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Resting Membrane Potential

-70mV: This is the "Stretched Rubber Band" state where the neuron is quiet but pressurized and ready to fire.

The Na+/K+ Pump

The Maintenance Engine: It spends ATP to force 3 Sodium OUT and 2 Potassium IN, creating the negative charge and concentration pressure needed for a spark.

Concentration Gradient

The "Crowded Room" force: Nature hates imbalances, so Sodium is dying to get into the cell because it is way too crowded on the outside.

Electrical Gradient

The "Magnet" force: Since the inside is negative, the positive Sodium ions are physically pulled toward the interior like magnets.

The Threshold

-55mV: The "Point of No Return": If the neuron gets "poked" enough to hit this number, the voltage-gated gates burst open and you get a full action potential.

All-or-None Law

The Gun Trigger Rule: A neuron either fires at 100% or 0%

Depolarization

The +40mV Snap: When the gates open and Sodium rushes in explosively, flipping the cell from negative to positive.

Repolarization

The Reset: To stop the spark, Potassium (K+) rushes OUT of the cell to bring the voltage back down to a negative level.

Refractory Period

The "Wait Time": A brief moment after a spark where the gates are locked and the pump has to reset the balance so the signal doesn't accidentally travel backward.

Saltatory Conduction

The "Jump": In myelinated axons, the spark jumps between the Nodes of Ranvier, which is way faster and uses less energy than walking down the whole axon.

The Synaptic Gap

The Physical Break: Because neurons don't actually touch, the electrical spark must be converted into a chemical message to cross the empty space.

Vesicles

The Delivery Trucks: These are little bags that hold neurotransmitters at the terminal until the spark tells them to dump their cargo into the gap.

Exocytosis

The Cargo Dump: When Calcium enters the terminal, it triggers these vesicles to fuse with the membrane and spill the chemicals into the synapse.

EPSP

The "Excitatory" Poke: A signal that lets positive ions in, pushing the next neuron closer to -55mV so it will fire.

IPSP

The "Inhibitory" Chill: A signal that lets negative ions in, pulling the next neuron further away from its threshold so it stays quiet.

Ionotropic Receptors

The Doorbell: A fast receptor where the chemical lands and the gate opens immediately.

Metabotropic Receptors

The Intercom: A slow receptor that uses a "G-Protein" (second messenger) to trigger a complex chain reaction inside the cell.

Reuptake

The Vacuum: A way to clean the synapse by sucking the neurotransmitters back into the original neuron to be reused.

Enzymatic Degradation

The Paper Shredder: When specific proteins (enzymes) break the neurotransmitters into pieces to stop the signal.

Autoreceptors

The Thermostat: Sensors on the sending neuron that detect how much chemical is in the gap

Retrograde Messengers

The Feedback Loop: Chemicals (like Nitric Oxide) that travel backward from the receiving neuron to the sending neuron to give feedback.

Loewi’s Frog Heart Experiment

The Chemical Proof: He proved nerves use chemicals by slowing one heart with a nerve, then using that same water to slow a second heart.

Glutamate

The Main Gas Pedal: The primary excitatory neurotransmitter in the brain that tells neurons to "Fire!"

GABA

The Main Brakes: The primary inhibitory neurotransmitter that tells the brain to "Calm down."

Acetylcholine (ACh)

Movement & Memory: The chemical used to make your muscles contract and to keep your memory sharp.

Dopamine

Reward & Smoothness: Controls the "wanting" feeling (reward) and helps the Basal Ganglia make your body movements smooth.

Catecholamines

The Stress Trio: A group of chemicals including Dopamine, Norepinephrine, and Epinephrine.

Dorsal

Toward the back (like a shark fin).

Ventral

Toward the belly/front.

Anterior

Toward the face/front.

Posterior

Toward the tail/back.

Frontal Lobe

The CEO: Located at the front

Parietal Lobe

The Body Map: Located at the top/back

Occipital Lobe

The Eyes: Located at the very back

Temporal Lobe

The Ears & Faces: Located by the temples

Thalamus

The Switchboard: The relay station that takes sensory info and "plugs" it into the correct part of the cortex.

Hypothalamus

The 4 F's: Regulates the body's internal state (Fighting, Fleeing, Feeding, and Mating).

Medulla & Brainstem

The Survival Core: Controls the stuff you don't think about, like heart rate and breathing.

Corpus Callosum

The Bridge: The giant bundle of white matter "wires" that lets the left and right brain talk to each other.

Basal Ganglia

The Movement Smoothers: A group of structures that work with Dopamine to make sure your movements aren't shaky.

Sympathetic Nervous System

Fight or Flight: Speeds everything up (heart, lungs) to help you survive a threat.

Parasympathetic Nervous System

Rest and Digest: Calms you down and restarts digestion once the threat is gone.

Astrocytes

The Nurses: Star-shaped glia that feed the neurons and help build the Blood-Brain Barrier.

Oligodendrocytes

CNS Myelinators: They wrap the "wires" in the Brain and Spine to make the signal go faster.

Schwann Cells

PNS Myelinators: They wrap the "wires" in the rest of your Body (limbs, organs).

Microglia

The "Janitors" of the brain that clean up debris and dead cells.

Blood-Brain Barrier

The Security Guard: A tight wall of cells that prevents toxins in your blood from entering the brain's sensitive environment.

White Matter

The Wires: Mostly myelinated axons that carry information from one "processor" to another.

Gray Matter

The Processors: Mostly cell bodies and dendrites where the actual "thinking" and integration happen.

Cerebrospinal Fluid

The Cushion: The fluid in the ventricles that allows the brain to "float" so it doesn't hit the skull.

Meninges

The Wrappers: Three layers of protection (Dura, Arachnoid, Pia) that keep the brain contained and safe.

Anterior Commissure

The Secondary Bridge: A smaller bridge than the corpus callosum that also helps the two sides communicate.

Hindbrain

The Survival Center: The oldest part of the brain that handles stuff you don't think about.

Midbrain

The Reflex Station: Acts as a relay for basic visual and auditory reflexes.

Forebrain

The "Human" Brain: The newest, largest part of the brain that handles complex thought and senses.

Here are the specific cards for Section 6 (Major CNS Structures & Functions) and Section 7 (Other Important Concepts).

I’ve made sure to include the directional terms, the specific lobes, the spinal cord laws, and the cellular structures exactly as they appeared on your study list.

Copy this block for Section 6 & 7:

Dorsal

Toward the back: Think of a shark’s dorsal fin

Ventral

Toward the belly: In the spinal cord, this is where motor commands exit to the muscles.

Anterior

Toward the front: Toward the face or the "front" end of the organism.

Posterior

Toward the back/tail: Toward the rear end of the organism.

Medial

Toward the middle: Moving toward the center line of the body or brain.

Lateral

Toward the sides: Moving away from the center toward the left or right sides.

Frontal Lobe

The CEO: Located at the front

Parietal Lobe

The Body Map: Located at the top/back

Occipital Lobe

The Eyes: Located at the very back

Temporal Lobe

The Ears & Faces: Located by the temples

Bell-Magendie Law

Sensory In / Motor Out: The rule that sensory information enters through the dorsal roots and motor information exits through the ventral roots.

Hindbrain

The Survival Center: The oldest part of the brain (Medulla, Pons, Cerebellum) that handles vital survival functions like breathing and balance.

Midbrain

The Reflex Station: A middle relay area that handles basic visual and auditory reflexes (like jumping at a loud noise).

Forebrain

The "Human" Brain: The largest part of the brain (Cortex, Thalamus, Hypothalamus) that handles complex thought and emotion.

Thalamus

The Switchboard: The main relay station that takes sensory info and "plugs" it into the correct part of the cortex.

Hypothalamus

The 4 F's: Regulates the body's internal state (Fighting, Fleeing, Feeding, and Mating) and controls hormones.

Medulla

The Survival Core: Part of the hindbrain that controls automatic vitals like heart rate, breathing, and sneezing.

Brainstem

The Life Support: Made of the medulla, pons, and midbrain

Corpus Callosum

The Main Bridge: The giant bundle of white matter "wires" that allows the left and right hemispheres to communicate.

Anterior Commissure

The Secondary Bridge: A smaller wire bundle that also connects the two hemispheres, specifically the temporal lobes.

Basal Ganglia

The Movement Smoothers: A group of structures that work with dopamine to make sure your movements are smooth and planned.

CNS vs. PNS

Core vs. Outer: The Central Nervous System is the Brain/Spine

Sympathetic Nervous System

Fight or Flight: The part of the PNS that speeds up heart rate and prepares the body for action/stress.

Parasympathetic Nervous System

Rest and Digest: The part of the PNS that calms the body down and restarts digestion after stress.

Neuron Structure Flow

Dendrites -> Soma -> Axon: Info is received by Dendrites, integrated in the Soma, and sent out via the Axon.

Astrocytes

The Nurses: Star-shaped glia that provide nutrients to neurons and help form the Blood-Brain Barrier.

Oligodendrocytes

CNS Myelinators: Glial cells that wrap axons in myelin specifically within the Brain and Spinal Cord.

Schwann Cells

PNS Myelinators: Glial cells that wrap axons in myelin in the rest of the body (Peripheral system).

Microglia

The Janitors: Immune-like glia that clean up debris, dead cells, and infections in the brain.

White Matter

The Wires: Areas of the brain made of myelinated axons that carry information between regions.

Gray Matter

The Processors: Areas of the brain made of cell bodies and dendrites where information is actually processed.

Blood-Brain Barrier

The Security Guard: A tight wall of blood vessels that protects the brain from toxins and bacteria in the blood.

Ventricular System

The Cushion: Chambers filled with CSF (Cerebrospinal Fluid) that let the brain float so it doesn't hit the skull.

Meninges

The Wrappers: Three protective layers (Dura, Arachnoid, Pia) that act as a shock absorber for the brain.

86 Billion

The Neuron Count: The approximate number of neurons found in the human brain.

Brain Plasticity

The brain's ability to change: It can rewire itself by changing the strength of existing synapses or growing new ones based on experience.

Short-term vs. Long-term Synaptic Changes

Seconds vs. Days: Short-term is usually just a temporary boost in neurotransmitter release

Hebb’s Rule

"Neurons that fire together, wire together": If Cell A consistently helps fire Cell B, the connection between them gets stronger.

LTP (Long-Term Potentiation)

The long-lasting strengthening of a synapse: This is the cellular basis of learning and memory.