Thursday Flashcards
Agonist
Activate the receptors for certain neurotransmitters and ultimately make the effects of the neurotransmitter stronger.
Blood-brain barrier
A semi-permeable membrane that protects the brain from substances that may cause brain injury.
Depolarization
When an electrical impulse reaches the cell body, gated channels open up and allow sodium ions to rush into the cell. This increase in sodium alters the balance of charge, making the cell more positive than it was when it was resting (-70mv). This change in charge is known as depolarization.
Excitatory v. Inhibitory Signals
Excitatory neurotransmitters are chemicals that excite connecting neurons and cause them to fire when they are released from the terminal buttons. Inhibitory neurotransmitters inhibit the next neurons from firing. Inhibitory and excitatory neurotransmitters balance each other out, attempting to create a homeostasis within the brain and body.
Refractory Period
Period of time during which a cell is incapable of repeating an action potential (recovery time)
-Occurs after an action potential and generally lasts one millisecond
-While the neuron is busy returning everything to normal, it doesn’t respond to an incoming stimuli
Serotonin
Connected to feelings of well-being and happiness (regulation of emotion). It regulates the sleep cycle along with melatonin, and also regulates intestinal movements
-Inhibitory
-Serotonin is a major part of many popular drug treatments for depression and anxiety
Dopamine
“Pleasure Chemical of the Brain” Released into the pleasure centers of the brain, related to reward and motivation (learning)
-Inhibitory
-It is also associated with addiction, movement, and motivation
-Person will repeat behaviors that lead to the release of dopamine
Norepinephrine
Associated with response to danger, attention & responding action in the brain
-Excitatory
-Its effect in the body is to contact blood vessels to increase blood flow
GABA “Calming”
Inhibitory transmitter that slows things down, calming the central nervous system “natural tranquilizer”, GABA also contributes to motor control and vision
-Inhibitory
-GABA increases sleepiness an decreases anxiety alertness, memory, and muscle tension
Glutamate
Major excitatory neurotransmitter, involved with most normal operations of the brain including, thinking, long-term memory, and learning
-Excitatory
-Most common neurotransmitter in the brain
Endorphins
Relieve pain and stress, “Brain’s natural aspirin”, feelings of pleasure/euphoria
-Inhibitory
-Released in the brain during exercise, excitement, pain, and sexual activity, and produce a feeling of well-being or even euphoria
All-or-None Principle
When a neuron fires it is at full strength or not at all, strength of action potential is constant
-The neuron does not reach the threshold or a full action potential is fired
Action Potential
An action potential is part of the process that occurs during the firing of a neuron
-During the action potential, part of the neural membrane opens to allow positively charged ions inside the cell and negatively charged ions out.
Threshold
Level of stimulation that a cell body (soma) uses to decide whether to tell the axon to create electricity
Acetylcholine (ACh)
Principal neurotransmitter involved in thought, learning and memory. In the body, it is involved in activating muscle action.
-Excitatory
-First neurotransmitter discovered
