Respiration

These flashcards cover essential concepts related to the respiratory system and gas exchange processes.

Why is oxygen important for respiration?

Oxygen serves as an electron acceptor in the oxidation of carbon-based fuels, yielding large amounts of energy for aerobic metabolism.

What was the Great Oxygenation Event?

It was a period when cyanobacteria produced oxygen through photosynthesis, leading to a significant rise in atmospheric O2.

What are the Dalton and Henry laws in relation to gas exchange?

Dalton's law states that the total pressure exerted by a mixture of gases is the sum of the partial pressures of each gas. Henry's law relates to the solubility of gases in liquids.

What is the function of respiratory pigments like hemoglobin?

Respiratory pigments increase the amount of oxygen that blood can carry, facilitating gas exchange.

How do fish gills function for gas exchange?

Fish gills use a countercurrent exchange system, where blood flows opposite to the water flow, maximizing oxygen absorption.

What is negative pressure breathing and how do mammals utilize it?

Negative pressure breathing involves the contraction of intercostal muscles and diaphragm to pull air into the lungs.

What is the role of myoglobin?

Myoglobin stores oxygen in muscles and has a higher affinity for O2 than hemoglobin, acting as an emergency O2 reserve.

How does the Bohr shift affect oxygen delivery?

The Bohr shift occurs when increased CO2 lowers blood pH, decreasing hemoglobin's affinity for O2, which enhances O2 delivery to tissues.

What adaptations do diving mammals have for respiration?

Diving mammals have high blood-to-body volume ratios, store O2 in myoglobin, and have physiological adaptations for conserving oxygen while diving.

What occurs in the lungs regarding CO2 transport?

In the lungs, CO2 diffuses out of the blood when partial pressures favor its escape, allowing for efficient gas exchange.

What is hemoglobin?

Hemoglobin is a protein in red blood cells that carries oxygen from the lungs to the body's tissues and returns carbon dioxide from the tissues back to the lungs.

What is the function of oxygen affinity in hemoglobin?

Oxygen affinity refers to the degree to which hemoglobin binds to oxygen. Higher affinity means hemoglobin binds oxygen more tightly.

What is the Bohr effect?

The Bohr effect explains how increased levels of carbon dioxide and decreased pH reduce hemoglobin's affinity for oxygen, facilitating oxygen release in tissues.

What factors can affect hemoglobin's oxygen affinity?

Factors include pH levels, carbon dioxide concentration, temperature, and 2,3-bisphosphoglycerate (2,3-BPG) levels.

What is the significance of hemoglobin saturation?

Hemoglobin saturation indicates the percentage of hemoglobin molecules in the blood that are bound to oxygen, essential for assessing respiratory function.

What is the difference between oxyhemoglobin and deoxyhemoglobin?

Oxyhemoglobin is hemoglobin bound to oxygen, while deoxyhemoglobin is hemoglobin without bound oxygen.

What is the structure of hemoglobin?

Hemoglobin is composed of four polypeptide chains (two alpha and two beta) and four heme groups that contain iron, allowing for oxygen binding.

How does pH influence hemoglobin oxygen affinity?

A decrease in pH (increase in acidity) lowers hemoglobin's oxygen affinity, promoting oxygen release in tissues needing it most.

What role does 2,3-BPG play in hemoglobin function?

2,3-BPG binds to deoxyhemoglobin, decreasing its affinity for oxygen and facilitating oxygen release in tissues during conditions of hypoxia or high altitude.

What is cooperativity in hemoglobin?

Cooperativity refers to the phenomenon where the binding of one oxygen molecule to hemoglobin increases the likelihood of additional oxygen molecules binding to the remaining sites.

How does temperature affect hemoglobin's oxygen affinity?

Increased temperature reduces hemoglobin's affinity for oxygen, promoting oxygen unloading in metabolically active tissues generating heat.

What is methemoglobin?

Methemoglobin is a form of hemoglobin that cannot bind oxygen due to iron being in the ferric (Fe3+) state instead of the ferrous (Fe2+) state.

What is negative pressure gas exchange?

Negative pressure gas exchange is a mechanism used by mammals where the diaphragm contracts, creating negative pressure in the thoracic cavity, allowing air to flow into the lungs.

How does negative pressure assist in ventilation?

Negative pressure increases lung volume and decreases pressure inside the lungs compared to the atmosphere, driving air into the lungs during inhalation.

What role does the diaphragm play in negative pressure gas exchange?

The diaphragm is a muscle that, when contracted, lowers the pressure in the thoracic cavity, facilitating the drawing in of air into the lungs.

What is the significance of pleural pressure in negative pressure breathing?

Pleural pressure is the pressure within the pleural cavity, and it must remain negative relative to atmospheric pressure to keep the lungs inflated during respiration.

How do intercostal muscles contribute to negative pressure gas exchange?

Intercostal muscles expand the ribcage during inhalation, enhancing the negative pressure created by the diaphragm to facilitate airflow into the lungs.

What happens to gas exchange during expiration?

During expiration, the diaphragm relaxes, the chest cavity decreases in volume, and positive pressure is created in the lungs, pushing air out of the lungs.