Breathing Mechanics and Gas Exchange

breathing

What is the simple term for pulmonary ventilation?

Inspiration

What is the term for moving air into the body, also called inhilation?

Expiration

What is the term for moving air out of the body, also called exhalation?

760 (mm Hg)

What is the amount of Atmospheric Pressure (P_atm) that respiratory pressure is always described relative/compared to?

alveoli (lungs)

Intrapulmonary Pressure (P_pul) is pressure in the what?

equalize

Intrapulmonary Pressure (P_pul) rises and falls with the phases of breathing and at certain points can do what with atmospheric pressure?

pleural cavity (around the lungs)

Intrapleural Pressure (P_ip) is pressure in the what?

negative (less than)

Intrapleural Pressure (P_ip) rises and falls with the phases of breathing and is always what compared to intrapulmonary pressure and atmospheric pressure?

recoil, surface tension

· Forces that act on the lungs to cause collapse:

-  Lungs’ tendency to (BLANK); due to their elasticity

-  (BLANK) of alveolar fluid

elasticity

· Forces that oppose collapse:

-  Natural (BLANK) of chest wall

negative

When the forces that act on the lungs to collapse and forces that oppose lung collapse interact, it causes what type of P_ip that is need or else the lung collapses?

Transpulmonary Pressure

What is the term for the difference between intrapulmonary and intrapleural pressures?

Atelectasis

What is the term for lung collapse when air enters the pleural cavity through a chest wound or rupture of the visceral pleura?

Pneumothorax

What is the term for the presence of air in the intrapleural space?

treatment of this requires removing the air so it can reinflate

volume and pressure

Pulmonary ventilation depends on what two aspects that change?

pressure varies inversely with volume

What does Boyle’s Law state about gas at a given temperature?

low

Will the pressure of gas be low or high in a large volume container?

Diaphragm

What contracts and flattens while the thoracic cavity volume increases during inspiration?

Intercostal mucles

What is responsible for lifting the rib cage and pulling the sternum superiorly when contracting and also helps to expand the thoracic cavity?

pressure gradient

In inspiration, what is responsible for the air rushing into the lungs when the changes cause a drop in intrapulmonary pressure compared to atmospheric pressure?

lower

Is intrapulmonary pressure higher or lower in the lungs compared to atmospheric pressure during inspiration?

Quiet

What type of expiration is passive

- Inspiratory muscles relax and the lungs recoil

— reducing thoracic volume

— Intrapulmonary pressure increases compared to atmospheric pressure forcing air out of the lungs

Forced

What type of expiration is active

- Contraction of the abdominal walls

— Increases intra-abdominal pressure

— Depresses rib cage

Airway Resistance

What is the term for the friction of air encountered in respiratory passageways?

pressure

[Regarding Airway Resistance]

Flow = a change in what? (divided by) resistance

large, diffusion

Airway resistance is insignificant because:

- Diameter of airway is (BLANK)

- Airflow stops at terminal bronchioles and (BLANK) takes over

Surface Tension

What term describes that Liquid molecules are more strongly attracted to each other than to the Gas molecules?

alveolar fluid

What is responsible for covering and reducing the size of alveolar walls to their smallest size?

Surfactant

What is the term for the detergent-like complex of lipids and proteins that helps reduce the surface tension of alveolar fluid which makes the energy required to overcome those force be less?

Lung Compliance

What is the term for the distensibility of the lungs?

Determined by:

— Distensibility of the lung tissue and surrounding thoracic cage

— Alveolar surface tension

Diminished/Reduced by:

— Reduction in the natural resilience of the lungs

— Blockage of smaller passages

— Reduction in surfactant production

— Reduction of thoracic cage flexibility

Tidal Volume (TV)

What is the term for the amount of air that moves into and out of the lungs with each breath?

Inspiratory Reserve Volume (IRV)

What is the term for the amount of air that can be inspired forcibly beyond tidal volume?

Expiratory Reserve Volume (ERV)

What is the term for the amount of air that can be forced from the lungs after a normal expiration?

Residual Volume (RV)

What is the term for the amount of air that remains in the lungs after a forced expiration? (amount of air that can never be taken out of the lungs)

Dead Space

What is the term for the amount of AIR that fills the conducting passageways and never contributes to gas exchange

Anatomical (Dead Space)

What is the specific term of dead space for the volume of the conduits (passageways)?

Alveolar (Dead Space)

What is the specific term of dead space for the alveoli that do not participate in gas exchange?

Total (Dead Space)

The combination of anatomical and alveolar dead space equivalates to what?

Dalton’s Law of Partial Pressure

What is the law that states: total pressure exerted by a mixture of gases is the sum of the pressures exerted independently by each gas in the mixture?

Partial Pressure

What is the term for the pressure exerted by each gas in a mixture of gasses?

Atmospheric Air

The following all make up what?

1. 1. Nitrogen

2. 2. Oxygen

3. 3. Carbon Dioxide

4. 4. Water Vapor

(Partial pressure) gradients and (gas) solubilities, Matching alveolar ventilation (and pulmonary blood perfusion), Structural characteristics (of respiratory membrane)

What are the three factors influencing the movement of oxygen and carbon dioxide across the respiratory membrane?

Oxygen

The partial pressure of what gas is shown below?

Venous blood: 40 mm Hg

Alveoli: 104 mm Hg

— Goes from high pressure (alveoli) to low pressure (venous blood/deoxy)

— Moves from alveoli to the blood along the gradient

Carbon Dioxide

The partial pressure of what gas is shown below?

Venous blood : 45 mm Hg

Alveoli: 40 mm Hg

— Goes from high pressure (venous blood/deoxy) to low pressure (alveoli)

— Moves from deoxy blood along gradient to alveoli of the lungs

amount, constrict, dilate

[Ventilation-Perfusion Coupling]

For gas exchange to be efficient =

The (BLANK) of gas reaching the alveoli (ventilation) should match the blood flow in the pulmonary capillaries (perfusion)

— If ventilation is low, capillaries (BLANK) to reduce blood flow

— If ventilation is higher, capillaries (BLANK) to increase blood flow

Thin membrane, Large surface area

What are the 2 aspects of the respiratory membrane that make it more efficient for gas exchange and diffusion?

reversed

For internal respiration, gas exchange in the body tissues, what happens to partial pressure and diffusion gradients are compared to external respiration in which the following occurs?

(Do you understand what oxygen and carbon dioxide is going to do in these following conditions?)

— PO₂ in tissues (40 mm Hg) is lower than arterial blood (104 mm Hg)

— PCO₂ in tissues (45 mm Hg) is higher than arterial blood (40 mm Hg)

bound to hemoglobin, dissolved in plasma

What are the two ways to transport oxygen in the body?

Fully (Saturated)

What is an oxyhemoglobin called when the hemoglobin is carrying 4 oxygen?

Partially (Saturated)

What is an oxyhemoglobin called when the hemoglobin is carrying 1/2/3 oxygen?

PCO₂, Temperature, (blood) pH, 2.3 BPG

What are the 4 ways to regulate the rate that hemoglobin (Hb) binds and releases oxygen (O_²)?

always changing affinity, not linear

What does the curve of the influence of PO₂ on Hemoglobin Saturation tell regarding the relationship between oxygen and hemoglobin?

Plateau

Which part of the influence of PO₂ on Hemoglobin Saturation curve is described:

1. Loading oxygen onto hemoglobin at lungs (high partial pressure = at lungs)

2. High affinity, oxygen wants to bind with hemoglobin

3. Protective mechanism – even with a drop in PO2, i.e. at altitude, we can still adequately load hemoglobin with oxygen

Steep

Which part of the influence of PO₂ on Hemoglobin Saturation curve is described:

1. Oxygen is unloading from hemoglobin at tissues (Low partial pressure = at tissues)

2. Affinity is lower between oxygen and hemoglobin (oxygen is likely to unbind from hemoglobin

3. Reserve – with a drop in PO2 in the body, i.e. strenuous exercise, we still have oxygen to deliver

right, lowering

The following factors shift the curve (right/left) thus (increasing/lowering) affinity, easier to release oxygen in a strenuous exercise scenario

1. PCO₂ (increase)

2. Temperature (increase)

3. pH (decrease)

4. 2,3 BPG (increase)

left, increasing

The following factors shift the curve (right/left) thus (increasing/lowering) affinity, harder to release oxygen thus good for keeping oxygen

1. PCO2 (decrease)

2. Temperature (decrease)

3. pH (increase)

4. 2,3 BPG (decrease)

dissolved in plasma, bound to hemoglobin, bicarbonate ion in plasma

What are the 3 ways of transferring Carbon Dioxide in the body?

carbonic anydrase

What is the term for the enzyme only found in RBC responsible for making carbonic acid?

move out (into circulation)

Bicarbonate is made in the RBC but what does it do to result in the chloride shift?

Chloride Shift

What is the term for the influx of Cl^- ions to compensate for the loss of negative charge with bicarb leaving the RBC?

lungs, splits, out

In the (BLANK), CO₂ must be freed from the bicarbonate

• Must go back to the RBC for this and reverses the above reaction: bicarb combines with H⁺ in the presence of carbonic anhydrases forming carbonic acid in the RBC.

• Chloride moves out of the RBC.

• Carbonic acid is very unstable, so it (BLANK) into CO₂ and water.

• CO₂ moves (BLANK) of the RBC to be expired.

Haldane Effect

What (effect) states that lower oxygen levels and lower Hb saturation with O2, the more carbon dioxide the blood can carry?

oxygenation

What is the term for oxygen in the blood?

Medulla and Pons (Respiratory Centers)

What are the 2 respiratory centers that can control respiration?

Ventral Respiratory Group (VRG)

What part of the Medullary Respiratory Centers:

• Inspiratory center: pacesetting

• Impulses along the phrenic nerve to the diaphragm and along the intercostal nerves to the external intercostal muscles

• If suppressed, respiration stops

inspiratory center

What is the term for “pacesetting” in the medullary respiratory centers?

Dorsal Respiratory Group (DRG)

What part of the Medullary Respiratory Centers:

• Unclear about exact function

• Plays a role in forced breathing

Pons Respiratory Centers

Which control of respiration (respiratory centers):

• Influence and modify the activity of medullary neurons

• Smooth transitions between inspiration and expiration

• Pontine respiratory group (PRG) or pneumotaxic center

  • Transmits inhibitory impulses to the inspiratory center of the medulla

(Inspiratory) depth

What is determined by how actively the respiratory centers stimulates the motor neurons serving the respiratory muscles (deep of a breath taken)?

Greater frequency, greater recruitment = greater force of contraction

Rate

What is determined by how long the inspiratory center is active or how fast it is switched off (breaths taken in a minute)?

Pulmonary Irritant Reflex

What is the term for when:

• Stretch receptors in the lungs signal medullary centers to end inspiration

  • When lungs recoil, these receptors are inhibited, and inspiration begins again

Stretch (receptors)

What in the lungs is responsible for stopping expiration (exhaling) in the Inflation Reflex?

Hypothalamic

[Factors Influencing Breathing Rate and Depth]

(BLANK) Controls:

• Strong emotion and pain activate the sympathetic centers

Cortical

[Factors Influencing Breathing Rate and Depth]

(BLANK) Controls

• Conscious control

  • Holding our breath or take a deep breath

  • Bypass the medullary centers

Chemical

[Factors Influencing Breathing Rate and Depth]

(BLANK) Factors:

• Chemoreceptors: perceive changes in CO₂, O₂, and H+ in arterial blood

PCO2

Which of the following has the most potent and closely controlled regarding Factors that Influencing Breathing Rate and Depth?

• PCO2

• Temperature

• pH

• 2,3 BPG

Hypercapnia

What is the term for rising PCO₂ levels which causes:

• hyperventilation to remove excess CO₂ out of the blood

Hypocapnia

What is the term for low levels of PCO₂ causing:

• hypoventilation; even apnea

PO₂

[Factors Influencing Breathing Rate and Depth]

What influences:

• Chemoreceptors in the aortic arch and the carotid bodies are the O₂ sensors

O₂ has to drop substantially to stimulate increased breathing

• Remember why: oxygen-hemoglobin curve

Chronic Obstructive Pulmonary Disease (COPD)

What is the term for a group of diseases characterized by chronic bronchitis and obstructive emphysema?

Patients typically have:

• History of smoking

• Dyspnea: difficulty of breathing

• Coughing and pulmonary infections

  • Respiratory failure

Dyspnea

What is the term for difficulty of breathing?

Obstructive Emphysema

What is the term for the permanent enlargement of alveoli and deterioration of alveolar walls?

• Lungs lose their elasticity which obstructs outflow of air

  • Accessory muscles must be recruited to breathe

  • Bronchioles collapse during expiration

Asthma

What is characterized by episodes of coughing, dyspnea, wheezing, and chest tightness?

Tuberculosis (TB)

What is the name of an infectious bacterial disease —

• Spread by coughing and enters body through inhaled air

• Symptoms: fever, night sweats, weight loss, cough, spitting up blood

Lung (Cancer)

The following describes what?

• 1/3 of cancer deaths in the US

• Strongly associated with cigarette smoking

• Nasal hairs, sticky mucus, and cilia become overwhelmed with smoking

  • These are our body’s defenses