Chapter 3 Flashcards
Chronic traumatic encephalopathy (CTE)
a form of progressive brain damage that has been linked to repeated concussions
Neurons
cells in NS that communicate with one another to perform info-processing tasks
Cell body (soma) What processes occur here?
the part of a neuron that coordinates info-processing tasks and keeps the cell alive; largest component of the neuron; protein synthesis, energy production, and metabolism occur here
Dendrite
the part of a neuron that receives info from other neurons and relays it to the cell body; don’t touch axons
Axon
the part of a neuron that carries info to other neurons, muscles, or glands; don’t touch dendrite
Myelin sheath
an insulating layer of fatty material that covers most of the axon; axons insulated with myelin can more efficiently transmit signals to other neurons
Glial cells
Cells that form the myelin sheath and support the cells in the nervous system
Synapse
the region between the axon of one neuron and the dendrites/cell body of another
What are the 3 major types of neurons?
- Sensory neurons: have specialized endings on their dendrites that receive signals for senses and convey the info to the brain via the spinal cord
- Motor neurons: carry signals from the spinal cord to the muscles to produce movement; have long axons
- Interneurons: most common type of neuron that connects sensory neurons, motor neurons, and other interneurons; some carry info from sensory neurons to NS, some carry info from NS to motor neurons, some perform variety of info-processing functions within NS
What are the two stages that compose the electrochemical actions?
- Conduction: the movement of an electric signal within neurons, from the dendrites to the cell body, then throughout the axon
- Transmission: movement of electric signals from 1 neuron to another over the synapse
Resting potential
the difference in electric charge between the inside and outside of a neuron’s cell membrane; in resting state, high [ K+] and - protein ions inside neuron’s cell membrane, high [Na+] and [Cl-] outside of neuron’s cell membrane
Action potential
an electric signal that is conducted along a neuron’s axon to a synapse; need to reach threshold for AP to occur
What facilitates the conduction of an action potential?
Myelin sheath
Nodes of Ranvier
the breaks between clumps of myelin
Saltatory conduction
When an electric current passes down the length of a myelinated axon, the charge seems to “jump” from node to node rather than having to traverse the entire axon; helps speed the flow of info down the axon
Refractory period
the time following an action potential during which a new action potential cannot be initiated
Terminal buttons
knoblike structures that branch out from an axon and contain neurotransmitters
Neurotransmitters
chemicals that transmit info across the synapse to a receiving neuron’s dendrites
Receptors
located in dendrites of the receiving neuron (postsynaptic neuron), parts of the cell membrane that receive the neurotransmitter and initiate or prevent a new electric signal
Acetylecholine
a neurotransmitter involved in a number of functions (ex. voluntary motor control)
Dopamine
a neurotransmitter that regulates motor behavior, motivation, pleasure, and emotional arousal; high levels linked to schizophrenia, low levels linked to Parkinson’s disease
Glutamate
major excitatory neurotransmitter in brain that enhances transmission of info between neurons
GABA (gamma-aminobutyric acid)
primary inhibitory neurotransmitter in the brain; too much glutamate or too little GABA can cause seizures
Norepinephrine
a neurotransmitter that is particularly involved in states of vigilance, or heightened awareness of dangers in the environment