BIO1 4THQ 2.1

• Nerve nets


  - Interconnected neurons

  - sense locomotion
• Muscles when contracting don't stretch
• Tissue and specialized cells


  • Provide information about the environment
  • Serve as signalling pathways, integrates information to generate responses
• Porifera (sponge)


  • No networked nervous system
  • Possess ciliated sensory cells that control water flow and sense
• porifera reproduction


  Mass release of sperm cells to reproduce
• Echinoderm (starfish/sea star)


  eyespot - detect light intensity/ change in light
• Eyes


  Put to detect the light internity (change in light)
• Planaria (Flatworms)


  • Cerebral ganglia concentration of nerve cells
  • Cerebral
  • Cerebellum
• Mollusks


  • Bivalves 3 sets ganglia (horse shells, clams)
  • Gastropods 6 sets ganglia
• cephalization


  Have established brain & spinal cord
• Nervous System


  Collection of tissue and specialized cells that provide information about the environment
• Nervous System


  • Serve as signaling pathways, integrates information to generate responses
• Porifera


  • Do not have networked nervous system
  • Possess ciliated sensory cells which sense and control water flow
• Cnidarian (Jellyfish)


  • Have diffuse nervous system – simplest style
  • Possess nerve nets – mesh of interconnected neurons
• Echinoderm (Sea star)


  • Nervous system is modified from a nerve net but more evolved than cnidarians
• Planarian (Flatworm)


  • Cerebral ganglia – concentration of nerve cells
• Annelid (Earthworm)


  • Possess paired ventral nerve cords that run along the underside of their body
  • Nerve cord originate from cerebral ganglion
  • Ganglionic swelling of cord is found in each body segment
  • Afferent and efferent neurons are found in lateral nerves
• Arthropods (Insects)


  • Nervous system consists of a "dorsal brain and a ventral, ganglionated longitudinal nerve cord from which lateral nerves extend in each segment"
• Mollusk (Octopus)


  • Bivalves – nervous system is composed of three sets of ganglia
  • Gastropods – six sets of ganglia
  • Cephalopods – have most complex nervous system
• Two Main Divisions of Vertebrate (Human) Nervous System

  • Central Nervous System (CNS)
  • Peripheral Nervous System (PNS)
• Central Nervous System (CNS)


  Brain and spinal cord, main control of the body
• Peripheral Nervous System (PNS)

  Composed of sensory receptors and nerves that branch off the brain spine
• The nervous system serves as the control and communicating system of the body
• Three broad functions of the nervous system

  • Detecting stimuli
  • Interpreting
  • Initiating appropriate responses
• Brain


  Responsible for the integration
• Spinal cord


  Transmits messages to and from the brain, and controls spinal reflexes
• Peripheral Nervous System


  Plays an important role in regulating the movement and the internal environment of the organism
• Two Divisions of Peripheral Nervous System

  • Sensory Division
  • Motor Division
• Sensory Division (Afferent)


  Transmits information from the peripheral organs, through the sensory nerves, to the CNS
• Sensory Division


  Sensory nerves arise from sensory receptors and carry messages to the central nervous system for processing
• Sensory Division


  Keeps the CNS aware of the external and internal environments, includes sense organs and internal receptors that monitor internal state
• Motor Division (Efferent)


  Carries impulses from the CNS to the effectors for response or action through the motor neurons
• Further subdivisions of Motor Division

  • Somatic nervous system (SNS)
  • Autonomic nervous system (ANS)
• Somatic nervous system (SNS)


  Involves the neurons that carry impulses to the voluntary (skeletal) muscles
• Autonomic nervous system (ANS)


  Regulates visceral functions over which there is generally no conscious control, e.g. heart rate, gut peristalsis
• Autonomic nervous system (ANS)


  Manages involuntary visceral function through the reflex action
• Branches of Autonomic Nervous System

  • Parasympathetic division
  • Sympathetic divisions
• Your brain can generate electricity
• endocrine system


  nervous system works with the endocrine system in communicating signals and regulating biological processes for the body to maintain homeostasis
• Neural regulation


  is relatively more rapid that hormonal regulation