2. AP Biology 2007-2008 Nervous System

3. AP Biology 2007-2008 Where does most absorption occur in the digestive system? Which structures mechanically break down food? How to the circulatory system and digestive system work together?

4. AP Biology

5. Why do animals need a nervous system?  What characteristics do animals need in a nervous system?  fast  accurate  reset quickly Remember… think about the bunny… Poor bunny!

6. AP Biology Nervous system cells: The Neuron dendrites cell body axon synaptic terminal  Structure fits function  many entry points for signal  one path out  transmits signal signal direction signal direction dendrite  cell body  axon myelin sheath transmitters

7. AP Biology Nervous system cells dendrites cell body axon synaptic terminal  Neuron  a nerve cell signal direction signal direction dendrite  cell body  axon transmitters Detect Signal Controls Cell Transmits Signal Down Cell Place Where Signal goes to next neuron How are the circulatory and respiratory systems related? How does the respiratory system help maintain homeostasis in our body? Chemicals that Cross the synapse

8. AP Biology Peripheral Nervous System  Job: Transmit information from the sense organs to the central nervous system. “From the outside in”  Structures: All nerves that are not a part of the brain or spinal cord.  Analogy to home heating system: When the temperature drops outside, this is like a signal sent into your heating system

9. AP Biology Central Nervous System  Job: Processes and relays information. Responds to the peripheral nervous system.  Structures: brain, spinal cord  Analogy to home heating system: The heater “responds” to the initial signal by turning on.

10. AP Biology Hypothalamus  Job: Control center for recognizing hunger, thirst, fatigue, body temperature  Structures: inside the central part of the brain  Analogy to home heating system: This is like the thermostat. Controls when the heater turns on or off by recognizing signal from outside (temp)

11. AP Biology Transmission of a signal  Think dominoes!  start the signal  knock down line of dominoes by tipping 1 st one  trigger the signal  propagate the signal  do dominoes move down the line?  no, just a wave through them!  re-set the system  before you can do it again, have to set up dominoes again  reset the axon

12. AP Biology Synapse Impulse has to jump the synapse!  junction between neurons  has to jump quickly from one cell to next What happens at the end of the axon? How does the wave jump the gap?

13. AP Biology axon terminal synaptic vesicles muscle cell (fiber) neurotransmitter acetylcholine (ACh) receptor protein Ca ++ synapse action potential Chemical synapse  Events at synapse  release neurotransmitter to synapse  diffusion  An Electric Signal briefly changes to a chemical signal We switched… from an electrical signal to a chemical signal

14. AP Biology

16. 2007-2008 Ponder this… Any Questions??