INTRODUCTION TO ANATOMY AND PHYSIOLOGY

The Nervous System

The Nervous System is responsible for all of our emotions, thoughts, and sensations – the five senses are:

  • SIGHT
  • SMELL
  • HEARING
  • TASTE
  • TOUCH

The system can be said to provide us with a sense of identity and consciousness (who we are, what we are and our environment [where we are]) thus providing us with the ability to survive and if required alter and change the environment around us!

As seen in the module on the Endocrine system – the Nervous System responds quickly to any requirement or stimuli and works effectively to provide the necessary response.  However, the system does work in conjunction with the Endocrine system,

It is made up of millions of nerve cells that all communicate with one another to control the body and maintain homeostasis. These cells detect what is happening both inside and outside the body, interpret these happenings and cause a response. The nervous system has three functions.

  1. Sensory Function – a stimulus is something that provokes a response, a change in the temperature of the air or a pin prick to a finger. The sensory receptors pick up stimuli that are taking place both inside and outside the body. All the information gathered by these sensory receptors is called sensory input.
  2. Integrative Function – once the nervous system has a sensory has new sensory input, it analyses, processes, and interprets this information in the brain and spinal cord. It is also able to store the information and make decisions regarding it.
  • Motor Function – having picked up a change in the environment and decided what to do about it, the final function of the nervous system is the ability to act or respond to a stimulus by glandular secretions or muscular contractions. This is called motor output.

The nervous system is divided into several subsystems:

Central Nervous System (CNS) and the Peripheral Nervous System (PNS).

The PNS is then subdivided into the somatic and autonomic nervous system, the autonomic nervous system is then divided into the sympathetic and parasympathetic nervous system.

The central nervous system is made up of the brain and the spinal cord and its function is analysing and storing information, making decisions, and issuing orders. It is where memories are made and stored, emotions generated, and thoughts conceived. The peripheral nervous system is made up of nerve cells that reach every part of the body and consist of cranial nerves and spinal nerves.

The somatic nervous system allows us to control our skeletal muscles. It is sometimes called the voluntary nervous system and contains, sensory neurones and motor neurones.

The autonomic nervous system controls all processes that are automatic or involuntary. Sympathetic and parasympathetic.

The structure of the peripheral system, face, and neck:

  • 12 pairs of cranial nerves
  • 31 pairs of spinal nerves
  • 5thcranial nerve (trigeminal)
  • 7thcranial nerve (facial)
  • 11thcranial nerve (accessory)

 

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