Biological Psych Flashcards
Define glia.
Glia is a type of cell that supports the neurons in ways such as insulating them, synchronising activity among neighbouring neurons, and removing waste products.
What are neurons made of?
A cell body, dendrites, and an axon.
Define cell body.
The cell body contains the nucleus of the cell, and keeps neurons alive, contains substances for growth, and determines whether to fire.
What are dendrites?
Dendrites are widely branching structures that receive input from other neurons and transmit that to the cell body.
What is an axon?
The axon is a single, long, thin, straight, fiber with branches near its tip that transmits messages away from the cell body to other neurons, muscles, or glands.
What are myelin?
Myelin is an insulating sheath that speeds up the transmission of impulses along an axon, and are found in vertebrate axons.
Define action potential.
Action potential is an excitation that happens when a nerve is stimulated; it travels along an axon to the axon’s terminal tip at constant strength, regardless of how far it travels.
Define the all-or-none law.
The all-or-none law of the action potential states that an axon cannot vary the strength or velocity of its action potentials.
What are the advantages and disadvantages of an action potential?
(+) Action potentials are able to reach different parts of your body at full strength.
(-) They take time, which means that the information being transmitted is ~1/20th second out of date.
How do action potentials work?
- When excitation reaches the axon’s threshold, it briefly opens some gates through which Na and K ions can flow. Na ions are attracted by the negative charge inside the cell and rush in. This influx of positively-charged Na ions is the action potential.
- As the +ve charge enters the axon at one point, it stimulates the next point along the axon and starts opening Na channels and repeating the process.
- After the Na and K gates close, Na ions flow out of the cell because they are more concentrated inside. They carry +ve charges with them, and this exit drives the inside of the axon back to resting potential.
- The sodium-potassium pump removes the extra Na ions and recaptures the escaped K ions.
Define synapse.
A synapse is the specialised junction between two neurons, often between the axon of one neuron and the dendrite or cell body of another neuron, through which communication occurs.
Define neurostransmitter.
A neurotransmitter is a chemical that activates receptors on other neurons, and is released by an action potential at the terminal button.
They carry information across the synaptic gap to the next neuron.
Define postsynaptic neuron.
The postsynaptic neuron is the neuron on the receiving end of the synapse.
How do synapse send messages?
- When an action potential reaches the terminal bouton, it releases a neurotransmitter.
- The neurotransmitter molecules diffuse across a narrow gap to receptors on the postsynaptic neuron.
- After a neurotransmitter excites or inhibits a receptor, it separates from the receptor, ending the message.
What are stimulants?
Stimulants are drugs that increase energy, alertness, and activity, and increase the effects of transmitters at their receptors.
What are the behavioural and physical effects of stimulant drugs?
Low dose levels enhance attention, while higher doses cause confusion, impaired attention, impulsiveness, higher heart rate, blood pressure, and body temperature, and a risk of convulsions, lung damage, and heart attack.
How do stimulant drugs affect neurons and transmitters?
Stimulant drugs inhibit the reuptake of dopamine and other transmitters, thus transmitters wash away from synapses faster than the presynaptic neurons can replace them.
The presynaptic neurons’ supply of transmitters dwindles, and the individual begins to experience mild lethargy and depression until neurons rebuild their supply.
Define hallucinogens.
Hallucinogens are drugs that induce sensory distortions, and can produce sudden emotional changes or a dreamlike state.
Define depressants.
Depressants are drugs that decrease arousal.
What are the effects of alcohol?
At moderate doses, it relaxes people by facilitating activity at inhibitory synapses.
At higher doses, it increases risk-taking behaviours by suppressing the fears and inhibitions that usually limit such behaviours.
Extreme drinking such as binge drinking suppresses breathing and heart rate to a dangerous degree; it causes liver damage, aggravates medical conditions, impairs memory, motor control, and damage to a baby’s brain, health and appearance during pregnancy.
What are narcotics?
Narcotics are drugs that produce drowsiness, insensitivity to pain, and decreased responsiveness.
What are the effects of use of opiate drugs?
Initially, opiates make people feel happy, warm, and content.
After the drug leaves the brain, the user begins to feel nauseous, anxious, pain, and exaggerated responsiveness to stimuli due to withdrawal.
What are the different parts of the vertebrate brain?
The hindbrain, midbrain, and forebrain.
The forebrain consists of the left and right hemispheres, whereby each hemisphere controls sensations and movement on the opposite side of the body.
The outer covering of the forebrain is the cerebral cortex.
What are the lobes present in the cerebral cortex?
Occipital, parietal, temporal, and frontal lobe
