Biopsychology

• Nervous System


  Specialised network of cells Primary internal communication system Based on electrical and chemical signalsTwo main functions

  1. Collect, process and respond to information in the environment
  2. Co-ordinate the working of different organs and cells in the body

  Two subsystems

  1. Central nervous system
  2. Peripheral nervous system
• Cerebral Cortex


  The surface layer of the forebrain (the two hemispheres). It is grey in colour and it is highly folded to make it possible to fit the massive amount of material inside the skull
• Central Nervous System (CNS)


  Consists of the brain and spinal cord and is the origin of all complex commands and decisions 
• Spinal cord


  Part of the central nervous system, a bundle of nerves from the brain transmitting nervous signals between the brain and the rest of the body.
• Peripheral Nervous System (PNS)


  Sends information to the central nervous system from the outside world, and transmits messages from the central nervous system to muscles and glands in the body
• Somatic Nervous System (SNS)


  Transmits information from receptor cells in the sense organs to the central nervous system. It also receives information from the central nervous system that directs muscles to act.
• Autonomic Nervous System (ANS)


  Transmits information to and from internal bodily organs. It is 'autonomic' as the system operates involuntarily (automatic). It has two main divisions: the parasympathetic and the sympathetic nervous systems
• Sympathetic Nervous System


  A division of the autonomic nervous system which activates internal organs for vigorous activities and emergencies. It consists of nerves that control, for example, increased heart rate and breathing, and decreased digestive activity. The sympathetic branch works in opposition to the parasympathetic branch of the autonomic nervous system.
• Parasympathetic Nervous System


  A division of the autonomic nervous sytsem which controls the relaxed state, conserving resources and promoting digestion and metabolism. The parasympathetic branch works in opposition to the sympathetic branch of the autonomic nervous system. One or the other is active at any time.
• Sensory Neuron


  These carry messages from the peripheral nervous system in the central nervous system. They have long dendrites and short axons.

  Located in the PNS clusters known as ganglia
• Motor Neuron


  These connect the Central Nervous System to effectors such as muscles and glands. They have short dendrites and long axons.

  Cell bodies within CNS but axons form part of PNS
• Relay Neuron


  These connect the sensory neurons to the motor or other relay neurons. They have short dendrites and short axons.

  97% of all neurons

  Most within the brain and visual system
• Cell body


  The part of a cell that contains the nucleus
• Nucleus


  The control centre of a cell containing genetic material
• Dendrites


  Branching projections from the end of a neuron carry nerve impulses from neighbouring neurons towards the cell body
• Myelin sheath


  A white fatty substance that protects the neuron and speeds up the transmission of messages along the length of the axon
• Nodes of ranvier


  The gaps in the myelin sheath that protect the axon of a neuron
• Axon


  The long projection of the neuron from the cell body
• Terminal buttons


  A swelling at the end of the axon
• Synapse


  The junction between two neurons
• Action Potential


  A short increase and decrease of electrical activity in the membrane of a neuron, transmitting a signal away from the cell body
• Synaptic vesicle


  Small sacs on the end of a presynaptic neuron that contain neurotransmitters that will be released into a synapse
• Neurotransmitters


  Brain chemicals released from synaptic vesicles that relay signals across the synapse from one neuron to another. Neurotransmitters can be broadly divided into those that perform an excitatory function and those that form an inhibitory function.
• Pre-synaptic terminal


  The end of the transmitting neuron, ending at the synaptic cleft
• Post-synaptic receptor site


  A receptor on the neuron that is receiving the information at the synapse. A neurotransmitter locks into a specific receptor on the receiving neuron and this triggers an electrical signal in the receiving neuron
• Synaptic gap/cleft


  The space between the pre- and postsynaptic neuron
• Excitation 


  When a neurotransmitter increases the positive charge of the postsynaptic neuron. This increases the likelihood that the postsynaptic neuron will pass on the electrical impulse.
• Inhibition


  When a neurotransmitter increases the negative charge of the postsynaptic neuron. This decreases the likelihood that the postsynaptic neuron will pass on the electrical impulse.
• Summation


  The process that determines whether or not an action potential will be triggered, based on the combined effects of the excitatory and inhibitory signals of the neurotransmitters
• Endocrine System


  One of the body's major information systems that instructs glands to release hormones directly into the bloodstream. These hormones are carried towards target organs in the body. Communicates via chemicals.
• Hormone


  A biochemical substance that circulates in the blood but only affects target organs. They are produced in large quantities but disappear quickly. Their effects are very powerful.
• Adrenaline


  A hormone produced by the arenal glands. These are part of the human body's immediate stress reponse. Adrenaline has a strong effect on the cells of the cardiovascular system - stimulating the heart rate, contracting blood vessels and dilating air passages
• Noradrenaline


  A hormone and a neurotransmitter that generally has an excitatory effect, similar to adrenaline. The hormone is produced by the adrenal gland.
• Fight or flight


  The way an animal responds when stressed. The body becomes physiologically aroused in readiness to fight an agressor, or in some cases, flee.
• Tend and befriend


  An adaptive response to stress for females, resulting in protection of offspring and relying on the social group for mutual defence. In contrast with the more male response of fight or flight.
• Hypothalamus


  A small subcortical brain structure made up of two centres - the lateral hypothalamus and the ventromedial hypothalamus
• Pituitary Gland


  Called the master gland of the body's hormone system because it directs much of the hormone activity
• Thyroid Gland


  A pair of small endocrine glands loacted in the neck that release hormones important for growth and the activity of cells in the body (metabolism).
• Thyroxine 


  One of the main hormones secreted by the thyroid glands, which controls metabolism
• Adrenal Glands


  Small glands located on top of each kidney that are part of the endocrine system. Various hormones and produced including adrenaline, noradrenaline, corticosteroids (including cortisol)