Respiration

Week 9

What does external (pulmonary) respiration mean

Exchange of gases between the lungs and the blood cells

What does internal (tissue) respiration mean

Exchange of gases between the blood cells and the tissues

What does dalton’s law mean | 2

• Sum of all pressures of non-reactive gases (% of pressures in lungs - O2, N, H, etc)

• Partial pressure of oxygen = PO2

How the fuck does oxygen transport work | 3

• Gas exchange occurs through diffusion

• Gas moves from high concentration (high PO2 in alveoli) to low concentration (low PO2 in alveolar capillaries)

• Oxygen diffuses across alveolar membrane and pulmonary capillary membrane and adheres to hemoglobin (hgb) molecule in RBC

What percent of O2 is bound to hgb

97%

Where is the 3% of O2 | 2

• Dissolved in plasma

• PaO2 or PO2 represents remaining 3% in mmHg

What is a pulse oximeter | 2

• Reads the percentage of bound hgb

• ANYTHING bound to hgb (CO, CO2)

How is 70% of CO2 transported | 2

• Transported in the blood in the form of bicarbonate ions, HCO3-

• Does this to be safely transported in blood (cause CO2 a toxic bitch)

How is 23% of CO2 transported

Bound to hgb (carbaminohemoglobin)

How is 7% of CO2 transported

Dissolved in plasma (PaCO2 or PCO2)

What is hemoglobin affinity | 3

• Affinity to O2 increases every time an O2 molecule binds to it (another one thank you)

• Affinity influenced by pH, CO2 concentration, temperature and enzyme 2-3DPG

• Changes to O2 can make hgb affinity more difficult for O2 to bind or release

What is the oxygen-hemoglobin dissociation curve | 3

• Relationship between PO2 and O2 bound to hgb

• How strong hgb hold on O2 is 

• Higher the PO2, more O2 binds with hgb

What happens during decreased affinity (right shift) | 7

• Decreased pH (acidosis), increase pH+ | Renal failure, CO poisoning

• PCO2 increase | Hypoventilating, COPD exacerbation 

• Temperature increase | Heat stroke, sepsis

What happens during increased affinity (left shift) | 6

• Increased pH (alkalosis), decrease H+ | Excessive vomiting (peds)

• PCO2 decrease | Hyperventilating

• Temperature decrease | Hypothermia

What is a capnography | 3

• End tidal CO2 - ETCO2

• Real time assessment of ventilation, respiration, acid-base balance and cardio-pulmonary perfusion during CPR (key marker for advanced airway placement)

• Normal range 35-45mmHg

Stages of ETCO2 | 5

• A-B: Baseline

• B-C: Expiration upstroke

• C-D: Expiratory plateau (alveolar ventilation)

• D: ETCO2 reading

• D-E: Inspiration

What happens on a capnography during hypoventilation | 3

• Prolonged waveform

• Baseline CO2 = 0

• ETCO2 > 45mmHg

What happens on a capnography during hyperventilation | 3

• Shortened waveform

• Baseline CO2 = 0

• ETCO2 < 35mmHg

What happens on a capnography during bronchospasm | 4

• Sharkfin (with/without prolonged expiration)

• Asthma, COPD, allergic reaction

• More force (harder to exhale than inhale, can’t chill harder)

• Wheezes

What is ventilation-perfusion mismatch (V:Q) | 2

• When one or more areas of the lung receive oxygen with decreased blood flow OR receive blood with decreased oxygen

• Blood that flows to injured lung doesn’t participate in gas exchange and when in returns to heart it is hypoxic

What happens in decreased Q | 4

• Normal ventilation with decreased perfusion

• PE (pulmonary edema) bloodclat in blood vessels

• Pulmonary HTN (constriction in blood vessels)

• Emphysema (COPD) shortness of breath

What happens in decreased V | 5

• Normal perfusion with decreased ventilation

• Atelectasis (collapsed lung)

• PE (pulmonary edema) water in lungs

• Bronchitis (COPD) narrow airway

• Pneumothorax (air in pleural/lung cavity)

Aging in Respiratory System | 4

• Elasticity of lungs decline (Worsen by smoking or sedentary lifestyle)

• Muscles tire and fail quicker (respiratory muscles included)

• More susceptible to lung infections (bronchitis, pneumonia) and take longer to recover

• Common to have many comorbidities

What does laryngospasm mean

Irritation of larynx causing closure of vocal cords (typically lasts a few secs)

What does bronchoconstriction mean

Narrowing of bronchi (results in wheezing)

What does bronchodilation mean

Widening of bronchi

What does ventilation mean

Process of moving air in and out of lungs

What does pulmonary respiration mean

The process of gas exchange in alveoli

What are beta-2 receptors

Line the bronchi and when stimulated cause bronchodilation