Module 20: Respiratory System Part 2

Efficient external respiration depends on three main factors. Name them.

1) PARTIAL PRESSURE GRADIENTS AND GAS SOLUBILITIES 2) STRUCTURAL CHARACTERISTICS OF THE RESPIRATORY MEMBRANE, including surface area 3) VENTILATION-PERFUSION COUPLING (matching alveolar air flow to pulmonary capillary blood flow)

A change in pH will change the respiratory rate even if CO2 and O2 levels are normal. A drop in pH will ________ the pulmonary ventilation while a rise in pH will _____ it down.

A change in pH will change the respiratory rate even if CO2 and O2 levels are normal. A drop in pH will INCREASE the pulmonary ventilation while a rise in pH will SLOW it down.

A drop in the Pco2 (_____) has the opposite effect. (it _____ the breathing rate) If the breathing is abnormally low, the breathing can stop completely (_____).

A drop in the Pco2 (hypocapnia) has the opposite effect. (it LOWERS the breathing rate) If the breathing is abnormally low, the breathing can stop completely (APNEA).

A graph plotting Hb saturation against PO2 shows how ______ & ______ of O2 is influenced by the PO2. This S-shaped curve is called the ______-____________ dissociation curve. Because of the S-shape, hemoglobin is almost completely ______ at a PO2 of 70 mmHg. (O2 loading and delivery to the tissues is adequate even when PO2 is ______ normal levels. If O2 levels in active tissues drop below the average of ___ mmHg, ______ oxygen dissociates and diffuses into the tissue.

A graph plotting Hb saturation against PO2 shows how BINDING & RELEASE of O2 is influenced by the PO2. This S-shaped curve is called the OXYGEN-HEMOGLOBIN dissociation curve. Because of the S-shape, hemoglobin is almost completely SATURATED at a PO2 of 70 mmHg. (O2 loading and delivery to the tissues is adequate even when PO2 is BELOW normal levels. If O2 levels in active tissues drop below the average of 40 mm Hg, MORE oxygen dissociates and diffuses into the tissue.

According to ______ LAW OF ______ ______, the ______ pressure exerted by a mixture of gases is the sum of the pressures exerted by each gas. The ______ pressure of each gas is directly proportional to its ______ in the mixture.

According to DALTON'S LAW OF PARTIAL PRESSURE, the TOTAL pressure exerted by a mixture of gases is the sum of the pressures exerted by each gas. The PARTIAL pressure of each gas is directly proportional to its PERCENTAGE in the mixture.

According to ______ LAW, if a mixture of gases is in contact with a liquid, each gas will dissolve in the liquid in proportion to its ______ pressure. At equilibrium, the partial pressure in the 2 phases will be ______.

According to HENRY'S LAW, if a mixture of gases is in contact with a liquid, each gas will dissolve in the liquid in proportion to its PARTIAL pressure. At equilibrium, the partial pressure in the 2 phases will be EQUAL.

According to Henry's Law, the amount of gas that will dissolve in a liquid also depends upon its ______. CO2 is ___ times more soluble in water than O2.

According to Henry's Law, the amount of gas that will dissolve in a liquid also depends upon its SOLUBILITY. CO2 is 20 times more soluble in water than O2.

All those changes ______ the affinity of hemoglobin for O2 and lead to an ______ O2 release. This is called a ______ shift of the O2-hemoglobin dissociation curve. Changes in the opposite direction ______ the affinity of hemoglobin for O2 and shift the curve to the ______.

All those changes LOWER the affinity of hemoglobin for O2 and lead to an INCREASED O2 release. This is called a RIGHT shift of the O2-hemoglobin dissociation curve. Changes in the opposite direction INCREASE the affinity of hemoglobin for O2 and shift the curve to the LEFT.

Alveolar gas has a different composition than atmospheric air. The PO2 is ______ but the PCO2 is ______ as is the PH20.

Alveolar gas has a different composition than atmospheric air. The PO2 is LOWER but the PCO2 is HIGHER as is the PH20.

Any bodily activity whether it's physical work or exercise, ________ oxygen use and production of CO2 and acids in the tissues. To keep Pco2, Po2, and pH constant during exercise, our minute ventilation has to go up ___ to _____ fold.

Any bodily activity whether it's physical work or exercise, INCREASES oxygen use and production of CO2 and acids in the tissues. To keep Pco2, Po2, and pH constant during exercise, our minute ventilation has to go up 10 to 20 fold.

_______ =breathing cessation - e.g., when Pco2 is abnormally low = respiration inhibited, slow & shallow

Apnea =breathing cessation - e.g., when Pco2 is abnormally low = respiration inhibited, slow & shallow

As CO2 ↑ & pH ↓ (more H+ = acidic), Hb affinity for O2 _________ so Hb __________ more O2 _________ tissues. What effect is this?

As CO2 ↑ & pH ↓ (more H+ = acidic), Hb affinity for O2 ↓ so Hb unloads more O2 into tissues! BOHR EFFECT

As they metabolize glucose they use O2 and the PO2 of the tissues ______. Oxidation of glucose produces CO2, which leads to an ______ PCO2 in the tissue, and heat which ______ the local temperature. CO2 forms carbonic acid which is a weak acid but still ______ the pH.

As they metabolize glucose they use O2 and the PO2 of the tissues DECREASES. Oxidation of glucose produces CO2, which leads to an INCREASED PCO2 in the tissue, and heat which INCREASES the local temperature. CO2 forms carbonic acid which is a weak acid but still LOWERS the pH.

Blood flow (________) through the alveolar capillaries and air flow (________) into the alveolar cavity have to be matched for an efficient gas exchange.

Blood flow (PERFUSION) through the alveolar capillaries and air flow (VENTILATION) into the alveolar cavity have to be matched for an efficient gas exchange.

Bronchioles react just the opposite from arteries/arterioles as they have to carry oxygen to alveoli with a ____ PO2, i.e. where the alveolar CO2 is high, bronchioles _______ to get the alveolus ventilated, and where the alveolar CO2 is low (high O2), bronchioles ________ as the alveolus does not need any O2 right now.

Bronchioles react just the opposite from arteries/arterioles as they have to carry oxygen to alveoli with a LOW PO2, i.e. where the alveolar CO2 is high, bronchioles DILATE to get the alveolus ventilated, and where the alveolar CO2 is low (high O2), bronchioles CONSTRICT as the alveolus does not need any O2 right now.

CARBONIC ANHYDRASE ENZYME is located inside the RBCs and catalyzes the production of most of the bicarbonate found in VENOUS blood. The bicarbonate ions quickly diffuses out of the ______ into the plasma.

CARBONIC ANHYDRASE ENZYME is located inside the RBCs and catalyzes the production of most of the bicarbonate found in VENOUS blood. The bicarbonate ions quickly diffuses out of the ERYTHROCYTES into the plasma.

_____ factors have the most influence on the respiratory centers. - If Pco2 levels rise in the blood (_____), more CO2 accumulates in the brain leading to a _____ in pH. This is turn stimulates the central chemoreceptors of the brainstem and __________ the depth and rate of breathing.

CHEMICAL factors have the most influence on the respiratory centers. - If Pco2 levels rise in the blood (HYPERCAPNIA), more CO2 accumulates in the brain leading to a DROP in pH. This is turn stimulates the central chemoreceptors of the brainstem and INCREASES the depth and rate of breathing.

If B has a total atmospheric pressure of 500 mmHg, and oxygen and carbon dioxide each constitute 30% of the atmosphere, which gas would be found in the highest concentration in your blood?

CO2

CO2 combines with water to form ______ acid (H2CO3) which is a ______ acid and quickly dissociates into ______ ions (H+) and ______ ions (HCO3). But this step is too slow on its own and it takes the enzyme ______ ______ to make it fast enough to work for our body.

CO2 combines with water to form CARBONIC acid (H2CO3) which is a WEAK acid and quickly dissociates into HYDROGEN ions (H+) and BICARBONATE ions (HCO3). But this step is too slow on its own and it takes the enzyme CARBONIC ANHYDRASE to make it fast enough to work for our body.

CO2 is carried in blood in the form of which 3 ways?

CO2 is carried in blood in the form of: a) DISSOLVED in plasma (7-10%) b) Bound to GLOBIN CHAINS OF HEMOGLOBIN as CARBAMINOHEMOGLOBIN (20%) c) As BICARBONATE ions (HCO3-) in plasma (70%)

As temp ↑, Hb affinity for O2 ____

DECREASES

Fully loaded (100%) or saturated Hb carries ___ molecules of O2 per Hb molecule. Hb is partially saturated when it carries ___ to ___ molecules of O2. In arterial (oxygen-______) blood the PO2 is ___ mmHg and Hb is ___% saturated, whereas in venous blood the PO2 drops to ___ mmHg and the oxygen saturation to ___%.

Fully loaded (100%) or saturated Hb carries 4 molecules of O2 per Hb molecule. Hb is partially saturated when it carries 1 to 3 molecules of O2. In arterial (oxygen-RICH) blood the PO2 is 100 mmHg and Hb is 98% saturated, whereas in venous blood the PO2 drops to 40 mmHg and the oxygen saturation to 75%.

Gas exchange between the lungs and the blood (______ respiration) and between the blood and the tissues (______ respiration) is based on ______ of gases along a concentration ______ from an area with ______ concentration to an area with ______ concentration.

Gas exchange between the lungs and the blood (EXTERNAL respiration) and between the blood and the tissues (INTERNAL respiration) is based on DIFFUSION of gases along a concentration GRADIENT from an area with HIGHER concentration to an area with LOWER concentration.

Hb saturation below normal = Hb ______ more O2 _____ tissues!

Hb saturation below normal = Hb UNLOADS more O2 INTO tissues!

Hemoglobin consists of 4 chains; 2 ______ chains and 2 ___ chains. They make up the protein part (______) of the molecule.

Hemoglobin consists of 4 chains; 2 ALPHA chains and 2 BETA chains. They make up the protein part (GLOBIN) of the molecule.

Higher brain centers such as the ________ (via limbic system) also influence breathing depth and rate (e.g. when we are cold, frightened, and in pain) The ________ cortex can directly change ventilation too.

Higher brain centers such as the HYPOTHALAMUS (via limbic system) also influence breathing depth and rate (e.g. when we are cold, frightened, and in pain) The CEREBRAL cortex can directly change ventilation too.

__________: increased depth & rate of breathing that exceeds the body's need to remove CO2. It causes CO2 levels to decline (hypocapnia)

Hyperventilation: increased depth & rate of breathing that exceeds the body's need to remove CO2. It causes CO2 levels to decline (hypocapnia)

In ______ capillaries the mechanism goes into reverse. HCO3- moves into the RBCs and binds with H+ to form H2CO3. H2CO3 is split by ______ ______ into CO2 and ______. CO2 diffuses out of the RBC and into the ______. At the same time, ______ ions move out of the RBCs in a reverse chloride shift.

In PULMONARY capillaries the mechanism goes into reverse. HCO3- moves into the RBCs and binds with H+ to form H2CO3. H2CO3 is split by CARBONIC ANHYDRASE into CO2 and WATER. CO2 diffuses out of the RBC and into the ALVEOLI. At the same time, CHLORIDE ions move out of the RBCs in a reverse chloride shift.

In the tissues, more oxygen dissociates from hemoglobin because of a ______ pH (______ effect) which frees up Hb to combine with CO2 to form carbaminohemoglobin.

In the tissues, more oxygen dissociates from hemoglobin because of a LOWER pH (BOHR effect) which frees up Hb to combine with CO2 to form carbaminohemoglobin.

Internal Respiration: The Po2 in tissue is always _______ than the Po2 in the blood. On average, tissue Po2 is ___ mmHg or less compared to a blood Po2 of ___ mmHg. This gradient of ___ mmHg will lead to O2 moving from the _______ to the _______. CO2 has a higher partial pressure in the _______ (___ mmHg) than the _______ (___ mmHg) and thus will move from the tissue to the blood.

Internal Respiration: The Po2 in tissue is always LOWER than the Po2 in the blood. On average, tissue Po2 is 40 mm Hg or less compared to a blood Po2 of 100 mm Hg. This gradient of 60 mmHg will lead to O2 moving from the BLOOD to the TISSUE. CO2 has a higher partial pressure in the TISSUE (45 mm Hg) than the BLOOD (40 mm Hg) and thus will move from the tissue to the blood.

Loading and unloading of O2 on hemoglobin is facilitated by a change in ______ of Hb that affects the ______ of Hb for O2; when O2 binds, Hb affinity for O2 ______, while release of O2 ______ Hb affinity for O2

Loading and unloading of O2 on hemoglobin is facilitated by a change in SHAPE of Hb that affects the AFFINITY of Hb for O2; when O2 binds, Hb affinity for O2 INCREASES, while release of O2 DECREASES Hb affinity for O2

Loading of Hb with O2 is called ____________ and leads to the formation of bright red ____________ Hb or ____________.

Loading of Hb with O2 is called OXYGENATION and leads to the formation of bright red OXYGENATED Hb or OXYHEMOGLOBIN.

Metabolically active tissues cause a number of changes in their environment that modify the ______ of hemoglobin and ______ its affinity for O2.

Metabolically active tissues cause a number of changes in their environment that modify the STRUCTURE of hemoglobin and DECREASE its affinity for O2.

Oxygen has ____ influence on the respiratory centers because even a drop in arterial Po2 down to 70 mm Hg will not change the oxygen ________ of Hb. Thus, a substantial drop in arterial Po2 (to 60 mm Hg or less) must occur in order to stimulate ________ ventilation.

Oxygen has LESS influence on the respiratory centers because even a drop in arterial Po2 down to 70 mm Hg will not change the oxygen SATURATION of Hb. Thus, a substantial drop in arterial Po2 (to 60 mm Hg or less) must occur in order to stimulate INCREASED ventilation.

Oxygen is carried in the _______ form (O2) in the blood. Only a small percentage (___%) dissolves in the ______. The rest is carried bound to the _______ in _______ (Hb). However, this bond is not a _______ bond but a _______ bond and oxygen can be released from it easily.

Oxygen is carried in the MOLECULAR form (O2) in the blood. Only a small percentage (1.5 %) dissolves in the PLASMA. The rest is carried bound to the IRON in HEMOGLOBIN (Hb). However, this bond is not a CHEMICAL bond but a LOOSE bond and oxygen can be released from it easily.

If Planet Reuter A has a total atmospheric pressure of 900 mmHg and Oxygen makes up 30% and Carbon dioxide 5%, what is the partial pressure for each?

PO2 = 270 mmHg PCO2 = 45 mmHg

The rate of loading and unloading of O2 is regulated by which 5 factors?

Rate of loading and unloading of O2 is regulated by: - Po2 - TEMPERATURE - BLOOD PH - Pco2 - CONCENTRATION OF BPG

The "hemo" part of hemoglobin comes from the pigment ___ that contains one atom of ______ at its core. Each molecule of Hb can transport ___ molecules of O2.

The "hemo" part of hemoglobin comes from the pigment HEME that contains one atom of IRON at its core. Each molecule of Hb can transport 4 molecules of O2.

The ______ effect states the amount of CO2 transported is affected by the Po2. The ______ the Po2 and hemoglobin saturation with O2, the ______ CO2 can be carried in the blood.

The HALDANE effect states the amount of CO2 transported is affected by the Po2. The LOWER the Po2 and hemoglobin saturation with O2, the MORE CO2 can be carried in the blood.

The HCO3- in plasma is the _____ _____ of the carbonic acid-bicarbonate buffer system. If the H+ concentration in blood rises and the pH goes _____, excess H+ is removed by combining with HCO3- . If the H+ concentration begins to drop and the pH goes _____, H2CO3 dissociates, releasing H+.

The HCO3- in plasma is the ALKALINE RESERVE of the carbonic acid-bicarbonate buffer system. If the H+ concentration in blood rises and the pH goes DOWN, excess H+ is removed by combining with HCO3- . If the H+ concentration begins to drop and the pH goes UP, H2CO3 dissociates, releasing H+.

The ________-________ reflex is a protective response to prevent ________ of the lungs. It is based on ________ receptors in the pleurae and airways that send INHIBITORY signals to the medullary respiratory centers that end inhalation and allow expiration to occur.

The HERING-BREUER reflex is a protective response to prevent OVERINFLATION of the lungs. It is based on STRETCH receptors in the pleurae and airways that send INHIBITORY signals to the medullary respiratory centers that end inhalation and allow expiration to occur.

The adjustments made to cope with less atmospheric pressure are called ________. They include an ________ in minute ventilation and an ________ in the ________ of the blood because of the increased RBC production.

The adjustments made to cope with less atmospheric pressure are called ACCLIMATIZATION. They include an INCREASE in minute ventilation and an INCREASE in the HEMATOCRIT of the blood because of the increased RBC production.

The best way to measure concentration of gases in mixtures is by measuring their ______ pressure.

The best way to measure concentration of gases in mixtures is by measuring their PARTIAL pressure.

The blood flowing into the lung in the pulmonary ARTERIES and ARTERIOLES is oxygen-______ and needs to be sent to areas with a ____ alveolar PO2. Therefore where alveolar PO2 is high, arterioles _______ to get the blood to the oxygen and where alveolar PO2 is low, arterioles ________.

The blood flowing into the lung in the pulmonary ARTERIES and ARTERIOLES is oxygen-DEPLETED and needs to be sent to areas with a HIGH alveolar PO2. Therefore where alveolar PO2 is high, arterioles DILATE to get the blood to the oxygen and where alveolar PO2 is low, arterioles CONSTRICT.

The farther we go from sea level, the more the atmospheric pressure ________. Quick travel to altitudes above 8000 feet may produce symptoms of ________ ________ ________ (AMS) such as headaches, shortness of breath, nausea, and dizziness. In severe cases, lethal cerebral and pulmonary edema may develop.

The farther we go from sea level, the more the atmospheric pressure DECREASES. Quick travel to altitudes above 8000 feet may produce symptoms of ACUTE MOUNTAIN SICKNESS (AMS) such as headaches, shortness of breath, nausea, and dizziness. In severe cases, lethal cerebral and pulmonary edema may develop.

The gas exchange between capillaries and tissues (_______ respiration) depends on partial pressures and diffusion _______. However, they are _______ compared to external respiration and O2 & CO2 move in _______ directions.

The gas exchange between capillaries and tissues (INTERNAL respiration) depends on partial pressures and diffusion GRADIENTS. However, they are REVERSED compared to external respiration and O2 & CO2 move in OPPOSITE directions.

The most powerful respiratory stimulus for breathing in a healthy person is an __________ in ____ in the blood.

The most powerful respiratory stimulus for breathing in a healthy person is an INCREASE in CO2 in the blood.

The outward shift of a ______ charged ion has to be balanced by the inflow of another ion with the same charge to keep the inside of the RBCs electrically neutral. This ion is ______ and the process is thus called the ______ ______.

The outward shift of a NEGATIVELY charged ion has to be balanced by the inflow of another ion with the same charge to keep the inside of the RBCs electrically neutral. This ion is CHLORIDE and the process is thus called the CHLORIDE SHIFT.

The partial pressure gradient (for O2) between the alveoli and the blood is ~____ mmHg (very steep) because the Po2 in the alveolus is _____ mmHg and the Po2 in the blood is ____ mmHg. This gradient causes O2 to move across the ____________ membrane from the ______ to the ______.

The partial pressure gradient (for O2) between the alveoli and the blood is ~64 mm Hg (very steep) because the Po2 in the alveolus is 104 mmHg and the Po2 in the blood is 40 mmHg. This gradient causes O2 to move across the RESPIRATORY membrane from the ALVEOLUS to the BLOOD.

The partial pressure gradient for CO2 is much lower (__mmHg) because the Pco2 in the blood is __ mmHg and the Pco2 in the alveolus is __ mmHg. This gradient is ____ sufficient to cause a diffusion of CO2 from the _______ to the ________. Because CO2 is ___ times more soluble in water (plasma) than O2, CO2 diffuses in equal amounts as O2.

The partial pressure gradient for CO2 is much lower (5 mmHg) because the Pco2 in the blood is 45 mmHg and the Pco2 in the alveolus is 40 mmHg. This gradient is STILL sufficient to cause a diffusion of CO2 from the BLOOD to the ALVEOLUS. Because CO2 is 20 times more soluble in water (plasma) than O2, CO2 diffuses in equal amounts as O2.

The respiratory membrane has to be extremely thin for gases to move across via _______. Any thickening or fluid collection in the alveoli will _______ gas exchange. The same can be said about the overall surface area. The larger it is, the _______ gas can be exchanged in a given time; reduction in surface area will _______ gas exchange too.

The respiratory membrane has to be extremely thin for gases to move across via DIFFUSION. Any thickening or fluid collection in the alveoli will IMPAIR gas exchange. The same can be said about the overall surface area. The larger it is, the MORE gas can be exchanged in a given time; reduction in surface area will IMPAIR gas exchange too.

Name the 2 respiration centers in the CNS.

There are 2 respiration centers in the CNS: • 1 PONTINE respiratory center in the pons and one MEDULLARY respiratory center in the medulla that consists of a VENTRAL & DORSAL group. Together these centers control DEPTH & RATE of breathing depending on body demands.

Unloading of oxygenation is called ____________ and produces dark red ____________/______ Hb or __________________.

Unloading of oxygenation is called DEOXYGENATION and produces dark red DEOXYGENATED/REDUCED Hb or DEOXYHEMOGLOBIN

↑ CO2 & ↓ pH (acidic) = ______ O2 unloading = _______ saturated

↑ CO2 & ↓ pH (acidic) = ↑ O2 unloading = less saturated

↑ O2 use by tissues = _____ CO2 production So Hb can carry more CO2 from tissues when they most need it! (e.g., are most active or hypoxic)

↑ O2 use by tissues = ↑ CO2 production So Hb can carry more CO2 from tissues when they most need it! (e.g., are most active or hypoxic)

↑ temp = ____ O2 unloading = _____ saturation

↑ temp = ↑ O2 unloading = ↓ saturation

↓ O2 levels, _____ Hb's affinity for CO2 (_____ CO2 /Hb binding) = ________ effect

↓ O2 levels, ↑ Hb's affinity for CO2 (↑ CO2 /Hb binding) = Haldane effect

↓ temp = _____ O2 unloading= ____ saturation

↓ temp = DECREASE O2 unloading= INCREASE saturation

↓ temp, CO2, & acidity all _____ O2 unloading & ______ saturation!

↓ temp, CO2, & acidity all ↓ O2 unloading & ↑ saturation!

↓CO2 & ↑pH (less acidic) = _____ O2 unloading = ______ saturated

↓CO2 & ↑pH (less acidic) = ↓ O2 unloading = MORE saturated