Respiratory System- Physiology Questions and Answers with verified solutions

Respiratory System- Physiology Questions and Answers with verified solutions A decrease in pH shifts curve to the _______, and an increase in pH shifts curve to the ______. - ANS- Right; Left A high Va/Q is related to what? - ANS- Dead space air A left atrial pressure greater than what can lead to acute pulmonary edema? - ANS- 20mmHg A respiratory pressure of -1 equals ________, and a respiratory pressure of +1 equals _________. - ANS- 759mmHg; 761mmHg A respiratory pressure of what is equal to atmospheric pressure? - ANS- 0 According to Boyles law, what would happen to the pressure of the gas if the size of the container decreased? - ANS- It would increase Air moves into the lungs when pressure inside the lungs is ______ than the atmospheric, and air moves out of lungs when pressure inside the lungs is _______ than atmospheric. - ANS- less; greater Alveoli are drawn to their smallest possible dimensions as H2O forms hydrogen bonds. What is this force of attraction called? - ANS- The Law of LaPlace An increase in heat shifts curve to the _______ and a decrease in heat shifts curve to the ______. - ANS- Right (requires higher PO2 for same % saturation of Hb); Left An increase in what by the pneumotaxic center will result in a quicker breathing rate? - ANS- Neuro signals Describe expiration - ANS- It begins with the relaxation of the inspiratory muscles. There is a pressure increase largely due to the recoil of the elastic fibers stretched during inspiration (a passive process) Describe perfusion in an upright position, and how the alveolar pressure compares to capillary pressure - ANS- There is less perfusion in the apex of the lungs (zone 1), and alveolar pressure is higher than capillary pressure. Describe the bronchial arterial system - ANS- *It is a high pressure-low flow system (HPc~32mmHg...at the level of the heart) *It receives 1-2% of resting CO During inspiration, air flows in along its pressure gradient until intrapulmonary pressure is _______ to Atm pressure. - ANS- equal How can you determine whether pulmonary edema is heart (cardiogenic) or lung (non-cardiogenic) related? - ANS- By looking at pulmonary wedge pressure How many ml of O2 would dissolve in 1L of arterial blood if blood only contained plasma and no RBCs? - ANS- 3ml How many ml of Oxygen are found in 1L of oxygenated blood? - ANS- 200ml (so 197ml are bound to Hb, and 3ml are dissolved in plasma) How many mm of Hg is equal to atmospheric pressure at sea level? - ANS- 760mmHg How many mmHg are we at before inspiration, and during? - ANS- 756 (-4)mmHg; 754(-6)mmHg (This pulls the lungs outward) How much of the tidal volume reaches alveoli to be involved in alveolar ventilation, and where does the remaining amount end up? - ANS- 350ml; The rest remain in air spaces of nose, pharynx, larynx, trachea, bronchi, and bronchioles. These pathways are known as anatomical dead space. If our body system lacked hemoglobin what would not be able to take place? - ANS- Delivery of a sufficient amount of oxygen to our tissues If surfactant wasn't present in the alveoli, what would happen? - ANS- The alveoli would collapse between breaths In regard to peripheral chemoreceptors, what would stimulate respiratory centers if PO2 drops below 60mmHg? - ANS- Aortic bodies of the aortic arch and carotid bodies at the bifurcation of the common carotid arteries. In the apex of the lungs, where the alveoli are large, and perfusion is less than optimal, the Va/Q is what? - ANS- 4 L/min of Va to 2 L/min of Q, thus Va/Q=2 **This represents underperfusion and is 2.5 times the ideal value. (Similar to emphysema) Matching a sufficient volume of air in the alveoli to sufficient pulmonary blood flow demonstrates... - ANS- An ideal alveolar ventilation-to-perfusion ratio (Va/Q) Once carbonic acid dissociates, what happens? - ANS- The free H+ binds to Hb in RBC, which triggers the Bohr effect & releasing O2. PCO2 in alveolar capillaries favors what? - ANS- Splitting of CO2 from Hb to enter alveoli by diffusion