Nervous and endocrine system

• What is the nervous system?

  • A specialist network of cells in the body acting as our primary internal communication system
  • Collects, processes, and responds to environmental information
  • Co-ordinates organs and cells in the body
• What is the central nervous system made up of?

  • The brain and the spinal cord
• What is the brain responsible for in the CNS?

  • The brain is responsible for all conscious awareness acting as a control centre
  • Its' function and regulation maintains the body's internal environment
  • Its' outer layer (cerebral cortex) controls higher level processes like emotion and intelligence
  • Receives environmental information from sensory receptors
• What is the spinal cord responsible for in the CNS?

  • A collection of nerve cells acting as a pathway for sensory and motor signals between the brain and body
  • Connects nerves from the brain to the peripheral nervous system
  • Responsible for reflex actions
• What is the peripheral nervous system?

  • Transmits messages to and from the central nervous system
  • Made up of the somatic and autonomic nervous systems
  • Autonomic nervous system -> sympathetic NS and parasympathetic NS
• What are the roles of the somatic and autonomic nervous systems?

  • Somatic: controls skeletal muscle movement and receives information from sensory receptors
  • Autonomic: controls involuntary vital actions like breathing, digestion, heart rate, etc.
• What are the roles of the sympathetic and parasympathetic nervous systems?

  • Both branches regulate the same organs with opposite effects - either excitatory (increasing activity) or inhibitory (calming effect)
  • Sympathetic NS: prepares body for rapid action when under a perceived threat
  • Parasympathetic NS: relaxes the body once the emergency has passed
• What is the endocrine system?

  • A network of gland that control vital functions alongside the CNS but acts slower with more powerful and widespread effects
• What are glands? What are examples of glands?

  • Organs that produce hormones
  • Pituitary master gland: located in the brain and control the release hormones in all other endocrine glands
  • Thyroid gland produces the hormone thyroxine, which affects metabolic rate and in turn our growth
  • Adrenal gland produces adrenaline and cortisol
• What are hormones? What are examples of hormones?

  • Chemical substances that are secreted in the bloodstream and affect any cell in the body with a particular receptor for it
  • Thyroxine regulates the body's metabolic rate
  • Adrenaline increases heart rate and blood flow to prepare body for threat
• What is the fight or flight response?

  • When a stressor is perceived, the hypothalamus triggers activity in the sympathetic NS by activating the pituitary gland
  • The resting autonomic NS in a parasympathetic state becomes the sympathetic, psychologically aroused state
  • Release of adrenaline triggers physiological changes like increased heart rate and blood flow to enhance oxygen delivery to muscles, preparing to fight or run away
  • Once threat has passed, ANS returns to the parasympathetic state which reduces/calms down the effects caused by the sympathetic branch like slowing down breathing