Chapter 12 Worksheet Part VII

Death from amyotrophic lateral sclerosis usually results from respiratory infection secondary to compromised respiratory function. Why?

Amyotrophic lateral sclerosis, or Lou Gehrig's disease, is a rare neuromuscular disease that involves progressive destruction of the ventral horn motor neurons and fibers of the pyramidal tract. As the disease progresses, the sufferer loses the ability to speak, swallow, and breathe. Because the lungs have difficulty fully expanding, secretions may develop, causing respiratory infection.

A patient is admitted to the rehab unit five days after having a stroke. The nurse assesses his muscle strength and determines that he has right-sided weakness. Based on this assessment data, what part of the brain was injured?

Damage to localized areas of the primary motor cortex paralyzes the body muscles controlled by these areas. If the stroke is in the left hemisphere, the right side of the body will be weak or paralyzed.

Mrs. Sagalov has recently been diagnosed with Alzheimer's disease. What clinical symptoms is she likely to show, and what would probably be seen if her brain were examined?

Mrs. Sagalov is likely to show increasing cognitive deficits, including difficulties with memory and attention, and personality changes such as irritability, moodiness, and confusion. Her brain, particularly in the cerebral cortex and hippocampus, is likely to show senile plaques (clumps of cells and fibers around a protein core) and neurofibrillary tangles (twisted fibers within neuron cell bodies).

An 86-year-old patient with Alzheimer's disease was admitted to the hospital with dehydration. Her daughter states that her mother has been very confused and combative lately. Explain why the patient likely developed dehydration.

One of the simplest mechanisms for maintaining fluid balance is the thirst mechanism. Normally, when a person is thirsty, he or she drinks because the thirst center in the hypothalamus is stimulated. In this patient's confused and combative state, she is probably refusing or forgetting to eat or drink, thereby developing dehydration.

Robert was helping his son work on the son's car when he temporarily lost the ability to speak in a normal manner and had difficulty handing his son the requested tools. This episode lasted for several minutes and then he was himself again. Robert's son insisted that his dad see his doctor after this episode. What might be the doctor's diagnosis of Robert's episode and what could be the cause?

Robert experienced a TIA (transient ischemic attack) where brain cells are temporarily deprived of oxygen. The attack commonly lasts for only a short time but is a possible precursor of a more serious CVA.

Would damage to the frontal lobe or the medulla oblongata be more likely to result in death? Describe the overall functions of these brain regions.

Damage to the medulla oblongata would be more likely to lead to death. The medulla oblongata has a crucial role as an autonomic reflex center involved in maintaining homeostasis. For example, the cardiovascular center adjusts the force and rate of heart contraction and maintains blood pressure through adjustments in blood vessel diameter. Respiratory centers generate the respiratory rhythm and help control the rate and depth of breathing. The frontal lobe contains motor areas that control voluntary movement as well as association areas involved in working memory, task management, consciousness, and problem solving.

The location and arrangement of the arteries supplying the hippocampus make it particularly vulnerable to injury. How would memory be affected if the hippocampus suffered deterioration?

The hippocampus oversees the circuitry for learning and remembering spatial relationships. In other words, it acts as a switchboard, receiving and sorting information, helping to turn that information into a memory, and forwarding it to other parts of the brain. Without the help of the hippocampus we might learn, but we wouldn't remember.

Explain why heparin is used as an anticoagulant in the treatment of thrombotic strokes but contraindicated in a subarachnoid hemorrhage.

The most common cause of a stroke is a blockage of a cerebral artery by a clot. Heparin would keep more clots from forming. It would be contraindicated in a subarachnoid hemorrhage because it would not be effective in treating the bleeding from ruptured vessels.

A patient was admitted to the medical/surgical unit with a stroke that affected the motor neurons in the direct (pyramidal) pathway. This affected the loss of voluntary movement to his left side. What other problems might the patient experience?

The patient may have difficulty swallowing because of weakness to the mouth or throat muscles. The patient may also experience problems with urinary incontinence.

Susan and Robert are the parents of three children. One night while the family was sleepingh, a fire broke out next door. Susan and Robert heard the fire trucks and rushed out to see what was happening. None of the children woke up, even with the sound of sirens close to the house. Why did the parents wake up, but the children didn't?

The reticular formation activation system, which filters stimuli, awakened the parents, who were responsible for the safety of their children. It allowed the children to ignore the stimuli so that they could get their rest, because the parents were in charge of the situation.