196 ❯ STEP 4. Review the Knowledge You Need to Score High
❯ Answers and Explanations
15.Which of the following scenarios would be least
likely to initiate a response from the sympathetic
nervous system of the body?
A. Getting called on in class by the teacher
when you do not know the answer
B. Seeing a cop while you are driving too fast
on the highway
C. Walking through the woods and seeing a
bear in the near distance
D. Waking from a midafternoon nap as sun-
light strikes your face
E. Hearing a dish break on the kitchen floor
right behind you
- C—Most of the carbon dioxide traveling through
the bloodstream of the body is in the form of the
bicarbonate ion—HCO 3 –. Oxygen is the one that
likes to complex with hemoglobin. You should
try to avoid answer choice D when possible;
carbon monoxide is poisonous. Ferredoxin has
nothing to do with the transport of CO 2 —it is
involved in photosynthesis. - E—The thyroid gland is important to the main-
tenance of the body’s metabolic rate. An increase
in TSH leads to an increase in thyroxin (thyroid
hormone), which leads to an increase in the
metabolic rate of the body. - A—The LH surge brought about by the com-
bined effect of FSH and LH during the men-
strual cycle leads to ovulation in females. This is
essentially the release of an egg from its holding
pattern in the ovary that allows it to move toward
the uterus. - D—Aldosterone is released by the adrenal gland in
an effort to maintain appropriate levels of sodium
in the body. Its main site of action is the kidney. - C—Estrogen and progesterone work together to
maintain the endometrium, which is the site of
attachment for the growing fetus during preg-
nancy. Without these two hormones, the endo-
metrium sloughs off and is lost. - E—Lipase is the major fat-digestingenzyme of our
body. Bile salts help digest the fat by emulsifyingit
into small droplets contained in water. Amylase
digests carbohydrates. Trypsin and chymotrypsin
break down polypeptides.- B—Memory cells are produced after the body
first reacts to a foreign invader. The next time
the body is exposed to that invader, it can
respond much more quickly and efficiently.
Plasma cells produce the antibodies designed to
wipe out the antigens. Macrophages and neu-
trophils are both types of phagocytes, which gen-
erally roam around looking for nonspecific
garbage to pick up and destroy. - D—The quadriceps is the only muscle type on
this list that is not a smooth muscle. It is a skele-
tal muscle involved in voluntary movements. - C—The alveolus is the functional unit of the lung.
It is the true site of gas exchange during the respi-
ratory process. The trachea, larynx, bronchus, and
bronchioles are all tubes that the air passes through
on its way to this exchange center. - B—The medulla oblongata controls the involun-
tary actions of the body, including respiration. The
cerebellum controls balance, and the cerebrum is
in charge of higher thinking. The hypothalamus
monitors the concentration of many substances
throughout the body, and determines when cer-
tain hormones of the pituitary should be released
or cut down on. The amygdala controls our emo-
tions and is associated with rage and anger.