Module 10 Respiratory System

Question 1

Functions of Respiratory System (hint- 5 main functions)

Answer 1

• Transport of oxygen
• Remove carbon dioxide.
• Control blood acidity (pH)
• Temp regulation
• Defense

Question 2

Anatomy of Respiratory System

Answer 2

(Pharynx, Larynx, Trachea)
PLT

Question 3

Characteristics of Capillaries that maximize gas exchange (3)

Answer 3

• Thin endothelial walls
• large total cross-sectional area
• very low blood velocity

Question 4

Pressures of the Lungs

Answer 4

Intrapleural- Outside the lungs (756 mmHg pressure)
Intrapulmonary- Inside the lungs (760 mmHg pressure)

Question 5

Intrapleural Pressure/ Space includes two membranes

Answer 5

• (The parietal pleura): Lines and sticks to the ribs.
• (The visceral pleura): Surrounds and sticks to the lungs.

Question 6

Transpulmonary Pressure

Answer 6

Difference between the alveolar and intrapleural pressures

Question 7

What would happen if both intrapleural and intrapulmonary pressures were equal

Answer 7

The lung would collapse producing pneumothorax

Question 8

Explain Boyles Law of Ventilation

Answer 8

• When you inhale, the volume of air in your lungs increase, but the pressure decreases.
• When you exhale, the volume of air in your lungs decrease, but the pressure increases.

Question 9

Explain mechanisms of expiration at rest (3 things)

Answer 9

• Diaphragm and external intercostal muscles relax.
• Lungs to recoil to their original size.
• Volume decreases, the alveolar (intrapulmonary) pressure increases above atmospheric pressure.
• The pressure gradient is now reversed (high inside at 761 mmHg and low outside at 760 mmHg).

Question 10

Explain mechanisms of expiration during exercise

Answer 10

• Air must be forced out of the lungs.
• Requires contraction of the abdominal muscles and the internal intercostal muscles of the ribs.
• When these muscles contract, they further decrease the volume of the lungs.
• Creating a larger pressure gradient (much higher on the inside at 763 mmHg than outside at 760 mmHg.

Question 11

What is pulmonary compliance?

Answer 11

• Stretchability of the lungs—the more stretchable, the more compliant.
• Defined as the volume change that occurs because of a change in pressure.
• Determines ease of breathing.
• Lung that has decreased compliance is difficult to inflate, one with high is easy to inflate but difficult to deflate.

Question 12

Give the equation of pulmonary compliance

Answer 12

Compliance= Volume Change/ Pressure Change

Question 13

What are the two major factors of Pulmonary compliance?

Answer 13

1. Amount of elastic tissue (in alveoli, blood vessels, bronchi)
2. Surface tension of film of liquid lining alveoli

Question 14

What does pulmonary fibrosis cause to compliance?

Answer 14

It decreases the compliance

Question 15

What does normal aging and pulmonary emphysema cause to compliance?

Answer 15

Causes increase in compliance.

Question 16

What is pulmonary surfactant and how does it affect compliance? (Water droplet reference)

Answer 16

• Increases compliancy of lungs (Helps people breathe easier).
• Lipoprotein substance produced by type II (or great) alveolar cells and consists mostly of phospholipids.
• The forces will now be equal in every direction and the water drop will flatten out due to the decreased surface tension.

Question 17

What is a spirometer used to measure?

Answer 17

Lung volumes and capacities.

Question 18

List the four basic lung volumes and explain each of them.

Answer 18

1. Tidal volume: The volume of air entering or leaving the lungs during one breath at rest = (500 ml)
2. Inspiratory reserve volume: The maximum amount of air that can enter the lungs in addition to the tidal volume (2500 ml)
3. Expiratory reserve volume: The maximum amount of air that can be exhaled beyond the tidal volume (1000 ml)
4. Residual volume: The remaining air in the lungs after a maximal expiration (1200 ml)

Question 19

List the four basic lung capacities and explain each of them.

Answer 19

1. Inspiratory capacity: The maximum amount of air that can be inhaled after exhaling the tidal volume (equals tidal volume + inspiratory reserve volume)
2. Functional residual capacity: The amount of air still in the lungs after exhalation of the tidal volume (equals expiratory reserve volume + residual volume)
3. Vital capacity: The maximum amount of air that can be exhaled after a maximal inhalation (equals inspiratory reserve volume + tidal volume + expiratory reserve volume)
4. Total lung capacity: The maximum amount of air that lungs can hold (equal to vital capacity + residual volume).

Question 20

Explain what pulmonary ventilation is, what it consists of and its equation.

Answer 20

• Pulmonary ventilation (also called minute ventilation) is the amount of air that enters all the conducting and respiratory zones in one minute.
• The conducting zone: the area of the lungs where no gas exchange takes place (because there are no alveoli).
  (Upper respiratory system, everything but the lungs)
• The respiratory zone is the region of the lungs where alveoli are located.
  (Lungs)
• Determines amount of air and amount of oxygen available to body
  Equation 4: VE= Tidal Volume (ml) x Respiratory Rate (breaths/min)

Question 21

Explain what alveolar ventilation is and what it consists of.

Answer 21

• Volume of air entering only the respiratory zone each minute.

Question 22

Explain what dead space volume is, what dead space ventilation is (including its equation) and state the equation for alveolar ventilation.

Answer 22

• Dead space is the volume of air that is inhaled that does not take part in the gas exchange, because it either remains in the conducting airways or reaches alveoli that are not perfused or poorly perfused.
• The dead space volume in ml for a normal healthy subject is approximately equal to the person’s body weight in pounds (for example, if body weight is 100 pounds, dead space volume is 100 ml).
• The dead space ventilation (VD) is also a rate and considers not only the volume of the dead space but the respiratory rate as well.
  EQUATION: VD= Dead space volume x resp Rate
  Equation 5: VA= VE – VD
  VA= Alveolar Ventilation (ml/min)
  VE= Pulmonary Ventilation (ml/min)
  VD= Dead Space Ventilation (ml/min)

Question 23

Explain the importance of partial pressure to oxygen and carbon dioxide transportation.

Answer 23

• Just like the movement of blood through vessels and the movement of air into and out of the lungs, oxygen and carbon dioxide move down a pressure gradient.
• In this case, the gradient is a partial pressure gradient.
• Consequently, oxygen and carbon dioxide will move from areas of high partial pressure to low partial pressure.

Question 24

Explain the equation for partial pressure and give an example.

Answer 24

Equation 6: Partial pressure of a gas= Total pressure of all gases x Fractional concentration of the one gas
Example: Partial pressure of O2 (PO2) in air at sea level
PO2= 760 20.93/ 100
PO2= 159 mmHg

Question 25

Explain how partial pressure is used to allow gas diffusion across the alveoli.

Answer 25

- Blood entering the lungs has a partial pressure of oxygen (PO2) of 40 mmHg and a partial pressure of carbon dioxide (PCO2) of 46 mmHg. - Alveoli: PO2 of 105 mmHg and a PCO2 of 40 mmHg. - Oxygen will move from the alveolar space (PO2 of 105 mmHg) to the blood stream (PO2 of 40 mmHg). - Carbon dioxide will move from the blood (PCO2 of 46 mmHg) to the alveolar space (PCO2 of 40 mmHg).

Question 26

State the route O2 and CO2 takes throughout the Circulatory system using partial pressure.

Answer 26

1. Blood leaving the lungs has a high PO2 (100 mmHg) and low PCO2 (40 mmHg) 2. Blood returns to the left side of the heart and is pumped to the systemic circulation. 3. Blood enters tissue beds with the same PO2 (100 mmHg) and PCO2 (40 mmHg). 4. Cells have a low PO2 (40 mmHg) and high PCO2 (46 mmHg) inside. 5. As blood flows through capillaries, oxygen diffuses into the cells and carbon dioxide diffuses out down respective partial pressure gradients. 6. Blood leaving the tissue will have equilibrated with cells; it will have a PO2 of 40 mmHg and PCO2 of 46 mmHg. Blood returns to the right side of the heart to be pumped to the lungs, and the process repeats.

Question 27

One form of oxygen transport is dissolved in plasma, explain this form of transport.

Answer 27

- Oxygen is carried in the blood dissolved in the plasma, and it is carried in red blood cells (RBCs) attached to a protein called hemoglobin. - Hemoglobin can carry much more oxygen - Very little oxygen is transported in the blood dissolved in plasma.

Question 28

Another form of oxygen transport is through red blood cells and hemoglobin. Describe this form of transport including what a hemoglobin is.

Answer 28

- 99% of oxygen is carried in red blood cells (RBCs) attached to a large molecule called hemoglobin (Hb). - Each molecule of hemoglobin can carry 4 oxygen molecules.

Question 29

What is another term for red blood cells?

Answer 29

Erythrocytes

Question 30

Name the process of red blood cell production. Including which added acids and entities are required for the production of them.

Answer 30

- The production of RBCs, a process called erythropoiesis, takes place in bone marrow, and requires the presence of amino acids, iron, folic acid, and vitamin B12. - Amino acids and iron are required because they are both components of hemoglobin, the oxygen carrying molecule. - Folic acid is essential for the formation of new DNA and for normal cell division. - Vitamin B12 are required because folic acid can’t perform its function without it.

Question 31

A hormone is needed to control RBC production, state this hormone.

Answer 31

- The control of erythrocyte production requires the hormone erythropoietin (or EPO for short). - Drop in oxygen caused by a decrease in cardiac output, lung disease, high altitudes, or a decrease in the number of RBCs and/or total hemoglobin content. - Testosterone also stimulates the secretion of EPO.

Question 32

Describe the chemical makeup of a hemoglobin.

Answer 32

- Each molecule of hemoglobin contains 4 subunits. - Each subunit contains a single heme molecule attached to a polypeptide. - Combined, the 4 polypeptides are called globin. - Each hemoglobin molecule can carry 4 oxygen molecules. - Iron molecule gives blood its red color. - When the blood leaves the lungs after picking up oxygen, the hemoglobin is almost completely saturated with oxygen. - Oxygen (O2) binds easily with hemoglobin (Hb) in a reversible reaction to produce oxyhemoglobin (HbO2).

Question 33

Loading and unloading of oxygen from hemoglobin: How does the amount of O2 determine the direction of the following reaction? O2 + Hb ->/<- HbO2.

Answer 33

- If the PO2 is high (in the lungs), then O2 will bind to Hb, forming HbO2. - Where PO2 is low (in the tissue), the reaction will reverse and O2 will unload from Hb.

Question 34

What is the hemoglobin dissociation curve?

Answer 34

- Dissociation curve shows the “dissociation” (unloading) of oxygen (O2) from hemoglobin (Hb) at different blood PO2. - Temperature and acidity (pH) also affect the dissociation of oxygen (O2) from hemoglobin (Hb). - When exercising, the body warms up and the working muscles produce lactic acid, increasing the acidity of the blood. - Low temperatures and decreased acidity will have the opposite effect on Hb and O2.

Question 35

State and describe Carbon Dioxide Transport. (hint: carried in blood in three forms).

Answer 35

1. Like O2, CO2 can be dissolved and carried directly using partial pressure. 2. CO2 can also be carried as a bicarbonate ion (HCO3-) 3. It can also be attached to proteins in the blood, forming carbamino compounds.

Question 36

Partial pressure transportation

Answer 36

- CO2 can be dissolved in plasma, but CO2 is 20 times more soluble and will dissolve much easier. - The PCO2 levels in the blood vary from 40 mmHg on the arterial side and 46 mmHg on the venous side.

Question 37

Bicarbonate ion transportation

Answer 37

- About 70% of the total CO2 carried in the blood is carried as bicarbonate ions (HCO3–) - The reaction shows: CO2 reacting with water to produce carbonic acid (H2CO3) with the help of the enzyme carbonic anhydrase. CO2 + H2O <-/-> H2CO3 <-/-> HCO3- + H+ - Carbonic acid then dissociates quickly into bicarbonate ions (HCO3–) and hydrogen ions (H+). - This is a reversible reaction.

Question 38

Carbamino Compound transportation

Answer 38

- Hemoglobin (Hb), which has unloaded some of its oxygen to the tissue, is one of the most abundant proteins that can carry CO2. - CO2 attaches to the globin portion of hemoglobin and forms carbamino hemoglobin (HbCO2), shown in equation: CO2 + Hb <-/-> HbCO2

Question 39

Loading and unloading of Carbon dioxide

Answer 39

The equations are all reversible. CO2 + Hb <-/-> HbCO2 CO2 + H20 <-/-> H2CO3 <-/-> HCO3– + H+ - The direction of each reaction, determined by the amount of carbon dioxide (CO2) present in the plasma—the PCO2.

Question 40

Where does spontaneous and voluntary respiration originate from.

Answer 40

- Spontaneous respiration originates in the medullary respiratory center of the medulla oblongata of the brainstem and is produced by rhythmic activity from the neurons much like the pacemaker of the heart. - The voluntary center is in the cerebral cortex.

Question 41

Inhalation: Explain the two areas in the medulla oblongata situated in the medullary respiratory center.

Answer 41

1. Inspiratory center, which activates the inspiratory muscles (during inhalation) 2. Expiratory center, which activates the expiratory muscles (during an active exhalation).

Question 42

Explain what happens during exhalation.

Answer 42

- Recall quiet exhalation is a passive process involving only the relaxation of the inspiratory muscles. - The lung’s own elastic properties and recoiling of muscle cause exhalation at rest. - Forceful exhalation (during exercise, for example) requires contraction of the abdominal muscles and the internal intercostal muscles of the ribs. - Signals to these muscles originate in the expiratory center of the medulla. - While this center is active, the inspiratory center is inhibited.

Question 43

Describe what happens during inhalation and exhalation.

Answer 43

Inhalation Body is at rest; the inspiratory center is active for roughly two seconds. 1. Enough time to activate the muscles of inspiration (diaphragm and external intercostal muscles), producing a small inhalation. 2. During this time, the expiratory center is inhibited. 3. The inspiratory area will then shut down and the expiratory center will become active. Exhalation 1. When expiration is active (as shown at right), the muscles of expiration (abdominal and internal intercostal muscles) contract and force the air out of the lungs. 2. During this time, the inspiratory center is inhibited.

Question 44

What is the apneustic and pneumotach centers.

Answer 44

- The pneumotach center regulates the rate of breathing. - Apneustic center controls the depth of an inhalation and exhalation.

Question 45

Regulation of Respiration: Describe how it relates to the negative feedback system.

Answer 45

Set point- Gas concentrations PO2, PCO2 Control center- Medullary respiratory centers. Effector- Muscles of Respirations Controlled Variable- Lung ventilation Sensor- To detect gas concentration.

Question 46

What are chemoreceptors and describe the types.

Answer 46

- Chemoreceptors are special receptors that detect the concentration of oxygen, carbon dioxide, or hydrogen ions (H+) in the blood. 1. A peripheral group of chemoreceptors is in the aortic arch and carotid sinus (much like the baroreceptors) of the cardiovascular system). * These chemoreceptors, located in the carotid sinus and aortic arch, are primarily sensitive to oxygen (O2) concentrations and only slightly sensitive to carbon dioxide (CO2) levels in the blood. * Detects small changes in O2. * Detects large changes in CO2. 2. A central group is in the medulla of the brainstem (close to the respiratory center). * Detects levels of H+ in interstitial fluid. * Indirectly detects CO2 levels.