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The Nervous System. Two Components Central Nervous System Brain o Cerebrum  Frontal Lobe  Parietal Lobe  Temporal Lobe  Occipital Lobe o Cerebellum.

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Presentation on theme: "The Nervous System. Two Components Central Nervous System Brain o Cerebrum  Frontal Lobe  Parietal Lobe  Temporal Lobe  Occipital Lobe o Cerebellum."— Presentation transcript:

1 The Nervous System

2 Two Components Central Nervous System Brain o Cerebrum  Frontal Lobe  Parietal Lobe  Temporal Lobe  Occipital Lobe o Cerebellum o Medulla Spinal Cord Peripheral Nervous System Nerves o movement, senses, etc. Neurotransmitters

3 Cerebrum Divided into two hemispheres Majority of what is considered "brain" Made up of 4 lobes o Parietal Lobe o Temporal Lobe o Frontal Lobe o Occipital Lobe Major functions o Movement  Conscious movement

4 Cerebrum cont'd... o Senses  Processes information from body (smell, sight, feel, taste, sound) o Speech  Comprehension  Communication o Learning and Memory Made of nerve cells (grey matter) White nerve fibers connect signal from nerve cells and other parts of brain/ body

5 Cerebellum "little brain" Two hemispheres, folded to achieve more surface area regulation and coordination of voluntary movement posture balance

6 Medulla Lower portion of brainstem Controls involuntary movement o Heartbeat o Breathing o Swallowing o Vomiting o Defecation o Reflexes

7 Occipital Lobe Function: o Vision o Perception 532/occipita.htm\

8 Temporal Lobe Function: Sense of Hearing Aspects of Memory Emotional Behavior

9 Temporal Lobe Epilepsy (TLE) Two Types: o Mesial TLE o Lateral TLE Etiologies: o Relation with febrile seizures (seizures that result from increases in body temperature, common in infants whose temperature maintenance is immature) o Generally related to prolonged seizure Symptoms: o Simple Partial Seizures (SPS) o Complex Partial Seizures (CPS) o Secondarily Generalized Tonic-Clonic Seizures (SGTCS) Treatments o Medication  Phenytion, Carbamezepine, Calproate, and Phenobarbital Phenytion, Carbamezepine, Calproate, and Phenobarbital  Newer drugs, though, like gabapentin, topiramate,Levetiracetam andlamotrigine, promise similar efficacy with fewer side-effects. gabapentintopiramateLevetiracetamlamotrigineside-effects  Basically such medication functions by decreasing the excitation of neurons or by enhancing their inhibitionneurons o Excision Surgery

10 Frontal Lobe Functions Motor activity Speech Reasoning Emotions Problem Solving Spontaneity Memory Language Initiation Judgment Impulse Control Social Behavior Sexual Behavior

11 Frontal Lobe Fun Facts Very vulnerable to injury and the most common region of injury due to location and size Reaches full maturity around age 25 Frontal Lobe damage can result in... o Little spontaneous facial expression o Difficulty speaking o Increase or decrease in socialization o Dramatic decrease in creativity and problem solving skills o Mental flexibility and spontaneity impairment

12 Parietal Lobe Functions Processes information about o Touch o Taste o Pressure o Pain o Heat/cold Functions: Movement Orientation Recognition Language Processing

13 Parietal Lobe Fun Facts Parietal Lobe is divided into two functional regions o One integrates info to form a single perception o The other lets the body know where it is in space in relation to the world around it Damage to the Parietal Lobe may cause o Neglecting part of the body or space (makes it hard to care oneself) o Inability to perceive objects normally

14 Hippocampus part of the limbic system (emotion system of the brain) o in charge of transferring information into memory part of the temporal lobe (inside fold; not visible from outside) Necessary for making new memories [Alzheimer's disease (mentioned later) affects the hippocampus first and severly] involved in severe mental illnesses Directly affected by estrogen o estrogen increases "synaptic density" or the number of connections to other nerve cells

15 Hypothalamus maintains homeostasis regulates hunger, thirst, response to pain, levels of pleasure, sexual satisfaction, anger, aggresive behavior and more regulates functioning of parasympathetic and sympathetic nervous systems (regulates pulse, blood pressure, breathing,etc.) It recieves info from... o vagus nerve; gives info about blood pressure and how full the stomach is o reticular formation of brainstem; gives info about skin temp. o optic nerve; gives info about light and darkness o unusual neurons lining the ventricles, it gets info about contents of the cerebrospinal fluid incluidng toxins that lead to vomiting o limbic system/olfactor nerves; give info that regulate eating and sexuality o it's own receptors; give inof about ion balance and temp of the blood

16 Hypothalamus Sends instructions by... o autonomic nervous system  control of blood pressure, heartrate, breathing, digestion, sweating, and all sympathetic/parasympathetic functions o pituitary gland  neurally and chemically connected to this gland  gland pumps hormones releasing facors into blood stream  hormones regulate growth and metabolsim

17 Amygdala FEAR o couples a learned sensory stimulus (dog snarling = danger) to an adaptive response (fight or flight) Sensory input o visual o auditory o somatosensory cortices (the part of the brain where sensory signals are sent) Outputs o hypothalamus o brainstem involved in mood and conscious emotional response to an event damage (rare) o no response to fearful events o inability to recognize fear in the facial expression of others

18 Spinal Cord Pathway connecting brain + peripheral nervous system Protected by spinal column ( bone ) o made up of 31 segments  8 cervical  12 thoracic  5 lumbar  5 sacral  1 coccygeal o pair of spinal nerves exit from each segment

19 Neurons Neurons are specialized to carry "messages" through electrochemical processes Like all cells of the body, neurons o Are surrounded by a cell membrane o Have a nucleus that contain genes o Contain cytoplasm, mitochondria, and other organelles o Carry out basic cellular processes such as protein synthesis and energy production

20 Neurons Neurons are different from other cells because... o They have specialized extensions called dendrites and axons o Communicate with each other through electrochemical processes o Contain specialized structures (ex. Synapses) and chemicals (ex. Neurotransmitters)

21 Anatomy of Neurons Dendrites bring info TO the cell body o Many to a cell o No myelin insulation o Branch near cell body Axons take info AWAY from cell body o Generally only one to a cell o Usually have myelin o Branch further from cell body Myelin Sheath is made of electrically-insulating material and surrounds the axon of a neuron. The myelin sheath increases the speed at which impulses travel along the axon.

22 Dendrites Axon Myelin Sheath Terminal button Or terminal end Som a It’s a neuron!

23 Impulse Transmission A synapse is a small gap separating neurons o Types of synapses (axodendritic, axosomatic, axoaxonic) In order for neurons to communicate, an electrical impulse must travel down an axon to the synaptic terminal (the “bulb” end of an axon)

24 Impulse Transmission cont. At the synaptic terminal, the electrical impulse will trigger the release of neurotransmitters into the space between neurons The neurotransmitters then bind with receptor sites on the postsynaptic ending (the membrane on the other neuron) The binding to receptor sites influences the electrical response in the post synaptic neuron

25 Neurotransmitters Neurotransmitters can be… excitatory or inhibitory Excitatory neurotransmitters increase the probability of the electrochemical impulse being transmitted to the adjoining cell Inhibitory neurotransmitters decrease this probability A balance is necessary…. If a stroke or trauma damages the tract of inhibitory motor neurons (neurons not able to inhibit neurotransmitters to other motor neurons) … result is excessive contractions of muscles Remember: a typical neuron may have many synaptic connections with the synaptic terminals of many different axons

26 Sum Up of Neurons

27 Brain Abscesses What is a brain abscess? o a mass of immune cells, pus, and other material due to a bacterial or fungal infection What are its etiologies? or causes? o A bacterial or fungal infection that did not start in the brain...for example, an ear infection could cause a brain abscess if the bacteria travels through the blood (to brain)  most common source is a lung infection o sometimes parasites o introduction of infectious organism through injury (ex. knife wound) or surgery

28 Brain Abscesses Inflammation develops as a result of this infection Infected brain cells, white blood cells, and live/dead microorganisms collect in a limited area of the brain which may be enclosed by a membrane This immune response is good to isolate the infection, however... o The brain swells and the mass may put pressure on delicate brain tissue o Infected materials can block vessels of the brain

29 Brain Abscess Symptoms Headache Stiff or aching neck, shoulder, or back vomiting change in mental status (ex. drowsiness, confusion, instability, slow thought process, coma seizures fever and chills vision changes loss of muscle function Decreased sensation weakness language difficulties loss of coordination

30 Brain Abscess Treatment Brain Abscesses may be a serious medical emergency... If pressure in skull becomes high enough it may cause death Medication o Especially broad spectrum antibiotics that work against a number of different bacteria o Anti-fungal medication may be used (if infection is caused by fungus) Surgery (procedure depends on size and depth) o Opening and draining abscess o Entire abscess may be removed if small enough and enclosed in a sac

31 Brain Abscess Treatment cont. Needle Aspiration (for deep abscess) o Inject medication directly into mass Diuretics and steroids may be used to reduce swelling

32 Traumatic Brain Injury Sudden trauma to the brain o head is jolted/ hits an object o object pierces skull Mild cases - o Loss of consciousness, headache, confusion, lightheadedness, dizziness, blurred vision, ringing in the ears, bad taste in mouth, fatigue, behavioral changes, trouble with memory/concentration/thinking

33 TBI cont'd... Severe cases o Same symptoms as before o Also, headache that does not go away, repeated nausea, convulsions, inability to wake up from sleep, dilation of one or both pupils, slurred speech, weakness or numbness, loss of coordination, increased confusion

34 TBI cont'd... Treatment o quick medical attention - stabilize the patient to prevent further injury o Not much can be done to reverse the initial injury o Possible neurosurgery to remove hematomas (ruptured blood vessels) o Disabilities - problems with thinking, memory, senses, communication, mental health, o Coma - unconscious, unarousable, unresponsive, unaware o Vegetative state - unconscious, unaware, but periods of alertness o Persistent Vegetative state - vegetative state for more than one month

35 New Treatment Idea for TBI Technology Reviews Nov Some of the neural damage that accompanies TBI results from the impact. However, most occurs over days, weeks, or months later. The impact triggered a chemical cascade that triggered the inflammation and cell death. Scientists are trying to come up with treatments that prevent this slow degeneration. Instead of targeting neurons, like scientists have in the past to solve the degeneration problem, scientists are now targeting astroglia (or astrocytes) o these cells are thought to support neurons Eli Gunnarson, of the Karolinska Institute in Sweden, has found red-blood-cell booster hormone erythropoietin (EPO) protects against swelling by closing a channel that normally imports water into astroglia David Meaney and his colleagues at the University of Pennsylvania, have found that right after injury, astroglia receive a flood of calcium ions; which is toxic to neurons. If a drug could be developed that stops the flood by inhibiting the specific receptor on the cell's surface the degeneration could be stopped (a class of compounds has already been found to do this)

36 Other Diseases! Alzheimer's Disease o More common in women than men o Caused by atrophy of cerebral cortex and other forebrain territory o In some serious cases, the brain can weigh less than 1000 grams at death. Wallenberg Syndrome o Difficulty swallowing o Hoarseness o Caused by paralysis of vocal cords Wernicke Aphasia o Impairment in the comprehension of written and spoken language o Inability to speak substantive language 2/alzheimer.htm 2/wallenberg.htm 2/wernickes_aphasia.htm

37 Possible New Treatment for Alzheimer's Science Daily Feb Northwestern University research team found that insulin may slow or prevent damage and memory loss caused by toxic proteins in Alzheimer's disease, by shielding memory-forming synapses from harm Therapeutics designed to increase insulin sensitivity in the brain may help treat the disease; sensitivity to insulin decreases with age (a risk factor for Alzheimer's) Sergio T. Ferreira, member of research team, commented, "Recognizing that Alzheimer's disease is a type of brain diabetes points the way to novel discoveries that may finally result in disease-modifying treatments for this devastating disease

38 So How is the Nervous System Interrelated, Interconnected, and Interdependent with other systems?? The Nervous System works very much with the following systems and organs:  Skin  Eyes  Ears  Mouth  Endocrine System  Muscular System  Skeletal System  Circulatory System  Respiratory System  Immune System CAN YOU EXPLAIN HOW??


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