Chapter 3 (Part 1) Flashcards
Absolute refractory period
The interval where a second axn potential cannot be initiated, no matter how large a stimulus is applied
Axn potential
Change in electrical potential associated with the passage of an impulse along the membrane of a neuron
Afferent nerve fibres
Fibers that carry information inward to the CNS from the periphery of the body
Anion
- charged ion
Autonomic nervous system
Part of the PNS, controls muscle movement that happens outside of our conscious awareness and control
Axon
Long threadlike part of a neuton dedicated to transmitting information to other neurons
Bipolar neuron
Has a single dendrite exiting one side of cell body, and single axon exiting the other
Cation
+ charged ion
Central nervous system
Composed of brain + spinal cord
Dendrites
A branched extension of a neuron, dedicated to receiving information transmitted from other neurons
Depolarization
When the membrane potential becomes more positive
Diffusion
Forces that moves molecules from areas of high to low concentration
Effector
Organ/cell that is capable of receiving and responding to nerve impulses
Efferent nerve fibres
Fibres that carry information outward from the CNS to the periphery of the body
Electrostatic pressure
The forces of attraction/repulsion between ions
Excitatory Postsynaptic Potential (EPSP)
Temporary depolarization of the postsynaptic membrane potential
Glial cell
Most common cell in CNS, provide structure and perform various housekeeping tasks
Hyperpolarization
The membrane potential becomes more - than the resting potential
Inhibitory Postsynaptic Potential (IPSP)
Temporary hyper polarization of the postsynaptic membrane potential
Interneuron
Neuron, transmits impulses b/w other neurons
Leaky potassium channel
A potassium-selective pore that spans the cell membrane allowing potassium to pass through
Motor neuron
Most common form of effector neuron
Multipolar neuron
Composed of multiple dendrites extending from a single axon
Myelin sheath
A tube of fatty tissue that forms an insulating covering around the axon
Neural integration
The addition of the IPSPs and EPSPs
Neuron
Specialized cell that transmits nerve impulses
Neurotransmitter
Chemical substance that is released at the end of a neuron, caused by the arrival of a nerve impulse
Nodes of Ranvier
a gap in the myelin sheath of a nerve
Parasympathetic nervous system
Part of autonomic nervous system, helps to return the body to normal function after activation of the sympathetic
Peripheral nervous system (PNS)
Composed of the nervous system outside of the brain/spinal cord
Postsynaptic Potential
Brief depolarization/hyperpolarization of the membrane of the receiving neuron
Relative refractory period
Occurs during hyperpolariztion after an axn potential, a greater than normal stimulus is required to elicit another axn potential
Reuptake
When neurotransmitters are reabsorbed into the pre-synaptic cell
Saltatory Conduction
the propagation of axn potentials along myelinated axons from one node of Ranvier to the next
Sensory neurons
Transmit sensory information from the environment towards the rest of the nervous system
Sodium-Potassium Pump
Ion transporter, pushes 3 Na+ out and brings 2 K+ in
Soma
Cell body synonym
Somatic nervous system
Part of PNS, controls voluntary movement of muscles
Spatial summation
Several EPSPs from different pre-synaptic neurons occurring at the same time sum to create an axn potential
Sympathetic Nervous System
part of autonomic nervous system, involved with preparing the body for emergencies
Synapse
Junction b/w two neurons, small gap across which impulses pass by diffusion of neurotransmitters
Synaptic transmission
The process by which neurotransmitters are released by neurons to bind and activate the receptors of the other neuron
Synaptic vesicle
Located inside the terminal boutons, stores neurotransmitters that are released at synapse
Temporal summation
High frequency of EPSPs from a single neuron elicit postsynaptic potentials that create an axn potential
Terminal bouton
Location where connections to dendrites of nearby neurons are made
Unipolar neuron
Composed of one process leaving the cell body that eventually branches into two directions
Voltage dependent potassium channel
Opens when the membrane becomes depolarized allows K+ to leave cell
Voltage gated sodium channel
Allows Na+ to rush into the cell when the membrane potential is below -55mV
