The Medical College - Page 48
154.
Patients with heart failure have an active
pres-
sure curve (i.e., upper curve), which is
shifted
downward and to the right as compared with
that
of normal. Assuming the end diastolic
volume
and the mean aortic pressure remain
constant
and the ventricle is capable of ejecting
blood:
I.
stroke volume decreases.
II.
end systolic volume increases.
III.
ventricular work decreases.
IV.
end systolic volume decreases.
A.
I, II, and III only
C.
II and IV only
B.
I and III only
D.
IV only
155.
With time, the blood volume of patients
with
heart failure tends to increase resulting in
an
increased end diastolic volume with a
continued
downward shift in the active pressure curve
(i.e.,
upper curve). The increase in the end
diastolic
volume, as compared with the case of a
failing
ventricle without compensation referred to in
the
preceding question, will result
in:
I.
a stroke volume that may or may
not
increase.
II.
an increase in cardiac work.
III.
a decrease in end systolic volume.
IV.
an increase in stroke volume.
A.
I, II, and III only
C.
II and IV only
B.
I and III only
D.
IV only
156.
With a constant mean aortic pressure and
as
compared to normal, a compensated failure
will
show:
I.
an increase in stroke volume.
II.
a stroke volume that may or may
not
decrease.
III.
a decrease in cardiac work.
IV.
an increase in end systolic
volume.
A.
I, II, and III only
C.
II and IV only
B.
I and III only
D.
IV only
Passage III (Questions
157–163)
In a laboratory experiment, red blood cells
were
placed into 0.5 M solutions and the appearance
of the
solutions was observed two hours later with the
naked
eye.
Solution
Cells
0.5 M glucose
no change
0.5 M sucrose
no change
0.5 M urea
hemolysis of RBCs
0.5 M glycerol
hemolysis of RBCs
157.
How can the solutions of urea and glycerol
be
described with respect to the red blood
cells?
A.
isotonic
C.
hypertonic
B.
hypotonic
D.
none of the above.
158.
The reason for these results is
that:
I.
the number of particles in the urea
and
glycerol solutions is greater than that
in
the glucose and sucrose solutions.
II.
glucose and sucrose form coatings
around
the red blood cells, which prevent
their
breaking.
III.
glucose and sucrose enter the cells but
are
immediately metabolized, therefore
water
does not enter the cells.
IV.
urea and glycerol can enter the cell,
water
follows them into the cell because it
is
then in greater concentration
outside.
A.
I and II only
C.
III and IV only
B.
I and III only
D.
IV only
159.
The property of the cell membrane that
allows
for this phenomenon to be demonstrated
is
called:
A.
diffusion.
C.
impermeability.
B.
osmosis.
D.
semipermeability.
160.
The process by which a cell can move a
sub-
stance from a point of lower concentration to
a
point of higher concentration (against the
diffu-
sion gradient) is called:
A.
osmosis.
C.
turgor pressure.
B.
plasmolysis.
D.
active transport.
161.
Which of the following structures are NOT
con-
sidered modifications of the cell
membrane?
A.
basement membrane
B.
terminal bars
C.
desmosomes
D.
intercalated discs
User Comments Add a comment…