NEURAL CONTROL AND COORDINATION SHORT NOTES FOR ( NEET/ CLASS 11)
1. Central Nervous System (CNS)
| Component | Description | Function |
|---|
| Brain | Protected by cranium | Control centre of body |
| Spinal cord | Extends from brain | Reflex actions & impulse conduction |
2. Protection of Brain (Meninges)
| Layer | Position | Feature | Function |
|---|
| Dura mater | Outer | Tough, collagenous | Protection |
| Arachnoid | Middle | Web-like | Forms subarachnoid space |
| Pia mater | Inner | Thin, vascular | Nourishment to brain |
| Subarachnoid space | Between arachnoid & pia | CSF present | Shock absorption |
3. Brain Matter
| Type | Location | Composition | Function |
|---|
| Grey matter | Outside | Cell bodies | Processing |
| White matter | Inside | Myelinated axons | Impulse conduction |
4. Forebrain
| Part | Function |
|---|
| Cerebrum(largest part of brain 85%) | Thinking, memory, intelligence, voluntary actions |
| Corpus callosum | Connects two cerebral hemispheres |
| Hippocampus | Memory (short → long term) |
| Amygdala | Emotions |
| Thalamus | Relay centre for impulses |
| Hypothalamus | Temperature, hunger, thirst, endocrine control |
| Epithalamus (Pineal) | Biological clock |
5. Cerebral Cortex Areas
| Area | Function |
|---|
| Sensory area | Receives sensations |
| Motor area | Controls voluntary movement |
| Association area | Memory, learning, intelligence |
6. Midbrain
consist of four swellings on dorsal side of brain
| Structure | Function |
|---|
| Superior colliculi | Visual reflex (looking +head movment) |
| Inferior colliculi | Auditory reflex (listening from behind +head movment) |
| Cerebral aqueduct canal through | CSF passage |
7. Hindbrain
| Part | Function |
|---|
| Cerebellum | Balance & coordination |
| Pons | Bridge between brain parts, breathing control |
| Medulla oblongata | Heart rate, breathing, vomiting reflex |
| Brainstem | Midbrain + pons + medulla |
8. Structure of Neuron
9. Generation of Nerve Impulse
| Stage | Event |
|---|
| Resting membrane potential | –70 mV |
| Threshold stimulus | –55 mV |
| Depolarization | Na⁺ channels open |
| Repolarization | K⁺ channels open |
| Hyperpolarization | –90 mV |
| Na⁺/K⁺ pump | Restores ions (3 Na⁺ out, 2 K⁺ in, uses ATP) |
10. Transmission of Impulse (Chemical Synapse)
| Step | Process |
|---|
| Arrival of impulse | Ca²⁺ channels open |
| Vesicle fusion | Exocytosis |
| Neurotransmitter release | Into synaptic cleft |
| Binding | Receptors on postsynaptic membrane |
| Response | Excitation or inhibition |
11. Electrical vs Chemical Synapse
| Feature | Electrical | Chemical |
|---|
| Synaptic cleft | Absent | Present |
| Speed | Very fast | Slower |
| Direction | Bidirectional | Unidirectional |
| Neurotransmitter | Not required | Required |
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