Nervous System & Encrine System

• What is the primary function of the nervous system?

  Coordinates the body's responses
• How does the central nervous system respond to stimuli?

  By coordinating muscle contractions and gland secretions
• What type of actions are reflex actions?

  Automated and rapid
• What are the steps in the reflex arc?

  1. Pain stimulus detected by receptors
  2. Impulses travel along a sensory neuron to the CNS
  3. Impulse passes through a relay neuron
  4. Motor neuron carries impulse to the effector
  5. The effector responds
• How do neurons communicate with each other?

  Via synapses using chemical signals
• What happens when an electrical impulse reaches a synapse?

  A chemical is released that diffuses across
• What is the independent variable in the reaction time experiment?

  • Whether the subject has had caffeine or not
• What is the dependent variable in the reaction time experiment?

  • Distance the ruler travels
• What are the control variables in the reaction time experiment?

  • Age
  • Mass
  • Sex
• What is the endocrine system responsible for?

  Releasing hormones directly into the bloodstream
• What are hormones?

  Chemical messengers produced by glands
• How do hormones affect the body?

  They have slower effects that last longer
• What hormone is produced by the adrenal glands?

  Adrenaline
• What is the effect of adrenaline on the body?

  Increases heart rate and boosts glucose delivery
• What hormone is produced by the thyroid gland?

  Thyroxine
• What does thyroxine control in the body?

  Metabolic rate and growth development
• How is blood glucose controlled in the body?

  • Monitored by the pancreas
  • Insulin lowers blood glucose
  • Glucagon raises blood glucose
• What happens when blood glucose is too high?

  Pancreas releases more insulin
• What does insulin do in the body?

  Causes glucose to move into cells
• What happens when blood glucose is too low?

  Pancreas releases glucagon
• What does glucagon do in the body?

  Stimulates glycogen to glucose conversion
• What is Type 1 Diabetes caused by?

  Pancreas failing to produce insulin
• How is Type 1 Diabetes typically treated?

  With insulin injections
• What is a risk factor for Type 2 Diabetes?

  Obesity
• How is Type 2 Diabetes managed?

  With diet and exercise
• What are exocrine glands?

  Glands that secrete enzymes into ducts
• What is the function of salivary glands?

  To secrete enzymes for digestion
• What is homeostasis?

  Regulation of internal conditions
• Why is homeostasis important for cells and organisms?

  It helps maintain optimal internal conditions
• What are the key aspects controlled by homeostasis?

  • Body temperature
  • Water and ion levels
  • Blood glucose concentration
• What types of responses are involved in homeostasis control systems?

  Responses using nerves and hormones
• What are the components of all control systems in homeostasis?

  • Receptors that detect stimuli
  • Co-ordination centres (brain, spinal cord, pancreas)
  • Effectors that restore optimum levels
• What is the role of receptors in homeostasis?

  They detect stimuli
• What are co-ordination centres in the control system?

  Brain, spinal cord, pancreas
• What is the function of effectors in homeostasis?

  They bring about responses to restore levels
• What does a receptor do in the negative feedback mechanism?

  It detects a change in stimulus
• What does an effector do in the negative feedback mechanism?

  It produces a response to correct differences
• What is the role of the co-ordinating centre in the negative feedback mechanism?

  It compares the stimulus to a set point
• What is the negative feedback control mechanism?

  1. A receptor detects a change in stimulus
  2. An effector produces a response to correct the difference
  3. The co-ordinating centre compares the stimulus to a set point
• If blood glucose is too high:

  • the pancreas releases more of the hormone insulin.
  • Insulin causes glucose to move from the blood into the cells.
  • in liver and muscle cells excess glucose is converted to glycogen for storage.