Neurone Structure: Your Body's Wiring
Part of Nervous System — GCSE Biology
This deep dive covers Neurone Structure: Your Body's Wiring within Nervous System for GCSE Biology. Topic 2: Nervous System It is section 3 of 17 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 3 of 17
Practice
15 questions
Recall
20 flashcards
🔬 Neurone Structure: Your Body's Wiring
Figure 1: Structure of a motor neurone
Think of a neurone like a telephone cable. The axon is the long wire that carries the signal, the myelin sheath is the insulating plastic coating around the wire, and the dendrites are the branches that connect to other lines.
Parts of a motor neurone:
- Cell body — contains the nucleus and most of the cell's cytoplasm. This is the control centre of the neurone.
- Dendrites — short, branching extensions that receive electrical impulses from other neurones and carry them toward the cell body.
- Axon — a long, thin fibre that carries the electrical impulse away from the cell body toward the next neurone or effector. Some axons are over 1 metre long (from your spinal cord to your toes).
- Myelin sheath — a fatty layer that wraps around the axon in sections. It acts as an insulator and speeds up the transmission of electrical impulses by forcing the signal to jump between the gaps in the sheath.
- Axon terminals — branched endings at the tip of the axon that form synapses with the next neurone, muscle, or gland. This is where neurotransmitters are released.
There are three types of neurone, each with a slightly different shape. Sensory neurones have a long dendrite and a short axon. Motor neurones have short dendrites and a long axon. Relay neurones are short with many connections, found entirely within the CNS.