Psych paper two

• Define the nervous system


  A specialised network of cells in the human body

  >Communicates using electrical signals
• Two main functions of the Nervous System

  -To collect, process and respond to information in the environment.

  -To co-ordinate the working of different organs and cells in the body.
• What two systems make up the Nervous System?

  CNS (central nervous system) and PNS (peripheral nervous system)
• What two things make up the Central Nervous System?

  The Brain & The Spinal Cord
• Explain the brain


  -Centre of all conscious awareness

  -Highly developed in humans

  -Separates into 2 hemispheres
• Explain the spinal cord

  -Extension of the brain

  -Passes messages to/from the brain

  -Connects nerves to PNS

  
  

  -Responsible for REFLEXES
• Function of the Peripheral Nervous System

  To transmit messages via neurons to/from the CNS
• What two systems make up the Peripheral Nervous System?

  -Autonomic Nervous System

  -Somatic Nervous System
• What is the Autonomic Nervous System?


  Governs vital functions in the body (eg; breathing, heart rate, digestion, sexual arousal, stress)
• What is the Somatic Nervous System?

  Governs muscle movement & receives info from sensory receptors
• What two systems make up the Autonomic Nervous System?

  SYMPATHETIC & PARASYMPATHETIC
• What is the endocrine system?


  Works alongside nervous system to control vital bodily functions

  
  

  >More slow, but more powerful
• What produces hormones?


  Glands in the body

  >Such as thyroid
• How do hormones work?

  -Secreted from glands into BLOODSTREAM

  -Affect cells in many organs (powerful effects)
• Name the main endocrine glands in the human body

  -Hypothalamus

  -Pituitary Gland

  -Thyroid & Parathyroid

  
  

  -Adrenals

  -Pancreas

  -Ovaries & Testes
• What does the pituitary gland do?

  -Located in the brain

  -'Master Gland'

  -Controls release of hormones from all endocrine glands
• What occurs during fight/flight?

  -Endocrine System & ANS work together

  
  

  1. Stressor is perceived

  2. Hypothalamus activates pituitary gland

  3. Pituitary triggers SYMPATHETIC branch of ANS

  4. ANS turns to aroused sympathetic state
• Role of Adrenaline in Fight/Flight

  -ADRENALINE released from ADRENAL MEDULLA into blood

  -Triggers physiological changes in body (eg; increased HR)

  -Creates arousal necessary for fight/flight response
• What changes are caused during fight/flight by sympathetic state?

  -Increased HR

  -Increased breathing rate

  -Dilated pupils

  -Inhibited digestion

  -Inhibited saliva production

  -Contracted rectum
• Role of Parasympathetic branch of ANS in Flight/Flight


  -Threat passed = Parasympathetic returns body to resting state

  
  

  >Reduces activities that were increased during sympathetic state

  >'Rest & Digest Response'

  
  

  >Stimulated digestion & saliva, decreased HR & breathing, etc
• Role of Neurons


  Transmit signals electrically & chemically (communication for Nervous System)
• 3 Types of Neurons

  Sensory Neuron

  Relay Neuron

  Motor Neuron
• Sensory Neuron


  A neuron that picks up stimuli from the internal or external environment (SENSORY RECEPTORS) and converts each stimulus into a nerve impulse.

  
• Relay Neuron


  Connect sensory neurons to motor & relay neurons

  >SHORT DENDRITES & SHORT AXONS

  
• Motor Neuron


  Connect CNS to EFFECTORS (muscles & glands)

  >SHORT DENDRITES & LONG AXONS

  
• Cell body of neurons

  -AKA 'soma'

  
  

  INCLUDES:

  >Nucleus (Genetic material)

  >Dendrites protrude from cell body (Carry nerve impulses from neurons towards cell body)
• Axon


  Carries impulses AWAY from cell body down length of the neuron
• Myelin Sheath


  Fatty layer that protects Axon & Speeds up electrical transmission
• Terminal buttons


  -End of the axon

  -Communicate with next neuron across synapse
• What parts of nervous system are motor neurons located in?

  Cell bodies = Central Nervous System

  Axons = Peripheral Nervous System
• Electrical Transmission


  -The 'firing' of a neuron

  -Inside of the cell becomes positively charged, causing action potential to occur

  -Creates electrical impulse that travels down the axon
• Synaptic vesicle


  Storage site for neurotransmitters before they're ready to be released (PRE-SYNAPTIC NEURON)

  
  

  >Release triggered by electrical impulse
• Neurotransmitters


  Chemical messengers that cross the SYNAPTIC CLEFT
• How do neurotransmitters cross the synaptic cleft?

  Diffuse across
• How are neurotransmitters recieved by the post-synaptic neuron?

  -Neuron minds to receptors

  -LOCK & KEY THEORY
• What happens to neurotransmitters that don't bind to receptors?

  -Taken back to pre-synaptic neuron through the REUPTAKE CHANNEL
• Excitatory Neurotransmitters


  Cause excitation in recieving neuron

  >Neuron becomes POSITIVELY CHARGED

  >More likely to fire
• Inhibitory Neurotransmitters


  Cause inhibition in recieving neuron

  >Neuron becomes NEGATIVELY CHARGED

  >Less likely to fire
• Summation


  Decides whether or not the post-synaptic neuron fires

  
  

  >'Sums' up the excitatory & inhibitory influences

  >Excitatory overall = more likely to fire

  >Inhibitory overall = less likely to fire
• Localisation


  The theory that different areas of the brain are responsible for different behaviours, processes & activities