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THE NERVOUS SYSTEM

Learn about natural aging impacts on the nervous system, including cell degeneration, memory changes, and vision/hearing alterations. Explore the neuron and divisions of the nervous system at different levels. Gain insights into nervous impulses and neurotransmitters.

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THE NERVOUS SYSTEM

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  1. THE NERVOUS SYSTEM THE BRAIN, SPINAL CORD AND NERVES ARE PART OF THE NERVOUS SYSTEM

  2. NERVOUS SYSTEM NEUROLOGICAL NEURO

  3. Natural Aging Changes in the Nervous System • Brain cells degenerate • Nervous impulses • Responses/reflexes • Changes in sleep patterns • Memory changes • Changes in vision/hearing

  4. Learning the Nervous System:5 Levels Handout • Cell level (Neuron) • Central Nervous System (CNS) • Peripheral Nervous System (PNS) • Autonomic Nervous System (ANS • Somatomotor Nervous System

  5. DIVISIONS OF THE NERVOUS SYSTEM FOUR MAIN DIVISIONS OF NERVOUS SYSTEM • 1. CENTRAL NERVOUS SYSTEM; CONSISTS OF THE BRAIN AND SPINAL CORD • 2. PERIPHERAL NERVOUS SYSTEM; MADE UP OF ALL NERVES IN PERIPHERY

  6. DIVISIONS OF NERVOUS SYSTEM • AUTONOMIC NERVOUS SYSTEM- Having to do with involuntary smooth muscle controL 4. SOMATOMOTOR NERVOUS SYSTEM-Voluntary control, innervate skeletal muscle tissue

  7. NEURON • IT IS ALSO CALLED THE NERVE CELL • PARTS OF A NEURON: A CELL BODY, A NUCLEUS INSIDE THE CELL BODY, AND NERVE FIBERS • WE HAVE OVER 100 BILLION NEURONS

  8. NERVE FIBERS • DENDRITES CARRY IMPULSES TOWARD THE CELL BODY AS THEY RECEIVE MESSAGES FROM SENSORY ORGANS • AXONS ARE SINGLE NERVE FIBERS THAT CARRY IMPULSES AWAY FROM THE CELL BODY OFTEN TO MUSCLES • MANY AXONS ARE COVERED WITH A FATTY COVERING CALLED A MYELIN SHEATH

  9. THE MYELIN SHEATH INCREASES THE RATE OF TRANSMISSION OF AN IMPULSE AND INSULATES AND MAINTAINS THE AXON IN THE NERVE FIBERS OF THE PERIPHERY

  10. NERVE FIBERS • DENDRITES TEND TO BE SHORT AND HAVE MANY BRANCHES WHILE AXONS ARE LONGER AND BRANCH LESS. THE SPACE BETWEEN THE AXON OF 1 CELL AND THE DENDRITES OF ANOTHER IS CALLED A SYNAPSE.

  11. NERVE IMPULSES (Handout) Neurons are excitable. When stimulated, they undergo chemical changes that produce tiny traveling waves of electricity called impulses. These pass to other neurons, initiating similar responses from them. These impulses are all over the body, about 100 millivolts in strength and lasting just 1 millisecond! These impulses “jump” from 1 neuron to another at the synapse. When the electrical impulse arrives at the synapse, it triggers the release of chemicals called neurotransmitters.

  12. NERVE IMPULSES (Handout) NEUROTRANSMITTERS CROSS THE INCREDIBLY THIN SPACE BETWEEN THE SENDING AND RECEIVING NEURON (SYNAPSE). THEY EITHER TRIGGER A NEW IMPULSE OR ACTIVELY INHIBIT IT FROM FIRING. IF THE CHEMICALS ARE NOT PRODUCED IN THE RIGHT AMOUNTS, THE MESSAGE PATHWAY BECOMES “CONFUSED” OR BLOCKED.

  13. Video

  14. NERVES • COMBINATION OF MANY NERVE FIBERS • LOCATED OUTSIDE THE BRAIN AND SPINAL CORD

  15. AFFERENT OR SENSORY NERVES CARRY MESSAGES FROM ALL PARTS OF THE BODY TO THE BRAIN AND SPINAL CORD • EFFERENT OR MOTOR NERVES CARRY MESSAGES FROM THE BRAIN AND SPINAL CORD TO MUSCLES AND GLANDS “SAME” = Sensory Afferent, Motor Efferent

  16. CENTRAL NERVOUS SYSTEM: BRAIN AND SPINAL CORD

  17. BRAIN • SURROUNDED BY BONE • PROTECTED BY MEMBRANE CALLED MENINGES • CUSHIONED BY CEREBRAL SPINAL FLUID (CSF)

  18. CEREBRUM • LARGEST SECTION OF THE BRAIN • FORMED IN FOLDS • 2 HEMISPHERES (R/L)? • 4 LOBES • RESPONSIBLE FOR REASONING, THOUGHT, MEMORY, SPEAKING, MOVEMENT, EMOTIONS, • INTELLIGENCE

  19. CEREBRUM • The outer portion of the cerebrum is called the CEREBRAL CORTEX. This area is mostly composed of cell bodies and appears gray. • The inner portion is composed of axons and dendrites and appears white. • Each of the 4 lobes has certain activities they are responsible for.

  20. The Frontal Lobe • The Frontal Lobe is responsible for: • motor functions • language • Impulse control • Social behavior

  21. The Parietal Lobe • The Parietal Lobe is responsible for: • Sensory functions • Spatial awareness • Pain • Math

  22. The Temporal Lobe • The Temporal Lobe is responsible for: • Personality changes • Emotions • Memory • Hearing • Alzheimer’s Disease affects this lobe

  23. The Occipital Lobe • The Occipital Lobe is responsible for: • Visual perception • Interprets what you see

  24. Next section of the brain……..CEREBELLUM • SECTION BELOW THE BACK OF THE CEREBRUM • RESPONSIBLE FOR: • COORDINATION OF MUSCLES • BALANCE AND POSTURE • EQUILIBRIUM

  25. Next section of the brain…….DIENCEPHALON • Between cerebral hemispheres/deep deep inside brain • Includes: 1. Thalamus- processing center, initiates movement, sorts information 2. Hypothalamus- controls pituitary gland, regulates body temperature, water balance in body 3. Epithalamus- Pineal gland/Secretes melatonin for sleep/wake cycle

  26. Next section of the brain……….BRAINSTEM INVOLUNTARY MOVEMENTS OF VITAL CENTERS (HEART RATE, BLOOD PRESSURE, RESPIRATORY RATE_ 1. Midbrain- visual/auditory reflexes 2. Pons- respiratory center 3. Medulla Oblongata- connects to the spinal cord, control center for respiratory rate, blood vessels,swallowing, heart rate

  27. SPINAL CORD • CONTINUES DOWN FROM THE MEDULLA OBLONGATA • ENDS AT THE FIRST OR SECOND LUMBAR VERTEBRAE (17”LONG AND ¾”THICK

  28. SPINAL CORD • Protected by vertebral bone structure, CSF, and meninges: 1. Dura Mater- outer 2. Arachnoid Mater- middle, mostly CSF 3. Pia Mater- inner membrane/vascular

  29. The Spinal Cord • CARRIES SENSORY (AFFERENT) MESSAGES UP TO THE BRAIN • CARRIES MOTOR (EFFERENT) MESSAGES FROM THE BRAIN TO THE NERVES, WHICH GO TO MUSCLES AND GLANDS • Nerves innervateor go into organs and muscles from spinal cord

  30. PERIPHERAL NERVOUS SYSTEM • CONNECTS CNS TO “PERIPHERY” • CONSISTS OF CRANIAL NERVES AND SPINAL NERVES • AFFERENT AND EFFERENT NERVES

  31. CRANIAL NERVES • 12 cranial nerves that arise from the brain

  32. SPINAL NERVES • THIRTY-ONE PAIRS AND THEIR BRANCHES • CARRY MESSAGES TO AND FROM THE SPINAL CORD • BOTH SENSORY(AFFERENT) AND MOTOR NERVES(EFFERENT), OR MIXED NERVES

  33. DISORDERS OF PNS • Neuralgia- nerve pain • Bell’s Palsy- Cranial Nerve VII is damaged causing facial paralysis • Sciatica- pain from Sciatic Nerve in buttocks • Polio- CNS infection with PNS results (atrophy from damage to motor neurons) • Myasthenia Gravis- muscular weakness caused by degeneration of nerve/muscle junction. Lack of neurotransmitter acetylcholine

  34. AUTONOMIC NERVOUS SYSTEM • The nerves INNERVATE the organs. Under Involuntary control.

  35. AUTONOMIC NERVOUS SYSTEM • HELPS MAINTAIN A BALANCE IN THE INVOLUNTARY FUNCTIONS OF THE BODY, BUT ALLOWS THE BODY TO REACT IN TIMES OF EMERGENCY • TWO DIVISIONS: SYMPATHETIC AND PARASYMPATHETIC

  36. SYMPATHETIC NERVOUS SYSTEM • ACTS IN TIMES OF EMERGENCY SUCH AS FIGHT OR FLIGHT • PREPARES THE BODY TO ACT • INCREASES HEART RATE AND RESPIRATION • RAISES BLOOD PRESSURE • SLOWS ACTIVITY IN THE DIGESTIVE TRACT

  37. PARASYMPATHETIC NERVOUS SYSTEM • COUNTERACTS THE ACTIONS OF THE SYMPATHETIC AFTER THE EMERGENCY • SLOWS THE HEART RATE AND RESPIRATION • LOWERS THE BLOOD PRESSURE • INCREASES THE ACTIVITY IN THE DIGESTIVE TRACT

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