Download Chapter 6 The tumor is encapsulated (surrounded by a layer of

Chapter 6
1. The tumor is encapsulated (surrounded by a layer of connective tissue), and its cells
have a "normal" appearance for the organ. These are indications that Ms. Bennett’s
tumor is benign.
2. Ms. Malcolm’s physician recommends a biopsy of the axillary lymph nodes because the
tumor is malignant and therefore capable of metastasizing. Since the axillary lymph
nodes are the closest lymph nodes to the mammary glands, these would be the first
lymph nodes biopsied for possible metastasis. Wandering cancer cells from the breast
can easily lodge there and "seed" the lymph node, resulting in the development of a new
tumor.
3. The mitotic index is a measure of cell division. An abnormally high mitotic index for a
specific tissue or organ suggests cancer.
4. Some tumors increase in size more rapidly in the presence of certain chemicals that
stimulate cell growth and division. In the case of breast cancer, one of these chemicals
is estrogen. By using tamoxifen to block estrogen’s ability to bind to its receptor, the rate
of tumor growth would be decreased.
5. Even though X rays can induce mutations and thereby increase a person’s risk of
developing cancer, X rays are also able to detect very small masses that may not be
palpable (either by the woman during a BSE or by a clinician during a physical
examination). The sooner the mass is detected, the sooner a diagnosis can be made—
and if the woman has cancer, the sooner treatment can be started. These factors
combine to increase the patient’s odds of survival. Thus, X rays carry both risks and
benefits, but this is a case in which the benefits considerably outweigh the risks.
6. Anaerobic fermentation generates lactic acid. As lactic acid accumulates, the
intracellular pH decreases. This drop in pH can change the shape of cellular proteins.
Since enzymes are proteins, the shape of the enzyme is altered. This conformational
change can lead to decreased enzymatic activity. As more and more enzymes are
affected by the pH, there is increased inhibition of catalytic reactions, eventually leading
to cessation of the metabolic pathways in the cell.
7. In both hypothermic injury and dystrophic calcification, crystals (ice and calcium crystals,
respectively) are formed in the cell. These crystals can damage the plasma membrane
and disrupt the osmotic balance of the cell.
8. Gouty arthritis more commonly affects the great toe than other joints because every time
a person takes a step, the toe moves, thus being subjected to a great deal of mechanical
stress. Activities such as running, jumping, and standing on tiptoe increase the
mechanical stress on the great toe still further.
9. Drinking more water induces the body to produce more urine. This increases the rate of
urate excretion from the body, thus helping to prevent urate from accumulating to the
level that it accumulates in the tissues and causes joint inflammation.
10. The rehydration step would be unnecessary.