Your Nervous System Central Nervous System

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Explain CNS Relays messages Relays messages Processes information Processes information Analyzes information Analyzes information

Parts of CNS 1. The Spinal Cord 2. The Brain

Protections Skull and Vertebrae Skull and Vertebrae 3 protective layers called meninges 3 protective layers called meninges 1. Dura Mater (outer layer): consists of connective tissues, blood vessels, and nerves. 2. Arachnoid Layer (middle layer): elastic and weblike 3. Pia Mater (inner layer): contains nerves and blood vessels. 4. Cerebrospinal fluid a clear watery liquid a clear watery liquid separates the middle and inner layers separates the middle and inner layers Acts as shock absorber Acts as shock absorber exchange of nutrients between blood and nervous system exchange of nutrients between blood and nervous system

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

The Brain The Brain The brain is the control center of the body The brain is the control center of the body It is about 2% of your body weight and uses 20% of your body’s oxygen It is about 2% of your body weight and uses 20% of your body’s oxygen

Parts of the Brain Divided into three parts Divided into three parts Cerebrum Cerebrum Cerebellum Cerebellum Brain Stem Brain Stem

Cerebrum 1. Largest part of the brain – Learning and Senses 2 hemispheres- Right and Left 2 hemispheres- Right and Left Connected by the Corpus Callosum Connected by the Corpus Callosum Right side controls- left side Right side controls- left side Left side controls – right side of body Left side controls – right side of body Four sections - LOBES Four sections - LOBES 1. Frontal Lobe 2. Parietal Lobe 3. Occipital Lobe 4.Temporal Lobe 3. Occipital Lobe 4.Temporal Lobe

Gray Matter vs. White Matter Gray Matter – Absence of myelin in masses of neurons accounts for the gray matter of the brain – Cerebral Cortex 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 White Matter - Myelinated neurons gives neurons a white appearance – inner layer of cerebrum

Cerebellum Second largest Second largest located below the cerebrum at back of skull located below the cerebrum at back of skull This part is responsible for the balance and muscle coordination This part is responsible for the balance and muscle coordination

Brain Stem Connects the brain to spinal cord Connects the brain to spinal cord The Two Regions act as “switchboard” The Two Regions act as “switchboard” Medulla Oblongata – Controls heart rate, breathing rate, and flow of blood through the blood vessels. Medulla Oblongata – Controls heart rate, breathing rate, and flow of blood through the blood vessels. Pons – Relays signals between the cerebrum and the cerebellum Pons – Relays signals between the cerebrum and the cerebellum

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

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

Spinal nerve Central canalGray matter White matter Meninges Section 35-3 Cross Section of the Spinal Cord

Spinal Cord Link between brain and rest of body (PNS) Link between brain and rest of body (PNS) 31 pairs of spinal nerves 31 pairs of spinal nerves Reflexes processed directly by spinal cord Reflexes processed directly by spinal cord Reflex – quick, automatic, unconscious responses Reflex – quick, automatic, unconscious responses Result of reflex arcs – shortest nerve pathways Result of reflex arcs – shortest nerve pathways

Elaboration Nicotine in the Body and Brain Nicotine in the Body and Brain

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

Drugs That Affect the Synapse

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 Section 35-5 Commonly Abused Drugs Drug TypeMedical UseExamplesEffects on the body

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

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

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

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

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

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

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

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

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

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