerve Fibers
A
- Fibers that carry information inward to the central nervous system fro mthe periphery of the body.
7
Q
Peripheral Nervous System is divided into two parts:
Somatic Nervous System
A
- Recieves sensory information from sensory organs (eyes, ears, etc.)
- Controls volunary movement of muscles.
8
Q
Peripheral Nervous System is divided into two parts:
Autonomic Nervous System
A
- Controls the things happening outside of our conscious awareness
EX. Smooth muscles, heart muscles, glands.
9
Q
The autonomic system can be divided yet again into two systems:
Sympathetic Division
A
- Preparing the body for emergencies aka fight or flight response
EX. Increasing heart rate, dilating pupils etc. - Releases adrenaline from the adrenal gland.
10
Q
The autonomic system can be divided yet again into two systems:
Parasympathetic System
A
- Helps the body return back to its normal function after activating the sympathetic nervous system.
- increases and conserves the body’s energy resources
EX. Slow down heart rate, lowering blood pressure etc.
11
Q
Dendrites
A
- A branched extension of neurons to receive information transmitted from another neuron.
12
Q
Axon
A
- Dedicated to passing infomation to other cells.
13
Q
Effectors
A
- An organ or cell that is capable of receiving and responding to nervous inpulse.
- nerve impulse from axon can be sent to other neurons, or cells like the muscle or glands
14
Q
Synapse
A
- The junction between neurons
- Small gap across which the stimulation from one neuron must cross to diffuse neurotrasmitter.
15
Q
Terminal boutons
A
- Found at the end of an axon, where connections to dendrites of nearby neurons are made.
16
Q
Action Potential (simple def)
A
- The change in electric potential associated with the passage of an impulse along the membrane of a neuron.
17
Q
Myelin sheath
A
- Special glial cell in the shape of fatty tissue tubes around the axon.
- Myelin also serves to speed up the conduction of the action potential along the axon.
18
Q
Sensory Neurons
A
- Transmit sensory information from the environment towards the rest of the nervous system.
EX. sound, light, taste, or touch, is gathered from the various receptors and sent inwards
19
Q
Motor Neurons
A
- Most common effector neurons
- Activates the msucles of the body, controlling movement
EX. A nerve impulse or action potential conducted from the motor neuron along its axon will cause the associated muscle to contract.
20
Q
Interneurons
A
- Neurons that trasmit impulse between other neurons
- come in a number of different varieties
21
Q
Multipolar neuron
A
- Most popular neuron, composed of multiple dendrites extending from the cell bodt and only a single axon
22
Q
The bipolar neuron
A
- Has a single dendrite exiting one side of the cell body with a single axon exiting the other
- These neurons have dendrites terminate at receptor cells
23
Q
Unipolar neuron
A
- only a single dendrite leaving the cell body which eventually branches in two directions
24
Q
Resting Potential
A
- Membrane potential when neuron is at rest (-70mv)
- Intracellular fluid is more negative than outside the cell.
25
Q
Absolute refractory period
A
- The interval where a second action potential cannot be initiated, no matter how large the stimulus
26
Q
Hyperpolarize
A
- The membrane potenital becomes more negative than the resting potential
- an accumulation of K+ around the outside of the membrane. until the K+ ions in the vicinity of the membrane diffuse away.
27
Q
Relat ive refractory period
A
- Occurs during hyperpolarization after an action potential; a greater than normal stimulus is required to elicit another action potential.
28
Q
All-or-nothing law
A
- Once threshold is reached and the sequence begins, the action potential will occur in exactly the same way each time. There are no larger or smaller action potentials—either an action potential occurs or it does not.
29
Q
Oligodendrocyte
A
- Sheath found in the central nervous system
30
Q
Schwann cell
A
- Sheath found in the peripheral nervous system
31
Q
Nodes of ranvier
A
- discrete segments with patches of bare membrane between segment
- instead the action potential jumps from one node to the next via saltatory conduction because the axon is not exposed to extracellular fluid.
32
Q
Synaptic transmision
A
- Process by which neurotransmitters are released by neurons to bind and activate the receptors of another neuron.
- Messages are carried from one neuron to another over a very thin gap between the terminal bouton of one neuron and the dendrite of the next.
33
Q
Synapse
A
- Junction between two neurons, consists of a very small gap across which impulses pass by diffusion of neurotransmitters.
34
Q
Neurotransmitter
A
- A chemical substance that released at the end of a neuron; caused by arrival of nerve impulse
35
Q
Postsynaptic potential
A
- Brief depolarization or hyperpolarization of the membrane of the recieving neuron.
- bring it either closer to or further away from its threshold and thus influence the likelihood that an action potential will occur.
36
Q
Synaptic vesicle
A
- Located inside the terminal bouton
- stores the various neurotransmitters that are released at the synapse
- When the action potential arrives from the axon, these vesicles fuse with the presynaptic membrane and release the neurotransmitters into the synaptic cleft which is then diffused across to the postsynaptic membrane and attach themselves to proteins (receptor sites) at the postsynaptic membrane.
37
Q
Excitatory postsynaptic potential (EPSP)
A
- A temporary depolarization of the postsynaptic membrane potential
- Excites the neuron
EX. When the neurotransmitter binds to the receptor, the gate in this ion channel opens and allows a flow of ions to cross the membrane into the postsynaptic cell producing the postsynaptic potential. If the ion channel is designed to allow a positively polarized ion (Na+ for example) to flow into the cell, the postsynaptic potential will be depolarized
38
Q
Inhibitory postsynatic potential (IPSP)
A
- A temporary hyperpolarization of of the postsynaptic membrane potential
