Unit 4 - AP Psychology

neuron 

a type of cell in the nervous system that carries electrical impulses and communicates through neurotransmitters. also called a nerve cell

soma

the portion of the nerve cell containing genetic info that determines how a neural cell functions 

mitochondria: located in the soma of the nerve cells-structures that turn oxygen and glucose into energy 

dendrites

branch-like structures on a neuron that mostly extend from the soma specialized to receive information in the form of neurotransmitters from other neurons

they receive chemical messages from other neurons, which initiate cell firing at the receptor sites that are specifically designed for specific neurotransmitters 

receptor site

a specific region located on the dendrites that receives neurotransmitters

axon

the long tube like extension extending from the soma, which sends the electrical message (action potential) away from the cell body of the neuron

these can be very long

axon hillock

the area located at the end of the soma where axon begins

the action potential starts here 

myelin sheath

-the white fatty, insulating substance produced by specialized glial cells that covers the axon some neurons 

-provides insulation and increase the speed of the electrical message (action potential)

-the regularly spaced gaps In the myelin sheath allow the action potential to jump from one gap to another and speed up neurotransmission 

-these gaps enable efficient ion exchange, resulting in the electrical message (action potential) jumping quickly across gaps in saltatory conduction 

-contain the sodium potassium pumps and allow for the repolarization of a neuron during the refractory period 

axon terminal branches 

located at the end of the axon, the sections where the axon splits into several parts, allowing information from the cell to be sent to several other neurons 

terminal button

located at the ends of axon branches, these containing neurotransmitters (stored in vesicles)

synaptic vesicles 

tiny sacs located inside the terminal buttons responsible for storing and releasing neurotransmitters 

synapse 

the extremely small space between the terminal button of the sending neuron and the receptor site on the receiving neuron’s dendrite

there is no physical contact between nerve cells 

multiple sclerosis (MS)

-damage to the myelin sheath can impair signal transmission, leading to muscle control loss and paralysis, as seen in the disease MS

-the ms disease is where the immune system attacks the myelin sheath, causing demyelination and nerve damage

-this can lead to fatigue, walking difficulties, numbness, tremors, vision problems, and cognitive issues 

myasthenia gravis (MG)

-the immune system attacks acetylcholine receptors or the neuromuscular junction structure, reducing receptor availability and impairing inside contraction 

-affects the muscles controlling eye movement, facial expressions, chewing, etc.

-in a healthy neuromuscular junction, the neurotransmitter acetylcholine is released, binds to muscle cell receptors, opens ion channels, and triggers muscle contraction

glial cells

a type of cell located in the nervous system thought to play a role in learning and memory that produces myeline and supports and nourishes neurons

protection, nourishment, insulation, and produce the myeline sheath that coats the axons

nerve impulse/action potential

the period in which a brief electrical impulse travels along the axon because the cell is depolarized

this occurs when a neuron sends a message 

selective permeability of the axon

the axon membrane sometimes allows ions to move in and out

these are gates along the axon, which sometimes open, allowing for the transferring of ions, and sometimes closed (preventing ion transfer)

resting potential/polarization

the period in which the electrical potential of the neuron is not active, and the cell is in a state of polarization

during this period, the fluid filled interior of the axon has a negative charge, and the exterior has a positive charge 

the electrical charge of the inside of the axon of a resting neuron is -70 millivolts

action potential/depolarization

occurs when the interior of the Xon changes to a less negative or slightly positive charge due to the ion exchange

the ion exchange, and thus the electrical charge, travels down the axon section by section

sin and pout-during the actions potential, sodium goes in the axon and potassium goes out of the axon 

domino effect

analogy for how action potentials travel down the axon section by section-as sodium enters and potassium exits

the resulting change in charge opens the gates in the next section 

threshold

the minimum level of stimulus necessary for a neuron to fire

all or none law

the principle that a neuron fires completely and at full strength, or it does not fire at all

refractory period/repolarization

the time when a neuron temporarily cannot fire because the sodium potassium pump is resetting ions to their original resting potential state 

presynaptic neuron/sending neuron

the nerve cell whose axon terminal buttons release neurotransmitters into the synapse, sending the message in the form of neurotransmitters across the synapse to the receiving neuron 

postsynaptic neuron/receiving neuron

the nerve cell dendrites receive the message in the form of neurotransmitters sent across the synapse by the sending neuron cell 

neurotransmitter

a chemical messenger released by neurons that travels across the synapse and allows neurons to communicate with one another

reuptake

the process of neurotransmitters returning to the presynaptic terminal buttons after they have been released into the synapse and have activated the postsynaptic neuron 

breakdown

neurotransmitters are broken down by enzymes to clear synapse

neural network

a circuit of communication

it consists of groups of neurons that are connected to one another that send and receive messages

steps in a neural impulse 

-resting potential (polarization) 

-threshold (all or nothing law)

-action potential (depolarization) section by section down the axon like dominos (sin and pout for the ion exchange)

-refractory period (repolarization) axon resets to the original resting potential with sodium ions on the outside and potassium ions inside with an interior charge of about -70 mv

excitatory neurotransmitter

increase the likelihood that the receiving neuron will fire an action potential

inhibitory neurotransmitter

decrease the likelihood that the receiving neuron will fire an action potential

dopamine

-initiation of voluntary movement and posture

-reward and pleasure

-learning and attention

-oversupply: Parkinson’s disease, tremors, rigidity, and loss of movement control

-undersupply: schizophrenia, delusions, hallucination, language and movement disturbances

acetylcholine

-memory

-muscle contraction

-stimulating the release of certain hormones

-oversupply: muscle spasms so severe that victim cannot breathe

-undersupply: memory problems of Alzheimer’s disease

serotonin 

-mood

-appetite

-sleep

-sensory perception 

-oversupply: positive mood and reduced aggression, confusion, restlessness, seizures

-undersupply: increase of aggression, depression, eating disorders, sleep wake disorders, obsessive compulsive disorders,

norepinephrine

-work as both a neurotransmitter and hormone

-arousal, attention, vigilance, mood, sleep, closely linked to serotonin, fight or flight response

-oversupply: anxiety and mania

-undersupply: depression

glutamate

-major excitatory neurotransmitter

-learning and memory

-numerous brain functions

-key role in long term potentiation

-oversupply: key factor in the overstimulation of the brain that leads to migraines or seizures

GABA

-major inhibitory 

-neurotransmitter 

-relaxation and sleep-calming effect on the central nervous system 

-oversupply: increases sleepiness, reduces alertness & anxiety & memory & muscle tension

-undersupply: anxiety disorders, seizures, insomnia, neurons will fire too frequently, Huntington’s disease 

endorphins

-pain relief

-produced when individuals experience pain, stress, fear, anxiety, and even following intense exercise

-oversupply: high pain thresholds and lack of pain

-undersupply: lower pain thresholds

substance p

-responsible mainly for nociception (pain perception)

-oversupply: result in the experience of pain

-undersupply: result in lack of pain

psychoactive/psychotropic drug

a chemical substance that causes changes in awareness, thought, mood, or perception

these substances may be agonists or antagonists and include both prescription medications and illegal drugs 

agonist drugs

a type of drug that is effective at increasing the transmission of a given neurotransmitter by stimulating receptor sites

antagonist drugs

a type of drug that is effective at preventing neurons from firing by blocking the receptor sites resulting in an overall decrease in the transmission of a given neurotransmitter

reuptake inhibitor 

a type of drug that is effective at increasing the transmission of a given neurotransmitter by blocking the reuptake of process allowing the neurotransmitter to stay in the synapse longer to increase transmission 

central nervous system

the part of the nervous system consisting of the brain and spinal cord-the parts encased in the skull and spine

spinal reflex arc

-rapid, automatic reactions that occur before communication with the brain is completed, such as the knee jerk

1. skin receptors are stimulated by the hot stove

2. sensory neurons send a pain signal to the spinal cord

3. interneurons in the spinal cord communicate a message to the motor neurons

4. the motor neurons send a signal for movement to the muscles

5. muscles in the hand are instructed by the motor neurons to move the hand away from

peripheral nervous system 

the broad term for the nervous system that includes all of the nerves outside of the brain and the spinal cord

it is responsible for connecting 

somatic nervous system

division of the peripheral nervous system that includes all of sensory and motor nerves that move information from the sensory receptors to the CNS as well as all of the nerves sending information from the CNS to exert control over muscles

this division is made up of nerves that travel between the sensory receptors and voluntary muscles through sensory and motor nerves 

autonomic nervous system

consists of nerves that control automatic functions by integrating the CNS with bodily organs and glands

this system regulates automatic or involuntary events

sympathetic nervous system

the subdivision of the autonomic nervous system that is responsible for arousing the body and mobilizing its energy during times of stress, also called the fight-flight freeze system.

this system works by speeding heart rate, increasing respiration rare, decreasing digestion, and producing hormones related to stress

parasympathetic nervous system

the subdivision of the autonomic nervous system responsible for calming the body and conserving energy by slowing the heart rate, decreasing respiration, and increasing functions related to digestion 

digestive functions increase when this nervous system is active 

nerves

bundles of neuron fibers (axons) from many neurons

sensory nerve

nerve cells that respond to physical stimuli from the environment by sending messages to the brain and nervous system

peripheral nervous system 

motor nerve 

nerve cells that carry messages from the brain to move the muscles and glands 

peripheral nervous system 

interneuron

facilitate the communication between sensory and motor neurons

they are located in the brain and spinal cord

they form connections between the sensory and motor neurons

central nervous system 

traumatic brain injury (TBI)

damage caused to brain tissue by external forces, leading to disrupted function

it can be diagnosed through neurological findings, posttraumatic amnesia, skull fracture, or loss of consciousness due to brain injury

autopsy

the study of the brain of an individual who has a brain injury post-mortem to see if any changes observed in their behavior can be connected to brain injury

functional magnetic resonance imaging (fMRI)

-uses magnetic fields to produce images of the brain and track real-time brain activity by measuring blood flow carrying oxygen to active brain tissues

-takes advantage of the fact that deoxygenated blood is magnetic (due to iron in hemoglobin). When neurons are activated, the fresh blood washes away deoxygenated blood, indicating the brain regions that are more active

-purpose is to understand structure and function

-pros: allows researchers to examine both brain structure and function with out exposure to radioactive materials or radiation/less expensive to use repetitively 

-cons: cannot be used for patients with a metallic implant/unknown if repeated exposure might be harmful/expensive to buy/needs sophisticated researchers to actually use the technology