Biopsychology: the nervous system

• The nervous system is a specialised network of cells in the human body and is our primary internal communication system.
• Two main functions of the nervous system:

  • collect, process and respond to information.
  • co-ordinate the working of different organs and cells in the body.
• The nervous system is divided into two sub-systems:

  1. Central Nervous System (CNS): this system includes the brain and spinal cord.
  2. Peripheral Nervous System (PNS): this system includes all of the nervous system throughout the rest of the body.
• The central nervous system (CNS):
• The peripheral nervous system extends beyond the CNS and transmits messages to the whole body from the brain and vice versa. It has two divisions: the somatic system and the autonomic system.
• PNS: Somatic system -

  Main job is to transmit and receive messages from the senses such as visual info from the eyes and auditory info from the ears. It also directs muscles to react and move - controls skeletal muscle movement (sensory and motor).
• PNS: Autonomic system -

  Helps transmit and receive information from the organs (purely motor) and is further divided into two systems:

  1. Sympathetic pathway (which increases activity) such as breathing, heart rate, sexual arousal and stress response.
  2. Parasympathetic pathway (which saves the body's natural activity levels) by decreasing activity or maintaining it/
• Fight or flight:

  • the fight of flight response is generated from the autonomic nervous system, specifically the sympathetic branch.
  • its a reflex response designed to help an individual manage physically when under threat: activated in times of stress as the body perceives stress to be a threat.
  • the fight or flight response helps an individual react quicker than the normal and facilitates optimal functioning so they can fight the threat or run away from it which happens in a series of steps.
• Sympathetic state - physical changes

  • Increases heart rate = to speed up the blood flow to vital organs, and improve spread of adrenaline around the body.

  • Dilated pupils = to improve vision.
  • Increases breathing rate = to increase oxygen intake.
• Female response to fight or flight:

  • Flight or flight disadvantageous for females because confronting or fleeing from a predator would make it difficult to protect her offspring.
  • Early research into fight or flight was based exclusively on male animals because they were preferred for research, due to female hormones fluctuating.