The nervous system

What are the main components of a nervous response?

Detection by receptors, transmission via neurones, response by effectors.

Describe spinal cord structure.

Spinal cord has grey matter (cell bodies), white matter (axon tracts), dorsal (sensory), ventral (motor) roots.

Define a reflex arc.

Reflex arc: rapid, involuntary response pathway bypassing the brain for immediate reactions.

Compare nerve nets and complex nervous systems.

Nerve nets (simple organisms, e.g., Cnidaria) diffuse, no centralisation; complex systems (vertebrates) highly centralised.

What are neuron structures/functions?

Dendrites receive signals, axons transmit impulses, myelin sheath speeds transmission.

Explain how nerve impulses are transmitted.

Action potentials propagate along neurones due to voltage changes across membrane.

How does synaptic transmission occur?

Synaptic transmission: neurotransmitter release, binding to receptors, initiating postsynaptic action potential.

How can drugs affect nerve transmission?

Drugs alter synaptic transmission, enhancing/inhibiting nerve impulses.