Biopsych yr 1

• what is the nervous system?

  a specialised network of cells and our primary communication system

  
  

  subdivided into CNS and PNS
• what is the central nervous system?

  consists of the brain and spinal cord

  passes messages to and from the brain and connects nerves to the PNS
• what is the function of the brain?

  maintains life and centre of all conscious awareness

  
• what is the function of the spinal cord?

  carries messages from the PNS to the brain and vice versa

  responsible for reflex actions
• what is the peripheral nervous system (PNS)?

  sends info to CNS from outside world, transmitting messages from CNS to muscles and bodily glands

  
  

  consists of autonomic and somatic nervous systems
• what is the autonomic nervous system?

  transmits involuntary instructions from the CNS to organs therefore responsible for vital functions

  
  

  divided into sympathetic and parasympathetic
• what is the sympathetic nervous system (ANS)?

  increases bodily arousal for fight or flight
• what is the parasympathetic nervous system (ANS)?

  responsible for regulating the steady internal state
• what is the somatic nervous system?

  voluntary control of skeletal muscles and receives and transmits info from CNS

  
  

  can be from sensory info or CNS
• what are the two types of nerves in the somatic nervous system?

  afferent - to CNS

  efferent - from CNS
• what is an acute stressor?

  short term/immediate trigger that prompts a stress response

  
  

  responded to by sympathetic nervous system
• what is the sympathetic adrenal medullary system (fight or flight response)?

  1. higher brain centres perceive stressor

  2. hypothalamus activated

  3. ANS activated in brain stem

  4. adrenal medulla stimulated

  5. adrenaline released into bloodstream

  6. physiological changes

  7. parasympathetic branch activated when stressor passes

  8. body goes back to steady state
• what are examples of physiological stresses that are caused by sympathetic NS activation?

  increases breathing rate

  increases heart rate

  increases blood sugar

  pupils dilate

  decreases digestion
• what is a neuron?

  a nerve cell; the basic building block of the nervous system

  
  

  processes and transmits messages through electrical and chemical signals
• what are dendrites?

  protrude from cell body

  received electrical transmission and carries to cell body
• what is an axon?

  carries impulses away from the cell body

  covered in myelin sheath
• what is the purpose of myelin sheath?

  protects axon

  speeds up electrical impulse transmission

  
  

  segmented by NODES OF RANVIER - to speed up transmission further
• what are terminal buttons?

  at end of axon

  communicate with next neuron
• what is the process of electrical transmission?

  stimulus activates neuron

  inside of cell becomes positively charged for a split second causing an action potential to occur

  electrical impulse created that travels down the axon
• what is a sensory neuron?

  carries sensory info from environment and PNS to the CNS

  
  

  LONG dendrites

  SHORT axons
• what is a relay neuron?


  connect the sensory neurons to the motor neurons

  
  

  SHORT dendrites

  SHORT axons
• what is a motor neuron?

  connects the CNS to effectors (muscles)

  
  

  SHORT dendrites

  LONG axons
• what is a synapse?

  gap between neurons where impulses are electrically transmitted
• what are neurotransmitters?

  brain chemicals released from synaptic vesicles that relay signals across a synapse

  they can be excitatory and inhibitory
• what is excitation and inhibition?

  excitation - when neurotransmitter increases positive charge which makes the neuron more likely to fire the impulse

  
  

  inhibition - when the neurotransmitter increases negative charge which makes the neuron less likely to fire

  
  

  DECIDED BY PROCESS OF SUMMATION - net positive and negative totalled
• what is the only neurotransmitter that it only inhibitory?

  GABA
• what is the process of synaptic transmission?

  1. electrical impulse arrives at pre-synaptic terminal

  2. release of neurotransmitter from synaptic vesicles

  3. travels across synapse

  4. fits into post synaptic receptor site

  5. ion channel opened

  6. flooding of ions (+/-)

  7. action potential becomes more or less likely (excitation or inhibition)

  
• what is the endocrine system?

  major information system that instructs glands to release hormones directly into the bloodstream towards target organs
• what is a gland and a hormone?

  gland - organ in the body that secretes a particular chemical

  
  

  hormone - chemical substances that circulate in the bloodstream that only effect target organs and lead to a range of physiological effects
• name some examples of glands and the hormone released

  pituitary - growth hormone

  thyroid - thyroxin - cell metabolism

  adrenal - adrenaline - fight or flight

  pineal - melatonin - induces drowsiness & sleep
• what is negative feedback?

  a response to a change in the body that counteracts or opposes the initial change to bring body back to normal
• what is the fight or flight response?

  a physiological reaction that occurs in response to a perceived harmful event, attack, or threat to survival

  
  

  reflex response in response to an acute stressor