Biopsychology

• How does the endocrine system work?

  The pituitary gland in the brain is a 'master gland' which secretes several hormones into the blood in response to body conditions.

  
  

  These hormones in turn act on other glands to stimulate other hormones to be released to bring about effects.

  E.g. in certain conditions, the pituitary gland makes and secretes thyroid-stimulating hormone (TSH) which stimulates the thyroid to release thyroxine.
• What is the difference between endocrine and nervous system?

  Compared to the nervous system the effects of hormones are slower but they act for longer in the endocrine system.
• What is the endocrine system, including its function?

  The human endocrine system is composed of glands that synthesise chemical substances such as hormones and secrete them directly into the bloodstream.

  
  

  The blood carries the hormone around the body, and when it reaches a target cell/organ it produces an effect.
• What is the all or nothing principle?

  The size of the impulse is independent of the side of the stimulus.

  
  

  If the intensity of the stimulus is below the threshold value, no action potential/impulse will be initiated.

  
  

  If the intensity of the stimulus is above the threshold value, any further increase in intensity does not result in a greater action potential being released.
• What needs to happen for a neuron to fire?

  For a neuron to fire, a post- synaptic potential is needed. Neurons have a resting potential of -70MV, the voltage must meet the -55MV threshold for the neuron to fire.
• What is summation?

  Multiple small changes in voltage triggered by neurotransmitters are summed and the net effect determines weather the post synaptic neuron is more / less likely to fire.
• Give an example of neurotransmitters that can do both.

  Serotonin released by neurons to control mood.
• What do inhibitory neurons do?

  Allow negatively charged particles to enter the post synaptic neuron.

  Creates inhibitory post synaptic potentials (IPSP) which makes serve impulses less likely to occur.

  
  

  E.g. GABA which is the main inhibitory neurotransmitter in the brain.
• What do exhitatory neurons do?

  Allow positively charged particles to enter the post synaptic neuron. They create excitatory post synaptic potential (EPSP) which makes nerve impulses more likely to occur.

  
  

  E.g. acetylcholine which is released by neurons controlling muscles.
• What is the process of synaptic transmission?

  The nerve impulse arrives at the pre-synaptic terminal, causing the synaptic vesicles to travel down to the pre-synaptic membrane. The pre-synaptic membrane and synaptic vesicle fuse, causing the release of neurotransmitters into the synaptic cleft. The neurotransmitters diffuse across the synaptic cleft towards the post-synaptic terminal, where they bind to post-synaptic receptors. As a result, the receptors change shape and allow charged particles to flow into the post-synaptic terminal, creating small changes in voltage in the neuron. Once there is a large enough change in voltage, a nerve impulse is triggered. Meanwhile, the neurotransmitters are released back into the synaptic cleft, where they are sucked back into the pre-synaptic membrane by re-uptake proteins.
• Where are nerve impulses triggered?

  Cell body.
• What are two other words for nerve impulse?

  Electrical transmission and action potential.
• Where are motor neurons found?

  Cell bodies may be in CNS, axons in the PNS
• Where are relay neurons found?

  brain and visual system
• Where are sensory neurons found?

  PNS in clusters called ganglia.
• What is the structure and function of motor neurons?

  connects CNS to effectors e.g. muscles + glands.

  Short dendrites + long axons
• What is the structure and function of relay neurons?

  connect sensory neurones to motor neurons or other relay neurons.

  Short dendrites + long axons.
• What is the structure and function of sensory neurons?

  carries impulses from PNS to CNS. Long dendrites + short axons.
• What are the three types of neurons?

  Sensory, relay, motor.
• What are synapses?

  gaps between neurons.
• What is the function of the nodes of ranvier?

  gaps between th myelin sheath which speeds up electrical transmissions. By causing the impuluse to "jump" across.
• What is the function of the myelin sheath?

  a fatty layer that protects axons and speeds up electrical transmissions.
• What is the function of axons?

  carry electrical impulses away from the cell body.
• What is the function of dendrites?

  branched structures that carry nerve impulses from neighbouring neurons towards the cell body.
• What is the function of a cell body?

  contains a nucleus and therefore genetic material.
• What provides the nervous system with its primary means of communication and how?

  Neurons by transmitting nerve impulses.
• Describe the breakdown of the nervous system including the function of each sub group.

  The human nervous system is split into the central nervous system (handles complex commands and decisions) and the peripheral nervous system (transmits information between the CNS via neurons).

  
  

  The CNS splits into the brain (Centre of all conscious awareness) and spinal cord (Connects the brain and PNS, and controls reflex actions)

  
  

  The PNS splits into autonomic (Governs vital bodily functions e.g. breathing and digestion, and involuntarily transmits information to/from the organs) and somatic (Governs muscle movement and transmits information from receptors in sense organs to the CNS, and receives information from the CNS that directs muscles)

  
  

  The autonomic nervous system splits into sympathetic (fight or flight) and parasympathetic (opposes the sympathetic returning the body to its resting state)
• What is the function of the nervous system?

  to coordinate the organs in order to collect, process, and respond to information in the environment.
• What is the nervous system?

  specialised network of cells acting as our primary communication system based on electrical and chemical impulses.
• What happened to Phineas Gage?

  An iron rod went through his skull and damaged his frontal cortex resulting in a personality change. He survived for 13 years.
• What does Phineas Gage give evidence for?

  That the brain can recover from very traumatic injury

  That the frontal cortex is involved in personality and behaviour
• What is the primary motor cortex especially important for?

  Complex movement - not basic ones e.g. crying
• What does the amount of neuronal connections depend on?

  The amount of somatosensory cortex needed for an area e.g. the face needs a large amount of somatosensory cortex
• Where is the primary visual cortex?

  The occipital lobe