Q15. The most powerful respiratory stimulus for breathing in a healthy person is ________.a) loss of oxygen in tissuesb) increase of carbon dioxide in bloodc) decrease of oxygen in bloodd) increased muscle activity

4.Explain how the air is inhaled during breathing in humans.

39) Diaphragmatic breathing is effective only when done lying down.Group of answer choicesTrueFalse

Which ONE of the following statements about mechanisms of breathing is CORRECT?Group of answer choicesMovement of air out of the lungs occurs via a pressure gradient created by expanding the thoracic cageWhen surface tension between parietal and visceral pleura is broken, lungs may collapse and this is largely due to elastic recoilThe diaphragm is responsible for quiet breathing because its attachments to the ribs help expand the thoracic cageRhythmic contractions of the diaphragm are controlled by the brainstem and transmitted from the thoracic spinal cord via the phrenic nerveUpper ribs tend to expand the thoracic cage by increasing its tranverse diameter and lower ribs tend to expand it in the anteroposterior dimension Flag question: Question 5Question 51 ptsWhich ONE of the following statements regarding the trachea is CORRECT?Group of answer choicesIt is posterior to the oesophagus in the neckIt divides into the main bronchi at the at vertebral level T3It contains cartilaginous rings that are deficient anteriorlyIt is lined by respiratory epitheliumIt begins at the level of the hyoid bone Flag question: Question 6Question 61 ptsWhich ONE of the following statements regarding the thoracic aorta is correct?Group of answer choicesThe ascending aorta arises from the left ventricle in the middle mediastinumThe descending aorta passes through the aortic hiatus of the diaphragm at the level T‑10The ascending aorta does not have any branchesThe descending thoracic aorta is located in the middle mediastinumThe aorta arches over the right main bronchus

Select all of the options that best complete the following sentence. When we exhale:the air has more carbon dioxide than inhaled airthe diaphragm and intercostal muscles relaxthe pressure in the lungs increases, forcing air outthe lungs expand

5) Which of the following will cause the largest increase in systemic arterial oxygensaturation in the blood?a) an increase in red cell concentration (hematocrit) of 20%b) breathing 100% O2 in a healthy subject at sea levelc) an increase in arterial PO2 from 40 to 60 mmHgd) hyperventilation in a healthy subject at sea levele) breathing a gas with 5% CO2, 21% O2, and 74% N2 at sea level