Genetics and Genomics Essay
Genetics and Genomics
1. One patient has a grade I tumor of the lung, while another patient has a grade IV tumor of the lung. Explain how tumors in various stages are similar and how they differ. (1 point) Both stage I and stage IV lung cancer is presented with cellular differentiation, loss of normal tissue structure, as well as irregular size and shape of the nucleus. Normal cells are able to divide and die cancer cells are pile up on top of each other forming a tumor. The staging and grading of cancer depends on evaluation of size of the tumor, degree of invasion extent of spread and differentiation of cells. Stage I lung cancer is a tumor less than 3cm ,has no evidence of invasion, well differentiated, whereas stage IV tends to be least differentiated have most anaplasia, can be any size and have spread to other organs. The similarity sometimes noted in symptoms that patient is presenting with. Two patients may present with same symptoms and have two different stages. However the survival rate is the same regardless of stage.
2. If a patient has breast cancer, how would angiogenesis and invasion influence tumor growth and metastasis? (1 point) Angiogenesis is a physiological process of developing new blood vessels. This normal process is not only supplying the normal cells but also nourishes the cancer cells. Small cancers are unable to develop new blood vessels, however larger cancers can. The process of invasion occurs between the beginning of the event and development of obvious tumor, some mutated cells die while others reproduce. The tumor at this point continues to grow and reproduce. Breasts tissue is very vascular and very close located to lymph nodes. Cells break off from the original tumor and travel through the lymphatic system and blood stream, to the other organs where they produce secondary tumors.
3. Compare and contrast the sympathetic and parasympathetic nervous systems. (0.75 point) Sympathetic nervous system originates in a spinal cord. The small neurons enter the ganglia near the cord, the ganglia forms a chain that spreads the impulse to neurons (postganglionic) which are responsible for reaching many organs and glands. Physiologic effects of sympathetic nervous system is vasoconstriction, elevated blood pressure, increased heart rate and contractility, increased respiratory rate, sufficient amount of blood flow to skeletal muscle, smooth muscle relaxation of the lungs, stomach, and urinary tract, sphincter contractions, dilated pupils and ciliary muscle relaxation, increased sweat gland secretion and reduced pancreatic secretions. Parasympathetic nervous system contrasts in the place of its origin, as it originates from central nervous system through cranial nerves from midbrain and medulla.
After leaving the CNS the long preganglionic fibers fiber of each parasympathetic nerve travels to a ganglion near a particular organ or gland, and the short postganglionic fibers enter the organ or gland. The sympathetic has opposite order. With parasympathetic nervous system blood pressure heart rate respirations are measured at low levels, GI tract is active after meal, pupils constricted. These two systems compensate each other’s activities.
3. A patient has increased intracranial pressure of 30 mmHg caused by a massive closed head injury. Explain the process of increasing intracranial pressure, and discuss possible complications if the pressure is not decreased. (1 point) With closed head injury, external force is applied to the head and brain causing a disturbance of physiologic constancy. The injury has an impact on brain’s compensatory mechanisms by overwhelming them to the point where they became no longer effective. This leads to increased intracranial pressure. As increased intracranial pressure continues to rise, leading to increased cerebral blood flow which it causes venous congestion. This adds more increase to intracranial pressure, which at this point causes cellular hypoxia. As cellular hypoxia occurs brain death is imminent.
4. Two individuals come to the emergency department with head injuries. A 25 years old, has just been in a motor vehicle accident (MVA) and has a temporal lobe injury. The other, 65 years old, has increasing confusion after a fall that happened earlier in the week. How could you clinically differentiate between the individual with the extradural hematoma and the individual with the subdural hematoma? Which one of these individuals requires priority surgical treatment? (1 point)
To clinically distinguish between these two injuries it is vital to understand the location of the injury, age of the individual, and extent of the injury. In this case the 25 year-old individual post motor vehicle accident has suffered extradural hematoma. The impact of the accident has caused blunt force trauma to head, which caused a rupture of meningeal artery. Arteries are generally are larger and bleed quicker, which predisposes this individual for quick blood loss. Irregular heart beat and breathing can lead to coma. The 65 year-old individual that has suffered a fall is presenting with subdural hematoma which involves veins, stretching of the veins causes them to tear and bleed. However since this patient is older and in older individuals brain cells die and brain shrinks there is more space in a brain so the veins stretch under low pressure and don’t bleed as fast. As this condition can cause increased intracranial pressure and lead to herniation of the brain it definitely requires immediate intervention. Nevertheless the priority surgical treatment will be the individual with extradural hematoma due to increased risk of bleeding.
6. What conditions must be present for a diagnosis of Reye syndrome? (0.25 point)
Reye syndrome is believed to be caused by Influenza A, B, and chicken pox. Aspirin also should be avoided with children as it may cause Reye syndrome. Some studies suggest genetic predisposition to Reye syndrome. Some of the conditions that must be existent with this disease are persistent vomiting, loss of consciousness, and effects memory function. Reye syndrome affects temporal lobe of the brain where memory is stored. The encephalopathy is caused by liver depositing lipids. While looking at physiologic symptoms, the cerebrospinal fluid is obtain, and will likely be positive for leukocyte. Treatments depend on the extent of the illness.