Brain and nervous system revision

• Nervous system


  A communication system between the body's internal cells and organs and the external world
• Main functions of the nervous system

  • To receive information
  • Process information
  • Coordinate a response to information
• Central nervous system


  Carries messages to and from the peripheral nervous system
• Components of the central nervous system

  • Brain
  • Spinal cord
• Peripheral nervous system


  Carries messages to and from the central nervous system
• Components of the peripheral nervous system

  • Somatic nervous system
  • Autonomic nervous system
• Subdivisions of the autonomic nervous system

  • Sympathetic nervous system
  • Parasympathetic nervous system
• Neuron


  An individual nerve cell that is specialised to receive, process and/or transmit information
• Neurons are the 'primary functional units' of the nervous system because of their vital role in enabling the nervous system to function as it does
• Not all neurons look the same, they vary in shape and size depending on where they are located
• Efferent motor pathway


  Neural pathway that will transmit motor messages from the central nervous system to be carried out in the peripheral nervous system
• Afferent sensory pathway


  Neural pathway that transmits sensory messages from the peripheral nervous system to the central nervous system
• Parts of the hindbrain

  • Cerebellum
  • Medulla oblongata
  • Pons
• Hindbrain


  • Involved in supporting vital bodily processes (e.g. breathing and sleeping)
  • Keeps us alive and is associated with the autonomic nervous system
• Cerebellum


  • Receives commands from the cerebral cortex
  • Involved in functions such as coordinating voluntary movements, balance, posture and movements associated with speech and vision
  • Involved in learning and memory where motor skills are important (e.g. learning an instrument or riding a bike)
  • Damage can lead to balance issues, challenges associated with detecting visual motion and loss of muscle coordination (associated with memory and learning)
• Medulla oblongata


  • Located at the base of the brain where the brainstem attaches to the spinal cord which keeps us alive
  • Involved in autonomic functions such as heart rate, breathing, swallowing and sneezing
  • Damage can cause death or severe heart problems
• Pons


  • Acts as a bridge connecting the cerebellum and cerebral cortex
  • Involved in sleep, arousal, facial expressions and hearing
  • If damaged you will have issues with sleep, arousal, facial expressions and hearing
• Midbrain


  • Centre of the brain which sits at the top most part of the brainstem
  • Connects the upper and lower areas of the brain
  • Involved in auditory and visual processing and plays a crucial role in motor control, pain inhibition and reward-based learning patterns
• Components of the midbrain


  • Substantia nigra
  • Reticular formation
• Substantia nigra


  • A collection of neurons producing dopamine, which is a neurotransmitter involved in movement and coordination
  • Damage is associated with Parkinson's disease
• Reticular formation


  • An arrangement of neuron clumps which are connected to a network that runs from the hindbrain to the forebrain
  • Plays a role in maintaining arousal, consciousness and motor control (redirecting attention)
  • Contains the reticular activating system (RAS), which causes alertness and awakening when stimulated
  • The RAS is responsible for attention, arousal, control of muscles and ability to focus; it filters out unnecessary information
• Forebrain


  • The largest region of the brain
  • Involved in several bodily functions, learning, memory, thinking and perception
• Components of the forebrain

  • Cerebrum
  • Thalamus
  • Hypothalamus
  • Pineal gland
  • Limbic system
• Hypothalamus


  • A small structure located under the thalamus
  • Regulates hormones involved in maintaining homeostasis through controlling body temperature, hunger, thirst and sleep
  • Damage can lead to issues controlling body temperature, feeling hungry after eating, sleeping problems and libido (sex drive)
• Thalamus


  • Located near the centre of the brain and has two halves, one in each hemisphere
  • Main function is to transport information to the relevant sections of the cerebral cortex for further processing, particularly sensory information (excluding smell)
  • Connects to the reticular activating system (RAS) and regulates arousal
  • Damage can cause coma, numbness, hypersensitivity, visual field loss and decreased taste depending on the part being affected
• Cerebrum


  • The largest, uppermost part of the forebrain and consists of two hemispheres
  • The corpus callosum joins the two hemispheres and allows information to be exchanged
  • Responsible for directing conscious motor activities and receiving and processing sensory information
• Cerebral Cortex


  • A thin layer that covers the cerebrum and is extensively folded
  • Specific areas are dedicated to a specific function
  • Most areas perform a wide array of functions
  • Functions are typically divided into sensory, motor and association areas
• Functions of the cerebral cortex

  • Sensory - Areas receive and process sensory information
  • Motor - Areas initiate voluntary movement
  • Association - Areas combine information from multiple brain regions, facilitating complex processes such as language, creativity and decision making
• Hemispheric specialisation


  • One hemisphere having a specialised function that is not possessed, or is controlled to a lesser extent by the other hemisphere
  • Left side - analytical, language, rational thought and logic
  • Right side - spatial and visual thinking, emotion, creativity and imagination
• Lobes of the cerebral cortex

  • Frontal lobe
  • Temporal lobe
  • Parietal lobe
  • Occipital lobe
• Frontal lobe


  • Important for planning, sequencing and executing of voluntary motor activity
  • Consists of prefrontal cortex, premotor cortex and primary motor cortex
• Prefrontal cortex


  • Involved in reasoning, problem solving, emotional regulation, attention, symbolic thinking and controlling behaviours
• Premotor cortex


  • Receives planned motor sequences from the prefrontal cortex, prepares the sequence of movements
  • Also sends information to the primary motor cortex
• Primary motor cortex


  • Signals the skeleton muscles, controlling execution of voluntary movements
  • Muscles that require precise control (such as fingers) are controlled by a larger portion
• Broca's area


  • Located in the left hemisphere only and contributes to speech production by coordinating the relevant muscles and communicating with other areas of the brain involved in language
  • Damage often causes very deliberate speech consisting of a few words with very simple grammatical structure
• Temporal lobe


  • Involved in processing sounds, as well as memory, emotional responses to sensory information and visual perception (e.g. recognising faces)
  • The primary auditory cortex is involved in identifying and responding to sound
• Wernicke's area


  • Located in the left hemisphere only
  • Responsible for the comprehension of speech by assigning meaning to the words being heard
  • Damage results in a fluent but receptive aphasia (unable to comprehend or express written or spoken language)
• Parietal lobe


  • Involved in spatial awareness, spatial reasoning, attention and processing somatosensory information
  • The primary somatosensory cortex receives and processes sensory information from the limbs, face and genitals
• Occipital lobe


  • Plays a crucial role in vision
  • The primary visual cortex receives and processes information from the visual sensory receptors in the retina
• Neuroplasticity


  • The process that involves adapting to both structural and functional changes to the brain
  • The ability for the brain to change structure due to external stimulus