Respiration in BIOL160 Chapter 34

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Questions and Answers

What is the primary purpose of gas exchange in organisms?

To support cellular respiration by taking in oxygen and releasing carbon dioxide.

List the three adaptations that facilitate gas exchange in animals.

Respiratory surfaces remain moist, are very thin, and have a large surface area.

How does diffusion support gas exchange?

Diffusion allows molecules to move from high to low concentration areas, facilitating gas exchange.

What are the two main parts of the human respiratory system?

The conducting portion and the gas-exchange portion. Signup and view all the answers

Why must respiratory surfaces remain moist?

Gases can only diffuse across moist membranes, as they need to be dissolved in water for diffusion. Signup and view all the answers

What role does the respiratory system play in cellular respiration?

It provides a continuous supply of oxygen and removes carbon dioxide produced during respiration. Signup and view all the answers

Explain the importance of having thin respiratory surfaces.

Thin respiratory surfaces minimize the distance gases must travel, enhancing gas exchange efficiency. Signup and view all the answers

What is the relationship between concentration gradients and gas exchange?

Concentration gradients are necessary for gases to diffuse; they ensure movement from areas of high concentration to low. Signup and view all the answers

What role does the epiglottis play during normal breathing?

The epiglottis tilts upward, allowing air to flow into the larynx. Signup and view all the answers

How are vocal sounds produced in the larynx?

Sounds are produced when exhaled air causes the vocal cords to vibrate. Signup and view all the answers

Describe the pathway air follows as it enters the respiratory system.

Air enters through the nose or mouth, travels through the nasal or oral cavity, into the pharynx, and then to the larynx. Signup and view all the answers

What happens to the epiglottis during swallowing?

The epiglottis folds downward, covering the larynx to direct substances into the esophagus. Signup and view all the answers

What is the function of the trachea in the respiratory system?

The trachea conducts air from the larynx to the bronchi and is reinforced with cartilage for support. Signup and view all the answers

Explain the branching process that occurs within the lungs.

Each bronchus splits into smaller bronchioles, which lead to microscopic alveoli for gas exchange. Signup and view all the answers

Identify the main components of the conducting portion of the respiratory system.

The main components include the nose, pharynx, larynx, trachea, and bronchi. Signup and view all the answers

What are the vocal cords and what is their significance?

Vocal cords are bands of elastic tissue in the larynx that vibrate to produce sound. Signup and view all the answers

What role do alveoli play in gas exchange?

Alveoli provide a large surface area for diffusion, allowing gases to efficiently enter and leave the bloodstream. Signup and view all the answers

How does the presence of surfactant in the alveoli assist the gas exchange process?

Surfactant prevents the alveolar surfaces from collapsing and sticking together during exhalation. Signup and view all the answers

Describe the composition of the respiratory membrane.

The respiratory membrane consists of a single layer of alveolar epithelial cells and the endothelial cells of capillaries. Signup and view all the answers

What is the significance of having approximately 300 million alveoli in an adult's lungs?

Having around 300 million alveoli maximizes the surface area for gas exchange, enhancing oxygen absorption and carbon dioxide release. Signup and view all the answers

Explain how gases diffuse in the lungs.

Gases diffuse across the respiratory membrane from areas of higher concentration to areas of lower concentration. Signup and view all the answers

What role do capillaries play in the gas exchange process?

Capillaries cover the alveolar surface and facilitate the transport of gases between the bloodstream and alveoli. Signup and view all the answers

Why is it important for the alveolar walls to be thin?

Thin alveolar walls allow for efficient gas diffusion between the air in the alveoli and the blood in the capillaries. Signup and view all the answers

Discuss how the moist environment of the alveoli aids in gas exchange.

The moist environment helps dissolve gases, facilitating their diffusion across the respiratory membrane. Signup and view all the answers

How does hemoglobin contribute to oxygen transport in the blood?

Hemoglobin binds to about 98% of the oxygen in the blood, with each molecule capable of carrying up to four O2 molecules. Signup and view all the answers

Describe the process of carbon dioxide transport in the bloodstream.

CO2 is transported in the blood in three ways: 10% dissolved in plasma, 20% bound to hemoglobin, and about 70% in the form of bicarbonate ions. Signup and view all the answers

What role do diffusion gradients play in gas exchange in the lungs and body tissues?

Diffusion gradients favor oxygen moving from areas of high concentration in the lungs to low concentration in the body, while CO2 moves from high concentration in body cells to low concentration in the lungs. Signup and view all the answers

What structural change occurs in hemoglobin when oxygen binds to it?

When oxygen binds to hemoglobin, it causes the protein to change shape, resulting in a change in color from deoxygenated maroon-red to oxygenated bright cherry-red. Signup and view all the answers

Explain the significance of bicarbonate ions in carbon dioxide transport.

Bicarbonate ions, formed from CO2 and water, play a crucial role in transporting about 70% of CO2 from tissues to the lungs, maintaining pH balance in the blood. Signup and view all the answers

How does the diaphragm contribute to the process of inhalation?

The diaphragm contracts and moves downward, enlarging the chest cavity and allowing air to flow into the lungs. Signup and view all the answers

What happens to the diaphragm and rib muscles during exhalation?

During exhalation, the diaphragm relaxes and domes upward while the rib muscles relax, causing the ribs to move downward and inward. Signup and view all the answers

What role does the respiratory center in the brain play in breathing?

The respiratory center regulates breathing rate and volume by sending impulses to the diaphragm and rib muscles. Signup and view all the answers

How does the body ensure constant CO2 levels during respiration?

CO2 receptors in the medulla detect CO2 levels and adjust the breathing rate to maintain low levels of CO2 in the blood. Signup and view all the answers

In what way is inhalation considered an active process?

Inhalation is active because it requires the contraction of the diaphragm and rib muscles to draw air into the lungs. Signup and view all the answers

What triggers the contraction of the diaphragm and rib muscles?

The contraction is stimulated by nerve impulses originating from the respiratory center in the brain. Signup and view all the answers

Describe the process of passive exhalation.

Passive exhalation occurs when the diaphragm and rib muscles relax, reducing the chest cavity size and allowing air to escape from the lungs. Signup and view all the answers

What is the significance of the diaphragm's dome shape when relaxed?

When relaxed, the diaphragm assumes a dome shape, which signifies that it is not contracting and allows for passive exhalation. Signup and view all the answers

Flashcards

Inhalation

The process of breathing that draws air into the lungs.

Exhalation

The process of breathing that pushes air out of the lungs.

Diaphragm

The muscle that forms the lower boundary of the chest cavity. It contracts and moves down during inhalation, and relaxes and domes upward during exhalation.