Biopsychology

• Central nervous system

  • Brain and spinal cord
  • Brain has two hemispheres and an outer cerebral cortex, protected by the skull
  • Brain controls complex processes: logic, language, vision and creativity
  • Spinal cord extends down from the brain stem, protected by vertebrae in the spine
• Peripheral nervous system

  • Neurones that carry impulses to and from the CNS
  • Sensory neurones - receptors to CNS
  • Motor neurones - CNS to effectors
  • Neurones bundled together to form nerves
• Somatic nervous system

  • Transmits information about external stimulation from skin and muscles to the CNS
  • Makes us aware of pain, pressure and temperature
  • Controls voluntary (conscious) movements
• Autonomic nervous system

  • Involuntary control of homeostatic mechanisms
  • To and from internal organs regulating respiration, heart rate and digestion
  • Regulates fight-or-flight
  • Sympathetic and parasympathetic divisions are antagonistic
  • Sympathetic - uses energy, prepares the body for action
  • Parasympathetic - restores energy, returns body to rest
• Endocrine system

  • A group of glands that release and produce hormones to regulate the body
  • A gland is a tissue or organ which secretes hormones directly into the blood e.g. pituitary gland, thyroid gland and Thymus
  • Uses hormones as signalling molecules (chemical messengers transported in the blood), released by endocrine glands
  • Can be slow to have effect, but have long-lasting effects
  • Hormones act on target tissues by binding to a specific receptor on the cell surface, triggering a response
• Adrenal glands

  • Above the kidneys
  • Cortex (outside)
  • Medulla (centre)
  • Medulla produces adrenaline in response to stress
  • Most cells of the body have adrenaline receptors, triggering a wide range of physiological changes
  • Medulla also produces noradrenaline, a neurotransmitter and hormone
  • Increases alertness, arousal and cognitive attention, constricts blood vessels to maintain blood pressure under stress
• Fight-or-flight

  • Occurs when we perceive a threat, leading to heightened awareness brought about by the sympathetic nervous system and adrenaline
  • Responses include pupils dilating, heart and blood pressure increasing, breathing rate and depth increasing, etc.
• Control of fight-or-flight

  1. Sense organ receptors detect stimuli linked to a threat
  2. Cerebral hemispheres in the brain process the information
  3. Hypothalamus increases activity of sympathetic division of the autonomic nervous system
  4. Sympathetic nervous system triggers release of adrenaline and noradrenaline from the medulla of adrenal glands
  5. Adrenaline triggers physiological changes, preparing for action
  6. Once the threat has passed, the parasympathetic division of the nervous system returns the body to rest