Organization and Control of Neural Function
Riku is a 19-year-old college student. One morning, after a long night of studying, Riku woke up and made himself a hot cupofcoffee and toast.
Much to his surprise, when he brought the cup to his mouth to drink, the coffee spilt onto the table. Riku went to the bathroom mirror and noticed the left side of his face seemed to droop. He quickly got dressed and ran to the medical clinic on the college campus. As he ran, his left eye began to feel scratchy and dry, but he could not blink in response. The physician at the clinic listened to Riku’s story and then did a careful cranial nerve examination. She concluded that Riku had Bell palsy, an inflammatory condition of the facial nerve most likely caused by a virus.
- What are an afferent neuron and efferent neuron? What are efferent components of the facial nerve and their actions?
- Under certain circumstances, axons in the peripheral nervous system can regenerate after sustaining damage. Why is axonal regeneration in the central nervous system much less likely?
- At a healthy myoneural junction, acetylcholine is responsible for stimulating muscle activity. What mechanisms are in place to prevent the continuous stimulation of a muscle fiber after the neurotransmitter is released from the presynaptic membrane?
Case Study 2
Somatosensory Function, Pain, and Headache
Ramandeep is an active 23-year-old. She works as a part-time nurse during the day and is studying for a postgraduate certificate in the evening. Ramandeep started to wear a bite plate at night after she began to experience jaw pain and headaches. Sometimes the pain radiated to her ear, and she would apply a hot water bottle to it to ease the discomfort. Her husband mentioned to her that he heard her grinding her teeth at night while she was sleeping. She knew then that her headaches might be from temporomandibular joint syndrome, and she went to her dentist to confirm her thoughts. In addition to the bite plate, the dentist also recommended she should continue with the application of heat, use NSAIDs when needed, and incorporate regular relaxation exercises throughout her stressful days.
- What effect does heat have on nociceptors so that it makes a good nonpharmacologic treatment for pain?
- Heat and cold treatment are both hypothesized to have an effect on the release of endogenous opioids. What are these chemicals, and why are they hypothesized to be beneficial in the body?
- Using your knowledge of physiology, how do NSAID analgesics function in the management of pain?
Case Study 3
Disorders of Motor Function
John is 63 years old and receives home care by an occupational therapist twice a week. His therapist is currently working with John on maintaining joint flexibility and balance. John demonstrates resting tremor, so his therapist is also working on adaptive techniques, so John can continue to use his hands to write, use the computer, and cook simple meals. John’s wife assists with his mobility and walks slowly beside him, holding his arm. Sometimes she needs to help him open his prescription bottles, so he can take his medicine, a combination of levodopa and carbidopa.
- What motor disease does John demonstrate? One of his signs is resting tremor. What is the difference between a resting tremor and an intention tremor?
- What is the advantage of combining levodopa with carbidopa? What is the benefit of anticholinergic drugs in the management of Parkinson disease?
- Parkinson disease involves the destruction of the substantia nigra and the nigrostriatal pathway. Where are these structures anatomically?
- The patient with Parkinson disease typically presents with a masklike facial expression. Why does he or she have a masklike facial expression? How are the eyes, mouth, and laryngopharynx affected by this disease?
Case Study 4
Disorders of Brain Function
Bonnie is a 70-year-old woman who lives alone. One evening, she felt light-headed and dizzy. When her head began to ache, she decided to take an analgesic and go to bed early. The following morning, upon awakening, she was unable to move the bed sheets with her right arm. At this point she was experiencing tingling sensations in her limbs, and she had difficulty keeping her balance. She dialed 911 for help, and by the time the ambulance arrived, she was confused and unable to articulate her words although she knew what information he was asking of her. In the hospital, she was examined and treated for ischemic stroke.
- Stroke, or brain attack, involves brain tissue injury. Describe ischemic penumbra and what factors contribute to the survival of the neurons involved. What happens if the cells of the penumbra are unable to be preserved?
- Compare and contrast hypoxia and ischemia. What condition is more dangerous to the brain? Explain your answer.
- Knowing what you do about the effects of ischemia on the brain, why would someone with ischemic stroke develop cerebral edema?
- What type of aphasia was Bonnie exhibiting when talking to her caregivers? Explain your answer.
Case Study 5
Sleep and Sleep Disorders
Jessica is six years old. Her parents recently saw her pediatrician because they were concerned about the sleeping difficulties Jessica has been having. Often she would scream out loud in her sleep. Her parents would rush to her room and find her sitting upright in bed, panting heavily in a state of panic. Jessica would not respond to her parent’s words of consolation, and the next morning she would have no memory of the incident at all. Her parents were worried about the anxiety their daughter was experiencing and asked the pediatrician what they could do about her nightmares. The pediatrician explained Jessica was likely suffering from sleep terrors and carefully described what that meant.
- What are the similarities and differences between nightmares and sleep terrors?
- What are the characteristics of motor, sensory, and autonomic function during REM sleep? What is thought to be the importance of this stage of sleep?
- Jessica’s pediatrician said that the careful management of sleep hygiene may help to decrease the incidence of her sleep terrors. What is included in an overview of the general features that demonstrate good sleep hygiene?
Case Study 6
Disorders of Thought, Emotion, and Memory
Ella is 88 years old and was living at home until very recently. Her children, who visited her regularly, noticed she was becoming more forgetful. At first, she mislaid objects, and then she began to forget her doctor’s appointments. With time, her personality changed and she became withdrawn. At home she would forget to turn off the stove or leave the kettle on until it boiled dry. After seeking advice from a gerontologist and social worker, Ella’s children placed her in a nursing home with a unit equipped for patients with Alzheimer disease.
- What is dementia? Why is Alzheimer disease based on a “diagnosis of exclusion”?
- What are the macroscopic and microscopic features of the brain that are typical in Alzheimer disease?
- One of Ella’s children brought her a new pair of slippers to wear in the nursing home. A minute after she received them, Ella could not remember the exchange and asked what they were doing on her bed. What part of the brain has largely been affected to produce this behavior, and what is the pathophysiology involved?
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