Week 5: Neurons Flashcards
Neurons, Hormones and Behaviour, Psychopharmacology
Dendrites
Part of a neuron that extends away from the cell body and is the main input to the neuron.
Soma
Cell body of a neuron that contains the nucleus and genetic information, and directs protein synthesis.
Axon
Collection of nerve cells found in the brain which typically serve a specific function.
Synapse
Collection of nerve cells found in the brain which typically serve a specific function.
Myelin Sheath
Substance around the axon of a neuron that serves as insulation to allow the action potential to conduct rapidly toward the terminal buttons.
Terminal Button
The part of the end of the axon that form synapses with postsynaptic dendrite, axon, or soma.
Spines
Protrusions on the dendrite of a neuron that form synapses with terminal buttons of the presynaptic axon.
Synaptic Gap
Protrusions on the dendrite of a neuron that form synapses with terminal buttons of the presynaptic axon.
Synaptic Vesicles
Groups of neurotransmitters packaged together and located within the terminal button.
Neurotransmitters
Chemical substance released by the presynaptic terminal button that acts on the postsynaptic cell.
Types of Neurons - Cells in the Brain
SENSORY - neurons that help us receive information about the world around us
MOTOR - neurons that allow us to initiate movement and behavior, ultimately allowing us to interact with the world around us.
INTERNEURONS - process the sensory input from our environment into meaningful representations, plan the appropriate behavioral response, and connect to the motor neurons to execute these behavioral plans.
Three main categories of neurons:
UNIPOLAR - structured in such a way that is ideal for relaying information forward, so they have one neurite (axon) and no dendrites. They are involved in transmission of physiological information from the body’s periphery such as communicating body temperature through the spinal cord up to the brain.
BIPOLAR - involved in sensory perception such as perception of light in the retina of the eye. They have one axon and one dendrite which help acquire and pass sensory information to various centers in the brain.
MULTIPOLAR - most common and they communicate sensory and motor information in the brain. For example, their firing causes muscles in the body to contract. Multipolar neurons have one axon and many dendrites which allows them to communicate with other neurons.
GLIA - While glial cells play a vital role in neuronal support, they do not participate in the communication between cells in the same fashion as neurons do.
Cell Membrane
A bi-lipid layer of molecules that separates the cell from the surrounding extracellular fluid.
ION Channels
Proteins that span the cell membrane, forming channels that specific ions can flow through between the intracellular and extracellular space.
Diffusion
The force on molecules to move from areas of high concentration to areas of low concentration.
Electrostatic Pressure
The force on two ions with similar charge to repel each other; the force of two ions with opposite charge to attract to one another.
Resting Membrane Potential
The voltage inside the cell relative to the voltage outside the cell while the cell is a rest (approximately -70 mV).
Sodium-Potassium Pump
An ion channel that uses the neuron’s energy (adenosine triphosphate, ATP) to pump three Na+ ions outside the cell in exchange for bringing two K+ ions inside the cell.
Action Potential
A transient all-or-nothing electrical current that is conducted down the axon when the membrane potential reaches the threshold of excitation.
Threshold of Excitation
Specific membrane potential that the neuron must reach to initiate an action potential
Excitatory Postsynaptic Potentials (EPSPs)
A depolarizing postsynaptic current that causes the membrane potential to become more positive and move towards the threshold of excitation.
Inihibitory Postsynaptic potentials (IPSPs)
A depolarizing postsynaptic current that causes the membrane potential to become more positive and move towards the threshold of excitation.
Ionotropic Receptors
Ion channel that opens to allow ions to permeate the cell membrane under specific conditions, such as the presence of a neurotransmitter or a specific membrane potential.
Endocrine System
Series of glands that produce chemical substances known as hormones
Hormones
Chemical messenger released by endocrine glands
Pituitary Gland
Secretes a number of key hormones, which regulate fluid levels in the body, and a number of messenger hormones, which direct the activity of other glands in the endocrine system
Associated Hormones: Growth hormone, releasing and inhibiting hormones (such as thyroid stimulating hormone)
Thyroid Gland
Secretes hormones that regulate growth, metabolism, and appetite
Thyroxine, triiodothyronine
Adrenal Glands
Sits atop our kidneys and secretes hormones involved in the stress response
Epinephrine, norepinephrine
Pancreas
Secretes hormones that regulate blood sugar
Insulin, glucagon
Diabetes
Disease related to insufficient insulin production
Gonads
Secrete hormones related to sexuality, sex, reproduction, and other phenomena, including physical/bodily aspects and behaviour. The gonads are either in the ovaries (usually tied to femaleness, but not always) and testes (usually tied to maleness, but not always).
Ovaries/Testes
Associated Hormones: Estrogen, progesterone, androgens, such as testosterone
Function: Mediate sexual motivation and behavior, reproduction
Pineal
Associated hormone: melatonin
Function: regulate some biological rhythms such as sleep cycles
Neurotransmitter
A chemical substance produced by a neuron that is used for communication between neurons.
Synapse
Junction between the presynaptic terminal button of one neuron and the dendrite, axon, or soma of another postsynaptic neuron.
Psychoactive Drugs
Junction between the presynaptic terminal button of one neuron and the dendrite, axon, or soma of another postsynaptic neuron.
Agonists
A drug that increases or enhances a neurotransmitter’s effect; “helper” that activates a recepter in your body, making it do something
morphine - binds to opioid receptors in brain to provide pain relief
Antagonists
A drug that blocks a neurotransmitter’s effect; blocker prevents receptor from doing it’s job
narcan - can reverse opioid overdoses by blocking effects at receptors in brian
Psychotropic Drug
A drug that changes mood or emotion, usually used when talking about drugs prescribed for various mental conditions (depression, anxiety, schizophrenia, etc.).
Pharmacokinetics
The action of a drug through the body, including absorption, distribution, metabolism, and excretion.
Metabolism
Breakdown of substances.
Enzyme Induction
Process through which a drug can enhance the production of an enzyme.
Polypharmacy
The use of many medications.
Enzymes
A protein produced by a living organism that allows or helps a chemical reaction to occur.
Nucleus
Collection of nerve cells found in the brain which typically serve a specific function.
