3 LESSON_Q3

• Nervous system


  The master coordination and communication system of the body
• Divisions of the nervous system

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


  • Serves as the main processing center for the entire nervous system
  • Consists of the brain and spinal cord
• Parts of the brain

  • Cerebrum
  • Cerebellum
  • Brain stem
• Spinal cord


  Serves as a channel for signals between the brain and the rest of the body, and controls simple musculoskeletal reflexes without input from the brain
• Divisions of the Peripheral Nervous System (PNS)

  • Somatic Nervous System
  • Autonomic Nervous System
• Somatic Nervous System


  • Associated with the voluntary control of body movements
  • Consists of spinal nerves and cranial nerves
• Autonomic Nervous System


  • Associated with the involuntary control of body movements
  • Has two subdivisions: Sympathetic and Parasympathetic
• Neuron


  • The basic unit of the nervous system
  • Has three parts: cell body, dendrites, and axon
• Nerve impulse


  • Electrochemical in nature
  • Electrical as it travels inside the neuron and uses chemicals called neurotransmitters when it crosses the synapse towards the next neuron
• Synapse


  The gap between the tip of the axon of one nerve cell and the dendrite of the next nerve cell
• Types of neurons


  • Sensory neurons
  • Motor neurons
  • Interneurons
• Stimulus


  Any factor in the environment that may trigger a nerve impulse
• Response


  A reaction to a stimulus
• An organism must be able to respond to a stimulus in order to survive
• Neuron


  The basic unit of the nervous system. It has three main parts - the dendrites, cell body and axon. The signals created in this type of cell is electrical in nature.
• Types of neurons


  • Sensory neurons
  • Motor neurons
  • Interneurons
• Central Nervous System (CNS)


  The division of the nervous system that serves as the control and processing system for the entire nervous system
• Peripheral Nervous System (PNS)


  The division of the nervous system that connects all other parts of the body to the CNS
• Stimulus


  Any input from the environment as perceived by the 5 senses
• Response


  The appropriate action created by the CNS in response to a stimulus
• Sympathetic Nervous System


  The system that sets the body into a dynamic mode when we feel stressed or sense danger
• Parasympathetic Nervous System


  The system that maintains body functions and restores the body to normal or relaxed mode after the stress or danger has passed
• Reaction time is how much time passes before a response is rendered after perceiving a stimulus
• Experiment to determine reaction time

  1. Volunteer holds ruler

  2. Hand at edge of ruler waiting to catch

  3. Volunteer releases ruler randomly

  4. Catch ruler as soon as motion is perceived
• The perception of seeing the ruler falling is the stimulus. The brain interprets this signal and formulates a response to move the hand muscles to catch the ruler.
• Evaluating the distance the hand catches the ruler gives an idea of the reaction time
• Nervous System


  Uses electrical impulses and neurotransmitters, signal is electrochemical in nature
• Endocrine System


  Uses hormones as signals, signal is purely chemical in nature
• Endocrine glands and their hormones

  • Pituitary - Oxytocin, Vasopressin, Growth Hormone, ACTH, Prolactin, LH, FSH
  • Thyroid - Thyroxin, Calcitonin
  • Parathyroid - Parathyromone
  • Thymus - Thymosin
  • Adrenal - Adrenaline
  • Pancreas - Insulin, Glucagon
  • Testes - Androgen, Testosterone
  • Ovaries - Estrogen, Progesterone
• Pituitary gland


  Stimulates growth, and controls the functions of other glands
• Thyroid gland


  Regulates body metabolism, and causes storage of calcium in bones
• Parathyroid gland


  Controls the calcium levels in the body, and normalizes bone growth
• Thymus gland


  Enables the body to produce certain antibodies
• Adrenal gland


  Prepares the body for action, controls the heart rate and breathing in times of emergency
• Pancreas


  Regulates blood sugar levels
• Testes


  Control maturation and male characteristics
• Ovaries


  Influence female traits, and support reproductive function
• Hormones regulate and balance the working of organs, tissues, and cells in the body
• Hormonal imbalance can result in disorders like dwarfism, gigantism, goiter, obesity, osteoporosis