Biology Forum Human Biology Nervous system

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      I need some help with a couple of questions.

      1.Factors that Could Affect Neuromuscular Junctions

      I. Increase in the production of adrenaline
      II. Inhibition of cholinesterase synthesis
      III. Inhibition of acetylcholine release
      IV. Blockage of receptor sites for acetylcholine in the muscle

      Identify all the factors that would cause muscles used in breathing to lose their ability to function.
      Question 35 options:

      II and III
      II, III, and IV
      I, II, and IV
      I and II

      2.A stroke has caused damage to certain areas of the brain. Upon examination, a doctor notices that the person has difficulty understanding speech and the left side of the body is paralyzed. Identify the specific areas of the brain that are damaged, and explain how this damage might cause problems.

      Hint :Specifically, which speech area? Remember that nerves from one side of the body cross over to the other brain hemisphere at the region of the pons. Some other sources, identify the cross over in the medulla.

      3.Dopamine and serotonin are neurotransmitters produced by certain neurons in the brain. One effect of dopamine is that it brings about feelings of euphoria (pleasure). Serotonin affects the control of moods in a person. After being secreted into the synapse, dopamine is reabsorbed by transmitting neurons.

      The illegal drug cocaine causes an overspill of dopamine from transmitting neurons and blocks the reabsorption of dopamine by these neurons. After the dopamine is released, cocaine slowly breaks down into inactive substances.

      What is the general mood of an individual under the influence of cocaine? Does cocaine increase the speed of nerve transmission in the brain or remain longer than normal in the synapse? What effect does this have?

      4.In a classic experiment, the strength of a neural stimulus and the resulting muscle contraction are compared. A single motor neuron that synapses with a muscle fibre is suspended. The other end of the muscle fibre is attached to a mass. If an electrical stimulus is sufficient to cause an impulse in the neuron, the muscle will contract and life the mass. The following data were obtained from the experiment. Analyze the data and answer the following questions.

      a) Define "threshold potential." What is the minimum size of the stimulus required to reach the threshold potential for this motor neuron?
      b)Explain the all-or-nothing response. Then predict the mass that could be lifted at 3 mV of stimuli and at 4 mV of stimuli.
      c)Choose a specific example of a sensory neuron, and explain neural stimulation and impulses in terms of the threshold potential and the all-or-nothing response.

      Strength of Stimuli
      Mass lifted by muscle contraction (g)

      Thank you in advance to anyone willing to help. These are only 4 of 64 questions so im happy once i get them answered XD

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