Respiratory Systems and Gas Exchange in Animals: Key Concepts and Laws

What is the primary function of the respiratory system?

The uptake and transport of O2 to tissues and the removal of metabolic CO2 from cells.

What are the products of cellular respiration?

ATP (energy), CO2, and water.

What is the chemical equation for cellular respiration?

C6H12O6 + 6O2 → 6CO2 + 6H2O + Energy

Why is oxygen availability a critical factor for animal distribution?

Oxygen concentration varies significantly in different environments, such as soil and water, and is essential for cellular respiration.

How does oxygen behave in water compared to air?

Oxygen diffuses slowly into water and has low solubility in water.

What does Avogadro's Law state regarding gases?

Equal volumes of different gases at the same temperature and pressure contain the same number of gas molecules.

What is the mathematical relationship defined by Avogadro's Law?

V ∝ n (Volume is proportional to the amount of gas).

What does Gay-Lussac's Law state?

The pressure of a gas is directly proportional to its temperature if the volume remains constant.

What is the formula for comparing a gas under two different temperatures according to Gay-Lussac's Law?

P1/T1 = P2/T2

What does Boyle's Law state?

The pressure exerted by a gas is inversely proportional to its volume if the temperature remains constant.

What is the mathematical formula for Boyle's Law?

P1V1 = P2V2

What does Henry's Law describe?

The amount of gas that dissolves in a liquid is directly proportional to the pressure of that gas above the liquid and its solubility.

What is the formula for Henry's Law?

C = kH * P (where C is concentration, kH is the solubility coefficient, and P is pressure).

How does pressure affect the solubility of a gas in a liquid?

Solubility increases as the pressure of the gas above the liquid increases.

What factors influence the solubility coefficient (kH) of a gas?

The type of gas, the temperature, and the type of liquid.

How does water temperature affect the solubility of oxygen?

The solubility coefficient (kH) for oxygen decreases as water temperature increases.

How does ionic strength affect the solubility of oxygen?

The solubility coefficient (kH) for oxygen decreases as ionic strength increases.

What does Dalton's Law state regarding gas mixtures?

The partial pressure of each gas in a mixture is independent of the other gases present.

How is the total pressure of a gas mixture calculated?

PTOTAL = P1 + P2 + P3... (the sum of the partial pressures of all gases present).

What unit of temperature must be used when applying gas laws?

Kelvin (K).

How is partial pressure of a gas calculated?

Fractional composition of the gas multiplied by the total pressure of the mixture.

What happens to atmospheric oxygen availability as elevation increases?

It decreases because the overall density of air decreases.

What are the four components of a vertebrate gas transfer system?

Ventilation, diffusion across respiratory epithelium, bulk transport by blood, and diffusion across capillary walls.

What must happen to respiratory gases before they can cross membranes?

They must first dissolve in a fluid.

What is the primary function of respiratory pigments?

To bind oxygen after it diffuses across the respiratory epithelium, increasing blood oxygen-carrying capacity.

What are the four protein chains in hemoglobin called?

Globin chains.

What is the role of the iron atom in the heme group?

It is located in the center of the porphyrin ring and binds oxygen.

How does fetal hemoglobin (HbF) differ from adult hemoglobin (HbA)?

Fetal hemoglobin contains two gamma chains instead of two beta chains and has a higher oxygen affinity.

What is the primary location of myoglobin in vertebrates?

The cytoplasm of muscle cells.

Which respiratory pigment is copper-based and found in many arthropods and molluscs?

Hemocyanin.

What is the color of oxygenated hemocyanin?

Light blue.

What percentage of oxygen is carried physically dissolved in the blood versus bound to hemoglobin?

Approximately 1.5% is dissolved, and 98.5% is bound to hemoglobin.

What is the oxygen-carrying capacity formula?

1.34 ml O2 multiplied by the hemoglobin concentration in g/dL.

What is the P50 index?

The partial pressure of oxygen at which 50% of hemoglobin is saturated.

Why is the oxygen-hemoglobin dissociation curve sigmoidal?

Due to subunit cooperativity, where binding of one oxygen molecule enhances the binding of others.

What is allosteric regulation?

The alteration of protein activity by the binding of an effector molecule at a site other than the active site.

What are the two structural states of hemoglobin?

Tense (T) state and relaxed (R) state.

What is the Bohr effect?

The shift of the oxygen-hemoglobin dissociation curve to the right due to increased H+ or CO2, reducing oxygen affinity.

How does temperature affect the oxygen-hemoglobin dissociation curve?

Increased temperature shifts the curve to the right, decreasing oxygen affinity.

What is the function of 2,3-biphosphoglycerate (2,3-BPG)?

It increases the ability of hemoglobin to unload oxygen at systemic tissues.

What is the term for oxygen bound to hemoglobin?

Oxyhemoglobin.

What is the term for carbon dioxide bound to hemoglobin?

Carbaminohemoglobin.

What is hypoxia?

Insufficient oxygen at the cellular level.

What is anoxia?

The complete absence of oxygen at the cellular level.

What is hypercapnia?

Excess carbon dioxide at the cellular level.

What is hypocapnia?

Below-normal carbon dioxide levels.

Which vertebrate group lacks red blood cells, hemoglobin, and myoglobin?

Antarctic icefishes.

What happens to the oxygen-hemoglobin reaction when blood PO2 is high?

The reaction shifts to the right, favoring oxygen loading.