2. Regents Biology 2003-2004 Why do animals need a nervous system?  Because the world is always coming at you!  Take in information  Regulation Remember… think about the bunny… Poor bunny!

3. Regents Biology 2003-2004 Nervous System  Central nervous system  CNS  brain & spinal chord  Peripheral nervous system  nerves from senses  Take in info from environment  nerves to muscles  Allow for response cerebrum cerebellum spinal cord cervical nerves thoracic nerves lumbar nerves femoral nerve sciatic nerve tibial nerve

4. Regents Biology 2003-2004 Nervous cells dendrites cell body axon synapse (space)  Neuron  a nerve cell signal direction ONE WAY signal direction nucleus terminal branches

5. Regents Biology 2003-2004 Fun facts about neurons  Most specialized cell in animals  Longest cell  blue whale neuron  10-30 meters  giraffe axon  5 meters  human neuron  1-2 meters Nervous system allows for 1 millisecond response time

6. Regents Biology 2003-2004 signal direction Myelin coating - lipid  Axon coated with insulation made of myelin cells  speeds signal  signal hops from node to node  330 mph vs. 11 mph Multiple Sclerosis  immune system (T cells) attacks myelin coating  loss of signal Multiple Sclerosis  immune system (T cells) attacks myelin coating  loss of signal

7. Regents Biology 2003-2004 Synapse synapse Junction between nerve cells  1st cell releases chemical to trigger next cell – neurotransmitters  proteins – remember 3-D shape??  where drugs affect nervous system Drugs – 1. block receptor sites on receiving neuron 2.Bind with neurotransmitter to change shape 3.Prevent release of neurotransmitter

8. Regents Biology 2003-2004 axon myelin vessicle terminal branch channel protein dendrite exocytosis (active transport) synapse protein Mitochondia – R – provide ATP

9. Regents Biology 2003-2004 3 Types of neurons sensory neuron (from senses) receive stimulus interneuron (CNS -brain & spinal chord) motor neuron (to effector – muscle/gland) produces response

10. Regents Biology 2003-2004 Human brain

11. Regents Biology 2003-2004 Primitive brain  The “lower brain”  medulla oblongata  basic body functions  breathing, heart, digestion, swallowing, vomiting  homeostasis  cerebellum  coordination of movement and balance

12. Regents Biology 2003-2004 Higher brain  Cerebrum  2 hemispheres  left = right side of body  right = left side of body  Corpus callosum  connection between 2 hemispheres

13. Regents Biology 2003-2004 Division of Brain Function  Left hemisphere  “logic side”  language, math, logic operations, vision & hearing details  fine motor control  Right hemisphere  “creative side”  pattern recognition, spatial relationships, non-verbal ideas, emotions, multi-tasking

14. Regents Biology 2003-2004 Simplest Nerve Circuit – Reflex Arc  Reflex, or automatic response  signal only goes to spinal cord - FASTER  advantage  essential actions  don’t need to think or make decisions about (automated)  blinking  balance  pupil dilation  startle – “fight or flight”

15. AP Biology Reflex ARC 2003-2004