1. Chapter 35 The Nervous System

2. Nervous System Functions 1. Receive & relay information throughout body 2. Monitor & respond to internal and external changes

3.  Brain  Spinal Cord  Nerves Cells are unique – called neurons Consists of:

4.  Central Nervous System (CNS) – brain & spinal cord  Peripheral Nervous System (PNS) – sensory & motor neurons that carry information to & from CNS. Two Major Divisions:

5. Nerve /Brain Facts  We can’t make new neurons  The brain is made up of 100 billion neurons  We make new nerve connections when we learn

6. Nerve/Brain Facts (cont.)  We use 100% of our brain  Nerve impulses can travel 395 feet per second

7. Bundles of nerve fibers

8. What are neurons?  Cells that carry electrical nerve impulses throughout body  3 parts

9. Anatomy of a Neuron  Dendrite: receives nerve impulse from other neurons & conducts them to cell body

10. Anatomy of a Neuron (cont.)  Axon: sends nerve impulse from cell body to other neurons & muscles.

12. Anatomy of a Neuron (cont.)  Myelin Sheath: membrane surrounding axon faster nerve conduction faster nerve conduction

13. Anatomy of a Neuron (cont.)  Cell Body: contains organelles mitochondria, nucleus, etc.mitochondria, nucleus, etc.

14. Neuron Dendrite Cell Body

15. 1.Nerve Impulse occurs 2.Neurotransmitters are released in synapse 3.Muscle contracts or response to stimuli occurs How Neurons Work

16.  Nerve impulse (a.k.a. action potential) – is an electrical charge traveling the length of a neuron Touch, loud noise, smell, etc.Touch, loud noise, smell, etc. Steps of How Neurons Work:

17.  Impulse reaches end of axon, vesicles (small sacs) release Neurotransmitters: chemicals that carry impulses between neurons How Neurons Work

18.  Neurotransmitters cross the synapse and cause a response (ex. muscle to contract) How Neurons Work

19. Neurotransmitters  Serotonin & Dopamine “feel good” type of chemicals “feel good” type of chemicals

20. How Neurons Work  Neurons have a gap between them: synapse Gap between axon of 1 neuron & dendrite of another neuronGap between axon of 1 neuron & dendrite of another neuron

21. Types of Neurons 1.Sensory neurons 2.Motor neurons 3.Interneurons

22. 1. Sensory Neurons  Carry impulses from skin and sensory organs to brain and spinal cord

23. 2. Motor Neurons  Carry impulses from the brain and spinal cord to muscles or glands causing a response

24.  Receives impulse from sensory neurons & carries impulse to motor neurons 3. Interneurons

25. Problems due to Neurotransmitters Parkinson's Disease: dopamine producing neurons destroyed (lack of movement)Parkinson's Disease: dopamine producing neurons destroyed (lack of movement) Depression: deficit in serotonin &/or dopamineDepression: deficit in serotonin &/or dopamine Schizophrenia: high level of dopamineSchizophrenia: high level of dopamine

26. Epilepsy Seizures due to large numbers of impulses sent simultaneously Affects 1 out of every 200 people in U.S. & 50 million people worldwide

27. Multiple Sclerosis  Body attacks myelin sheath  Causes nerve impulses to short circuit

28. Studying The Brain  CAT Scan: used to locate tumors, damaged regions & blood clots  AKA CT Scan – computed axial tomography

29. Studying The Brain (cont.)  PET Scan: used to look at brain activity Positron emissions tomography

30. Studying The Brain (cont.)  MRI: used to look at brain tissue MRI of an individual with MS Magnetic resonance imaging

31. Central Nervous System:  Consists of brain and spinal cord

32.  Brain has 4 main parts: CerebrumCerebrum CerebellumCerebellum Brain stemBrain stem HypothalmusHypothalmus CNS continued:

33.  Cerebrum named by region: Frontal Lobe – judgment, impulsesFrontal Lobe – judgment, impulses Parietal Lobe – understand & process informationParietal Lobe – understand & process information Cerebrum:

34. Occipital Lobe – visually processOccipital Lobe – visually process Temporal Lobe – controls hearing & recognitionTemporal Lobe – controls hearing & recognition Cerebrum continued:

35.  Coordination & movement  Body movements, posture, muscle tone, & equilibrium Cerebellum:

36.  Controls vital life processes such as: RespirationRespiration SwallowingSwallowing DigestionDigestion Heart rateHeart rate Blood pressureBlood pressure Brain Stem:

37.  Emotions & instincts  Controls body temperature, thirst, hunger, hostility, & pain Hypothalamus: