Review on Neurophysiology

• The nervous system is a communications and control network that allows an organism to interact in appropriate ways with its environment
• • Central Nervous System 
  • Central control hub of the nervous system
• • Peripheral Nervous System: Relays information to & from the environment and the CNS
• Astrocyte: Forms the Blood-Brain Barrier (BBB). It restricts passage of ions, nutrients, pathogens and pharmaceutics in the brain
• Neuron: Is the functional unit of the nervous system and aid information transmission
• Ependymal cells: Controls the production and flow of cerebrospinal fluid (CSF), brain metabolism and waste clearance  
• Microglia: Macrophages of the CNS 
• Oligodendrocytes: Involved in production of myelin in the CNS (Myelin helps with faster transmission of signals). It myelinates MANY axons in the CNS
• Schwann cells: Involved in the production of myelin in the PNS (Myelin helps with faster transmission of signals). It myelinates only ONE axon in the PNS 

   
• Satellite cells: Regulates microenvironment in a fashion similar to that of astrocytes
• CELLULAR COMPONENTS OF THE PNS: Neuron, Schwann cells, Satellite cells
• CELLULAR COMPONENTS OF THE CNS: Astrocyte, Neuron, Ependymal cells, Microglia, Oligodendrocytes
• Soma (the cell body):

  • Houses the nucleus and other organelles
  • Metabolic & integrative center of the neuron
• Dendrites 

  • Transmit information TOWARDS the soma from other neurons
• Axon 

  • Transmits information AWAY from the soma to the nerve endings 
  • Can be myelinated or unmyelinated
• Sensory Neuron  

  • Are neurons that let you feel, see, hear and smell what is happening around you
  • Transmits signal to interneuron → CNS
• • Motor Neuron 
  • Are neurons that control your muscles
  • Carries signals from the CNS to the muscles
• Interneuron : Collects  information from sensory neurons and transmits them to the CNS
• 3 TYPES OF THE NEURON: Sensory neuron, Motor neuron, Interneuron
• SENSORY DETECTION

  • Neurons transduce environmental energy into neural signal 
  • Accomplished by special neurons (sensory receptors)
  • Various forms of energy that can be sensed are mechanical, light, sound, chemical and thermal
• INFORMATION PROCESSING

  • Information progressing mechanisms involve both electrical and chemical events and includes the following: 
  • Transmission of information 
  • Transformation of information and recombination with other information (neural integration) 
  • Perception of sensory information 
  • Storage and retrieval of information (Memory) 
  • Planning and implementation of motor commands 
  • Thought processes and conscious awareness 
  • Learning 
  • Emotion
• EXPRESSION BEHAVIOR

  • An organism's response to its environment
  • Language 
  • Learning and memory
• FUNCTIONS OF NERVOUS SYSTEM: SENSORY DETECTION, INFORMATION PROCESSING, EXPRESSION BEHAVIOR
• REGIONS OF THE CNS

  • The Cerebral Cortex 
  • The Brain Stem 
  • The Cerebellum 
  • The Thalamus 
  • The Limbic System
• • Cerebrospinal fluid: surrounds the brain providing protection, lubrication, nourishment and waste removal
• THE CEREBRAL CORTEX has 4 lobes:

  • Frontal Lobe 
  • Parietal Lobe 
  • Temporal Lobe
  • Occipital Lobe
• • Corpus Callosum: Divides the 2 hemispheres and also aids in relaying information to each other
• FRONTAL LOBE

  • Most anterior lobe 
  • Role: emotions and decision making 
  • Coordinates movements 
  • Determines similarities and differences
• PARIETAL LOBE

  • Located behind the frontal lobe 
  • Involved in processing sensory information  
  • Left parietal lobe: symbolic functions in language and mathematics
  • Right parietal lobe: understanding pictures and maps
• TEMPORAL LOBE

  • Auditory Cortex: Processes auditory information and responsible for processing spoken language
  • Hippocampus: part of the limbic system involved in memory storage
• OCCIPITAL LOBE

  • Most posterior lobe
  • Major visual processing center
• THE BRAINSTEM

  • Motor movement, breathing and auditory & visual processing
• THE BRAINSTEM is made of:

  • Midbrain  
  • Pons 
  • Medulla Oblongata 
  • Reticular Formation (found in the brainstem rather than 'makes up' the brainstem)
• MIDBRAIN

  • Function: relay system, transmitting information for vision and hearing 
  • Role: motor movement, pain, and the sleep/wake cycle
• PONS: Micturition Center, Pneumotaxic & Apneustic Centers
• MEDULLA OBLONGATA: Vasomotor center, Respiratory center, Swallowing, Coughing & Vomiting Center
• RETICULAR FORMATION

  • Made up of nerve cells that run through the spinal cord and into the brain stem 
  • Serve as a major integration and relay center for many vital brain systems to coordinate functions necessary for survival
• CEREBELLUM

  • Located under the occipital lobe 
  • Function: movement, balance, coordination
• THE THALAMUS

  • Regulates alertness, sleep, & consciousness
  • Receives information from the senses and forwards it to the other parts of the brain
• THE LIMBIC SYSTEM

  • Located in the frontal and parietal lobes 
  • Helps in processing emotion, behaviour, motivation, long-term memory, and olfaction