Unit 2: Respiratory & Immune

Addy Le'Ectasis is a neonate born at 33 weeks gestation. She is breathing rapidly and her lips have a blue tinge. Her mother is healthy, but has a history of asthma and one episode of pneumonia she got out in the community.

Respiratory Physiology and Pathology

1. Prematurity is a major risk factor for respiratory distress

syndrome (RDS). What explains the phenomenon of RDS? In

other words, what substance is missing or in low amount and

what cell type typically makes this substance? How does this

cause RDS?

2. In healthy newborns, breathing is usually initiated

automatically,indicated by loud crying and visible breathing.

An important trigger for breathing is based on chemoreceptors

in the body. What three chemicals are chemoreceptors

detecting and indicate if the receptors are responding to high

or low levels of these chemicals. Where are these receptors

located?

3. Select all of the following that would favor an increased

breathing rate.

A. Alkalosis.
B. Acidosis.

C. Hypercapnia.

D. Hypocapnia.

4. An oxygen dissociation curve is shown for your reference.

Fetal hemoglobin has a stronger affinity for oxygen due to the

expression of different globin chains. Which of the following is true?

A. A higher affinity for oxygen will shift the curve to the left.

B. A higher affinity for oxygen will shift the curve to the right.

C. Oxygen dissociation in active tissue is lower than in inactive tissue.

D. There is no reason for fetal hemoglobin to have higher oxygen

affinity compared to adult hemoglobin, but it occurs this way due to

different timing of gene expression.

5. Although breathing is generally automatic, we do have the ability to consciously control breathing. What is the primary muscle responsible for respiration? What nerve innervates this muscle?

O2 dissociation curve.

Depiction of vasculature.

Histology slide.

Respiratory anatomy.

Asthma

6. It is indicated that the mother has a history of asthma, which has a genetic component, putting Addy at increased risk. Consider the nervous system response during an asthma attack. Discuss which branch of the autonomic nervous system is overactive and what receptors are being activated.

7. Asthma attacks are characterized by an overactive immune response to something that is usually not-harmful and is termed a type I hypersensitivity reaction. With those around you, research what a type I hypersensitivity reaction is and explain what happens during it.

8. Spirometry and pulmonary function tests (one type is body plethysmography) are used to assess lung function for those who have breathing problems. Explain the difference in what these two tests measure. Which of these tests would be more likely to be completed in a clinic-setting and why?

Type I hypersensitivity reaction.

Body plethysmography.

Pharmacology

9. Chronic asthma is typically treated with inhalers. Two different drug classes are used: glucocorticoids and B2-agonists. Explain how each one of these helps with the symptoms of asthma (in other words, what are the mechanisms of action)?

Albuterol sulfate inhaler.

Glucocorticoid inhaler.

Extend Your Knowledge: Chest X-Rays

A chest x-ray, also known as a chest radiograph, is a helpful diagnostic tool. X-rays can be used to diagnose conditions such as chronic obstructive pulmonary disease (COPD), pneumothorax, or pneumonia. Read more at Radiopaedia.

10. Examine the two chest radiographs. The left one is normal and the right one shows a diagnosis of pneumonia. Answer the following questions regarding the chest radiographs.

A. In the left radiograph, what is the large, intense (white) structure extending the width of the inferior border?

B. In the left radiograph, what is indicated by the two arrows?

C. Explain the primary finding on the chest radiograph on the right that supports the diagnosis of pneumonia.

Normal PA chest radiograph.

Pneumonia PA chest radiograph.