Question 311#

What is the typical vital capacity in a male?

A. 300 ml

Correct Answer E:

Respiratory physiology: lung volumes:

Tidal volume (TV):

• Volume inspired or expired with each breath at rest
• 500ml in males, 350ml in females

Inspiratory reserve volume (IRV) = 2-3 L:

• Maximum volume of air that can be inspired at the end of a normal tidal inspiration
• Inspiratory capacity = TV + IRV

Expiratory reserve volume (ERV) = 750ml:

• Maximum volume of air that can be expired at the end of a normal tidal expiration

Residual volume (RV) = 1.2L:

• Volume of air remaining after maximal expiration
• Increases with age
• RV = FRC - ERV

Vital capacity (VC) = 5L:

• Maximum volume of air that can be expired after a maximal inspiration
• 4,500ml in males, 3,500 ml in females
• Decreases with age
• VC = inspiratory capacity + ERV

Question 312#

Which one of the following techniques would be most suitable to detect and quantify a viral protein?

A. Polymerase chain reaction

Correct Answer C:

Molecular biology techniques:

• SNOW (South - NOrth -West)
• DROP (DNA - RNA - Protein)

Molecular biology techniques:
The following table shows a very basic summary of molecular biology techniques:

Question 313#

Which one of the following significance tests is used to analyze data which is measured and follows a normal distribution?

A. Chi-squared test

Correct Answer E:

Student's t-test is used to analyze parametric data. The other tests are used on non-parametric data.

Significance tests: types:

The type of significance test used depends on whether the data is parametric (something which can be measured, usually normally distributed) or non-parametric.

Parametric tests:

• Student's t-test - paired or unpaired
• Pearson's product-moment coefficient - correlation

Non-parametric tests:

• Mann-Whitney U test - unpaired data
• Wilcoxon signed-rank test - compares two sets of observations on a single sample
• Chi-squared test - used to compare proportions or percentages
• Spearman, Kendall rank - correlation

Paired data refers to data obtained from a single group of patients, e.g. Measurement before and after an intervention. Unpaired data comes from two different groups of patients, e.g. Comparing response to different interventions in two groups.

Question 314#

Which one of the following statements regarding leptin is incorrect?

A. Is produced mainly by the hypothalamus

Correct Answer A:

Leptin is secreted by adipose tissue.

Obesity: physiology:

Leptin:

Leptin is thought to play a key role in the regulation of body weight. It is produced by adipose tissue and acts on satiety centres in the hypothalamus and decreases appetite. More adipose tissue (e.g. in obesity) results in high leptin levels.

Leptin stimulates the release of melanocyte-stimulating hormone (MSH) and corticotrophin-releasing hormone (CRH). Low levels of leptin stimulates the release of neuropeptide Y (NPY).

Ghrelin:

Where as leptin induces satiety, ghrelin stimulates hunger. It is produced mainly by the fundus of the stomach and the pancreas. Ghrelin levels increase before meals and decrease after meals.

Question 315#

A study compares the sensitivity of two tests for colorectal cancer. The first test has a sensitivity of 85% whilst the second test has a sensitivity of 91%.

What type of significance test should be used for comparing the two results?

A. Wilcoxon matched-pairs

Correct Answer D:

As percentages are being compared the chi-squared test should be used.

Significance tests: types:

The type of significance test used depends on whether the data is parametric (something which can be measured, usually normally distributed) or non-parametric.

Parametric tests:

• Student's t-test - paired or unpaired
• Pearson's product-moment coefficient - correlation

Non-parametric tests:

• Mann-Whitney U test - unpaired data
• Wilcoxon signed-rank test - compares two sets of observations on a single sample
• Chi-squared test - used to compare proportions or percentages
• Spearman, Kendall rank - correlation

Paired data refers to data obtained from a single group of patients, e.g. Measurement before and after an intervention. Unpaired data comes from two different groups of patients, e.g. Comparing response to different interventions in two groups.