Coordination And Control: Mammalian Nervous System
14.1 Mammalian Nervous System
Overview
- Nervous system = coordinates and regulates body functions.
- Two main parts:
- Central Nervous System (CNS) → brain + spinal cord.
- Peripheral Nervous System (PNS) → nerves outside CNS.
Types Of Neurones
| Neurone | Function | Adaptations |
|---|---|---|
| Sensory | Carries impulses from receptors to CNS | Long axon, dendrites |
| Relay | Connects sensory + motor neurones in CNS | Short, many connections |
| Motor | Carries impulses from CNS to effectors (muscles/glands) | Long axon, ends at effector |
Reflex Arc
- Receptor → Sensory neurone → Relay neurone → Motor neurone → Effector.
- Reflex = fast, automatic, protective response.
Written And Compiled By Sir Hunain Zia, World Record Holder With 154 Total A Grades, 7 Distinctions And 11 World Records For Educate A Change O Level And IGCSE Biology Full Scale Course
Synapse
- Junction between two neurones.
- Impulse causes release of neurotransmitter into gap.
- Neurotransmitter diffuses → triggers impulse in next neurone.
- Synapses ensure impulses travel one way only.
Key Terms
- Impulse: electrical message along neurone.
- Effector: muscle (contracts) or gland (secretes).
- Reflex: automatic, rapid response for protection.
Written And Compiled By Sir Hunain Zia, World Record Holder With 154 Total A Grades, 7 Distinctions And 11 World Records For Educate A Change O Level And IGCSE Biology Full Scale Course