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Part B: Nervous system function (17 marks) Jenny had surgery to set her broken bone; this was done under general anaesthesia.The unlabelledgraph of theaction potentialphases has beenprovided toassist with youranswers 1. When nerve cells are at rest, there is a resting membrane potential (RMP; phase #1 ongraph) for the neuron cell membrane. Describe how the RMP is generated. (3 marks)2. Jenny is conscious and alert when certain neurons in her brain are active. Her neuronsdepolarise, produce action potentials, repolarise and hyperpolarise. Definedepolarization and hyperpolarization and explain their relationship to threshold. (3marks). 3. Jenny’s nerve cell membranes have both leak (passive) potassium channels andvoltage-gated potassium channels. Explain how these channels differ, in terms ofwhere in the cell they are located and in how they work. (3 marks) 4. Anaesthesia to be used for Jenny’s procedure will affect her neurons forconsciousness and sensation of pain. The anaesthetic acts by opening more potassiumleak (passive) channels. How does this make Jenny’s neurons less likely to producethe action potentials that would normally keep her awake and experience pain? (3marks)5. Skeletal muscle has similar types of potassium leak (passive) channels that react withthe general anaesthesia. What might be the effect on Jenny’s skeletal musclecontraction during surgery? Explain. (2 marks) 6. Prior to surgery, Jenny’s pre-op blood testing revealed hyperkalaemia (indicated highlevels of extracellular potassium. What effect would elevated extracellular potassiumhave on muscle and nerves cells? (3 marks) Part C: General questions on Nervous System Function (6.5 marks)1. In terms of nerve communication,a. Why might a patient experience sensations of tingling and numbness in theirlips/tongue/face/neck? Suggest possible steps in nerve transmission that may be affected(3 marks) b. Suggest likely affected peripheral nerves that may cause paralysis in the face andmouth; Justify your choice. (3.5 marks) Part D: Skeletal muscle function (24.5 marks) You will need to research this topic.Search terms and topics: Malignant Hyperthermia (MH); Ryanodine (RyR) receptors;Halothane binding to variant RyR1 receptor.Brian Wilson is an 18-year-old male student who was healthy until two days ago when heexperienced severe abdominal pain, fever, and vomiting. A visit to his GP revealed that hehad acute appendicitis. Brian is in excellent health but during the surgery, his bodytemperature began to rise quite quickly. Medical staff managed this emergency and laterdiagnosed a genetic condition called Malignant Hyperthermia (MH) that causes a rapid rise incore body temperature, severe muscle contractions and respiratory distress under generalanaesthesia (with Halothane). 1. How do Brian’s skeletal muscles contribute to his body temperature? (2 marks) 2. In a normal muscle cell, describe the sequence of events and cell locations that lead tocalcium release for contraction. (4 marks) 3. During Brian’s sedation, Halothane anaesthetic caused an adverse effect by binding withBrian’s variant RyR1 ryanodine receptor located in his skeletal muscle cells. At whatlocation in Q2 did this occur? Explain what happened at the molecular level that causedthe severe muscle contractions. (4 marks) 4. This MH condition causes a hypermetabolic state in skeletal muscle, which is triggeredby high demands for ATP during uncontrolled muscle contractions. a. Explain what “hypermetabolic” means. (1 mark) b. Discuss the impact of the hypermetabolic state on chemical demands and adjustments tometabolism in Brian’s skeletal muscle cells. (10 marks) c. How does ATP contribute to maintaining calcium concentration gradients in muscles?(1.5 marks) 5. Suggest a likely mode of action for a drug to reduce excessive skeletal musclecontraction during in any future procedures where Brian needs anaesthesia. (1 mark) 6. What effect do you expect this drug would this have on Brian’s body temperature? Why?(1 mark)

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