Exam 1

  • Soma (cell body): Contains the nucleus; keeps the neuron alive.

  • Nucleus: Holds DNA, controls cell functions.

  • Dendrites: Branches that receive messages from other neurons.

  • Axon: Long fiber that carries electrical signals (action potentials) away from soma.

  • Myelin sheath: Fatty insulation around axon; speeds signal transmission.

  • Nodes of Ranvier: Gaps in myelin where action potential jumps (“saltatory conduction”).

  • Axon terminal / Terminal buttons: Ends of axon; release neurotransmitters.

  • Vesicles: Small sacs in terminal buttons that hold neurotransmitters.

  • Synapse: Gap between neurons where neurotransmitters cross.

Glial cells:

  • Schwann cells: Make myelin in the PNS.

  • Oligodendrocytes: Make myelin in the CNS.

  • Astrocytes: Support, clean up neurotransmitters, help form blood-brain barrier.

  • Microglia: Immune defense in the brain.

  • Ependymal cells: Make cerebrospinal fluid.

⚡ Neurotransmitters

  • Dopamine: Movement, reward, learning (low = Parkinson’s; high = schizophrenia).

  • Serotonin: Mood, sleep, appetite (linked to depression).

  • Acetylcholine (ACh): Muscle action, memory (low = Alzheimer’s).

  • Substance P: Pain perception.

  • Endorphins: Natural painkillers, euphoria.

  • GABA: Major inhibitory NT (slows down brain activity).

  • Glutamate: Major excitatory NT (learning & memory).

  • Oxytocin: Bonding, trust, social behavior.

  • SSRIs (Selective Serotonin Reuptake Inhibitors): Drugs that keep serotonin in the synapse longer → treat depression/anxiety.

🏗 CNS & PNS Structures

CNS = brain + spinal cord;

PNS = everything else.

Four lobes:

  • Frontal: Thinking, decision-making, movement, speech.

  • Parietal: Touch, spatial processing.

  • Temporal: Hearing, language, memory.

  • Occipital: Vision.

Key brain regions:

  • Limbic system: Emotions & memory.

    • Amygdala: Fear, aggression.

    • Hippocampus: Memory formation.

    • Olfactory bulb: Smell, connects to emotion/memory.

  • Thalamus: Relay station for sensory info.

  • Hypothalamus: Hunger, thirst, sex, homeostasis.

  • Cerebellum: Balance, coordination.

  • Pons: Sleep, arousal, relay between cortex & cerebellum.

  • Pituitary gland: Master hormone gland.

  • Broca’s area: Speech production (frontal lobe).

  • Wernicke’s area: Language comprehension (temporal lobe).

  • Corpus callosum: Connects left & right hemispheres.

🔋 Neural Communication

  • Action potential: Electrical signal along axon (all-or-none).

  • Resting potential: Neuron at rest, inside negative compared to outside.

  • Active transport (Na+/K+ pump): Moves ions to restore resting potential.

  • Refractory period: After action potential, neuron can’t fire again immediately.

  • Exocytosis: Release of neurotransmitters from vesicles into synapse.

  • Presynaptic neuron: Sends signal.

  • Postsynaptic neuron: Receives signal.

  • Spatial summation: Many inputs at once trigger neuron to fire.

  • Temporal summation: Repeated inputs over time trigger firing.

  • Agonist: Drug that mimics/enhances neurotransmitter (ex: nicotine mimics ACh).

  • Antagonist: Drug that blocks neurotransmitter (ex: curare blocks ACh).

  • Depolarization: Inside of neuron becomes less negative (more likely to fire).

  • Hyperpolarization: Inside becomes more negative (less likely to fire).