Nervous System - Formula Sheet

Key Quantitative and Pathway Relations

Peripheral Nerve Count Equation

Total PNS Nerves = 2 x (Cranial Nerve Pairs + Spinal Nerve Pairs) = 2 x (12 + 31) = 86 total nerves (or 43 pairs).

Neuron Impulse Conduction Capacity

Transmission Rate = up to 1,000 impulses per second per neuron. Synaptic Interconnections = up to 10,000 synaptic contacts per neuron.

Brain Structural Composition

Fat Content Percentage = approximately 60% of human brain dry weight, requiring Essential Fatty Acids obtained from dietary sources.

Reflex Neural Pathway Sequence

Stimulus leads to Sensory Receptor, which leads to Sensory Neuron, which leads to Spinal Cord Central Interneuron, which leads to Motor Neuron, which leads to Effector Organ, resulting in Response.