Download Critical Thinking Chapter 3

Critical Thinking Chapter 3
1. Phagocytes gather in the air sacs of the lungs, especially in the lungs of smokers. What
is the connection?
2. Some people have too few receptors for the cholesterol-carrying low-density lipoprotein
(LDL). As a result, cholesterol builds up in blood vessel walls, restricting blood flow and
leading to high blood pressure. By what cellular transport process is cholesterol taken up
from the blood in a person with normal numbers of LDL receptors?
3. Hydrocortisone is an anti-inflammatory drug that can be injected or given topically
(applied to the skin). What properties does the topical cream have to have for it to be
effective?
4. A “red hot” bacterial infection of the GI tract irritates the intestinal cells and interferes
with digestion. Such a condition is often accompanied by diarrhea. On the basis of
osmosis, why would this occur?
5. A patient recovering from surgery was mistakenly given a transfusion of 5% salt solution
instead of a 0.9% physiological saline solution. The patient immediately went into shock
and soon after died. What caused the patient’s shock?
6. An infant is brought in with chronic diarrhea, which her mother says occurs whenever the
baby drinks milk. The doctor diagnoses lactose intolerance. She explains to the parents
that their baby is unable to digest milk sugar and suggests adding lactase to the baby’s
milk. How would lactose intolerance lead to diarrhea? How does adding lactase prevent
diarrhea?
7. Liver cells store excess glucose in the form of glycogen. If the liver is packed with
glycogen, what transport mechanism would be used to transport more glucose into the
liver cells and why?
8. Two solutions, A and B, are placed in a U-tube and separated by a semipermeable
membrane. Over time, the level of fluid on side A increases. Which solution initially had
the higher concentration of solute?
9. Why can cancer cells be easily recognized in most cases?
10. In the anatomy lab, students are exposed to the chemical preservatives phenol,
formaldehyde and alcohol. Outer cells break down these toxins very effectively. What
cellular organelle is responsible for this?
11. Before the invention of refrigerators, pioneers preserved meat by salting it. Explain why
this works.
12. For the following solutions, indicate whether they would be considered isotonic,
hypertonic, or hypotonic to red blood cells.
a. 0.5% saline
c. 10% saline
b. 0.9% saline
d. tap water