🧠 Human Neural System: Control & Coordination

⭐ Key NEET Concepts

  1. CNS vs. PNS: Central (brain + spinal cord) vs. Peripheral (all body nerves)
  2. Nerve Fibre Types: Afferent (body → CNS) vs. Efferent (CNS → body)
  3. PNS Divisions: Somatic (voluntary muscles) & Autonomic (involuntary organs)
  4. Autonomic Subtypes: Sympathetic & Parasympathetic systems
  5. Neuron Structure: Cell body + Dendrites + Axon (with Nissl’s granules)

🌐 Neural System Basics

All animals have a neural system made of special cells called neurons! These cells:

  • 🔍 Detect stimuli
  • 📩 Receive signals
  • ⚡ Transmit messages

Fun fact: Simpler animals (like Hydra 🪸) have basic neuron networks, while insects 🐝 and humans have more complex systems!

🚀 Human Neural System: 2 Main Parts

1. Central Neural System (CNS) 🧠💪

  • Includes: Brain + Spinal Cord
  • Job: Processes info & makes decisions (like the body’s command center!)

2. Peripheral Neural System (PNS) 🌐

  • Includes: All nerves connected to the CNS
  • Two types of nerve fibres:
    • 👉 Afferent: Carry signals from body → CNS (e.g., “Ouch, hot pan!”)
    • 👈 Efferent: Carry signals from CNS → body (e.g., “Move your hand!”)

🔧 PNS Subdivisions

SystemPathwayControls
SomaticCNS → Skeletal musclesVoluntary actions (e.g., waving 👋, running 🏃‍♂️)
AutonomicCNS → Involuntary organs/smooth musclesAutomatic functions (e.g., heartbeat ❤️, digestion 🍕)

Note: Autonomic system splits into Sympathetic (fight/flight) and Parasympathetic (rest/digest)!

🧩 Neuron: Building Block of the Neural System

Each neuron has 3 key parts:

  1. Cell Body:
    • Contains cytoplasm & cell organelles
    • Holds Nissl’s granules (special protein-making granules!)
  2. Dendrites:
    • Short, branched fibres
    • Receive signals 📶
  3. Axon:
    • Long fibre (transmits signals away from cell body)

Think of neurons like 🌐 wiring that carries electricity (impulses) through your body!

💡 Quick Summary

  • CNS = Boss 🧠, PNS = Messengers 📨
  • Afferent = Sensors 🔔, Efferent = Doers 🏃‍♀️
  • Neurons = Tiny signal towers 📡 with 3 parts!

You’ve got this! The neural system is like your body’s internet – fast, connected, and super smart! 💪😄