What the exam asks
- Concept application (MCQ & EBQ): Identifying which neurotransmitter, hormone, or neural structure explains a behavior or symptom in a scenario.
- Sequence and mechanism (MCQ): Ordering the steps of an action potential or tracing a spinal reflex arc.
- Research and data (MCQ sets & AAQ): Interpreting studies where neurotransmitter or hormone levels are measured as dependent variables or manipulated as independent variables.
Core ideas
Neurons, glial cells, and the reflex arc
The nervous system consists of two main cell types:
- Neurons: Nerve cells that receive, integrate, and transmit electrochemical information.
- Glial cells (glia): Support cells that provide structure, insulation (forming myelin), nutrition, and waste removal for neurons, playing a vital role in learning and neural communication.
| Structure | Function in Neural Transmission |
|---|---|
| Dendrites | Branching fibers that receive chemical messages from adjacent neurons. |
| Cell body (soma) | Contains the nucleus; integrates incoming signals and keeps the cell alive. |
| Axon | Long single fiber that sends the electrical impulse (action potential) away from the soma. |
| Myelin sheath | Fatty tissue layer (made by glial cells) insulating the axon to speed up neural impulses. |
| Axon terminals | Terminal branches that release chemical messengers (neurotransmitters) from vesicles. |
| Synapse | The microscopic gap (synaptic cleft) between the axon terminal of the sending neuron and the dendrite of the receiving neuron. |
In a reflex arc, three types of neurons work together in the spinal cord to produce an automatic response before the brain processes pain:
- Sensory (afferent) neurons carry incoming information from sensory receptors to the spinal cord and brain.
- Interneurons inside the spinal cord and brain process the signal and link sensory and motor neurons.
- Motor (efferent) neurons carry outgoing instructions from the central nervous system to muscles and glands.