Question

A 60 year old male truck driver was taken to the nearest hospital because of vomiting and mild abdominal A pain that caused him to shake vigorously and lose consciousnes. Upon arrival, his vital signs were taken:

Vital Functions​​Blood pressure​​​90/50 mm Hg

Resting heart rate​​110 beats per minute

Resting respiration rate​​18 breaths per minute

Body temperature​​98oF

Blood analysis​​RBC count​​​normal

​​​WBC​​​​normal

​​​Platelets​​​​normal

​​​Erythropoietin​​​elevated

​​​PaCO2​​​​50 mm Hg high

​​​PaO2​​​​60 mm Hg low

Because heart attack was initially suspected, the patient was given four 80mg aspirin tablets while an EKG was ordered. His EKG recording seemed to indicate the occurrence of a heart attack so he was asked to stay overnight for close monitoring. While resting, the patient requested for some water / food in which he took a couple of spoonfuls of a clear chicken soup. After a little while, the patient said he needed to defecate in which he was then helped to sit up. While in this position, the patient started to vomit again - he ejected vomitus and stool of ground coffee color. Upon further questioning, it was revealed that he has been a chronic alcohol drinker without food during those drinking bouts. Also, he confessed he would drink those 5-hour energy drinks that are high in caffeine content in order to keep him awake while on long distance driving. Endoscopy was immediately ordered which confirmed that his stomach lining has bleeding ulcers.  

Assess his respiratory functions.

A) Which division of the ANS would be activated to alter his tidal volume? What neurotransmitter and corresponding membrane receptor is involved? Where would it exert its effects in the respiratory airway? How does the neurotransmitter alter the activity of its target tissue? How specifically would this impact alveolar ventilation?

B) Based on the plasma gas levels (PCO2 and PO2), which sensory receptors would be involved? Where are these located? How will their firing rate be altered by the gas levels? To which control center would they relay their impulses and how will the control center respond? What respiratory muscles will be activated? Overall, how would these chemicals impact his respiration rate?

Answer 1

1. The patient is suffering from hypoxia and hypercapnia.

• Sympathetic system will be activated
• Acetylcholine will be released and the receptor activated is beta2
• It will cause bronchodilation by acting on the bronchi
• It causes dilation of the bronchi
• It will increase alveolar ventilation

2.

• Peripheral chemoreceptors will be activated
• They are located in the aortic arch and the bifurcation of the common carotid arteries
• Their firing rate will increase
• They stimulate the medullary inspiration neurons which will increase their firing rate
• They will act on the external intercostal muscles, diaphragm
• All these activities will increase the inspiration rate