Module 9: Pgs 76-85

Acetylcholine

Acetylcholine is a neurotransmitter, which is a chemical released by a nerve cell or neuron. ... Acetylcholine causes muscles to contract, activates pain responses and regulates endocrine and REM sleep functions. Deficiencies in acetylcholine can lead to myasthenia gravis, which is characterized by muscle weakness.

Depolarization

Action potentials happen when the neuron opens protein channels in its membrane. These channels allow sodium ions to flow from outside the cell into the cell. The sudden rush of sodium into the cell changes the electrical charge inside of the cell from negative to positive, which also changes the outside from positive to negative. The entire depolarization-to-repolarization event happens in about 2 milliseconds, allowing neurons to fire action potential in fast bursts permitting neuronal communication.

Threshold

Psychologists study sensory thresholds to learn how humans and animals process sensory information.

Action potential

Psychologists use the concept of action potential threshold to explain how neurons send information to each other.

Neurons

A Neuron is a specialized nerve cell that receives, processes, and transmits information to other cells in the body. We have a fixed number of neurons, which means they do not regenerate

Neurotransmitters

A neurotransmitter is a chemical messenger that carries, boosts, and modulates signals between neurons and other cells in the body. In most cases, a neurotransmitter is released from the axon terminal after an action potential has reached the synapse

Threshold

A sensory threshold is the level of strength a stimulus must reach to be detected. An absolute threshold is the lowest level of strength necessary for detection.

Myelin Sheath

Along unmyelinated fibers, impulses continuously move as waves, but, in myelinated fibers, they "hop" or propagate by saltatory conduction.

Agonist

An agonist is a chemical or a drug that binds to receptors in the brain and causes a reaction. A receptor is the part of a nerve that receives and reads chemical signals. It then transmits the information to the brain and nervous system using electrical signals.

Antagonist

An antagonist is a chemical or drug that binds to receptors in the brain and prevents an agonist from having a reaction

axon

An axon or nerve fiber, is a long, slender projection of a nerve cell, or neuron, that conducts electrical impulses away from the neuron's cell body or soma.

Agonist

Antagonists and agonists are key players in the chemistry of the human body and in pharmacology.

Norepinephrine

Because the release of norepinephrine affects other organs of the body, it is also referred to as a stress hormone.

Dopamine

Dopamine also helps regulate movement and emotional responses, and it enables us not only to see rewards, but to take action to move toward them.

Dopamine

Dopamine is a neurotransmitter that helps control the brain's reward and pleasure centers.

Neurotransmitters

Each neurotransmitter can directly or indirectly influence neurons in a specific portion of the brain, thereby affecting behavior.

Hyperpolarization

Hyperpolarization is the opposite of depolarization and is when the cell is becoming more negatively charged.

Synapse

In the central nervous system, a synapse is a small gap at the end of a neuron that allows a signal to pass from one neuron to the next. Synapses are found where nerve cells connect with other nerve cells.

Serotonin

It is commonly regarded as a chemical that is responsible for maintaining mood balance. Serotonin is created by a biochemical conversion process. Serotonin is manufactured in the brain and the intestines

Synapse

It is important to know that the neurotransmitters and receptors work like a lock and key; that is, they both have certain shapes and only specific neurotransmitters can fit into certain receptors.

Norepinephrine

Norepinephrine is a chemical released from the sympathetic nervous system in response to stress. It is classified as a neurotransmitter, a chemical that is released from neurons.

Acetylcholine

One example is the black widow spider uses venom that causes a flood of ACh into muscle cells and results in violent, uncontrollable muscle contractions, paralysis, and death for it's prey.

Serotonin

Serotonin is an important chemical neurotransmitter in the human body.

Myelin Sheath

Structure of a typical neuron. Myelin is a dielectric (electrically insulating) material that forms a layer, the myelin sheath, usually around only the axon of a neuron. It is essential for the proper functioning of the nervous system.

Action potential

The action potential threshold in a neuron is the point of depolarization at which the neuron fires, transmitting information to another neuron.

All-or-none response

The all-or-none law is a principle that states that the strength of a response of a nerve cell or muscle fiber is not dependent upon the strength of the stimulus. If a stimulus is above a certain threshold, a nerve or muscle fiber will fire.

Dendrite

The dendrites act as a "net", to catch/sense feelings outside the body.

Neurons

The neuron is the basic working unit of the brain, a specialized cell designed to transmit information to other nerve cells, muscle, or gland cells.

Reuptake

The process of reuptake, for example, affects serotonin. Serotonin is a neurotransmitter (a chemical messenger). It is produced by nerve cells in the brain and is used by nerves to communicate with one another.

Reuptake

The reabsorption of a secreted substance by the cell that originally produced and secreted it.

axon

The signal always travels in the same direction - the signal comes into the neuron through the dendrites, through the cell body (soma), to the axon, and then out the terminal buttons to the dendrites of the next neuron. In this way information travels all around your body by going from neuron to neuron.

All-or-none response

There are no big or small action potentials in one nerve cell - all action potentials are the same size. Therefore, the neuron either does not reach the threshold or a full action potential is fired - this is the "ALL OR NONE" principle. Action potentials are caused when different ions cross the neuron membrane.

Antagonist

They are sometimes called blockers; examples include alpha blockers, beta blockers, and calcium channel blockers.

Dendrite

are the branched projections of a neuron that act to propagate the electrochemical stimulation received from other neural cells to the cell body, or soma, of the neuron from which the dendrites project.

Refractory Period

cell will fail to respond to normal stimuli during the refractory period.

Hyperpolarization

is a change in a cell's membrane potential that makes it more negative. It inhibits action potentials by increasing the stimulus required to move the membrane potential to the action potential threshold.

Depolarization

is a change in the difference between the electric charge on the inside and the outside of the cell membrane and is when the cell becomes positively charged

Refractory Period

refers to the period of time during which the response to a second stimulus is significantly slowed because a first stimulus is still being processed.