The Nervous System

Types Central Nervous System (CNS)Peripheral Nervous System (PNS)

Diagram

Types of Neurons Sensory neuron - nerve cells that carries impulses from a sense receptor to the brain or spinal cord. Relay neuron- The nerve cell that connects sensory and motor neurons Motor neuron- The nerve cell that transmits impulses from the brain or spinal cord to a muscle or gland Neuron video (start at 1:10) Neurotransmission-

Central Nervous System (CNS) Consists of brain and spinal cord Major parts of the brain are: Forebrain Midbrain hindbrain Forebrain – contains the thalamus and hypothalamus, as well as the cerebrum, which is the largest part of brain Fxns: receiving and processing sensory information, thinking, perceiving, producing and understanding language, and controlling motor function

CNS Cont. Midbrain – with the hindbrain, they make up the brainstem. Midbrain connects the hindbrain and forebrain through the brainstem Fxns in auditory and visual response, and motor function Hindbrain – extends from spinal cord. It contains the pons and cerebellum Fxns: maintain balance, movement coordination, and involved in senses information Spinal cord – transmits messages from the brain to areas of the body and vice versa. The nerves of the spinal cord are grouped into bundles, creating nerve fibers

Peripheral Nervous System (PNS ) PNS mainly connects CNS and environmental stimuli to allow body to respond properly. PNS divided into 2 systems: Somatic Nervous System: governs voluntary actions and body reflexes Autonomic Nervous System: regulates involuntary actions such as breathing and digestion

Somatic Nervous System Controls all voluntary movements Consists of 3 parts: Spinal Nerves: Peripheral nerves that carry sensory information into spinal cord and motor commands Cranial Nerves: Nerve fibers that carry information from and to the brainstem. The information carried are related to smell, taste, vision, eye muscles, ears, etc Association Nerves: integrate sensory input and motor output

Autonomic Nervous System (ANS ) Functions as a control system, mostly below the level of consciousness Controls heart rate, digestion, respiratory rate, pupil dilation, perspiration, and sexual arousal ANS is divided into 2 systems: Parasympathetic Nervous System Sympathetic Nervous System

“Fight-or-Flight” System Main function is to prepare your body in emergencies and helps you in stressful situations A person in a fight-or-flight mode may have increased blood pressure, breathing rate, and heart rate, dilated pupils, run faster, and have an adrenaline rush

Parasympathetic Nervous System “Rest-and-digest” System Its major function is to keep the body in its normal state by helping the body breath regularly, excrete hormones, and eat and digest food.

Diseases Multiple Sclerosis Huntington’s Disease Aphasia Amyotrophic Lateral Sclerosis (ALS)

Multiple Sclerosis Chronic inflammation disease of CNS where the body’s immune system eats myelin sheath Myelin sheath, protective cover of nerve fibers, is lost and as a result, communication between brain, spinal cord, and rest of the body is interrupted Damaged myelin = travelling impulses is slowed or blocked Causes: viruses, environmental factors, genetic factors, autoimmune disorders

Multiple Sclerosis Cont. Symptoms: Loss of vision Weakness in limbs Fatigue Slurred speech Electric shock sensations from certain head movements Treatments: To slow progress: Beta interferon, type of drugs that reduces number and severity of attacks To treat symptoms: physical therapy, muscle relaxants, and medication to reduce fatigue

Inherited disorder affecting people mostly in their 40’s and 50’s Affects spinal cord and brain, where abnormal cells are found Huntington is formed from an abnormal gene which prevents brain cells from protecting themselves against toxic chemicals. This worsens when the amount of neurotransmitters in the brain decrease Huntington’s Disease

Huntington’s Disease Cont. Symptoms: uncontrollable jerky movements rapid eye movements memory problems change in mood Death occurs 15 – 20 yrs after first symptoms No cure Medicine for treating symptoms: Depression: Tricyclic antidepressants Movement disorders: drugs that also treat parkinsonism and dystonia Antisocial behavior: drugs such as Chlorpromazine

Aphasia Neurological disorder due to damage on language parts of the brain from usually a stroke or brain damage Inability to speak and/or understand written and spoken language Affects mostly adults and those who experienced stroke Causes : usually stroke brain injury brain tumor symptom of epilepsy

Aphasia Cont. During stroke, the most common cause, brain tissues are damaged due to lack of oxygen and blood to the brain Treatment: Language therapy Rehabilitation with speech pathologist Patient practices how to read, write, follow directions, and repeat what they hear EQ6ew

Amyotrophic Lateral Sclerosis (ALS) “Lou Gehrig’s Disease” A-myo-trophic: No muscle nourishment Motor neurons from the brain and spinal cord that connect to muscles are affected Degeneration of motor neurons leads to their death. As a result, control of muscle movement is lost Degenerated motor neurons cannot send impulses to muscle fibers. Therefore, muscles do not receive nourishment and begins to atrophy as a result Effect: Paralyzed in later stages

ALS Cont. Symptoms: –Muscle weakness in arms, legs, muscles used in talking, breathing, swallowing –Difficulty breathing and swallowing –Muscle cramping Currently no cure or treatment (death usually occurs 3-5 years after diagnosis) Certain drugs, such as riluzole, slows ALS progression

Links nVkA- Crash course- nervous systemhttps:// nVkA- system.htmlhttp:// system.html

Works Cited ans/introduction-to-autonomic-nervous-system/somatic-compared-to-autonomic- nervous-system/ ans/introduction-to-autonomic-nervous-system/somatic-compared-to-autonomic- nervous-system/ system/the-peripheral-nervous-system-pns/ system/the-peripheral-nervous-system-pns/ html?cat=4http://voices.yahoo.com/major-functions-sympathetic-parasympathetic html?cat=4 peripheral_nervous_system.shtmlhttp:// peripheral_nervous_system.shtml sclerosis/basics/definition/con http:// sclerosis/basics/definition/con