NU 545 UNIT 7 WITH 70+ QUESTIONS & CORRECT
ANSWERS
Describe the specific chromosomal abnormality responsible for Down Syndrome - ANSWER-The most well known aneuploidy (those that do not contain a multiple of 23 chromosomes) in an autosome is trisomy of the 21st chromosome. J.Langdon Down 1st described the the disease in 1866. Down syndrome is seen in 1 in 800 births. IQ's between 25 and 70. Facial features: low nasal bridge, epicentral folds, protruding tongue, and flat low set ears. Congenital heart defects in 1/3 to 1/2 of live born children. Decreased ability to fight respiratory conditions and an increased susceptibility to leukemia. By age 40 symptoms resembling Alzheimer develop. 97% of Down Syndrome's cases are caused by nondisjunction during the formation of one of the parent's gametes or during early embryonic development.3% from translocations. Risk increases with maternal age.
Causes of mental retardation. - ANSWER-Chromosomal abnormalities.
What gene abnormality causes cystic fibrosis? - ANSWER-Like autosomal dominant diseases, those caused by autosomal recessive alleles are rare in populations, although the number of carriers for recessive diseases can be high.The most common lethal recessive disease in white children, cystic fibrosis, occurs in about 1 in 2500 births. Approximately 1 in 25 whites carries one copy of an allele that can cause cystic fibrosis (see Chapter 36). Because an individual must be homozygous for a recessive allele to express thedisease, the carriers are phenotypically normal. Because most recessive alleles are maintained innormal carriers, they are able to survive in the population from one generation to the next.As with many autosomal dominant diseases, many autosomal recessive diseases are characterized by delayed age of onset, incomplete penetrance, and variable expressivity.
How is a recessive gene inherited? - ANSWER-Autosomal recessive diseases occur when both parents are carriers of the same disease and their child inherits an 1 / 4
altered gene from each of them. Children of carrier parents have:A 25% chance of inheriting two altered genes and developing the disease.
Inheritance of Hemophilia A? - ANSWER-Hemophilia A and hemophilia B are inherited in an X-linked recessive pattern. The genes associated with these conditions are located on the X chromosome, which is one of the two sex chromosomes. In males (who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the condition. In females (who have two X chromosomes), a mutation would have to occur in both copies of the gene to cause the disorder. Because it is unlikely that females will have two altered copies of this gene, it is very rare for females to have hemophilia. A characteristic of X- linked inheritance is that fathers cannot pass X-linked traits to their sons.
Inheritance of Hemophilia A? - ANSWER-In X-linked recessive inheritance, a female with one altered copy of the gene in each cell is called a carrier. Carrier females have about half the usual amount of coagulation factor VIII or coagulation factor IX, which is generally enough for normal blood clotting. However, about 10 percent of carrier females have less than half the normal amount of one of these coagulation factors; these individuals are at risk for abnormal bleeding, particularly after an injury, surgery, or tooth extraction.
Risk factors for DM II; why is obesity an important risk factor for DM II? - ANSWER-An important risk factor is TCF7L2 which encodes a transcription factor involved in the secretion of insulin. Another association has been found between a common allele of the gene that incomes peroxisome proliferator- activated receptor gamma (PPAR-y), a nuclear receptor that is involved in adipocyte differentiation and glucose metabolism. This receptor is the target of thiazolidinediones (TZD's) a class of drugs commonly used to increase insulin sensitivity in those with type 2 diabetes. The 2 most important risk factors for DM II are positive family history and obesity; the latter increases insulin resistance.
Definition of carcinoma - ANSWER-Cancer arising from in epithelial cells
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How do cancer cells gain access to the circulation? - ANSWER-cells gain access to circulation through new tumor-associated blood vessels or angiongesis Mobile tumor cells are able to enter circulation (leakly newsly made blood vessels) once in circulation, cells must be able to withstand the physiological stress of travel in the blood and lymphatic circulation Sometimes they bind to blood platelets=protect themselves
What is adjuvant chemotherapy? - ANSWER-Adjuvant chemotherapy is an approach to fighting cancer that combines different forms of healing.Chemotherapy and radiation, or chemotherapy and surgery are used together.Usually the chemotherapy will be used after all of the known and visible cancer has been removed surgically or with radiation. Adjuvant chemotherapy aims to destroy hidden cancer cells that remain but are undetectable.Adjuvant means additional. Adjuvant chemotherapy is given to patients after primary treatment, when the doctor thinks there is a high risk the cancer will return. After a primary treatment of surgery or radiation, adjuvant chemotherapy reduces the risk of recurrence. The elimination of undetectable microscopic cancer cells that may have traveled to other parts of the body is the goal of adjuvant chemotherapy.When adjuvant chemotherapy doesn't result in a full cure it does make the intervals between a cancer relapse longer. Adjuvant chemotherapy typically begins within three to five weeks of the surgical removal of the cancer and has different treatment lengths depending on the cancer. For breast cancer, the adjuvant chemotherapy is administered for three to nine months. In the case of colon cancer, treatment rarely last more than six months.
Most common time childhood cancers are diagnosed? - ANSWER-Childhood and adolescent cancers are often associated with specific peak times of physical growth and may occur as a consequence altered cellular regulatory mechanisms at a given time in the child or adolescents development. Embryonal tumors most often develop before the age of 5 years, acute lymphoblastic leukemia occurs most often in younger children, and bone tumors occur most often in adolescents. 3 / 4
DES exposure prenatally - ANSWER-Diethylstibestrol (DES) which was prescribed by physicians to treat spontaneous miscarriage. Identified as a transplacental chemical carcinogen because a small percentage of the daughters of the women who took DES developed adenocarcinomas or the vagina and cervix.
Where do most childhood cancers arise from? - ANSWER-Most childhood and adolescent cancers arise from the mesodermal germ layer that gives rise to the connective tissue, bone, cartilage, muscle, blood, blood vessels, gonads, kidney, and the lymphatic system. Leukemia and brain tumors account for 61% of childhood cancers.
Pediatric cancers and the N-myc oncogene. - ANSWER-Oncogenes and tumor suppressor genes are associated with the development of childhood cancer. Proto- oncogenes code for proteins that help regulate normal cell growth and differentiation. If mutated, proto-oncogenes become oncogenes that help to turn normal cells into cancer cells. Changes produced by specific oncogenes cause the cell cycle to become dysregulated. An example of an oncogene identified in pediatric cancer is N-myc,which is involved in neuroblastoma and glioblastoma.Tumor-suppressor genes arise from genes that normally suppress cancer cell proliferation but have lost their suppressor function, thus leading to uncontrolled growth. Some childhood cancers identified with tumor-suppressor genes include osteosarcoma, leukemia, rhabdomyosarcoma, retinoblastoma, and Wilms tumor.
Gland responsible for thermoregulation and cooling? - ANSWER-The eccrine sweat glands are distributed over the body, with the greatest numbers in the palms of the hands, soles of the feet, and forehead. These secretions are important in thermoregulation and cooling of the body through evaporation.
Clinical manifestation of pressure ulcers. - ANSWER-Pressure ulcers are ischemic ulcers resulting from unrelieved pressure, shearing forces, friction, and moisture.Decubitus ulcer refers to an ulcer or pressure sore that results when an individuallies or sits in one position for a long time. Individuals with darkly
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