The Nervous System

1. The Nervous System

2. Overview • The Nervous System controls and coordinates all the functions of the body. • The Nervous System consists of two main sub-divisions: • Central Nervous System (CNS) • Peripheral Nervous System (PNS) • The Peripheral Nervous System is divided into two sub-divisions: • Somatic- voluntary • Autonomic- involuntary

3. http://inside.salve.edu/walsh/cns_pns.jpg

4. Structure and Function of the Neuron • Neuron is the scientific name for a Nerve Cell. • Neurons consist of 3 basic structures: • Cyton, or cell body. • Dendrites- receive messages, impulses, and send them to the cell body. • Axons- send messages away from the cell body. • Nerve impulses travel from one neuron to another across synapses, or spaces in between the cells. • The “jumping across” the synapse is facilitated (helped) by chemicals called Neurotransmitters.

5. Dendrites– Branched parts of a neuron that receive impulses from other neurons. Cyton- Contains cytoplasm and the nucleus. Impulses pass through here to the axon. Axon- Single long fiber that carries impulses away from the cell body. A Neuron Parts of the Cell

8. Myelin coating signal direction • Axon coated with insulation made of myelin cells • speeds signal • signal hops from node to node • 330 mph vs. 11 mph myelincoating • Multiple Sclerosis • immune system (T cells) attacks myelin coating • loss of signal

9. Synapse Junction between nerve cells • 1st cell releases chemical to trigger next cell • where drugs affect nervous system synapse

10. Types of Neurons Neurons can also be classified by the direction that they send information: ･Sensory (or afferent) neurons: send information from sensory receptors (e.g., in skin, eyes, nose, tongue, ears) TOWARD the central nervous system. ･Motor (or efferent) neurons: send information AWAY from the central nervous system to muscles or glands. ･Interneurons: send information BETWEEN sensory neurons and motor neurons. Most interneurons are located in the central nervous system.

11. Reflexes • Stimulus- a change in the environment. • Response/Reaction- how the body reacts to a stimulus. • ReflexArc- the pathway that an impulse follows to illicit a response to a stimulus.

12. Central Nervous System • Brain • Spinal cord

13. Protections Skull and Vertebrae 3protective layers called meninges Dura Mater (outer layer): consists of connective tissues, blood vessels, and nerves. Arachnoid Layer (middle layer): elastic and weblike Pia Mater (inner layer): contains nerves and blood vessels. Cerebrospinal fluid a clear watery liquid separates the middle and inner layers Acts as shock absorber exchange of nutrients between blood and nervous system

14. The Brain • Coordinates body activities • Made up of approximately 100 billion neurons • Uses 20% of bodies oxygen and energy • Divided into three major parts- • the Cerebrum • the Cerebellum • the Brain Stem (Medulla Oblongata, Pons)

15. Cerebrum • Largest part of the brain • Thinking • Memory is stored • Movements are controlled • Impulses from the senses are interpreted.

16. Cerebrum specialization • Regions specialized for different functions • Lobes • frontal • speech, control of emotions • temporal • smell, hearing • occipital • vision • parietal • speech, tastereading parietal frontal occipital temporal

17. Gray Matter vs. White Matter Gray Matter – Absence of myelin in masses of neurons accounts for the gray matter of the brain – Cerebral Cortex White Matter - Myelinated neurons gives neurons a white appearance – inner layer of cerebrum 1. Grey matter is made up of nerve cell bodies, and white matter is made up of fibers.2. Unlike the white matter, the neurons of grey matter do not have extended axons.3. Grey matter occupies 40 percent of the brain, while white matter fills 60 percent of the brain.4. Grey matter has a grey color because of the grey nuclei that comprises the cells. Myelin is responsible for the white appearance of the white matter.5. Processing is concluded in the grey matter, while white matter allows communication to and from grey matter areas, and between the grey matter and the other parts of the body.6. Grey matter has no myelin sheath, while white matter is myelinated.

19. Responsible for the coordination of muscles and is the center of balance Cerebellum

22. Center of heart beat, respiration, and other involuntary actions Medulla

23. Other Structures inside the Brain Thalamus– receives messages from sensory receptors; relays information to proper regions of cerebrum Hypothalamus - Regulates hunger, thirst, fatigue, anger, etc… Control of pituitary for endocrine function

24. Cerebrum Thalamus Pineal gland Hypothalamus Cerebellum Pituitary gland Pons Medulla oblongata Spinal cord Section 35-3

25. The Spinal Cord • Extension of the brain stem • Bundles of neurons that carry impulses from all parts of the body to the brain and from the brain to all parts of your body

26. The Peripheral Nervous System Your brain and spinal cord are connected to the rest of your body by the peripheral nervous system. The PNS is made up of 12 pairs of nerves from your brain called cranial nerves, and 31 pairs from your spinal cord called spinal nerves. Spinal nerves are made up of bundles of sensory and motor neurons bound together by connective tissue. For this reason, a single spinal nerve can have impulses going to and from the brain at the same time. Some nerves contain only sensory neurons, and some contain only motor neurons, but most nerves contain both types of neurons. Somatic and Autonomic Systems The peripheral nervous system has two major divisions. The somatic system controls voluntary actions. It is made up of the cranial and spinal nerves that go from the central nervous system to your skeletal muscles. The autonomic system controls involuntary actions-those not under conscious control-such as your heart rate, breathing, digestion, and glandular functions. These two divisions, along with the central nervous system, make up your body's nervous system. Research Visit the Glencoe Science Web site at tx.science.glencoe.com for more information about the nervous system. Make a brochure outlining recent medical advances.

27. Peripheral Nervous System • Connects body to brain & spinal cord • 12 pairs of nerves from your brain (cranial nerves) • 31 pairs from your spinal cord (spinal nerves) • Bundles of sensory and motor neurons held together by connective tissue • Two divisions • Somatic • Autonomic

28. http://www.christopherreeve.org/Research/Research.cfm?ID=178&c=21http://www.christopherreeve.org/Research/Research.cfm?ID=178&c=21

29. Divisions of the PNS: Somatic Nervous System • Controls voluntary actions • Made up of the cranial and spinal nerves that go from the central nervous system to your skeletal muscles Autonomic Nervous System • Controls involuntary actions-those not under conscious control-such as your heart rate, breathing, digestion, and glandular functions

30. Drugs and the Nervous System Drug – any substance, other than food that changes the structure or function of the body Legal Illegal

31. Commonly Abused Drugs Section 35-5 Used to increase alertness, relieve fatigue Used to relieve anxiety, irritability, tension Used to relieve pain Stimulants Depressants Opiates Amphetamines Barbiturates Tranquilizers Morphine Codeine Increase heart and respiratory rates; elevate blood pressure; dilate pupils; decrease appetite Slow down the actions of the central nervous system; small amounts cause calmness and relaxation; larger amounts cause slurred speech and impaired judgement Act as a depressant; cause drowsiness, restlessness, nausea Drug Type Medical Use Examples Effects on the body

32. 1. Stimulants Increase Heart rate Blood pressure Breathing Release of neurotransmitters at some synapses in the brain Deplete neurotransmitters and lead to: Fatigue Circulatory problems Hallucinations Depression

33. 2. Depressants Decrease Heart rate Breathing rate Blood pressure Relax muscles Relieve tension Enhances release of neurotransmitters that prevent nerves cells from firing Alcohol with depressants can lead to death – depresses CNS to a point one stops breathing

34. 3. Opiates Mimics endorphins Endorphin – natural chemical in brain that helps overcome pain When person stops taking Brain has adjusted to high levels of endorphins Cannot produce enough natural endorphins Suffer uncontrollable pain and sickness

35. 4. Cocaine Sudden release of Dopamine Powerful Stimulant Increases heart rate and blood pressure First time users can have heart attack Dopamine – neurotransmitter in brain that is released to give feeling of pleasure and satisfaction

36. 5. Marijuana Active ingredient (THC) tetrahydrocannabinol More destructive to lungs than cigarettes 5 marijuana cigs = 120 conventional cigs Results in: Lower WBC count by 40% - susceptible to infections Teens – inhibits maturity Retards normal brain growth Memory loss Inability to concentrate Fall short on memory as well as math and verbal skills Males – reduced testosterone levels and increases estrogen levels Females – disturbs menstrual cycle DNA damage to eggs

37. More Effects (FYI) Impaired perception Loss of coordination Increased risk of accidents Impaired judgement Loss of motivation Diminished inhibitions Increased heart rate Anxiety, panic attacks, and paranoia Hallucinations Damage to the respiratory, reproductive, and immune systems Increased risk of CANCER Psychological dependency

38. 6. Alcohol Depressant Slows down CNS 40% of 50,000 highway deaths are caused by drinking and driving 1/3 of homocides attributed to effects of alcohol $150 billion dollars of U.S. economy alcohol abuse treatment Fetal Alcohol Syndrome (FAS) Drinking while pregnant Heart defects, malformed faces, delayed growth, poor motor development

39. Alcohol and Disease Long-term alcohol use or bouts of excessive consumption Destroys liver cells Cirrhosis of liver – formation of scar tissue that prevents blood flow through liver

40. Drug Abuse Intentional misuse of any drug for nonmedical purposes Addiction – uncontrollable dependence on a drug

41. Only Way to Prevent Addiction and Effects of Drugs NOT taking them to begin with

42. Famous People that have Died of Drug Overdoses • Michael Jackson Andy Gibb • Britany Murphy David Ruffin • Elvis Presley Heath Leger • Jim Morrison John Belushi • Janis Joplin River Phoenix • Chris Farley • Freddy Prinze • Judy Garland • Brad Renfro • Dana Plato • Kurt Cobain • Anna Nicole Smith • Ike Turner • Brandon and Bruce Lee

43. Diseases, Conditions, and Syndromes of the Nervous System

44. Parkinson’s Disease • Parkinson's disease affects the way you move. It happens when there is a problem with certain nerve cells in the brain. • Normally, these nerve cells make an important chemical called dopamine. Dopamine sends signals to the part of your brain that controls movement. It lets your muscles move smoothly and do what you want them to do. When you have Parkinson’s, these nerve cells break down. Then you no longer have enough dopamine, and you have trouble moving the way you want to. • Parkinson’s is progressive, which means it gets worse over time. But usually this happens slowly, over a period of many years.

45. Parkinson’s Disease The four main symptoms of Parkinson’s are: • Tremor, which means shaking or trembling. Tremor may affect your hands, arms, or legs. • Stiff muscles. • Slow movement. • Problems with balance or walking.

46. Occurs when there is not enough oxygen going to the brain. http://www.hulu.com/watch/18352 9 Stroke

47. Autism • Overview • Autism is a developmental disorder that appears in the first 3 years of life, and affects the brain's normal development of social and communication skills. • Symptoms • Most parents of autistic children suspect that something is wrong by the time the child is 18 months old and seek help by the time the child is age 2. Children with autism typically have difficulties in: • Pretend play • Social interactions • Verbal and nonverbal communication • Some children with autism appear normal before age 1 or 2 and then suddenly "regress" and lose language or social skills they had previously gained. This is called the regressive type of autism. • People with autism may: • Be overly sensitive in sight, hearing, touch, smell, or taste (for example, they may refuse to wear "itchy" clothes and become distressed if they are forced to wear the clothes) • Have unusual distress when routines are changed • Perform repeated body movements • Show unusual attachments to objects

48. A seizure is: A sudden, brief disruption of the normal functioning of neurons in the brain

49. A seizure may appear as: A sudden cry and fall, followed by • Convulsive movements of all limbs • Shallow/interrupted breathing - cyanosis • Loss of bowel/bladder control • Slow return to consciousness, post-seizure confusion and/or fatigue This is a generalized tonic-clonic or “grand mal” seizure.

50. or a seizure may be… • Blank staring, chewing, other repetitive purposeless movements • Wandering, confusion, incoherent speech • Crying, screaming, running, flailing • A sudden loss of muscle tone and fall • Picking at clothes, disrobing This is one type of partial seizure known as a complex partial seizure.