Nervous System 1

• Comparing the Nervous and Endocrine Systems
• Nervous System


  • Neurons work through chemical called neurotransmitters
  • Neurotransmitters attach to receptors over travelling a very short distance
  • Works very fast
• Endocrine System


  • Glands that control by chemical signals called hormones
  • Hormones reach target all by travelling long distances in blood
  • Works slowly compared to Nervous System
• • Nervous System regulates effectors (muscles, glands) directly
  • Endocrine System regulates effectors indirectly
• • Nervous System uses electrical signals
  • Endocrine System uses chemical signals
• • Nervous System has short, rapid effects
  • Endocrine System has long-lasting, gradual effects
• Function of the Nervous System is to transmit messages in our body by linking sensory receptors that detect stimuli and effectors that respond to those stimuli
• Transmission of these messages is carried out by nerve impulses that act fast
• Nervous System


  • Divided into Central Nervous System (CNS) and Peripheral Nervous System (PNS)
• Central Nervous System (CNS)


  • Subdivided into brain and spinal cord
• Peripheral Nervous System (PNS) is divided into sensory pathway and motor pathway, which is subdivided into Somatic nervous system (SNS), Autonomic nervous system (ANS) and Enteric nervous system (ENS)
• Autonomic nervous system is subdivided into sympathetic and parasympathetic nervous systems
• Nervous system has two types of cells: neurons and neuroglia (supporting cells)
• Neurons


  • Sensory neurons carry impulses to central nervous system, motor neurons carry impulses from central nervous system to effectors, interneurons provide more complex reflexes and associative functions
• Neuronsaccording to their structure are?


  • Multipolar, bipolar, and unipolar
• Neuron cell body contains nucleus and maintains the neuron, not the branches
• Dendrites receive electrical signals from other neurons, axon passes on the signal (nerve impulse)
• Neuroglia


  • Schwann cells in PNS and oligodendrocytes in CNS produce myelin sheaths surrounding axons
  • Astrocytes support neurons, remove waste, help maintain environment, help form blood brain barrier
  • Microglia are white blood cells of the brain that clear away infection or dead cells and protect the brain from disease
• Multiple Sclerosis is a condition where the myelin is lost due to the injury of oligodendrocytes, resulting in weak nerve conduction and loss of coordination
• What are the two branches to the PNS

  Sympathetic nervous system: fight or flight response (emergency actions)

  Parasympathetic nervous system: Daily activities (Slows heart rate down, signals pancreas to release insulin)