Pt. 1

• Spinal cord

  -> Receives sensory information from the body (via the PNS) and sends these messages to the brain for processing

  -> Receives motor information from the brain and sends it to relevant parts of the body (via the PNS) to control muscles, glands, and internal organs so appropriate actions can be taken

  -> Damage to spinal cord results in paralysis below the damage
• PNS

  -> Peripheral nervous system-> Network of nerves outside the CNS that transmits information to and from the CNS
• SNS

  -> Somatic/skeletal nervous system-> Network of nerves that carry information to the CNS and motor information from the CNS-> This system is under complete voluntary control
• ANS

  -> Autonomic nervous system-> Network of nerves that carries messages between the CNS and the heart, lungs, and other internal organs and glands-> Regulates and controls the functioning of internal organs automatically (without having to think about it), and functions fairly independently of the CNS in maintaining the body's internal states and processes
• Sympathetic nervous system

  -> Arouses the body when we experience an extreme emotion, feel threatened, or suddenly experience stress-> It can very easily prepare the body for an immediate response in an emergency by releasing adrenalin, leading to higher energy supplies, alertness, and heart rate-> Uses the fight-flight-freeze response
• Functions of nervous system

  -> Receive information: the vibrating air molecules are received at the ear and sent to the brain via the auditory nerve-> Process information: the brain processes the auditory information and interprets the sound as your mobile phone's ring tone-> Coordinate a response to information: the brain sends messages along nerve pathways to activate muscles to pick up the phone, check who's calling, and speak
• CNS

  -> Central nervous system-> Consists of the brain and spinal cord-> Processes information received through sensory systems and other parts of the body, and activates appropriate actions
• Brain

  Network of cells that processes information from the body's internal and external environments and directs responses
• Parasympathetic nervous system

  -> In the absence of threat the parasympathetic nervous system helps to maintain the internal body environment in a steady, balanced state-> Counterbalances the activities of the sympathetic nervous system and restores the body to a state of calm once the need for the sympathetic nervous system activation has passed
• Sympathetic nervous system effects

  -> Pupils dilate (enhances vision by allowing more light)-> Digestive activity lowers (allows blood to momentarily flow to other areas)-> Bronchi relaxes (increases breathing, more O2)-> Heart rate accelerates (more blood and O2)-> Bladder constricts
• Parasympathetic nervous system effects

  -> Constricts pupils-> Digestive activity continues-> Bronchi goes back to normal (steady breathing)-> Heart rate inhibits-> Bladder constricts