Your nervous system is like your body's electrical wiring -... Show more
Biology116 views·Updated May 16, 2026·2 pagesUnderstanding the Nervous System: Nerve Cells and Synapses Explained
J
Jess Drew@rj2105
1
of 2
The Nervous System and Neurone Types
Think of your nervous system as your body's control centre - it's built from individual neurones, your brain, and your spine working together. There are three main types of neurones, and they're all specially adapted to carry electrical signals super quickly.
These neurones have brilliant adaptations: the myelin sheath (like insulation on a wire), branched terminals for better connections, and long, thin shapes for efficient signal travel. Your nervous system splits into two parts: the CNS (Central Nervous System) - your brain and spine - and the PNS (Peripheral Nervous System) - all your other nerves.
Here's how information flows: Stimulus → Receptor Cell → Sensory Neurone → Relay Neurone + CNS → Motor Neurone → Effector → Response. Motor neurones carry signals away from your CNS to muscles (effectors), with their cell body at the dendrite end. Sensory neurones are different - their cell body sits in the middle of the axon, and they carry information from your senses towards your CNS.
Quick Tip: Remember that sensory neurones sense things and send signals TO your brain, while motor neurones send messages FROM your brain to make muscles move!
2
of 2
Synapses and Reflex Actions
Relay neurones only exist in your CNS and are absolutely crucial for reflexes - they're more rounded than other neurones and act like middlemen between sensory and motor neurones. But how do neurones actually "talk" to each other? That's where synapses come in.
When an electrical signal reaches the axon terminal, it triggers calcium channels to open. Here's the clever bit: neurotransmitter-filled vesicles are already docked at the membrane using proteins. The calcium ions bind to these proteins, pulling the vesicles closer until the membranes merge and release neurotransmitters into the synaptic cleft.
Reflex arcs are your body's emergency response system. A stimulus hits receptor cells, travels via sensory neurones to your spinal cord, gets processed by relay neurones, then shoots back through motor neurones to effector muscles - all without your brain getting involved! This means you can pull your hand away from something hot before you've even consciously felt the pain.
Remember: Reflexes bypass your brain completely - they're processed in your spinal cord, which is why they're so incredibly fast!
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Biology116 views·Updated May 16, 2026·2 pagesUnderstanding the Nervous System: Nerve Cells and Synapses Explained
J
Jess Drew@rj2105
Your nervous system is like your body's electrical wiring - it controls everything from blinking to breathing. Understanding how neurones (nerve cells) work and communicate through synapses will help you grasp how your body responds to the world around you,... Show more
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The Nervous System and Neurone Types
Think of your nervous system as your body's control centre - it's built from individual neurones, your brain, and your spine working together. There are three main types of neurones, and they're all specially adapted to carry electrical signals super quickly.
These neurones have brilliant adaptations: the myelin sheath (like insulation on a wire), branched terminals for better connections, and long, thin shapes for efficient signal travel. Your nervous system splits into two parts: the CNS (Central Nervous System) - your brain and spine - and the PNS (Peripheral Nervous System) - all your other nerves.
Here's how information flows: Stimulus → Receptor Cell → Sensory Neurone → Relay Neurone + CNS → Motor Neurone → Effector → Response. Motor neurones carry signals away from your CNS to muscles (effectors), with their cell body at the dendrite end. Sensory neurones are different - their cell body sits in the middle of the axon, and they carry information from your senses towards your CNS.
Quick Tip: Remember that sensory neurones sense things and send signals TO your brain, while motor neurones send messages FROM your brain to make muscles move!
2
of 2Sign up to see the content. It's free!
- Access to all documents
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Synapses and Reflex Actions
Relay neurones only exist in your CNS and are absolutely crucial for reflexes - they're more rounded than other neurones and act like middlemen between sensory and motor neurones. But how do neurones actually "talk" to each other? That's where synapses come in.
When an electrical signal reaches the axon terminal, it triggers calcium channels to open. Here's the clever bit: neurotransmitter-filled vesicles are already docked at the membrane using proteins. The calcium ions bind to these proteins, pulling the vesicles closer until the membranes merge and release neurotransmitters into the synaptic cleft.
Reflex arcs are your body's emergency response system. A stimulus hits receptor cells, travels via sensory neurones to your spinal cord, gets processed by relay neurones, then shoots back through motor neurones to effector muscles - all without your brain getting involved! This means you can pull your hand away from something hot before you've even consciously felt the pain.
Remember: Reflexes bypass your brain completely - they're processed in your spinal cord, which is why they're so incredibly fast!
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