NERVOUS SYSTEM AND DNA

• Nervous System


  Composed of central nervous system and peripheral nervous system
• Central nervous system


  • Contains brain and spinal cords
  • Main function: process information received from the body's internal and external environments and to activate appropriate responses
• Peripheral nervous system


  • Contains the nerves that connect the central nervous system to the rest of the body
• Types of neurons


  • Sensory neurons
  • Inter neurons
  • Motor neurons
• Neuron


  An individual nerve cell that is specialised to receive, process and/or transmit information
• Role of a neuron

  1. Dendrites receive information from other neurons

  2. Soma integrates information

  3. Axon transmits information
• Parts of a neuron

  • Dendrite
  • Soma/Cell body
  • Nucleus
  • Axon
  • Nodes of Ranvier
  • Myelin Sheath
  • Axon terminals
  • Terminal Buttons
  • Synapses
• Axon


  A single, tubelike extension that transmits neural information to other neurons
• Dendrite


  A part of the neuron that is on the inside and finger-like, transmits information to the soma (cell body)
• Myelin Sheath


  A white, fatty substance (made up of certain types of glial cells) that surrounds and insulates the axon, allowing for rapid movement of the message along the axon without being interrupted or distorted
• Axon Terminals


  Small structures like sacs that store and secrete neurotransmitter that is manufactured by the neuron and carries its chemical message to other neurons or cells
• Soma


  The body of an organism, where all the information is integrated before sent to the Axon
• Synapses


  The gap between each neuron, connect neurons and help transmit information from one neuron to the next
• Nodes of Ranvier


  The gaps formed between the myelin sheath where the axons are left uncovered, allow the generation of a fast electrical impulse along the axon
• Nucleus


  An oval shaped membrane-bound structure found in the soma or body of the neuron, to guide the axon hillock that generates the impulses throughout the axon
• Spinal cord


  The long, thin bundle of nerve tissue that extends from the base of the brain to the lower back, receives sensory information from the body and sends these messages to the brain for processing, receives motor information from the brain and sends it to relevant parts of the body to control muscles, glands and internal organs
• Types of neurons


  • Sensory neurons
  • Motor neurons
  • Interneurons
• Relationship between different neurons

  • Sensory neurons carry neural messages to CNS
  • Motor neurons carry neural messages from CNS to effectors
  • Interneurons carry neural messages through CNS
• The frontal lobe is responsible for cognition, language, associative processes including learning and memory, and motor coordination. It enables the brain to think abstractly and creatively, solve problems, reflect upon events and make judgments.
• The primary motor cortex in the frontal lobe controls motor coordination, sending messages to muscles to control movement.
• The occipital lobe is entirely dedicated to managing our vision, interpreting how we see things around the world.
• The parietal lobe is the control centre for all the body's somatosensory input, giving us our sense of touch, our ability to understand form through touch, and our recognition of stimuli from our own bodies (pain, temperature, pressure, etc). It also aids in some speech and visual functions.
• The primary somatosensory cortex, located in the parietal lobe, is involved in the recognition of stimuli from our own bodies and the outside world (pain, temperature, pressure, etc).
• The temporal lobes are primarily responsible for processing auditory information from the ears. They also house some peripheral language and speech functions, and give us our musical abilities.
• The cerebellum coordinates fine muscle movements and regulates posture and balance. It is particularly active when learning a new movement or performing a sequence of movements where the next movement cannot be predicted in advance.
• The brain stem regulates life support systems, such as heart rate, breathing, and blood pressure.
• The medulla is the lowest part of the brain and a continuation of the spinal cord, connecting the brain to the spinal cord.
• The pons is involved in sleep, dreaming and arousal from sleep, as well as helping control breathing and coordination of some muscle movements.
• DNA structure


  • Phosphate group, sugar group (deoxyribose), base (one of 4: adenine (A), thymine (T), guanine (G), cytosine (C))
  • The line connecting the phosphate and sugar group is called the phosphodiester bond
  • Hydrogen bonds form between complementary base pairs (A-T, G-C)
• DNA has a double helix structure, with hydrogen bonds forming between complementary base pairs on opposite strands.