Biopsychology

• Nervous system


  Body wide system of nerve cells that collects information from the world, processes this information and then takes action by directing bodily organs and muscles via the transmission of electrochemical messages
• Divisions of the nervous system

  • Central nervous system (CNS)
  • Peripheral nervous system (PNS)
  • Autonomic nervous system (ANS)
  • Somatic nervous system (SNS)
• Central nervous system (CNS)


  Involves complex processing, includes the brain for all conscious and most unconscious processing, and the spinal cord which receives and transmits information and some reflex processing
• Peripheral nervous system (PNS)

  A body-wide network of messenger neurons, sensory afferent neurons take information to the CNS, motor efferent neurons take information away from the CNS
• Autonomic nervous system (ANS)


  The part of the PNS that controls actions of internal glands and is an involuntary system so not under conscious control
• Somatic nervous system (SNS)


  The part of the PNS that controls skeletal muscles, it's a voluntary system so under conscious control
• Parts of the ANS


  • Sympathetic system
  • Parasympathetic system
• Sympathetic system


  Part of the ANS, increases bodily activities, release of noradrenaline, activates the fight or flight response, increases heart rate, sweat, breathing rate, and dilates pupils
• Parasympathetic system


  Part of the ANS, decreases bodily activities, releases acetylcholine, activates the rest and digest response, decreases heart rate, sweat, and breathing rates, constricts pupils
• Homeostasis is maintained by a balance between the sympathetic and parasympathetic systems
• Endocrine system


  • Pituitary gland
  • Hypothalamus
  • Pineal gland
  • Thyroid gland
  • Adrenal glands
  • Ovaries
  • Testicles
• Pituitary gland


  Also known as the master gland, produces hormones that control the release of hormones from other glands
• Hypothalamus


  Hormone CRH links the nervous system to the endocrine system
• Pineal gland


  Hormone melatonin modulates sleep pattern, keeping the body to a day-night rhythm
• Thyroid gland


  Hormone thyroxine modulates metabolism, the rate of use in the body
• Adrenal glands


  Hormone adrenaline regulates the effect of the fight or flight response
• Ovaries


  Hormone estrogen develops secondary sexual characteristics in females
• Testicles


  Hormone testosterone leads to the development of secondary sexual characteristics in males
• Components of the reflex arc

  • Sensory neuron
  • Relay neuron
  • Motor neuron
• Sensory neuron


  Its function is to detect sensations, for example pain, at sensory receptors. An action potential then travels across the nerve, passing along the myelinated axon, and then the electrical signal is converted into a chemical signal to cross the synapse.
• Relay neuron


  Its function is to aid transmission, a new action potential forms in the dendrites, this neuron is in the spine and sends a signal to the CNS but also immediately sends a signal along its axon to the motor neuron.
• Motor neuron


  Its function is to detect the signal from the relay neuron by a synaptic transmission and then pass the signal along its own myelinated axon to stimulate an effector, for example a muscle group in the arm, moving it away from the source of pain.
• Synaptic transmission


  Neurotransmitters are released from the presynaptic neuron, they bind to receptors on the postsynaptic neuron, changing the chemistry within and potentially generating a new action potential.
• Neurotransmitters


  Chemical messages released by neurons, they are either excitatory (stimulate) or inhibitory (make less likely).
• Action potential generation


  The action potential travels down the axon of the presynaptic neuron, forcing vesicles containing neurotransmitters to merge with the cell membrane and release neurotransmitter into the synaptic cleft. Receptors on the postsynaptic neuron's dendrite membrane detect the presence of neurotransmitters, changing the chemistry within the postsynaptic neuron.
• Excitation


  Excitatory neurotransmitters increase the likelihood of a new action potential forming in the postsynaptic cell, the electrical charge inside becomes more positive and likely to fire (depolarization).
• Inhibition


  Inhibitory neurotransmitters decrease the likelihood of a new action potential forming in the postsynaptic cell, the electrical charge inside becomes more negative and less likely to fire (hyperpolarization).
• Summation


  The combined effect of all inhibitory and excitatory influences, resulting in a new action potential forming or not.
• Information can only be passed between the pre- and post-synaptic neurons in one direction, due to the structure of the synapse.
• Fight or flight response

  Stressor detected by the hypothalamus, HPA axis in the endocrine system activated, pituitary gland releases ACTH, adrenal cortex releases cortisol, hypothalamus activates the sympathetic branch of the ANS, adrenal medulla releases adrenaline.
• Role of adrenaline


  Psychological effects include increased anxiety, attention, and alertness. Physical effects include increased blood flow to the brain and skeletal muscles, quick thinking and reactions, decreased blood flow to the skin, digestive and immune systems, dilated pupils to improve vision, and faster breathing to increase oxygen.
• The fight or flight response is not designed for the modern world, it's maladaptive in most situations. It's frequently triggered by stimuli that cannot be run away from or fought, like exams.
• Acute stress


  A response to immediate pressures, exciting in small amounts and giving you focus and energy, but exhausting and maintained long-term.
• Chronic stress


  Frequent triggering of the fight or flight response, resulting in stress-related illness affecting the immune and circulatory systems.
• Localization of function - functions such as movement, speech/language, and memory are performed in distinct regions of the brain.
• Contralateral - each hemisphere of the brain controls the opposite side of the body, including both motor and sensory pathways and vision of the contralateral visual field.
• Hemispheric lateralization - the two hemispheres of the brain are specialized to perform different functions, with language centers in the left hemisphere and visuospatial tasks in the right hemisphere.
• Motor cortex


  Voluntary muscle motor movements across the body, it's contralateral, located at the back of the frontal lobe, separated from the somatosensory cortex by the central sulcus.
• Somatosensory cortex


  Receives sensory impressions from around the body, it's contralateral, located at the front of the parietal lobe, separated from the motor cortex by the central sulcus.
• Broca's area


  Located in the left frontal lobe, responsible for speech production, damage results in motor aphasia (difficulty producing fluent speech).