U04 - Biological Bases of Behavior Flashcards
1
Q
Neurons and its structure
A
- cell of the nervous system specialized for sending and receiving neural messages
- 100 billion, making over 100 trillion connections
- dendrites, cell body/soma, axon, axon terminals/terminal branches, and myelin sheath
2
Q
Action potentials
A
- The way neurons talk to each other, by firing off action potentials
- generated at the junction between the axon and cell body
- then move down the length of the axon
- When a neuron is depolarized by sufficient input, it reaches a threshold for producing action potential, this is called voltage threshold
- at peak of action potential, interior of cell more positively charged than outside
- action potential is all or nothing, not stronger or weaker
3
Q
Resting potential
A
- neuron is at rest, more negatively charged particles inside cell, the imbalance between intracellular and extracellular fluid results in an electrical charge across the membrane (70 millivolts)
- neuron cannot fire action potential at this resting tate
4
Q
Depolarization
A
- happens when the ions outside of the cell want to get through to the inside and the ion channels open up
- this movement causes the electrical charge across the membrane to begin to reverse
- polarize means far apart, depolarize means less far membrane, so this means that the extracellular and intracellular environment is decreasing
5
Q
Voltage threshold
A
- When a neuron is depolarized by sufficient input, it reaches a threshold for producing action potential
- once it’s reached, these voltage gated ion channels just open wide, positively charged sodium ions come flooding in from outside
- once threshold is reached, the action potential is inevitable
6
Q
repolarization
A
- At peak of action potential, additional channels open up that allow for another type of ion, potassium ions, to move across membrane
- they move from inside cell to outside, and negative direction comes out again
7
Q
Refractory period
A
- after action potential, at the end of repolarization, there is a temporary dip below resting potential, this is the refractory period
- at this period, it is hard to get neuron to fire again
- this period ensures that action potential is propagated forward, bc action potential moves like a wave along the axon
8
Q
Synaptic cleft
A
- At the end of axon, when the action potential (the electrical signal) reaches its end, the neurons don’t actually touch each other
- They are separated by the synaptic cleft
- electrical signals are unable to jump over this cleft so they are converted into a chemical one, neurotransmitters
9
Q
receptor
A
- channel in membrane of a neuron that binds neurotransmitters (receives it from the neuron across)
- binds neurotransmitters in lock and key fashion, where only a certain neurotransmitter can bind to a certain receptor
10
Q
Intracellular fluid and extracellular fluid
A
- watery chemical soup
- contains various electrically charged particles, or ions
- intracellular (inside the cell)
extracellular (outside cell)
11
Q
myelin sheath + glial cells = support neuron functioning
A
Myelin sheath makes signals travel faster.
Glial cells support, protect, and help neurons work properly.
12
Q
Excitation
A
- receiving neuron slightly depolarized
- excitatory currents are those that prompt one neuron to share information with the next through an action potential
- moves the neuron closer towards voltage threshold and increases likelihood of action potential
- excitatory inputs contract muscle
13
Q
Inhibitation
A
- receiving neuron slightly hyperpolarized
- moves the neuron further from threshold and reduces likelihood of action potential
- while inhibitory currents reduce the probability that such a transfer will take place
- inhibitory inputs tell muscles to relax
14
Q
GABA
A
- A type of neurotransmitters within a class of it
- GABA is within amino acids
- Binds to major inhibitory receptors; influences muscle tone
15
Q
Acetycholine
A
A class of neurotransmitters
- Binds to both inhibitory and excitatory receptors; contributes to muscle control
16
Q
Norepinephrine
A
Under monoamines, which is a class of neurotransmitters
- Involved in fight-or-flight response activation
17
Q
Serotonin
A
Under monoamines, which is a class of neurotransmitters
- Contributes to feelings of happiness and well-being, appetite, and sleep
18
Q
Dopamine
A
Under monoamines, which is a class of neurotransmitters
- Associated with reward and pleasurable experiences
19
Q
Endorphines
A
- Under neuropeptides, which is a class of neurotransmitters
- “endogenous morphine”
- promote feelings of pleasure and reduce pain
codes for opioid receptor where endorphins bind
20
Q
Psychoactive drugs
A
- chemical substances that alter a person’s thoughts, feelings, or behaviors by influencing the activity of neurotransmitters in the nervous system
- Psychoactive drugs are artificial chemicals introduced into the body that “piggyback” onto the preexisting infrastructure used by your body’s own neurotransmitters.
21
Q
Agonists & antagonists
A
Agonist:
- enhances action of a neurotransmitter
- by increasing release, block its reuptake or mimicking neurotransmitter and activating its postsynaptic receptor
Antagonist:
- inhibits actions of a neurotransmitter
- by blocking release, destroying neurotransmitter in synapse, binding to a postsynaptic receptor to block neurotransmitter
22
Q
Opioid addiction
A
- psychoactive drugs don’t just bind for a short period of time and then leave, if used for long time, they can change existing infrastructure that they’re hijacking and overpower reward function of endogenous opioids
- repeated use causes changes to receptor structure
- loss of sensitivity for naturally occurring rewards
- Repeated exposure to opioids alters the brain so that it functions normally only when the drugs are present and abnormally when they are not, resulting in addiction.
