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Titre 2 Devoir 2H (15 %) Renseignements et instructions Ce devoir est composé de questions à développement qui vous obligent à nommer, à définir, à décrire, à illustrer et à expliquer des notions de base en biologie humaine. Les réponses doivent : être élaborées et construites en phrases suivies ; utiliser des termes spécifiques à la biologie ; démontrer votre compréhension de ces notions ; être cohérentes, établissant clairement les liens entre les éléments mentionnés. Chacune des questions comporte un encadré qui détermine la longueur attendue de votre réponse. Accordez une attention particulière aux renseignements fournis dans l’énoncé des questions avant de rédiger vos réponses. Ils sont là pour vous guider dans l’élaboration de vos réponses, pour préciser les éléments importants à considérer. Lorsqu’une question comporte une mise en situation particulière, vous devez y faire référence dans la rédaction de votre réponse. Certains raccourcis ont été utilisés pour décrire des processus complexes dans ce cours de biologie ; la correction tient compte de ces descriptions ou explications simplifiées et n’exige pas que vous ayez fait des recherches supplémentaires. Faites parvenir votre devoir à votre tuteur en format Word. Question 1 L’organisation structurale et fonctionnelle du système nerveux [/15 points] Walking barefoot in the grass, you injure yourself by stepping on a thorn. Immediately, your leg folds back. Describe the structures involved and the path of nerve impulses during this simple reflex. (10 points) In each of the following situations, one of the elements related to the functioning of the nervous system is unable to perform its function. (5 points) Using the knowledge acquired in this course and the appropriate vocabulary, indicate, for each of the cases mentioned: - the structure (s) concerned; - the cause of the problem mentioned. i) i) Paralysis and insensitivity of the right part of the body with persistence of spinal reflex activity. ii) Students are in a windowless classroom with the door closed and sealed. A power failure occurs: no one sees anything anymore. Have they all gone blind? Or, what element necessary for the production of a nerve impulse is missing? How important is this element? iii) Loss of speech following a stroke. Question 2 Cellule nerveuse, substance grise et substance blanche [/20 points] a) Neurons specialize in the transmission of nerve impulses between various parts of the body. In a text that is well structured, coherent and written in your own words: - describe in detail the structure of a typical neuron; - indicate progressively the role of each part of this neuron.(8 points) b) A cut in the brain or spinal cord shows that some areas are greyish (gray matter), while others are bright white (white matter). In a text that is well structured, coherent and written in your own words: - Distinguish between gray and white matter based on the structure of a typical neuron. What would we see if we looked under a microscope at a sample of white substance and one of gray substance? - How are the white matter and the gray matter distributed in the brain? In the spinal cord? - Indicate the general role of the gray substance zones compared to the white substance zones.(12 points) Question 3 Information sensorielle et réponse motrice[/15 points] Around the age of 1 or 2, children "learn" to walk. Quickly, their hesitant approach becomes more assured and they control their balance better and better. These children acquire this ability to walk and its variants, run and climb, for a lifetime. In a well structured and coherent text based on the knowledge acquired in this course, describe how the nervous system can execute the coordinated movements necessary for walking while ensuring balance. Your response should include the following: - the name and location of the various receptors which constantly transmit to the child the relevant information on the position of his body; what are these receptors and what information do they send to the SNC; - the names of the brain centers involved; - the two motor pathways transmitting the impulses to the muscles. Question 4 La fonction intégrative du cerveau[/15 points] A friend’s mother is serving you a stew. You say: "The tasty soup is like the one my grandmother used to serve us in the country: I loved my grandmother very much! She is gone now. "You breathe a big sigh, your heart a little heavy, you even have a tear in your eye! From the taste of pot-au-feu to tears, you live an experience which combines memories and feelings, vegetative functions and relationship life. Several structures and functions of the nervous system are mentioned in the described situation: reception of information, processing of information, emotion, somatic nervous system (voluntary actions), vegetative nervous system (involuntary actions). State the nerve structures seen in your lesson that are responsible for these different manifestations. Write a coherent and well-structured text where you will demonstrate that you have grasped the interrelationships that are established between the parts of the nervous system in this particular life experience. Do not forget to name the parts of the nervous system involved (vegetative, somatic, limbic, etc.) and the nervous structures involved (receptors, effector, centers, brain areas, nuclei, nerves, etc.). Your text must constantly refer to the stages of the experience described: from the stimulus - either the taste of the stew - to the reaction - or the tear to the eye. Question 5 Les grandes voies nerveuses[/15 points] You check the temperature of a child's bath water by dipping the fingers of your left hand into it. In a coherent and well-structured text using the appropriate vocabulary and the knowledge acquired in your course, including that resulting from the observation of diagrams, describe the path of the nerve impulse on the nerve path used. Your description should contain the answers to the following questions: - What nervous path is illustrated in this scenario? - What structure, at the start of this path, gives rise to nerve impulses? - What neurons are used by the influx along the route? - What regions of the body and nervous system are crossed by the influx during the journey? - At what precise level (precise zone of which cerebral hemisphere) will you be aware that the bath water is at the right temperature? Question 6 Le système nerveux autonome[/20 points] Why do most of the vegetative organs whose activity is regulated by the autonomic nervous system receive two different motor neurofibers? (4 points) The nervous system, in its autonomous portion, regulates homeostasis, regardless of the activity levels of the organism. (16 points) Explain how the ANS, through its neurotransmitters, produces different effects on the major systems of vegetative life depending on the circumstances. In your explanation, specify for each part of the ANS: - the neurotransmitter released at the junction between the motor neuron and the effector; - the circumstances which make one of the two systems sometimes dominate the other; - the effect of activating each of the two parts of the ANS on the different systems and organs of the body. 2|1 Devoir 1A © Cégep à distanceDevoir 2H8 | 8