Chapter 3: Biology and Behavior Flashcards
What are the two basic divisions of the nervous system?
the central nervous system and the peripheral nervous system
What is the central nervous system?
Made up of spinal cord and brain
What is the peripheral nervous system?
Made up of all the rest of the nerve cells in the body.
Consists of somatic and autonomic nervous system.
somatic- involved in voluntary behavior
autonomic- involved in involuntary actions, like heart rate
There are three stages of neurons transmitting a chemical or electrical signal. What are they?
- Reception- receive the signal
- Integration- incoming signals are assessed
- Transmission- signal is passed onto the next neuron
What are the three types of neurons?
Sensory neuron
Interneuron
Motor neuron
What are sensory neurons?
- transmit information from sensory receptors to the spinal cord
- somatosensory nerves- provide information from the skin and muscles
What are motor neurons?
Transmit signals from the spinal cord to an effector muscle to cause movement. The muscle contracts or relaxes.
What are interneurons?
Transmit signals in the brain or spinal cord within short or local distances.
What are excitatory and inhibitory signals?
excitatory- depolarize the membrane
inhibitory signals- hyper polarize the cell by increasing the negative charge inside the cell. Make it less likely to fire signal
What is the action threshold for neurons?
-55 millivolts. When the charge of the axon reaches this charge, action potential is fired
Describe the basic way an action potential is fired
- excitatory signal depolarizes membrane
- sodium gates open, sodium floods into axon
- potassium channels open, potassium leaves axon
- ratio is 3Na+: 2K+
What is the myelin sheath?
- made of glial cells, type of lipid
- insulates axon causing rapid transmission of signals
- allows for quick and frequent motor activity
Does a neuron fire at different strengths?
- No
- it has an all or nothing principle where the neuron fires at the same strength each time
- the stronger the stimulation, the more frequent the neuron fires
State and explain the different stages of terminating neurotransmitters influence.
- reuptake- neurotransmitters are taken back into the pre-synaptic knob
- enzyme deactivation- enzymes in synapse break down neurotransmitters
- Autoreception- autoreceptors monitor amount of neurotransmitter that’s released into synapse.
How do drugs alter neurotransmitters or the effects of them?
- alter production of N
- mimic shape of N and bind to post-synaptic receptors
- prevent re-uptake of N, so N remains in synapse and continues to bind to receptors
- raise or lower amount of N produced
What are agonists and antagonists (relating to neurotransmitters)?
- agonists- drugs and toxins that enhance neurotransmitter actions
- antagonists- drugs and toxins that inhibit neurotransmitter actions
How do agonist drugs/ toxins influence neurotransmitters?
- increase how much neurotransmitter is made
- block reuptake of neurotransmitter, so N continues to bind to receptors, enhancing the effects
- can mimic N, increasing N effects
How do antagonist drugs/toxins influence neurotransmitters?
- decrease amount of N made
- mimic shape of N and binding to receptors, preventing N binding
- destroy N in synapse
What are monoamine neurotransmitters? Give examples
- neurotransmitters that influence arousal, regulate behavior, feelings
- epinephrine, norepinephrine, serotonin, dopamine
What are the functions of Acetylcholine?
- motor control between nerves and muscles
- involved in memory, sleeping, learning, dreaming
What are the functions of epinephrine/adrenaline?
- flight/ flight reaction
- causes adrenaline rush
- monoamine
What are the function of norepinephrine?
- flight/flight reaction
- widening pupils, increasing blood pressure, widening air passages in lungs, narrowing blood vessels
- monoamine
Serotonin
- emotional states, dreaming, impulse control
- low levels cause depression
- selective serotonin reuptake inhibitors allow more serotonin in synapse to bind with receptors and enhance effects, used to treat depression
- monoamine neurotransmitter
Dopamine
- monoamine
- involved in motivation, reward, motor control
- guide us to things that will make us happy
- low levels- produce problems in motor control/movement, like Parkinson’s disease
GABA
- gamma aminobutyric acid
- prevents synaptic excitation from getting out of control
- low levels- cause epileptic seizures
Glutamate
- excitatory transmitter
- learning and memory
- high levels- produce seizures and destroy neurons
Endorphins
- natural pain redactors and reward
- drugs that bind to endorphin receptors reduce pain- people still experience pain but are detached from it
Early theory of brains- Gall and Spurzheim
- phrenology
- if a part of the brain is more used, it will enlarge and make a bump in the skull
- can measure people’s personalities by feeling the head
What is a psychophysiological assessment?
Measuring the relationship between behavioral states and bodily functions (body temp, blood temp, blood pressure)
Polygraphs
- lie detectors
- assume that liars show physical signs of stress- not reliable
Electrophysiology
- measurement of brain’s electrical activity
- not reliable for making conclusions- doesn’t isolate specific responses to stimuli. Measures all brain electrical activity
What is event-related- potential electrophysiology?
- multiple tests, one subject
- measures brain’s electrical activity in response to specific stimuli
Positron emission tomography (PET)
- radioactive material injected
- directly tracks substance to identify areas with increased blood flow during activities
Magnetic Resonance Imaging (MRI)
- powerful magnetic field disrupts brain’s activity
- measures energy from brain tissue- each tissue releases different amounts
Functional Magnetic Resonance Imaging (fMRI)
- measures blood flow by assessing changes in blood’s oxygen level to map brain
Transcranial Magnetic Stimulation (TMS)
- powerful magnetic field disrupts brain’s activity in specific regions
- limitations: measure in regions close to scalp for short durations
- used with imaging to determine region of brain necessary for specific psychological functions
