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The NERVOUS System

The NERVOUS System. Functions of theNervous System. Sensory Integrative Motor. Divisions of the Nervous System. Nervous System Schematic. Brain. Name of nerves going out of the brain. Name of nerves going into the brain.

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The NERVOUS System

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  1. The NERVOUS System

  2. Functions of theNervous System • Sensory • Integrative • Motor

  3. Divisions of the Nervous System

  4. Nervous System Schematic Brain Name of nervesgoing out of the brain Name of nervesgoing into the brain Voluntary Nervous System-Nerves that control skeletal muscleAutonomic Nervous System-Nerves that control smoothmuscle contraction, cardiacmuscle and glandular secretions Somatic Afferent Nerves– Ifnerve comes from skin,skeletal muscles or jointsVisceral Afferent Nerves- Ifnerve comes from body organs

  5. Neurons and Neuroglial Cells • Nerve- Transmit the impulse • Neuroglial Cells- Supports the nerve

  6. Parts of A Neuron • Cell Body (Soma or Perikaryon) • nucleus, cytoplasm, organelles of a neuron • Dendrites - tapered, highly branched processes protruding from the cell body • usually very short • AFFERENT FUNCTION • Axons - long, thin, cylindrical process • usually myelinated • EFFERENT FUNCTION

  7. Neuroglia • Nervous system cells that support, nurture and protect the neurons • Types of Neuroglia found in the CNS • Astrocytes • Oligodendrocytes • Microglia • Ependymal Cells • Types of Neuroglia found in the PNS • Neurolemmocytes (Schwann Cells)

  8. Astrocytes • Largest and most numerous • CNS • Help form the blood brain barrier • Help neuron receive nutritionfrom capillaries • Forms scar tissue in the brain • Most tumors of the brain arisefrom the astrocyte

  9. Oligodendrocytes • CNS • Form myelin to increasespeed of nerve impulse

  10. Microglia • CNS • Phagocytic cells that protect the central nervous system by engulfing and invading microbes • Clears away debris from dead cells

  11. Ependymal Cells • CNS • Helps form and circulate cerebral spinal fluid

  12. Neuroglia of the PNSSchwann Cells • Schwann Cells • PNS • Producing the myelin sheaths around the PNS neurons

  13. Neuron Action Potential Steps:1. Stimuli2. Na+/K+ channels open3. Na+ rushes in4. -55 mv- depolarization5. +30 mv- repolarization (K+ diffuses out of nerve cell6. -80 mv- hyperpolarization7. -70 mv resting membrane

  14. What is the brain made up of? Gray and White Matter • White Matter - the aggregation of myelinated processes from many neurons • Gray Matter - unmyelinated nerve found in the CNS

  15. Protection and Coverings of the Brain- Meninges • Protected by the cranial bones and the cranial meninges • Dura Mater - outer layer- “tough mother” • Arachnoid - middle layer “spider mother” • Pia Mater - inner layer “soft mother” • Also protected by cerebrospinal fluid

  16. Some nerves don’t travel to the brain- The Reflex Arc Rapid, unconscious andinvoluntary responses to stimuli1. Sensory receptor2. Sensory (afferent neuron)3. interneuron (spinal column)4. motor (efferent neuron)5. effector

  17. The BRAIN

  18. The BRAIN • One of the largest organs in the body • Controls all mental functions • Component of the CNS • Composed of over 100 billion neurons • Comprises 2-3% of body weight • Utilizes over 20% of body’s energy

  19. Major Divisions of the BRAIN • CEREBRUM - occupies most of the cranium and is divided into right and left halves called hemispheres • CEREBELLUM - the posterior-inferior portion of the brain • BRAIN STEM - consists of the medulla oblongata, the pons, and the midbrain • it is continuous with the spinal cord • DIENCEPHALON - located above the brainstem, composed primarily of the: • Thalamus -Hypothalamus What are each of the sections of the brain responsible for?

  20. Flow of CSF Formed from the blood by the choroid plexus found in the lateral ventricles, third ventricles and fourth ventricles. It flows through the subarachnoid space and is absorbed by the arachnoidvilli. ArachnoidVilli Lateral Ventricles Third Ventricles Cerebral Aqueduct Fourth Ventricles Subarachnoid Space FORMATION OF CSF

  21. You Tube video called “cerebrospinal fluid Circulation found at http://www.youtube.com/watch?v=SDMO4vYkqdg&feature=related Cerebrospinal Fluid Circulation

  22. Other parts of the Brain“The Brain Stem” • The most inferior portion of the brain • Connects the brain to the spinal cord • Composed of Three Areas • The Medulla Oblongata • The Pons • The Midbrain

  23. The Medulla Oblongata • Relay Station for sensory and motor nerve impulses. • Regulates heart rate, blood pressure, breathing, swallowing, coughing, sneezing and vomiting.

  24. The Pons • Relay station for motor and sensory neurons. • Regulates the rate and depth of breathing.

  25. The Midbrain • Relay station for motor and sensory neurons. • Regulates the rate and depth of breathing.

  26. Other Parts of the Brain“The Diencephalon” • Area of the brain containing the: • Thalamus- Relay for sensory impulses except smell • Hypothalamus – Regulates body temperature,water balance andmetabolism. It also regulatesthirst, hunger, blood pressure, pleasure, sexdrive, and sleep/wakecycles. It produces ADHand oxytocin.

  27. Lobes of the Brain“The Cerebrum” • Largest division of the brain” • Occupies most of the cranium • Accounts for 85% of brain mass • Divided into right and left hemispheres • Longitudinal Fissure • Corpus Callosum • Cerebral cortex - the outer surface area of the cerebrum • Composed mainly of gray matter • Contains billions of neurons

  28. The Cerebrum

  29. Lobes of the Cerebrum • Named after the bones that cover them • Frontal Lobe Parietal Lobe • Temporal Lobe • Occipital Lobe Source: QuickMedical. (2010). It’s Not the Kids’ Fault: It’s their Brains’. Quickmedical.com. Retrieved on November 15, 2011from http://www.quickmedical.com/blog/post/its-not-the-kids-fault-Its-their-brains.html.

  30. Nervous System Disorders and Homeostatic Imbalances

  31. Amyotrophic Lateral Sclerosis (ALS) • Also known as Lou Gehrig’s Disease • A relatively rare neurological disorder • A syndrome marked by muscular weakness and atrophy with spasticity and hyperflexion due to degeneration of the motor neurons of the spinal cord, medulla, and cortex • A degenerative disease • No known cure

  32. Tony Judt on Living with ALSYou Tube Video found at http://www.youtube.com/watch?v=mgHZruV-WmQ&feature=related

  33. Alzheimer’s Disease (AD) • Disabling neurological disorder that effects about 11% of the population • Fourth leading cause of brain death among the elderly • A chronic, organic, mental disorder, a form of pre-senile dementia due to atrophy of neurons of the frontal and occipital lobes • AD patients usually die from complications due to being bedridden

  34. Alzheimer’s Disease You Tube Video found at http://www.youtube.com/watch?v=q1BkfV2h09g

  35. Bacterial Meningitis • Infection of the meninges by the bacterium Haemophilus Influenzae • Usually affects children under age 5 • Symptoms include severe headaches and fever • Can lead to brain damage and even death if not treated

  36. 6-Year-Old Dies of MeningitisYou Tube Video found at http://www.youtube.com/watch?v=LvIVUFXm3E0&feature=relmfu

  37. Cerebral Palsy (CP) • A group of motor disorders due to loss of muscle control • Caused by damage to the motor areas of the brain during fetal development, birth, or infancy • About 70% of CP individuals are somewhat mentally retarded due to the inability to hear well or speak fluently • Not a progressive disease but the symptoms are irreversible

  38. 11 year-old boy with cerebral palsy receiving his first wheelchair in IndiaYou Tube Video found at http://www.youtube.com/watch?v=3YZS-7nexiQ&feature=related

  39. Epilepsy • Short, recurrent, periodic, attacks of motor, sensory, or psychological malfunction • Characterized by seizures which can result in involuntary skeletal muscle contraction, loss of muscle control, inability to sense light, noise, and smell, and loss of consciousness • Most epileptic seizures are idiopathic

  40. Absence SeizureYou Tube Video found at http://www.youtube.com/watch?v=YAJ8A1IwI4s&feature=related

  41. Multiple Sclerosis (MS) • The progressive destruction of the myelin sheaths of neurons of the CNS • The sheaths deteriorates to scleroses • hardened scars or plaques • “short circuits” nerve transmission • Cause is unknown • May be a type of an autoimmune disease • No known cure • Progressive loss of function with intermittent periods of remission

  42. Understanding Multiple SclerosisYou Tube found at http://www.youtube.com/watch?v=y8JOL4utRlc&feature=related

  43. Parkinson’s Disease (PD) • A progressive disorder of the CNS that usually affects individuals over 60 • Cause is unknown but a toxic environmental factor is suspected • Chemical basis of the disease appears to be to little dopamine and too much Ach • Treatment includes increasing levels of dopamine and decreasing Ach • Difficult because dopamine does not cross the blood brain barrier

  44. Michael J Fox Parkinson’s DiseaseYou Tube Video found at http://www.youtube.com/watch?v=ECkPVTZlfP8

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