The Nervous System

The Nervous System is made up of the Central Nervous System(CNS) and the Peripheral Nervous System(PNS).

Central Nervous System(CNS)

The CNS has two main functions, of controlling behaviours and regulating physiological processes by receiving and sending messages to and from various parts of the body. The CNS is split into two parts:

  •  The Spinal Cord:
    • Relays information between the brain and the rest of the body, allowing for bodily processes to be regulated and voluntary movement to be coordinated
  • The Brain: split into four areas
      • Cerebrum
        • Split into two hemispheres:
          • Left: aware of past and future, controls the right side of the body and is the logical side
          • Right: aware of the present, controlling the left side of the body and is the creative side.
            • These are joined by the corpus callosum which is a band of nerve fibres allowing for communication between the two
        • Split into four lobes:
          • Frontal: associated with reasoning and motor skills, sexual habits, risk taking and socialisation
          • Parietal: deals with sensory information, perceotion and spatial reasoning
          • Temporal: Deals with sound and language, linked to memory (hippocampus)
          • Occipital: deals with visual information
      • Cerebellum: associated with otor skills, balance and muscle coordination
      • Diencephalon: contains two key structures
        • Hypothalamus- regulates temperature, hunger and thirst, so is the link between the endocrine system and the nervous system
        • Thalamus- relay station for nerve impulses (from senses)
      • Brain Stem: regulates automatic functions while linking brain to spinal cord

Peripheral Nervous System(PNS)

The PNS is everything eithin the nervous system that isnt the brain or spinal cord. It is in charge of relaying nerve impulses from the CNS to the rest of the body and vice versa. It is split into two sections:

  • Somatic Nervous System: sends sensory information to and from CNS, allows for quick reflex actions
  • Autonomic Nervous System:regulates the involuntary actions of the body such as breathing and is vital for everyday functioning. This is further split into two subsections:
    • Sympathetic Nervous System- “Fight-or-flight”:
      • uses noradrenaline, a stimulant which allows for quick actions in emergency situations where we feel threatened. This sends neurons to every organ or gland when needed, and increases heart rate, blood pressure. and dilates blood vessels. It allows for the release of stored energy, enhancing functions needed for survival and temporarily stops non-vital functions such as urination and digestion
    • Parasympathetic Nervous System- “Rest-and-digest”:
      • uses acetylcholine, an inhibitant to restore calm after an emergency, slowing heartbeat, reducing blood pressure, restarts digestion and allows for energy conservation.