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Questions and Answers

What are the factors that determine partial pressure of a gas dissolved in a fluid?

The partial pressure of a gas dissolved in a fluid depends on the solubility of the gas, the total pressure of the gas mixture, and the temperature of the fluid. This is explained by Henry's Law.

How is air humidified in the respiratory passages?

Air is humidified in the respiratory passages as it travels through the nasal cavity, pharynx, trachea, and bronchi. The mucous membranes lining these passages are moist and warm, adding moisture to the inhaled air.

What comprises the respiratory unit?

The respiratory unit is a functional unit of the lung that includes the terminal bronchiole (small airways) and all alveoli that the bronchioles connect to, involved in gas exchange.

What are the different layers of the respiratory membrane?

The respiratory membrane consists of several layers: the alveolar epithelial cell layer, the shared basement membrane, the capillary endothelial cell layer, and the plasma membrane of the red blood cell. Signup and view all the answers

What are the factors that determine how rapidly a gas passes through the membrane?

The rate of gas diffusion through the respiratory membrane is influenced by several factors: the partial pressure gradient of the gas, the surface area of the membrane, the thickness of the membrane, the diffusion coefficient of the gas, and the solubility of the gas in the membrane. Signup and view all the answers

Explain the importance of why alveolar air must be slowly renewed by atmospheric air.

Alveolar air must be gradually replaced by atmospheric air to maintain adequate oxygen levels and remove carbon dioxide. This is achieved through ventilation. Signup and view all the answers

What happens in pulmonary edema?

Pulmonary edema occurs when fluid builds up in the alveoli and interstitial spaces of the lungs, impairing gas exchange. It is often characterized by shortness of breath and difficulty breathing. Signup and view all the answers

How O2 and CO2 diffused from alveoli to the pulmonary capillary blood?

Oxygen diffuses from the alveoli to the pulmonary capillary blood because the partial pressure of O2 in the alveoli is higher than the partial pressure of O2 in the blood. Likewise, carbon dioxide diffuses from the blood to the alveoli because the partial pressure of CO2 in the blood is higher than the partial pressure of CO2 in the alveoli. Signup and view all the answers

How is oxygen transported in arterial blood?

Oxygen is primarily transported in arterial blood bound to hemoglobin, a protein found in red blood cells. Signup and view all the answers

What are the factors that shift the oxygen-hemoglobin dissociation curve?

The oxygen-hemoglobin dissociation curve can be shifted by several factors, including changes in pH, temperature, carbon dioxide levels, and the presence of 2,3 BPG (2,3-bisphosphoglycerate). Signup and view all the answers

What are the chemical forms in which CO2 can be transported?

Carbon dioxide is transported in the blood in three main forms: dissolved CO2, bicarbonate ion (HCO3-), and carbaminohemoglobin. Signup and view all the answers

How oxygen is taken by the pulmonary blood during exercise?

During exercise, the pulmonary blood takes up oxygen more efficiently due to increased blood flow, increased ventilation, and a steeper partial pressure gradient for oxygen between the alveoli and the blood. Signup and view all the answers

What happens when carbon monoxide combines with hemoglobin?

Carbon monoxide binds to hemoglobin more strongly than oxygen, preventing oxygen from binding to hemoglobin and causing carbon monoxide poisoning. Signup and view all the answers

Where is the respiratory center located?

The respiratory center is located in the medulla oblongata and pons of the brainstem. Signup and view all the answers

What group of neurons control our inspiration and expiration, respiratory rhythm?

The dorsal respiratory group (DRG) controls inspiration, while the ventral respiratory group (VRG) controls both inspiration and expiration, and the rhythm of breathing. Signup and view all the answers

What stimulates the chemoreceptors?

Chemoreceptors respond to changes in the partial pressures of oxygen and carbon dioxide, as well as changes in blood pH. Signup and view all the answers

How is respiration regulated during exercise?

During exercise, the respiratory system responds to increased metabolic demands by increasing the breathing rate and depth of breathing, delivering more oxygen to the tissues and removing carbon dioxide. Signup and view all the answers

What is the effect of hypoxia on the body?

Hypoxia, or low oxygen levels in the body, can have various effects ranging from mild symptoms like fatigue and shortness of breath to severe consequences like organ damage and even death. Signup and view all the answers

Study Notes

Week 6: Principles of Gas Exchange

Gas Diffusion: Diffusion of O2 and CO2 across the respiratory membrane is governed by several laws.
Partial Pressures: Gases diffuse from higher to lower partial pressure.
Henry's Law: The solubility of a gas in a fluid is directly proportional to the partial pressure of the gas.
Graham's Law: The rate of diffusion of a gas is inversely proportional to the square root of its molecular weight.
Fick's Law: Diffusion rate is proportional to the surface area and the partial pressure difference, inversely proportional to membrane thickness.
Boyle's Law & Dalton's Law: These laws describe pressure-volume relationships and partial pressures in gases.
Ventilation-Perfusion Ratio (V/Q): The ratio of air flow (ventilation) to blood flow (perfusion) in the alveoli.
Respiration Parameters: Factors influencing partial pressures, including water vapor pressure, humidification in the respiratory passages.
Components of the Respiratory Unit: The anatomical structures involved in respiration.
Respiratory Membrane Layers: Layers through which gases diffuse in the lungs.
Diffusing Capacity: How rapidly gases diffuse through the membrane, influenced by surface area, membrane thickness, and diffusion coefficient.
Alveolar Ventilation: Factors determining how quickly gases pass through the membrane, including surface area and thickness.

Clinical Correlations

Alveolar Pressure and Gas Exchange: Alveolar pressure influences absorption of gases (O2 and CO2) during ventilation
Alveolar Partial Pressures: Alveolar ventilation affects the partial pressure of CO2 and O2, with alveolar PCO2 increasing with CO2 excretion and decreasing with alveolar ventilation.
Clinical Significance: Understanding these principles is crucial for interpreting respiratory abnormalities like COPD.
Physiological Shunt and Deadspace: Abnormal ventilation-perfusion ratios (V/Q) can indicate respiratory issues like physiological shunt or dead space.

Week 7: Regulation of Respiration

Respiratory Center Location: The brain stem houses the respiratory center (neurons) controlling inspiration/expiration.
Pneumotaxic Center: Involved in regulating the rhythm of breathing.
Chemical Control of Respiration: Changes in CO2 and H+ concentration affect the respiratory center, impacting breathing rate.
Peripheral Chemoreceptors: Respond to changes in blood oxygen.
Hypoxic States: Low arterial oxygen triggers chemoreceptor activation, increasing alveolar ventilation to restore oxygen levels.
Exercise and Respiration: Respiration is increased during exercise to meet the body's increased oxygen demands.
Neurogenic Control: The neural control during exercise can become learned.

Week 7: Oxygen Transport

Transport of Oxygen from Lungs to Tissues: How O2 and CO2 diffuse between lungs/tissue fluids and blood.
O2 Transport in Arterial Blood: O2 is carried in the blood primarily bound to hemoglobin.
Tissue Metabolism & PCO2: How tissue metabolism and blood flow impact interstitial PCO2.
Hemoglobin's Role: Hemoglobin plays a critical role in oxygen transport, buffering tissue oxygen levels.
CO2 Transport: How CO2 is transported in blood, including dissolved state and bicarbonate form.
Oxygen-Hemoglobin Dissociation Curve: Characterizes the saturation of hemoglobin with oxygen at various PO2 levels.
Factors Affecting the Curve: Factors like temperature, pH, and 2,3-DPG influence hemoglobin's affinity for oxygen.
Clinical Significance: Understanding these principles is crucial in conditions like hypoxia and carbon monoxide poisoning.

Week ? : Respiratory Insufficiency and Abnormalities

Respiratory Abnormalities: Methods for studying lung function, like maximal expiratory flow, forced expiratory volume, forced vital capacity.
Pathophysiology of Pulmonary Abnormalities: Understanding the physiological changes in diseases like pneumonia, asthma, atelectasis, and tuberculosis.
Hypoxia and Oxygen Therapy: Causes and effects of hypoxia, treatment strategies involving oxygen therapy and associated considerations.
Respiratory Insufficiency & Diagnosis: Physiological changes in conditions such as COPD, pneumonia, and tuberculosis, and diagnostic approaches.