Question

Chapter 4 Running Case: The Case of Will Smithers

A surprising amount of information can be learned about an individual just by studying their tissues. In this case, you have been assigned to shadow histopathologist Dr. Jonas Riehm as he attempts to identify the cause of death of 42-year-old Will Smithers. Mr. Smithers’ body was discovered in his car near an alley several miles from his home. There was no obvious cause of death, necessitating an autopsy to determine if the death was from natural causes or foul play. However, due to a clerical error, Mr. Smithers’ body was released and interred before a proper autopsy could be performed, and an official cause of death was not established. Fortunately, several tissue samples were taken before the interment and remain available for examination. Mr. Smithers’ family does not wish to have his body exhumed, so local law enforcement professionals have asked Dr. Riehm to examine the tissue samples in the hopes of determining the cause of death, and whether or not an exhumation is needed. The following sections have been taken from the official report that Dr. Riehm sent to the local coroner’s office. You are to report to Dr. Riehm’s office with your anatomy and physiology textbook. He expects students to answer questions related to the work that he does in his histopathology laboratory. Dr. Riehm enjoys teaching, and has a collection of microscope slides that he uses to introduce students to the fascinating universe of histology. He starts with the following definition: histology is the study of the normal structure of tissues. Although Dr. Riehm is an expert in the study of the diseases and abnormalities of tissues, he is a firm believer that you must be able to recognize normal tissue before you can understand diseased tissue. He has set up four microscope stations for students to view slides of normal tissues.

Parrt D - Module 4.4 Muscle Tissues

Dr. Riehm prepares to review slides of Mr. Smithers’ cardiac muscle tissue. He described regions of necrosis, or dead tissue, where cardiac muscle cells have died after being separated from the blood supply. This finding indicated that Mr. Smithers had a myocardial infarction, or heart attack. Dr. Riehm then poses this question: Are heart attacks always fatal? In other words, can we determine from this slide that this event preceded and therefore caused Mr. Smithers’ death? People survive heart attacks, don’t they? Dr. Riehm would need to look at the slides more closely later in the day before he completed this portion of his report. He was not ready to sign off on myocardial infarction as the cause of death just yet. Dr. Riehm reviewed the remaining slides in the set. He selected a blood vessel slide and discovered hypertrophy, or an enlargement of the smooth muscle, and damage to the endothelium lining the vessel walls. Both were signs of vascular disease, as was the finding of atherosclerosis, or plaque, which had probably clogged Mr. Smither’s arteries and veins. All of these were pathological findings that supported a diagnosis of vascular disease. Vascular disease increases the likelihood of myocardial infarction. Mix the cardiovascular findings with fatty liver disease, anemia, and enough alcohol, and that could explain this man’s death. But, it would still be speculation. All of these certainly could lead to a myocardial infarction, no doubt. There was evidence that a cardiac event had happened at some point in Mr. Smithers’ life. Like his fatty liver, these findings indicated that Mr. Smithers was unhealthy. A review of Mr. Smithers’ medical history or a report from his personal physician would be helpful in determining the relevance of these findings. A pathologist would probably need to see the actual heart itself to make a cause of death by myocardial infarction determination. Dr. Riehm reminded you to get those slides filed away so we could move on to the last set of samples from Mr. Smithers’ brain tissue. While making your flashcards, you see that skeletal muscle cells are multinucleated. Why do skeletal muscle cells have this property?

ANSWER:

Skeletal muscle fibers are formed by the fusion of osteogenic cells and the nucleus of each osteogenic cell is retained in the mature muscle fiber.

Skeletal muscle fibers are formed by the fusion of embryonic chondroblasts.

The original nucleus in a skeletal muscle fiber undergoes repeated rounds of mitosis.

Multinucleation is an advantage because of skeletal muscle fiber size and the amount of protein synthesis that takes place in these metabolically active cells.

Part E - Module 4.5 Nervous Tissue

Dr. Riehm began his review of Mr. Smithers’ nervous tissue slides. Mr. Smithers had suffered blunt trauma to the back of his head, and brain tissue revealed evidence of tissue swelling and neuronal damage. Was this injury the result of a fall or a deliberate blow to the head? It is possible that this information is related to Mr. Smithers’ cause of death, but Dr. Riehm was unable to make that determination. Unfortunately, there are too many unanswered questions surrounding the death of this man. Therefore, Mr. Smithers’ body must be exhumed. Access to his complete remains for autopsy would likely provide evidence that tissue samples could not. It seems that the case has nearly reached its conclusion, although there was still something odd about those nervous tissue slides. In addition to the trauma, there was some microscopic evidence of dementia, which would be unusual in a middle-aged person. Hopefully, a full pathology report could provide some explanation for these abnormal nervous tissue slides. Time was of the essence in this case, and there was only one last issue to address before the paperwork could be completed. You have been reviewing nervous tissue slides for hours. Dr. Riehm has asked you to discuss the structure and function of a neuron. Which of the following statements is correct?

ANSWER: .

Dendrites are always long unbranched processes that receive and carry signals toward the cell body.

Axons are long singular extensions of the cell body that carry nerve impulses away from the cell body.

Both axons and dendrites are highly branched extensions of the cell body that send and receive nerve impulses to and from the cell body.

Axons are always short, with numerous branches that carry nerve impulses away from the cell body.

Part F - Module 4.8 Tissue Repair

Finally, being thorough, Dr. Riehm wanted to review his assessment of the cardiac tissue slides. Finding evidence of fibrous tissue interspersed among cardiac muscle cells indicated that the heart had tried to heal itself. Mr. Smithers would have had to be alive long enough for scar tissue to form in his heart. The evidence from the cardiac tissue was consistent with an old myocardial infarction that Mr. Smithers survived. There was no evidence in the tissue samples to suggest that he had had an acute myocardial infarction. Dr. Riehm could only document what he observed in a small amount of cardiac tissue. Mr. Smithers could have had an acute and fatal myocardial infarction in a region of the heart from which no tissue samples were collected. From what he observed in the available tissue slide, however, it was unlikely that a cardiac event caused his death. His report would undoubtedly leave more unanswered questions about the cause of Mr. Smithers’ death. A full gross examination of Mr. Smithers’ heart was needed, which would require that his body be exhumed. Tissue repair and healing depends on adequate supplies of all of the following EXCEPT:

ANSWER

Entrance of cells of the immune system into the injured tissue.

Vitamin D from the diet.

Nutrition that supplies enough amino acids, vitamins, and other nutrients.

Blood flow to the injured tissue.

Answer 1

Part D: d. Multinucleation is an advantage because of skeletal muscle fiber size and the amount of protein synthesis that takes place in these metabolically active cells.

Part E: b. Axons are long singular extensions of the cell body that carry nerve impulses away from the cell body.

Each neuron consists of a axon, dendrites and cell body (soma). Axon is a long singular extension of the cell body that carries nerve impulses away from the cell body. Dendrites are the receiving end of the neuron.

Part F: b. Vitamin D from the diet.

Vitamin D is not involved in tissue repair and healing process.