Download HL Biology H5 - Transport 1. One type of heart disease is diastolic

HL Biology
1.
H5 - Transport
One type of heart disease is diastolic heart failure (DHF). A study was carried out to see if DHF
was related to abnormalities in the diastolic properties of the left ventricle. Two groups of
patients, one with DHF and the other the control group with no symptoms of DHF, were
assessed to compare:

changes in left ventricular diastolic pressure and volume

and stiffness of muscles leading to resistance of the left ventricle to stretch under
increasing pressure.
Graph 1 shows the mean lowest pressure in the left ventricle during diastole after the opening of
the atrio-ventricular valve. Graph 2 shows individual stiffness constants.
M R Zile et al., “Diastolic heart failure: Abnormalities in active relaxation and passive stiffness of the left ventricle”,
New England Journal of Medicine (2004), vol. 350, issue 19, pp. 1953–1959.
Copyright ©1994 Massachusetts Medical Society. All rights reserved
1
HL Biology
(a)
H5 - Transport
Identify the left ventricular diastolic volumes in patients and the control group that
correspond to a pressure of 5 mm Hg.
Patients:
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Control group:
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(1)
(b)
Compare the diastolic pressure-volume relationship of patients with DHF and the control
group.
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(2)
(c)
Distinguish between the stiffness constants in the two groups of patients.
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(1)
(d)
(i)
Suggest why in patients with DHF there is little or no increase in blood volume
pumped out of the left ventricle with each contraction during exercise.
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(1)
2
HL Biology
H5 - Transport
(ii)
Deduce how patients with DHF would respond to heavy exercise.
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(1)
(Total 6 marks)
2.
Poor nutrition of a woman during pregnancy has been associated with a variety of metabolic
disorders later in the life of her offspring.
During the second world war (WWII) the normally well-fed population of Holland suffered
famine over a relatively short and precisely defined period. The data available from this period
provided examples of fetuses that were affected by famine at specific periods during pregnancy.
Glucose tolerance was analysed in human adults 50–55 years of age who had suffered fetal
famine during WWII (Figure 1). High glucose levels in blood plasma indicate poor glucose
tolerance.
Figure1: Glucosetolerance
Plasmaglucose
concentration/
mmol 1–1
6.4
6.3
6.2
6.1
6.0
5.9
5.8
5.7
5.6
5.5
5.4
Born
before
famine
Late
pregnancy
M
id
pregnancy
Early
pregnancy
Conceived
after
famine
Periodof exposuretofamine
[Source: N Metcalfe and P Monaghan, (2001), Trends in Ecology and Evolution, 16, pages 254-260]
(a)
(i)
Identify the period of exposure to famine that produces the greatest decrease in
glucose tolerance.
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(1)
3
HL Biology
H5 - Transport
(ii)
Calculate the percentage change in plasma glucose concentration after exposure to
famine from early to late pregnancy.
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(1)
(iii)
Suggest a reason why glucose tolerance did not return to normal in people
conceived after the famine.
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(1)
(b)
Outline a possible cause of poor glucose tolerance.
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(1)
(c)
Suggest how poor glucose tolerance could be related to the occurrence of coronary heart
disease.
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(2)
(Total 6 marks)
4
HL Biology
3.
(a)
H5 - Transport
Distinguish between the mode of action of steroid and protein hormones.
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(2)
(b)
Explain the events of the cardiac cycle including systole, diastole and heart sounds.
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(6)
(Total 8 marks)
5
HL Biology
4.
H5 - Transport
Discuss factors which affect the occurrence of coronary heart disease.
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(Total 7 marks)
6