BS 2

• Parts of the nervous system

  • Central nervous system (brain, spinal)
  • Peripheral nervous system (nerves, neural tissues)
• Neurons


  The nerve cells and the functional unit of the nervous system
• Motor neurons


  • Only have one axon and several dendrites
• Axons


  • Covered with a fatty layer called a myelin sheath, they transmit signals over long distances
• Dendrites


  • Short and unsheathed
• Motor neuron syndromes


  • Upper motor neuron syndrome (weakness/paralysis, spasticity, hypertonia)
  • Lower motor neuron syndrome (paralysis, atonia, hypotonia)
• ALS


  An always fatal neurodegenerative disease in which a person's muscles waste away
• Synapses


  Connectors hooking dendrites, where nerve cells transmit signals
• Nerve signal transmission


  1. Sensory receptors

  2. Sensory neurons

  3. Interneurons

  4. Motor neurons

  5. Muscle contraction
• Gray matter


  • Internal structure and cell bodies of mature neurons
• White matter


  • Myelinated nerve fibers
• Meninges


  • Dura mater
  • Arachnoid
  • Pia mater
• Cerebrum


  • Processes perception, emotion, memory, and voluntary motor activity
• Lobes of the cerebral cortex

  • Frontal (motor activity, speech, personality)
  • Parietal (temperature, pressure)
  • Temporal (hearing, smell, language input)
  • Occipital (vision)
• Brain stem


  • Controls vital reflexes and functions like breathing, swallowing, hearing
• Cerebellum


  • Responsible for coordinating voluntary and involuntary movements, adjusting muscles for posture
• Diencephalon


  • Includes the thalamus and hypothalamus
• Thalamus


  Center for all sensory (except smell) and motor areas of the cortex
• Hypothalamus


  Regulates emotional expression, temperature, behavior, and many metabolic activities
• Cerebrospinal fluid


  Produced in the ventricles of the brain, surrounds the brain and spinal cord
• Parts of the autonomic nervous system


  • Sympathetic ("fight or flight")
  • Parasympathetic ("rest and digest")
• Evolution


  A process by which the physical characteristics of types of creatures change over time, new types of creatures develop, and others disappear
• Organisms


  • Their structures, traits, and abilities allowed them to adapt and survive in their environment
• Different evidences of evolution

  • Fossil Record
  • Genetic information
  • Comparative Anatomy
  • Embryonic Development
• Fossil record


  Traces of organisms that lived in the past and were preserved by natural process or catastrophic events
• Fossils document the existence of now-extinct past species that are related to present-day species
• Comparative anatomy


  Comparing the structures of different organisms to determine their evolutionary relationships
• Embryonic development


  Comparing the embryonic development of different organisms to determine their evolutionary relationships
• Genetic information


  Changes in the base sequence of DNA that may affect one gene or whole chromosomes, and can alter an organism's phenotype, including the development of new traits, disease susceptibility, or impact on survival and reproductive success
• Humans and chimpanzees have 98.8% similar DNA, with the 1.2% difference accounting for the difference in their appearance and traits
• There are around 8.7 million species of plants and animals in existence, but only around 1.2 million species have been identified and described so far, most of which are insects
• Diversity of species


  Caused by the process of gradual change during which new species arise from older species
• The source of diversity is evolution
• Catastrophism


  The idea that the earth and geological events had formed suddenly, as a result of some great catastrophe
• Uniformitarianism


  The idea that the Earth has always changed in uniform ways and that the present is the key to the past, meaning that large geological changes occurred not in catastrophic events but in gradual accumulation of small geological changes
• Lamarck's theory of need


  Organisms change in response to their environment, and their ability to survive helps them develop characteristics necessary for them to adapt to a given environment
• Lamarck's theory of use and disuse

  Organs not in use will disappear while organs in use will develop, and an organism can reshape or alter its traits depending on the importance of that trait to the organism
• Lamarck's theory of acquired characteristics

  Acquired traits of an organism that were influenced by the environment can be passed on to its offspring
• Charles Darwin


  The Father of Evolution, who proposed the Theory of Natural Selection, the process where organisms with favorable traits are more likely to reproduce and pass on these traits to the next generation, allowing organisms to adapt to their environment
• Darwin's concept of natural selection

  • Organisms struggle to survive to avoid extinction
  • Organisms vary in their physical, functional, and behavioral characteristics
  • Organisms which can best adapt to their environment would survive and produce better offspring (Adaptation)
  • There is a higher probability of the next generation of organisms to survive if they acquired the adaptive characteristics
  • Environmental conditions can affect the survival of organisms