Nervous Control


A reflex is a simple form of nervous response, mediated by the nervous system found in mammals.

Nervous organisation

the nervous system is divided into two main parts:

  • The central nervous system, CNS, composing the brain and spinal chord
  • The peripheral nervous system, PNS, which carries nerve impulses away from the CNS towards the effectors

The peripheral nervous system is divided further:

  • Sensory neurones, which carry impulses from receptors towards the central nervous system
  • Motor neurones, which carry nerve impulses from the central nervous sytem towardse effectors.

Motor neurones can agin be broken down into 2 catagories:

  • Voluntary nervous system, which carries impulses to body muscles and is under voluntary, or conscious, control.
  • Autonomic nervous system, which carries nerve impulses to body glans, smooth muscle(such as in the gut), and cardiac muscle. The autonomic nervous system is not under voluntary control.

The spinal cord

The spinal cord runs from the brain down the back in humans, and is a column of nervous tissue. At regular intervals, pairs of nerves merge.


The reflex arc occurs in humans when…


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