Exam 3 Flashcards
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The central nervous system (CNS) consists of the brain, the spinal cord, and most of the nerves in our fingers
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Myelinated axons transmit nerve impulses (AP’s) more slowly than non-myelinated axons.
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Axon terminals are the main receptive region of the neuron, while the dendrite(s) is the main secretory region.
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The arrival of neurotransmitters at NT receptors on the post-synaptic neuron’s membrane opens voltage gated ion channels.
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Most neurons receive both excitatory and inhibitory inputs from up to thousands of other neurons.
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During depolarization, the inside of a neuron becomes less negative
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Voltage-gated Ca+ channels open in response to a change in post-synaptic membrane potential
and participate in the generation and propagation of action potentials in a post-synaptic neuron.
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Immediately after an action potential has peaked, K+ gates open along that particular patch of axon.
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An IPSP causes depolarization of the post-synaptic neuron, making an action potential in that cell more likely to occur.
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Our brains can send nervous messages to effectors in our hands, but our hands cannot send nervous messages to our brains.
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By total number, there are more neurons in your brain and spinal cord than all the neurons in the entire rest of your body.
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Saltatory Conduction propagates action potentials faster than Continuous Conduction.
T
Definition of Neuron
Large, highly specialized cells that transmit impulses from one part of the body to another
Definition of Astrocyte
Most abundant glial cell of the CNS; one function is physically support neurons
Definition of Schwann cell
Surround nerve fibers in the PNS and form myelin sheaths
Definition of Oligodendrocyte
Cell which wraps nerve fibers and form myelin sheaths in the CNS
Definition of Microglial cell
Defensive cell in the CNS - have phagocytic capabilities; kind of small
Definition of Ependymal cell
Line the cavities of the CNS; associated with CSF
The actions of the ANS can best be described as what?
Involuntary
The nervous system division associated with the transmission of impulses from the CNS to effector organs is called the:
The motor division of the PNS
Somatic motor neurons are what type of neuron, structurally?
Multipolar
Which structural neuron type is the most abundant in the body?
Multipolar
What functional type of neurons transmit afferent nerve impulses?
Sensory
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Neurons have a high mitotic rate
F
What typically initiates a graded potential in a post-synaptic neuron?
Neurotransmitters binding to ligand-gated channels
What helps ensure that action potentials only travel one direction down an axon?
The refractory period
The opening of (a lot of) what kind of ion channels initiates an action potential?
Na+ channels
During an action potential, hyperpolarization is a condition in which, locally, the cell becomes __
negative than its resting potential, and this is caused by __ channels remaining open.
More / K+
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Histamines are the main neurotransmitters secreted by motor neurons innervating skeletal muscle
F
What neurotransmitters is associated with excitation of skeletal muscle cells?
ACh
The brain’s main inhibitory neurotransmitter is what?
GABA
