Chapter 7 & 8 Study GuideNervous & Endocrine Systems

  1. Jobs of the Nervous System:
  2. Receiving information –converting outside stimuli into nerve impulses, and bringing them to the brain to be interpreted and understood.
  3. Responding to information –reflexes help keep you safe, and messages from the brain out to the body let you function and do things you want or need.
  4. Maintaining homeostasis –keeping systems in balance.
  1. What is a neuron?
  2. Nerve impulse –the electrical signal carried along a nerve
  3. Structure of a neuron
  4. Axon –long part reaching toward the next neuron
  5. Dendrite –short ‘roots’ of a neuron, bring info in
  1. Kinds of Neurons
  2. Sensory Neuron –convert external stimuli into a nerve impulse
  3. Interneuron –pass nerve impulses through the nervous system
  4. Motor Neuron –send impulses from the brain out to muscles to control movement
  1. How a nerve impulse travels
  2. Impulses leave the cell body and travel down the axon
  3. At the end of an axon, the axon tip releases chemicals into the tiny liquid filled gap called a synapse.
  4. The chemicals (neurotransmitters) float across the synapse and stimulate the dendrite on the other side.
  5. The dendrite then sends an impulse up to its cell body.
  1. Divisions of the Nervous System
  2. Central Nervous System
  3. Brain
  4. 3 key parts
  5. Cerebrum - center for voluntary activity interprets sensory impulses, initiates some motor activities, and responsible for memory,thinking and reasoning
  6. Cerebellum –makes movement coordinated and maintains balance
  7. Brain Stem –center for involuntary functions (breathing, heart rate, digestion)
  8. Spinal Cord
  9. Carries nerve impulses to and from the brain
  10. Directs some reflex actions such as pulling away from a hot surface
  11. Peripheral Nervous System
  12. Somatic Nervous System –controls voluntary movement, receives sensory input
  13. Example: used in moving your arm to open the refrigerator
  14. Autonomic Nervous System –controls involuntary actions, and receives sensory input about homeostasis (balance of needs)
  15. Example: receives information about body temperature and communicates to the skin that it is time to sweat
  1. Senses
  2. Vision
  3. Structures of the eye
  4. A sheep’s eye is different from a human eye because it has a tapetum, which reflects light back through the retina. This is what makes a cat’s eyes appear to glow in the dark.
  5. Farsightedness –seeing far objects clearly, image focuses behind the retina
  6. Nearsightedness –seeing near objects clearly, image focuses in front of the retina
  7. Hearing
  8. Structures of the ear
  9. Smell & Taste
  10. You can taste only a few things, sweet, salty, bitter, sour
  11. You can smell more than 50 different smells
  12. Both respond to chemical stimulation
  13. When you taste, you use both your sense of taste and smell
  14. Touch
  15. The sense of touch is not found in one specific place (instead it is found in all areas of your skin)
  1. Endocrine System
  2. Endocrine glands
  3. Release chemicals into the circulatory system, where they are carried to other areas
  4. Hormones – the chemical products of an endocrine gland
  5. Hypothalamus
  6. Directs or controls the pituitary gland
  7. Responds to hunger and thirst
  8. Pituitary Gland
  9. Disruption in homeostasis – something out of balance
  10. Controls many other glands
  11. Regulates growth
  12. Thyroid Gland
  13. Controls metabolism
  14. Negative feedback – having a lot of one hormone in the blood prevents the release of other hormones
  15. Central heating systems use negative feedback – when the furnace heats the house enough, the thermostat is triggered and shuts off the furnace. Making heat tells the furnace to stop making heat.