Respiratory System: Gas Exchange and Partial Pressure

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Questions and Answers

What percentage of O2 is removed from water as it passes over the respiratory surface?

Less than 20%

More than 80% (correct)

All of it

More than 50%

What is the term for the process by which gases move from an area of higher partial pressure to an area of lower partial pressure?

Passive transport

Osmosis

Active transport

Net diffusion (correct)

What is the main difference between the respiratory surfaces of animals that live in water versus those that live in air?

Those in water are smaller

Those in water require greater efficiency (correct)

Those in water are less efficient

Those in water are more complex

What is the function of the nostrils in the mammalian respiratory system?

To filter, warm, humidify, and sample air for odors Signup and view all the answers

What is the term for the infolding of the body surface that allows for gas exchange?

Respiratory media Signup and view all the answers

Why do larger insects require ventilation of their tracheal system?

To meet oxygen demands Signup and view all the answers

How do the respiratory and circulatory systems interact?

They are separate but work together Signup and view all the answers

What is the term for the network of branching tubes that allows for gas exchange in insects?

Tracheal system Signup and view all the answers

What is the primary function of the pharynx in the respiratory system?

To direct air to the lungs and food to the stomach Signup and view all the answers

What is the mechanism used by fish gills to facilitate gas exchange?

Countercurrent exchange system Signup and view all the answers

What is the purpose of cilia and mucus in the respiratory system?

To move particles up to the pharynx Signup and view all the answers

What is the term for the volume of air inhaled and exhaled with each breath?

Tidal volume Signup and view all the answers

What is the function of surfactants in the alveoli?

To prevent the alveoli from collapsing Signup and view all the answers

What is the primary function of the air sacs in birds?

To serve as bellows that keep air flowing through the lungs Signup and view all the answers

What is the term for the maximum amount of air that can be inhaled and exhaled?

Vital capacity Signup and view all the answers

What is the term for the air that remains in the lungs after exhalation?

Residual volume Signup and view all the answers

In which part of the brain are the breathing control centers found?

Medulla Oblongata Signup and view all the answers

What is the mechanism that governs breathing?

The diaphragm and rib cage Signup and view all the answers

What is the primary mechanism of ventilation in amphibians?

Positive pressure breathing Signup and view all the answers

What is the site of gas exchange in birds?

Parabronchi Signup and view all the answers

What type of respiratory pigment is found in arthropods and many molluscs?

Hemocyanin Signup and view all the answers

How many cycles of inhalation and exhalation are required for air to pass through the entire system of lungs and air sacs in birds?

Two Signup and view all the answers

In which type of blood vessels does the partial pressure gradient favor the diffusion of oxygen into the interstitial fluids?

Capillaries Signup and view all the answers

What is the direction of air flow through the lungs in birds?

Unidirectional Signup and view all the answers

What is the primary function of hemoglobin in vertebrates?

To carry four molecules of oxygen from the lungs to the muscles Signup and view all the answers

What is the net result of the diffusion of CO2 in the lungs?

CO2 diffuses out of the blood Signup and view all the answers

How do diving mammals conserve oxygen?

By decreasing blood supply to muscles and stockpiling oxygen Signup and view all the answers

What is the role of hemoglobin in the transport of CO2?

Hemoglobin plays a minor role in CO2 transport Signup and view all the answers

What is the benefit of hemoglobin's ability to carry four molecules of oxygen?

It enables the blood to carry more oxygen Signup and view all the answers

What is the purpose of the high blood to body volume ratio in diving mammals?

To stockpile oxygen and deplete it slowly Signup and view all the answers

Study Notes

Gas Exchange and Respiratory Systems

Gas exchange involves the uptake of O2 and disposal of CO2 through respiratory surfaces, facilitated by net diffusion from areas of higher to lower partial pressure.
Tracheal systems in insects consist of a network of branching tubes throughout the body, requiring ventilation to meet O2 demands.

Respiratory Media and Surfaces

Respiratory media include air and water, with O2 availability being lower in water, necessitating greater efficiency in obtaining O2.
Animals require large, moist respiratory surfaces for gas exchange, which can include skin, gills, tracheae, and lungs.

Mammalian Respiratory System

The mammalian respiratory system consists of a system of branching ducts that conveys air to the lungs.
Nostrils filter, warm, humidify, and sample inhaled air for odors.
Pharynx directs air to the lungs and food to the stomach.
Larynx contains vocal cords where exhaled air passes over to create sounds.

Gas Exchange and Lung Function

Alveoli are air sacs at the tips of bronchioles where gas exchange occurs.
Oxygen diffuses through the moist epithelium into capillaries, while carbon dioxide diffuses from capillaries across the epithelium into the air space.
Surfactants coat the surface of alveoli to prevent collapse.
Lung volume increases as the rib muscles and diaphragm contract.

Breathing and Control

Breathing is the process of ventilating the lungs through inhalation and exhalation.
Control of breathing in humans is usually regulated by involuntary mechanisms in the medulla oblongata of the brain.
The rate and depth of breathing respond to pH changes in the cerebrospinal fluid.

Coordination of Circulation and Gas Exchange

Blood arriving in the lungs has a low partial pressure of O2 and a high partial pressure of CO2 relative to air in the alveoli.
Oxygen diffuses into the blood, and CO2 diffuses into the air in the alveoli.
In tissue capillaries, partial pressure gradients favor diffusion of O2 into interstitial fluids and CO2 into the blood.

Respiratory Adaptations in Other Animals

Amphibians, such as frogs, ventilate their lungs by positive pressure breathing.
Birds have 8 or 9 air sacs that function as bellows, keeping air flowing through the lungs with highly efficient ventilation.
Diving mammals conserve oxygen by changing buoyancy, decreasing blood supply to muscles, and deriving ATP in muscles from fermentation once oxygen is depleted.

Respiratory Pigments

Hemoglobin is a protein that transports oxygen, greatly increasing the amount of oxygen that blood can carry.
Hemocyanin is found in arthropods and many molluscs, using copper as the oxygen-binding component.
Diving mammals also store oxygen in their muscles in myoglobin proteins.

Carbon Dioxide and Hemoglobin

Carbon dioxide is transported in blood plasma, bound to hemoglobin, and also reacts with water to form H2CO3, which dissociates into H+ and bicarbonate ions (HCO3-).
Hemoglobin plays a minor role in transport of CO2 and assists in buffering the blood.
In the lungs, the relative partial pressures of CO2 favor the net diffusion of CO2 out of the blood.

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Description

Learn about the process of gas exchange in the respiratory system, including the uptake of oxygen and disposal of carbon dioxide. Understand the concept of partial pressure and its application to gases in mixtures and dissolved in liquids.