NERVOUS

• The central nervous system

  • Made up of brain and spinal cord
  • Processes and interprets sensory information received from peripheral nervous system
  • Generates motor responses for voluntary movement
  • Layers of protective meninges surrounding CNS to absorb impact
  • Bony encasements
• the brain

  • command centre of the nervous system
  • controls various functions such as cognition, emotion and voluntary movements
• peripheral nervous system

  • neural network outside the CNS
  • aids communication between CNS and the rest of the body
  • gathers sensory information from external and internal environments
  • conveys motor commands from CNS to muscles/glands
• subdivisions of PNS


  Somatic nervous system

  • Controls voluntary movements and transmits sensory information to CNS

  Autonomic nervous system

  • Manages involuntary functions like heartbeat, breathing and digestion
• further subdivision of autonomic nervous system


  sympathetic nervous system

  • activated during stress
  • fight or flight

  parasympathetic nervous system

  • active during rest
  • rest and digest
• The ocular system

  • Made up of the eye and optic nerve
  • Processes light received by the eyes into electrical signals which are processed into images
• Eyelids

  • Thin folds of skin that cover eye lined with eyelashes
  • Protection of dust and debris from entering tissue
• cornea

  • lined with conjunctiva to keep eyes moist
  • allows light penetration into the eye whilst protecting inner parts of the eye
• iris

  • coloured portion of eye with the pupil in the middle
  • lined with muscles to aim in constriction and dilation of the iris
  • allows light penetration to the retina
• lens

  • transparent disc that sits behind pupil
  • focuses light rays from pupil onto retina
• retina structure

  • innermost, light-sensitive layer of eye
  • lined with photoreceptors of two types; rods and cones
  • have photosensitive ganglion cells
• retina function

  • rods are sensitive to light intensity but not colour so provided monochrome image to brain
  • cones are sensitive to either red, green or blue waves. the brain combines these to form colour
  • ganglion cells are important in control pupillary response
• Fovea is the centre of the retina and has the highest concentration of cone cells as most light is received here
• Optic nerve

  • Part of CNS
  • Passes through light sensitive area of retina
  • No light receptors here
  • Connects retinal neurones to the brain for image generation
  • Produces blind spot
• visual cortex

  • part of cerebral cortex
  • receives nerve impulses via optic nerve and processes these to create images
• Neuronal anatomy

  • Neurones are the cells that make up nerves
  • Three neurones; sensory, motor, relay
• sensory


  transmits signals from sensory receptors to CNS
• motor


  carries signals from CNS to effectors
• relay


  connects sensory and motor neurones facilitating communications within CNS
• Dendrites


  Make connections with other neurones
• cell body


  contains nucleus and other organelles
• axon


  carries nerve impulses from cell to body
• myelin sheath


  made of Schwann cells wrapped around axon to speed up transmission
• nodes of ranvier


  gaps between schwann cells to allow quicker transmission
• axon terminal


  passes on action potential to new cell
• synapse


  junction between dendrite and axon terminal
• Frontal lobe


  Cognitive abilities

  • Planning, problem solving, decision - making and critical thinking

  Motor control

  • Contains primary motor cortex which controls voluntary movements

  Speech production

  Emotion and personality

  • Regulates behaviour, social interactions and emotional responses
• Parietal lobe


  Sensory processing

  • Responsible for interpreting touch, temperature, and pain

  Spatial orientation

  • Helps with understanding spatial relationships and navigation

  Integration of information

  • Combines sensory data to support perception and coordination
• Occipital lobe 


  Vision

  • Processes visual information, including light and colour

  Visual interpretation

  • Helps in recognising shapes, objects and distances
• temporal lobe


  hearing

  • contains the auditory cortex

  language comprehension

  • includes wernickes area, vital for understanding speech and language

  memory

  • plays a key role in forming and recalling long-term memories

  emotional regulation

  • interacts with the limbic system for emotional processing
• Cerebellum 


  Coordination

  • Regulates smooth and precise movements

  Balance and posture

  • Maintains physical stability and equilibrium

  Motor learning

  • Assists in acquiring and refining motor skills

  Timing and rhythm

  • Contributes to the timing of movements and rhythm perception
• spinal cord

  • serves as a communication pathway between the brain and the peripheral nervous system
  • plays a crucial role in reflex actions and the transmission of sensory and motor signals
• Reflex actions

  • Automatic responses to external stimulus
  • Ensures swift response to stimuli
  • Carried out by the PNS
• the reflex arc

  1. stimuli receptors register stimulus
  2. receptor generates an electrical impulse that is transmitted down sensory neurone
  3. inter-neurone in spinal cord relays messages between sensory and motor neurone
  4. impulse is transmitted down motor neurone to the effector
• inter-neurone also sends messages to the brain to interpret situations and carry out other movements if necessary
• The synapse

  • Junction between neurones where information is transmitted
  • assisted by neurotransmitters which are released into the gap to transmit the signal
• polarisation 


  refers to the different electrical charges on either side of the membrane caused by active transport of ions
• depolarisation


  the reversal of the charge difference
• repolarisation 


  The restoration of the original charge difference
• action potential 


  electrical impulse that is transmitted between neurones