Chapter Six

Central Nervous System (CNS)

Brain and spinal cord; integrates sensory information.

Peripheral Nervous System (PNS)

Nerves outside CNS; connects to limbs and organs.

Neurons

Basic cell type; generates electrical signals.

Glial Cells

Supportive cells; do not generate electrical signals.

Dendrites

Receive incoming information from other neurons.

Cell Body

Contains nucleus; integrates incoming information.

Axon

Carries outgoing signals to target cells.

Myelin Sheaths

Insulate axons; speed up signal conduction.

Oligodendrocytes

CNS cells that myelinate axons.

Schwann Cells

PNS cells that myelinate axons.

Saltatory Conduction

Jumping of action potentials between nodes.

Anterograde Transport

Transport of materials from cell body to axon.

Retrograde Transport

Transport of materials from axon to cell body.

Afferent Neurons

Carry information towards the CNS.

Efferent Neurons

Carry information away from the CNS.

Interneurons

Connect neurons within the CNS.

Synapse

Junction between two neurons for signal transmission.

Neurotransmitters

Chemicals released at synapses to transmit signals.

Resting Membrane Potential

Negative charge inside cell; -40 to -90 mV.

Na+/K+ ATPase Pump

Maintains concentration gradients of Na+ and K+.

Graded Potentials

Localized changes in membrane potential.

Action Potentials

Rapid, large changes in membrane potential.

Refractory Period

Time during which neuron cannot fire again.

Chemical Synapse

Utilizes neurotransmitters for communication.

Electrical Synapse

Direct electrical connection between neurons.

Excitatory Postsynaptic Potential

Depolarization that increases likelihood of action potential.

Inhibitory Postsynaptic Potential

Hyperpolarization that decreases likelihood of action potential.

Temporal Summation

Multiple stimuli at one synapse over time.

Spatial Summation

Simultaneous stimuli at multiple synapses.

Acetylcholine (ACh)

Neurotransmitter involved in muscle activation and memory.

Biogenic Amines

Small neurotransmitters derived from amino acids.

Neuropeptides

Chains of amino acids acting as neurotransmitters.

Cerebrospinal Fluid

Fluid that cushions and protects the brain.

Blood-Brain Barrier

Selective barrier protecting the brain from toxins.