Edexcel A Level (IAL) Biology -8.10 Central & Peripheral Nervous System- Study Notes- New Syllabus

Mammalian Nervous System

🌱 Introduction

The mammalian nervous system is a complex communication network that controls body functions by transmitting electrical impulses. It enables mammals to:

• Respond quickly to the environment
• Coordinate internal body activities
• Maintain homeostasis

It consists of two main divisions: Central Nervous System (CNS) and Peripheral Nervous System (PNS).

1. Central Nervous System (CNS)

• Structure:
  • Brain: Controls higher functions (thinking, memory, coordination, emotions)
  • Spinal cord: Connects brain to the body; acts as a reflex centre
• Function:
  • Integration: Processes incoming sensory information
  • Decision making: Generates appropriate responses
  • Reflex actions: Provides fast automatic responses
• Protection:
  • Encased in skull (brain) and vertebrae (spinal cord)
  • Cushioned by cerebrospinal fluid (CSF)
  • Surrounded by meninges

2. Peripheral Nervous System (PNS)

• Structure: All neurones outside CNS, includes sensory (afferent) and motor (efferent) neurones
• Function:
  • Sensory (afferent) nerves: Carry impulses from receptors to CNS
  • Motor (efferent) nerves: Carry impulses from CNS to effectors (muscles or glands)
• Divisions:
  • Somatic Nervous System: Controls voluntary actions (skeletal muscles)
  • Autonomic Nervous System: Controls involuntary actions (heart, glands, smooth muscles)

Key Points

• CNS: Integrates information, controls voluntary and involuntary responses
• PNS: Connects CNS with the rest of the body
• Sensory nerves = input to CNS
• Motor nerves = output from CNS
• Autonomic system ensures internal organs function automatically

📊 Summary Table