Physiology test 4

Match the methods and approximate quantities regarding how carbon dioxide is transported from the tissues to the lungs to be exhaled?

dissolved in blood: 7 bound to hemoglobin: 23 converted to bicarb: 70

An 11 year-old is to have his gall bladder removed. He is known to have one copy of an abnormal hemoglobin gene. This abnormal hemoglobin gene has higher affinity for oxygen. If the normal hemoglobin curve is the middle line, which curve is for the high affinity hemoglobin found in this patient According to this adjusted curve, how much oxygen would be delivered to this patient's tissues if their arterial PO2 is 100 mmHg and their venous PO2 is 40 mmHg During surgery, anesthesia depresses cellular function so venous PO2 often increases to ~50 mmHg. According to the patient's adjusted curve, how much oxygen will be delivered to the patient's tissues if the venous PO2 is ~50 mmHg during surgery Will breathing via ventilator (air will contain 95% oxygen) help this patient

dotted blue line 20 <5 No

Since Hemoglobin is found in red blood cells, the number of red blood cells will affect the oxygen carrying capacity of a patient's blood.

true

The PO2 of the blood is the primary determinant of the level of O2 saturation of hemoglobin.`

true

When hemoglobin is fully bound with oxygen it is said to be saturated. How many sites on Hemoglobin are filled with oxygen when it is saturated?

4

At a mountainous elevation of 18,000 feet, the total barometric pressure is 380 mmHg. If you maintained the same alveolar ventilation there as at sea level, what would your alveolar PO2 be closest to?

40

Select the best answer regarding the effects of Carbon monoxide :A small amount of CO in the air will not reduce arterial PO2 levels enough to be sensed by the peripheral chemoreceptors. The central chemoreceptors will detect the reduction in oxygen delivered to the cells and will increase their firing rate. The affinity between CO and hemoglobin is about the same as oxygen. CO results in less oxygen loading hemoglobin but unloading is not changed.

A small amount of CO in the air will not reduce arterial PO2 levels enough to be sensed by the peripheral chemoreceptors.

Which of the following is FALSE regarding exhalation in a healthy quietly-breathing person? CO2 will be displaced from hemoglobin Some air remains in the respiratory tract at end of exhalation. Alveolar pressure goes below atmospheric pressure No muscular effort is required to exhale. Alveolar pressure rises above atmospheric pressure Bicarbonate and H+ will be converted to CO2 and water.

Alveolar pressure goes below atmospheric pressure

Which statement about the factors that affect the affinity of hemoglobin for oxygen are FALSE? With decreasing pH, affinity decreases so that more oxygen is released from hemoglobin. Decreased blood temperature increases hemoglobin affinity for oxygen. CO2 increases the affinity of oxygen for hemoglobin so that hemoglobin binds oxygen more strongly. The affinity of hemoglobin for oxygen is higher than for carbon dioxide which results in oxygen being able to displace carbon dioxide from hemoglobin as the blood travels through the pulmonary capillaries. Decreased O2 partial pressure diminishes affinity and this favors oxygen unloading and delivery to the tissues.

CO2 increases the affinity of oxygen for hemoglobin so that hemoglobin binds oxygen more strongly.

Select the INCORRECT statement regarding gases: When you go to higher elevation, the PO2 is reduced because atmospheric pressure is reduced. The partial pressure of oxygen in the arterial blood is normally 100 mmHg. CO has a increased affinity of binding with hemoglobin which greatly reduces oxygen delivery to the cells. Carbon monoxide in the air results in a significant reduction in the PO2 of the arterial blood. The partial pressure of oxygen in the alveoli is lower than the air due to humidification of the air in the airways and the anatomical dead space.

Carbon monoxide in the air results in a significant reduction in the PO2 of the arterial blood.

Select all the true statements regarding respiration and the exchange of gases between the environment and the tissues. For oxygen delivery to the tissues, the affinity between oxygen and hemoglobin must decrease when the partial pressure of oxygen falls. For expiration, the volume of the lungs increases so air can move out of the lungs. During expiration, all the air from the lungs is moved to the environment. Rapid diffusion allows for equilibration of the PO2 between the alveoli and the pulmonary capillaries and the arterial blood. Due to the very thin membranes, diffusion of gases between the alveoli and pulmonary capillaries is very fast and efficient For inspiration, the volume of the lungs increases causing the pressure in the lungs to go below the atmospheric air pressure The affinity between oxygen and hemoglobin is high in the venous blood. The partial pressure of oxygen in the blood includes the amount of oxygen bound to hemoglobin. Oxygen poorly dissolves in blood plamsa. The partial pressure of oxygen in the blood is determined by the amount of oxygen dissolved in the blood plasma

For oxygen delivery to the tissues, the affinity between oxygen and hemoglobin must decrease when the partial pressure of oxygen falls. Rapid diffusion allows for equilibration of the PO2 between the alveoli and the pulmonary capillaries and the arterial blood . Due to the very thin membranes, diffusion of gases between the alveoli and pulmonary capillaries is very fast and efficient Oxygen poorly dissolves in blood plamsa. The partial pressure of oxygen in the blood is determined by the amount of oxygen dissolved in the blood plasma

The name of the protein that binds oxygen with high affinity is:

Hemoglobin

Select all the true statements regarding normal hemoglobin: Hemoglobin has a safety zone for oxygen binding so that even when the PO2 of oxygen slightly falls hemoglobin remains highly saturated. Hemoglobin has a higher affinity for oxygen when the PO2 is the plasma is high. Hemoglobin has a relatively lower affinity for oxygen when the PO2 is below 60 mm Hg. Hemoglobin has a higher affinity for Carbon dioxide than for Oxygen. Hemoglobin is found in the blood plasma.

Hemoglobin has a higher affinity for oxygen when the PO2 is the plasma is high. Hemoglobin has a relatively lower affinity for oxygen when the PO2 is below 60 mm Hg. Hemoglobin has a safety zone for oxygen binding so that even when the PO2 of oxygen slightly falls hemoglobin remains highly saturated.

Select all the true statements regarding normal hemoglobin: Hemoglobin has a safety zone for oxygen binding so that even when the PO2 of oxygen slightly falls hemoglobin remains highly saturated. Hemoglobin is found inside red blood cells. Hemoglobin has a higher affinity for oxygen when the PO2 is high. Hemoglobin has a relatively lower affinity for oxygen when the PO2 is below 60 mm Hg. Hemoglobin has a lower affinity for Carbon Monoxide than for Oxygen.

Hemoglobin has a safety zone for oxygen binding so that even when the PO2 of oxygen slightly falls hemoglobin remains highly saturated. Hemoglobin is found inside red blood cells. Hemoglobin has a higher affinity for oxygen when the PO2 is high. Hemoglobin has a relatively lower affinity for oxygen when the PO2 is below 60 mm Hg.

Select the statement that is INCORRECT. The affinity of oxygen for hemoglobin varies with the PO2 level. Hemoglobin's affinity for CO2 is greater than O2. Hemoglobin's affinity for CO is greater than O2. During exercise, skeletal muscle cells consume more oxygen resulting in a reduction in PO2 in those tissue capillaries of the active skeletal muscles. The affinity of oxygen for hemoglobin must decrease to unload oxygen and deliver it to the tissues

Hemoglobin's affinity for CO2 is greater than O2.

A healthy person living on the coast at sea level attempts to climb to a mountain peak at 14,000 feet, which of the following changes are expected? Increased firing of the chemoreceptors. Increased respiratory rate A lower pulse oximeter reading because of a reduction in the arterial PO2. Decreased hematocrit levels due to chronic hypoxia. Decreased respiratory rate The alveoli PO2 decreases because of lower total O2 composition (< 21%) in air at high altitude. Decreased 2,3 BPG levels which will cause a rightward shift of oxygen-hemoglobin dissociation curve to facilitate O2 loading hemoglobin.

Increased firing of the chemoreceptors. Increased respiratory rate A lower pulse oximeter reading because of a reduction in the arterial PO2.

A healthy young man living on the coast at sea level attempts to climb to a mountain peak at 14,000 feet, which of the following changes are expected? Decreased 2,3 BPG levels which will cause a rightward shift of oxygen-hemoglobin dissociation curve to facilitate O2 loading hemoglobin. Increased respiratory rate A lower pulse oximeter reading because of a reduction in the arterial PO2. Decreased hemoglobin/hematocrit due to chronic hypoxia. The alveoli PO2 decreases because of lower total O2 composition (< 21%) in air at high altitude. Increased firing of the peripheral chemoreceptors. Decreased respiratory rate

Increased firing of the peripheral chemoreceptors. Increased respiratory rate A lower pulse oximeter reading because of a reduction in the arterial PO2.

According to the hemoglobin saturation curves below, how much oxygen do Patients 1, 2, and 3 deliver if the amount of oxygen in blood LEAVING the lungs is 85 mm Hg and the amount of oxygen in the blood RETURNING TO the lungs is 45 mm Hg?

Patient 1: 8 Patient 2: 25 Patient 3: 70

Select all the answers that are true for chemoreceptors located in the carotid bodies and aortic arch: Sense arterial blood levels of PO2 and PCO2 Sense PCO2 of the arterial blood. Once activated, respond quickly to regulate respiratory rate Sense PO2 delivered to the tissues. Sense levels of PCO2 surrounding the brain tissues. Sense only PCO2 (not PO2). Sense PO2 when it drops below the normal 100 mmHg.

Sense arterial blood levels of PO2 and PCO2 Sense PCO2 of the arterial blood. Once activated, respond quickly to regulate respiratory rate

Select the statement that is false regarding pulmonary surfactant. Surfactant increases overall lung compliance All statement options regarding surfactant are true. Surfactant is produced by type I alveolar cells Surfactant decreases surface tension in the small alveolar air sacs Surfactant production begins in the late-gestational period so babies born prematurely often need ventilation until they can produce surfactant.

Surfactant is produced by type I alveolar cells -Surfactant is produced by type II alveolar cells. Type I alveolar cells make up the wall of the alveolar sacs.

In comparison to the partial pressure of oxygen (PO2) in atmospheric air: The PO2 in the alveoli is the same due to diffusion. The PO2 of the arterial blood is higher. The PO2 of the venous blood is higher. The partial pressure of CO2 in atmospheric air is higher. The PO2 in the alveoli is lower because some air stays in the lungs at the end of expiration.

The PO2 in the alveoli is lower because some air stays in the lungs at the end of expiration.

In comparison to the partial pressure of oxygen (PO2) in atmospheric air: The partial pressure of CO2 in atmospheric air is higher. The PO2 of the venous blood is higher. The PO2 in the alveoli is lower because water vapor is added in the lungs and some air stays in the lungs at the end of expiration. The PO2 of the arterial blood is higher due to the addition of hemoglobin. The PO2 in the alveoli is the same due to diffusion.

The PO2 in the alveoli is lower because water vapor is added in the lungs and some air stays in the lungs at the end of expiration.

Select the FALSE statements about the factors that affect the affinity between hemoglobin and oxygen. Decreased blood temperature increases hemoglobin affinity for oxygen. The affinity of hemoglobin for oxygen is lower than for carbon dioxide so carbon dioxide displaces oxygen as the blood travels through the tissue capillaries. CO2 increases the affinity of oxygen for hemoglobin so that hemoglobin binds oxygen more strongly. Decreased O2 partial pressure diminishes affinity and this favors oxygen unloading to the tissues. With decreasing pH, affinity decreases so that more oxygen is released from hemoglobin.

The affinity of hemoglobin for oxygen is lower than for carbon dioxide so carbon dioxide displaces oxygen as the blood travels through the tissue capillaries. CO2 increases the affinity of oxygen for hemoglobin so that hemoglobin binds oxygen more strongly.

Select the answer that is false regarding the effects of Carbon monoxide: Small amounts of CO being present in the inspired air may greatly reduce oxygen delivery to the tissue cells. A small amount of CO in the air will not reduce arterial PO2 levels enough to be sensed by the peripheral chemoreceptors. CO results in a large leftward shift in the O2-hemoglobin association curve. The affinity between CO and hemoglobin is 240 times greater than oxygen. The central chemoreceptors will detect the reduction in oxygen delivered to the cells and will increase their firing rate.

The central chemoreceptors will detect the reduction in oxygen delivered to the cells and will increase their firing rate.

During inspiration: The expiratory muscles contract to pull the air in. Air which is high in oxygen and low in carbon dioxide is moved out of the lungs. The diaphragm and intercostal muscles relax The diaphragm contracts and moves downward to decrease the pulmonary pressure. The pressure in the lungs increases above atmospheric pressure.

The diaphragm contracts and moves downward to decrease the pulmonary pressure.

Select the incorrect statement regarding external respiration. The partial pressure of oxygen decreases in the respiratory airways compared to the air because we can not exhale every bit of air from the lungs Since the cells consume oxygen, the partial pressure of oxygen in the blood as it travels through the tissue capillaries rapidly decreases from the PO2 in the arteriole blood The partial pressure of oxygen is higher in the air we breath than in the alveoli The partial pressure of CO2 in the arterial blood is the same as the venous blood. The partial pressure of oxygen in the arterial blood is normally the same as in the alveoli because of rapid diffusion

The partial pressure of CO2 in the arterial blood is the same as the venous blood.

During normal resting breathing, expiration is associated with: Air which is high in oxygen and low in carbon dioxide moving out of the lungs. The expiratory muscles contracting to squeeze the air out. The diaphragm contracting and moving downward to decrease the pulmonary pressure. The pressure in the lungs increasing above atmospheric pressure. The intercostal muscles contracting

The pressure in the lungs increasing above atmospheric pressure.

Select the INCORRECT statement regarding gases: Gases (O2 and CO2) move passively down their pressure gradients from higher to lower. When you go to higher elevation, the O2 composition is reduced below 21% of the atmospheric air . CO2 composes <1% of the atmospheric air. The partial pressure of oxygen in the air is 160 mmHg at sea level. O2 composes 21% of the atmospheric air.

When you go to higher elevation, the O2 composition is reduced below 21% of the atmospheric air.

Select the INCORRECT statement regarding gases: CO2 composes <1% of the atmospheric air. The partial pressure of oxygen in the air is 160 mmHg at sea level. Gases (O2 and CO2) move passively down their pressure gradients from higher to lower. O2 composes 21% of the atmospheric air. When you go to higher elevation, the O2 composition is reduced below 21% of the atmospheric air.

When you go to higher elevation, the O2 composition is reduced below 21% of the atmospheric air. -This is not true, The total atmospheric pressure is reduced at higher elevations but the oxygen still makes up 21%. Since total atmospheric pressure is lower, 21% of that lower total pressure reduces oxygen partial pressure.

PCO2 of 40 mmHg

arterial blood CO2 level

PO2 of 100 mmHg

arterial blood O2 levels

A decrease in the affinity of binding between oxygen and hemoglobin indicates a patient must have decreased O2 delivery to their cells.

false A decrease in affinity most likely indicates less binding of oxygen to hemoglobin in the arterial blood, however, unloading of oxygen in the tissue capillaries may be enhanced.

A leftward shift in the O2-hemoglobin saturation curve indicates an increase or a decrease Decrease in the affinity of binding between oxygen and hemoglobin. A rightward shift in the O2-hemoglobin saturation curve indicates an increase or a decrease Increase in the affinity of binding between oxygen and hemoglobin.

increase decrease

PO2 of 30 mmHg

level of O2 in the interstitial fluid around contracting muscle cells

The PO2 value refers only to the amount of oxygen dissolved in the plasma and the oxygen bound to hemoglobin does not contribute to the PO2 value.

true Correct. The partial pressure of a gas refers to the free gas and not when it is bound to a protein.

Where is the partial pressure of oxygen highest in a normal, resting person?

pulmonary vein

A decrease in PO2 in a pulmonary capillary bed will result in vasoconstriction of the arterioles that control blood flow to those pulmonary capillaries.

true Correct. When an alveolar sac has reduced ventilation, the PO2 levels will fall. If the capillaries that bring blood flow to that alveolar sac remain open, this will result in a reduction in the PO2 of the blood leaving the lungs and lead to a reduction in arterial PO2. That would not be good. A very important regulatory control mechanism exists to try to maintain high arterial PO2 levels. Thus, when the arterioles sense low PO2 levels in pulmonary capillaries, this causes the arterioles controlling the blood flow to those capillaries to constrict. This way less blood flows to areas where the alveolar are poorly ventilated. Instead, blood flow can be redirected to just the alveolar sacs that are well ventilated and receiving lots of fresh air with higher PO2 levels. If this feels a little counter-intuitive to what you learned for the regulation at the tissues it is. When PO2 levels decrease at the tissues, the arterioles dilate to try to send oxygen carrying blood to the cells that need it. To keep these two different areas/effects straight remember the main purpose of the two separate capillary beds. The pulmonary beds are to get oxygen into the blood. The tissue beds are to bring oxygen to the cells that need it the most.

PCO2 of 46 mmHg

venous blood CO2 levels

PO2 of 40 mmHg

venous blood O2 level