Week 6-Set 2 just outline VOCAB Neural and Endocrine

Motor Neurons

Channels of communication that carry outgoing neural information from the brain and spinal cord to muscles, organs, and glands.

Sensory Neurons

Channels of communication that carry incoming neural information from the body's sensory receptors inward to the brain.

Interneurons

Neurons within the brain and spinal cord that communicate internally and intervene specifically between sensory inputs and motor outputs.

Dendrites

The bushy, branching extensions of a neuron covered with synaptic receptors that receive incoming chemical signals from other neurons.

Cell Body (Soma)

The main, essential part of the neuron containing the nucleus

Axon

The long extension of a neuron that transmits information as neural impulses away from the cell body to other neurons, glands, or muscles.

Tracts

Bundles of neuron axons that travel together within the Central Nervous System (the brain and spinal cord).

Nerves

Bundles of neuron axons that travel together within the Peripheral Nervous System (the body).

Terminal (Axon Ending)

The small branching end of the axon containing vesicles that release chemical messengers known as neurotransmitters into the synapse.

Synapse

The tiny, fluid-filled gap between the axon terminal of the sending neuron and the dendrite receptor site of the receiving neuron.

Glial Cells

Abundant support cells in the nervous system that assist neurons by building the myelin sheath, supplying nutrients/oxygen, maintaining synapses, and stimulating repair.

Resting Potential (Polarization)

The default electrical state of an inactive axon, where negatively charged ions build up along the inside of the membrane and positively charged ions build up on the outside.

Sodium and Potassium (Resting State)

The primary ions involved in neural communication

Depolarization

The rapid electrical change that occurs when a neuron's firing threshold is reached, causing sodium channels to open so sodium ions rush inside, triggering an action potential.

Sodium Pump

The cellular mechanism that actively pumps sodium ions back out of the inside of the axon after depolarization to re-establish the resting potential.

Presynaptic Terminal

The sending side of the communication gap, located at the very tip of the axon terminal where neurotransmitters are spilled into the synapse.

Postsynaptic Terminal

The receiving side of the communication gap, located on the dendrite membrane where neurotransmitters bind to specific receptors.

Excitatory Effect

The effect of a neurotransmitter binding to a receptor that decreases polarity in the synapse, causing an influx of sodium and increasing the likelihood that the next neuron will fire.

Inhibitory Effect

The effect of a neurotransmitter binding to a receptor that increases polarity by allowing chloride and potassium into the synapse, raising the firing threshold and decreasing the likelihood that the next neuron will fire.

Reuptake

The recycling process where neurotransmitters are pulled back up into the presynaptic axon terminal after being released, turning off the signal.

Multiple Sclerosis (MS)

A chronic neural disease characterized by demyelination, which is the destruction of the protective fatty myelin sheath surrounding axons, slowing down communication.

Myasthenia Gravis

A neuromuscular disease caused by the immune system blocking or destroying the receptors for acetylcholine (ACH) at muscles and joints, causing severe muscle weakness.

Reflex Arc

A rapid, automatic, and protective neural pathway that controls a reflex action, usually involving sensory, interneuron, and motor neurons interacting strictly within the spinal cord.

Substance P

A specialized neurotransmitter that is intensely involved in the transmission of pain signals and inflammatory responses throughout the nervous system.

Adrenaline (Epinephrine)

A hormone produced by the adrenal glands that triggers the body's acute stress response, accelerating heart rate and increasing energy during fight-or-flight scenarios.

Leptin

A hormone produced by fat cells that acts on the brain to suppress appetite and signal a feeling of long-term fullness or energy abundance.

Ghrelin

A hormone secreted by an empty stomach that sends "I'm hungry" signals to the brain, stimulating appetite and food intake.

Melatonin

A hormone manufactured by the pineal gland that regulates the body's internal sleep-wake cycle and circadian rhythms, inducing drowsiness.

Oxytocin

A hormone and neurotransmitter involved in social bonding, trust, romantic attachment, and triggering contractions during childbirth.

Agonist

A drug or chemical that mimics a natural neurotransmitter, binding directly to dendrite receptors and successfully forcing the neuron to fire.

Antagonist

A drug or chemical that binds onto receptor sites and blocks them, preventing the natural neurotransmitter from connecting and keeping the neuron from firing.

Reuptake Inhibitors

Drugs that block the presynaptic neuron from reabsorbing neurotransmitters, leaving more chemicals floating in the synapse to repeatedly stimulate the receptors.