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Nervous System

Nervous System. A major control and communication system. Neuron. “neur-” means nerve, so a neuron is a nerve cell Cell body is the part where the organelles, such as the nucleus, are located Dendrite is the receiving end of the neuron Axon is the transmitting or conducting end of the neuron.

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Nervous System

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  1. Nervous System A major control and communication system

  2. Neuron • “neur-” means nerve, so a neuron is a nerve cell • Cell body is the part where the organelles, such as the nucleus, are located • Dendrite is the receiving end of the neuron • Axon is the transmitting or conducting end of the neuron

  3. Nerve • A group of neurons (specifically their axons) that are bundled together anywhere except the brain/spinal cord, is termed a nerve

  4. Nerve impulse • A nerve impulse is an electrical message traveling along a neuron.

  5. Synapse • A junction between adjacent neurons • Neurotransmitters are chemicals carrying nerve message across the synapse

  6. Myelin • Some neurons have their axons coated in a fatty substance called myelin. • Myelin increases the speed of nerve impulse transmission – as high as 200 mph • White matter

  7. Central Nervous System • Brain • Spinal Cord • Control, information processing • Thoughts are formed • Memory is stored

  8. Peripheral Nervous System • Carries messages to and from the CNS • Sensory – carries information towards the CNS • Motor – carries information away from the CNS to the muscles and glands

  9. PNS • Somatic motor information travels to skeletal muscles • Autonomic motor information travels to cardiac muscle, smooth muscle and glands; responsible for your Fight or Flight response

  10. Brain • “enceph-” means brain • Located in skull • Medulla oblongata is part of the brainstem and controls important reflexes that control breathing, heart rate and blood pressure. Also is the site where motor and sensory pathways cross.

  11. Brain • Hypothalamus is a center of homeostasis mechanisms such as hunger, thirst, water balance, temperature regulation; makes hormones, and controls the Autonomic Nervous System.

  12. Brain • Thalamus is a sensory relay center

  13. Brain • Cerebrum is the largest and highest center of the brain • Responsible for conscious awareness, thinking, intelligence, memory and deciding your response to sensory input.

  14. Brain • Electroencephalogram, or EEG, is a recording of the brain’s electrical activity, commonly called brain waves.

  15. Spinal cord • “myel-” means spinal cord • Located within your vertebrae • Sends sensory messages to your brain • Carries motor messages away from your brain

  16. Spinal Reflexes • A reflex is an autonomic, quick response to a stimulus. The reflex is repeatable. • Spinal reflexes involve the spinal cord and do not involve conscious thought from the brain.

  17. CNS Meninges • Meninges are tough, protective membranes that surround the brain and spinal cord. • Within the meninges is Cerebrospinal Fluid (CSF) that cushions and provides nourishment for the CNS • What is meningitis?

  18. Nervous System Pathology • Brain damage • The brain requires oxygen for aerobic metabolism. Lack of oxygen for more than 5 minutes can kill brain cells. • The brain requires glucose for metabolism. Lack of glucose for more than 15 minutes kills brain cells. • Neurons cannot undergo mitosis.

  19. Epilepsy • Brain fires abnormal signals that travel to skeletal muscles. • Skeletal muscles contract leading to seizures. • May lose consciousness in larger seizures • Causes are injury, infection, genetic predisposition, and many causes are unknown

  20. Epilepsy • Treatments include correcting the cause, if known; • Decreasing the frequency and magnitude of the seizures with medications.

  21. Multiple Sclerosis • Many “hard” scars form along the myelin sheaths of neurons • Autoimmune disease • Numerous short circuits occur resulting in difficulty in vision, memory, walking and judgment • Chronic disease that progresses slowly

  22. Cerebral Palsy • Motor centers are damaged at the time of birth • Causes include German Measles, radiation exposure, oxygen starvation to the baby’s brain at the time of delivery • Results in varying degrees of impairment of motor abilities.

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