Anatomy of the Respiratory System

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Questions and Answers

What role does pleural fluid play in the lungs?

It enhances oxygen transport through the blood.

It absorbs carbon dioxide during respiration.

It helps maintain lung volume by expanding the alveoli.

It reduces friction and produces surface tension. (correct)

Which statement about the lobes of the lungs is correct?

The left lung has a cardiac notch making it 10% smaller than the right lung. (correct)

The right lung consists of two lobes.

The left lung is larger and has more lobes than the right lung.

Both lungs have three lobes regardless of their size.

Which type of cells in the alveoli is primarily responsible for gas exchange?

Bronchiolar cells.

Type II alveolar cells.

Type I alveolar cells. (correct)

Surfactant cells.

What is the main function of Type II alveolar cells?

Producing surfactant to reduce surface tension. Signup and view all the answers

What anatomical feature contributes to the smaller size of the left lung?

The cardiac notch. Signup and view all the answers

What is the primary function of alveolar macrophages?

Clean debris in the alveoli Signup and view all the answers

Which muscle is mainly responsible for inhalation during normal quiet breathing?

Diaphragm Signup and view all the answers

How does the thorax expand during inhalation?

Through contraction of the diaphragm and external intercostals Signup and view all the answers

What mechanism primarily causes exhalation during normal breathing?

Elastic recoil of the chest wall and lungs Signup and view all the answers

In the case of arterial occlusion, how do O2 and CO2 levels in tissue cells typically change?

O2 levels decrease, CO2 levels increase Signup and view all the answers

What is the main function of the conducting zone in the respiratory system?

Conducts air to the lungs Signup and view all the answers

Which structure is most sensitive to triggering the cough reflex?

Carina Signup and view all the answers

What is the role of beta 2 (β2) adreno-receptors in the bronchioles?

Bind adrenaline to dilate bronchioles Signup and view all the answers

What occurs when beta 2 receptors are blocked?

Unable to dilate bronchioles Signup and view all the answers

What is the anatomical configuration of the trachea?

Extends from larynx to T5 and is C-shaped Signup and view all the answers

Which layer of the pleura directly covers the lungs?

Visceral pleura Signup and view all the answers

Which statement is true regarding the pleural cavity?

Must maintain negative pressure Signup and view all the answers

What is the largest segment of the bronchial tree that can be surgically removed?

3o segmental bronchi Signup and view all the answers

What is the primary function of oxygen in the tissues?

To facilitate the production of ATP Signup and view all the answers

During external respiration in the lungs, what is the partial pressure of oxygen (PO2) in the alveolar air?

105 mmHg Signup and view all the answers

What happens to carbon dioxide during internal respiration at the tissues?

It diffuses from tissue cells into systemic capillaries Signup and view all the answers

How much of the available oxygen is typically used by cells at rest?

25% Signup and view all the answers

What is the typical partial pressure of carbon dioxide (PCO2) in deoxygenated blood within pulmonary capillaries?

45 mmHg Signup and view all the answers

What is the role of hemoglobin in oxygen transport?

To bind and carry oxygen molecules Signup and view all the answers

Which statement accurately describes the diffusion of carbon dioxide during external respiration?

CO2 diffuses from high to low concentration Signup and view all the answers

What occurs to the partial pressure of oxygen in blood during external respiration?

It increases until it matches alveolar air Signup and view all the answers

Which of the following statements about oxygen diffusion is true?

Oxygen diffusion stops when PO2 levels are equal Signup and view all the answers

In which direction does oxygen flow during external respiration?

From the alveoli into the blood Signup and view all the answers

What occurs to oxygen in the pulmonary capillaries?

Oxygen loads onto hemoglobin. Signup and view all the answers

Which statement accurately describes the oxygen-hemoglobin dissociation curve?

It represents the average saturation of hemoglobin with oxygen. Signup and view all the answers

What role do peripheral chemoreceptors play in respiration?

They respond to changes in oxygen levels. Signup and view all the answers

Which condition describes the effective release of oxygen from hemoglobin to tissues?

Presence of acids and heat in metabolically active tissues. Signup and view all the answers

What happens to the central chemoreceptors if carbon dioxide levels are continuously elevated?

They become habituated and stop functioning effectively. Signup and view all the answers

Which of the following statements about the CO2 trap is correct?

It converts CO2 and H2O into carbonic acid in tissues. Signup and view all the answers

What is indicated by a 75% saturation of hemoglobin in deoxygenated blood?

Oxygen reserves are still retained in the blood. Signup and view all the answers

What factors influence the affinity of hemoglobin for oxygen?

Acids, CO2, and heat produced by tissues. Signup and view all the answers

Study Notes

Pleural Fluid

Lubricates the lungs and chest wall, allowing them to move smoothly during breathing.
Maintains surface tension, helping to keep the lungs expanded.

Lobes of the Lungs

The left lung has two lobes: the upper lobe and the lower lobe.
The right lung has three lobes: the upper lobe, middle lobe, and lower lobe.

Alveolar Cells

Type I alveolar cells: Primarily responsible for gas exchange, thin and flat.
Type II alveolar cells: Secrete surfactant, a substance that reduces surface tension in the alveoli and prevents collapse.

Anatomical Feature of the Left Lung

The heart is located on the left side of the chest, causing a small indentation in the left lung, known as the cardiac notch, contributing to its smaller size.

Alveolar Macrophages

Immune cells that reside in the alveoli.
Phagocytose foreign particles, debris, and pathogens, helping to protect the lungs from infection.

Inhalation

Diaphragm: The primary muscle for inhalation, contracts and flattens, increasing volume in the chest cavity.
External intercostal muscles: Assist in raising the rib cage, further expanding the thoracic cavity.

Exhalation

During normal quiet breathing, exhalation is primarily passive.
The diaphragm and intercostal muscles relax, reducing the volume of the chest cavity, effectively pushing air out of the lungs.

Arterial Occlusion - O2 & CO2 Levels

Oxygen levels will decrease in tissue cells due to reduced blood flow.
Carbon dioxide levels will increase as cells continue to produce it and its removal is hindered.

Conducting Zone

The passageways that conduct air to the respiratory zone.
This includes the trachea, bronchi, and bronchioles, which warm, humidify, and filter incoming air.

Cough Reflex Trigger

The carina, the point where the trachea divides into the right and left primary bronchi, is highly sensitive to irritants and initiates the cough reflex.

Beta 2 (β2) Adreno-receptors in Bronchioles

β2 receptors are located in the smooth muscle walls of the bronchioles.
They mediate bronchodilation, relaxing the smooth muscle and widening the airway, allowing easier airflow.

Beta 2 Receptor Blockade

Blocking these receptors has the opposite effect, causing bronchoconstriction and narrowing the airways, making breathing more difficult.

Trachea Structure

It is a cartilaginous tube with a smooth muscle layer.
The C-shaped cartilaginous rings provide structural support, preventing the airway from collapsing.

Pleura

Visceral pleura: The layer directly covering the lung surface.
Parietal pleura: The layer lining the chest cavity.

Pleural Cavity

The space between the visceral and parietal pleura.
It contains a thin layer of pleural fluid that lubricates the lungs and chest wall during breathing.

Bronchial Tree Surgical Removal

The lobar bronchus is the largest segment of the bronchial tree that can be surgically removed.

Oxygen Function in Tissues

Oxygen is essential for cellular respiration, a process that produces energy (ATP) for cellular activities.

Partial Pressure of Oxygen in Alveolar Air

During external respiration, the partial pressure of oxygen (PO2) in the alveolar air is typically around 100 mmHg.

Carbon Dioxide During Internal Respiration

Carbon dioxide (CO2), a waste product of cellular respiration, diffuses from the tissues into the blood.

Oxygen Usage by Cells at Rest

Cells at rest typically use about 25% of the available oxygen.

Partial Pressure of CO2 in Deoxygenated Blood

The typical partial pressure of carbon dioxide (PCO2) in deoxygenated blood within pulmonary capillaries is around 45 mmHg.

Hemoglobin Role in Oxygen Transport

Hemoglobin, a protein found in red blood cells, binds to oxygen in the lungs and delivers it to the tissues.

Carbon Dioxide Diffusion During External Respiration

Carbon dioxide diffuses from the blood into the alveoli.

Oxygen Partial Pressure During External Respiration

The partial pressure of oxygen (PO2) in blood increases during external respiration as it picks up oxygen from the alveoli.

Oxygen Diffusion

Oxygen flow is driven by its partial pressure gradient; it flows from areas of higher partial pressure to areas of lower partial pressure.

Oxygen in Pulmonary Capillaries

Oxygen moves from the alveoli into the pulmonary capillaries due to a higher partial pressure in the alveoli.

Oxygen-Hemoglobin Dissociation Curve

This curve shows the relationship between the partial pressure of oxygen (PO2) and the saturation of hemoglobin with oxygen.
It is sigmoidal in shape, indicating that hemoglobin's affinity for oxygen changes with PO2.

Peripheral Chemoreceptors Role

Located in large arteries, they are sensitive to changes in blood oxygen and carbon dioxide levels.
They send signals to the respiratory center in the brainstem to adjust breathing rate and depth.

Oxygen Release from Hemoglobin

Factors that promote the release of oxygen from hemoglobin include decreased PO2, increased PCO2, and increased acidity (lower pH).

Central Chemoreceptors and Elevated CO2

If carbon dioxide levels are continuously elevated, central chemoreceptors in the brainstem become more sensitive to changes in PCO2, leading to increased ventilation to remove excess carbon dioxide.

CO2 Trap

This refers to the tendency of carbon dioxide to accumulate in the blood, especially during hypoventilation.

75% Hemoglobin Saturation

A 75% saturation level of hemoglobin in deoxygenated blood indicates that tissues are actively using oxygen, and the blood is carrying a significant amount of deoxygenated hemoglobin.

Factors Influencing Hemoglobin Affinity for Oxygen

pH: Lower pH levels (more acidic) reduce hemoglobin's affinity for oxygen.
Temperature: Increased temperature decreases hemoglobin's affinity for oxygen.
2,3-BPG: An organic compound that binds to hemoglobin, reducing its affinity for oxygen, promoting oxygen release to tissues.

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Description

Explore the intricate anatomy of the respiratory system, covering both the upper and lower respiratory structures. Learn about the conducting and respiratory zones, as well as the key functions of components like the larynx, trachea, and bronchi. This quiz will enhance your understanding of how air travels and gas exchange occurs in the lungs.