Human Anatomy and Physiology - Alveoli Function
89 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary function of the pores of Kohn in the alveoli?

  • To allow movement of immune cells between alveoli (correct)
  • To maintain the structure of alveoli
  • To secrete mucus for trapping microorganisms
  • To facilitate gas exchange between blood and alveoli

Which gas diffuses from the alveoli into the blood during gas exchange?

  • Nitrogen
  • Water vapor
  • Carbon monoxide
  • Oxygen (correct)

What is the primary role of type I alveolar epithelial cells in the lungs?

  • Secretion of pulmonary surfactant
  • Production of alveolar macrophages
  • Maintenance of the gas-blood barrier and gas exchange (correct)
  • Defense against pathogens

What percentage of the total alveolar surface do type I alveolar epithelial cells comprise?

<p>90% (A)</p> Signup and view all the answers

What is the thickness of the alveolar-capillary membrane?

<p>0.5 micron (B)</p> Signup and view all the answers

What happens to the Pco2 levels in capillary blood after gas exchange?

<p>They fall (C)</p> Signup and view all the answers

At which anatomical level is the carina positioned?

<p>At the level of the aortic arch (C)</p> Signup and view all the answers

What is the main function of type II alveolar epithelial cells?

<p>Secretion of pulmonary surfactant (B)</p> Signup and view all the answers

Where does the pulmonary artery receive blood from?

<p>Right side of the heart (A)</p> Signup and view all the answers

What prevents the trachea from collapsing during bronchoconstriction?

<p>Cartilaginous rings (D)</p> Signup and view all the answers

What happens to the lungs when there is a severe loss of pulmonary surfactant?

<p>Alveolar instability and collapse (C)</p> Signup and view all the answers

How are alveolar macrophages formed?

<p>From blood monocytes that migrate into the alveoli (A)</p> Signup and view all the answers

Which arteries supply the tissues in the left side of the thorax?

<p>Bronchial arteries (D)</p> Signup and view all the answers

Which bronchus is wider and angles more directly toward the lung?

<p>Right bronchus (B)</p> Signup and view all the answers

What component primarily makes up pulmonary surfactant?

<p>Phospholipids (D)</p> Signup and view all the answers

What type of blood does the left atrium normally contain?

<p>Oxygenated blood (A)</p> Signup and view all the answers

What generation of the bronchial tree includes the main stem bronchi?

<p>First generation (A)</p> Signup and view all the answers

What is the main cause of diffusion stopping in the alveolar-capillary membrane?

<p>Equalization of pressures on both sides (B)</p> Signup and view all the answers

What effect does pulmonary disease have on surfactant synthesis?

<p>Reduces synthesis and storage of surfactant (C)</p> Signup and view all the answers

Which of these bronchioles have a diameter of less than 1 mm?

<p>Bronchioles (C)</p> Signup and view all the answers

Which cell type is most susceptible to injury in the pulmonary system?

<p>Type I alveolar epithelial cells (B)</p> Signup and view all the answers

In which part of the respiratory system does gas exchange primarily occur?

<p>Respiratory bronchioles (A)</p> Signup and view all the answers

Which generation of bronchi do the segmental bronchi belong to?

<p>Third generation (C)</p> Signup and view all the answers

How many alveoli are approximately contained in each terminal respiratory unit?

<p>2000 (D)</p> Signup and view all the answers

What is the primary factor that determines the direction of diffusion of gases in the lungs?

<p>The driving pressure difference between the alveoli and pulmonary capillaries (A)</p> Signup and view all the answers

How does supplemental oxygen affect the driving pressure of oxygen?

<p>It raises the driving pressure of oxygen (C)</p> Signup and view all the answers

What is true regarding the diffusion coefficient of gases?

<p>Carbon dioxide diffuses 20 times more rapidly than oxygen due to its higher diffusion coefficient (A)</p> Signup and view all the answers

Which condition would decrease the rate of gas diffusion across the alveolar-capillary membrane?

<p>Thicker alveolar-capillary membrane (A)</p> Signup and view all the answers

At high altitudes, what impact does gravity have on the diffusion of oxygen?

<p>It diminishes the driving pressure for oxygen (B)</p> Signup and view all the answers

Which of the following best describes gas transport within the body?

<p>Gas transport is facilitated by the blood and occurs via diffusion at the cellular level (B)</p> Signup and view all the answers

What happens to carbon dioxide in the lungs during diffusion?

<p>It moves from pulmonary capillaries into the alveoli (B)</p> Signup and view all the answers

How do conditions like pulmonary edema affect diffusion?

<p>They increase the thickness of the alveolar-capillary membrane (A)</p> Signup and view all the answers

What is one of the primary functions of the lymphatic system in the lungs?

<p>Producing antibodies (B)</p> Signup and view all the answers

What is the primary reason the lungs have a rich supply of lymphatic tissue?

<p>To manage exposure to external environments (B)</p> Signup and view all the answers

Which pressure is typically less than atmospheric pressure in a normal lung?

<p>Intrapleural pressure (B)</p> Signup and view all the answers

What is the term used for the movement of air into the lungs?

<p>Inhalation (D)</p> Signup and view all the answers

What typically measures pressure at sea level?

<p>760 mmHg (D)</p> Signup and view all the answers

What occurs during external respiration?

<p>Diffusion of oxygen and carbon dioxide between air and blood (A)</p> Signup and view all the answers

Which pressure is affected by the size of the thorax?

<p>Intrapulmonary pressure (C)</p> Signup and view all the answers

What type of particles does the lymphatic system in the lungs help to remove?

<p>Foreign particles and cell debris (D)</p> Signup and view all the answers

Which factor does NOT contribute to an increased work of breathing?

<p>Enhanced pulmonary surfactant production (B)</p> Signup and view all the answers

What is the primary function of pulmonary surfactant?

<p>To reduce surface tension in the alveoli (C)</p> Signup and view all the answers

Which muscle is NOT typically involved in accessory breathing?

<p>Latissimus dorsi (A)</p> Signup and view all the answers

What is the approximate tidal volume (VT) during normal breathing?

<p>500 to 600 mL (A)</p> Signup and view all the answers

Which pulmonary capacity represents the maximal amount of air that can be inhaled?

<p>Total lung capacity (TLC) (B)</p> Signup and view all the answers

Which gas exchange is referred to as internal respiration?

<p>Diffusion of gases in and out of cells (A)</p> Signup and view all the answers

What is the residual volume (RV) typically in the lungs after a forced expiration?

<p>1000 to 1200 mL (C)</p> Signup and view all the answers

Which volume is included in the calculation of inspiratory capacity (IC)?

<p>Tidal volume and inspiratory reserve volume (C)</p> Signup and view all the answers

Which structure separates the thoracic and abdominal cavities?

<p>Diaphragm (D)</p> Signup and view all the answers

How many lung segments are located in the right lung?

<p>10 (D)</p> Signup and view all the answers

What type of pleura adheres directly to the lungs?

<p>Visceral pleura (D)</p> Signup and view all the answers

Which area contains the heart, great vessels, and esophagus?

<p>Mediastinum (D)</p> Signup and view all the answers

What is the normal range of intrapleural pressure during inhalation?

<p>4 to -10 cm H2O (B)</p> Signup and view all the answers

Which muscles are responsible for decreasing the size of the chest during exhalation?

<p>Muscles of exhalation (C)</p> Signup and view all the answers

During deep inhalation, what intrapleural pressure can be generated?

<p>12 to -18 cm H2O (D)</p> Signup and view all the answers

What is the primary muscle responsible for the majority of the work of breathing during normal, quiet breathing?

<p>Diaphragm (D)</p> Signup and view all the answers

Which nerve is primarily responsible for controlling the diaphragm's actions during breathing?

<p>Phrenic nerve (C)</p> Signup and view all the answers

What occurs during exhalation in a healthy lung?

<p>It is a passive event. (D)</p> Signup and view all the answers

Which muscles are considered accessory muscles of ventilation during exercise?

<p>Sternocleidomastoid (B)</p> Signup and view all the answers

What is one of the main purposes of the conducting airways?

<p>To filter out pathogens (C)</p> Signup and view all the answers

During inhalation, how does the diaphragm affect the abdomen?

<p>It flattens and pushes down. (C)</p> Signup and view all the answers

Which group of muscles is primarily active during normal inhalation?

<p>External intercostal muscles (C)</p> Signup and view all the answers

What happens to the activity of the accessory muscles during exercise?

<p>They enhance chest expansion. (D)</p> Signup and view all the answers

What is the composition of the upper airway structures?

<p>All structures above the glottis (A)</p> Signup and view all the answers

What happens during inhalation when intrapulmonary pressure falls?

<p>Air enters the lungs and inhalation occurs. (A)</p> Signup and view all the answers

Which factors primarily determine the work of breathing?

<p>Elastic and resistive properties of the lungs. (D)</p> Signup and view all the answers

What happens during expiration when intrapulmonary pressure rises?

<p>Air exits the lungs and exhalation occurs. (D)</p> Signup and view all the answers

Which pulmonary disease is associated with decreased lung compliance?

<p>Atelectasis. (D)</p> Signup and view all the answers

Which condition is likely to increase airway resistance?

<p>Asthma. (B)</p> Signup and view all the answers

At what level is the carina typically positioned?

<p>Fifth thoracic vertebra (B)</p> Signup and view all the answers

What is the function of the C-shaped cartilaginous rings in the trachea?

<p>They prevent tracheal collapse (D)</p> Signup and view all the answers

Which bronchus is narrower and angles toward the left lung?

<p>Left bronchus (A)</p> Signup and view all the answers

What is the most common site of aspiration for foreign objects in the lungs?

<p>Right main stem bronchus (A)</p> Signup and view all the answers

What do the fourth to ninth generations of the bronchi consist of?

<p>Small bronchi (B)</p> Signup and view all the answers

What is the diameter of bronchioles?

<p>Less than 1 mm (A)</p> Signup and view all the answers

What marks the transition zone of the lungs for gas exchange?

<p>Respiratory bronchioles (A)</p> Signup and view all the answers

How many alveolar ducts does each respiratory bronchiole give rise to?

<p>10 to 16 (A)</p> Signup and view all the answers

How many segmental bronchi are included in the bronchial tree?

<p>18 (C)</p> Signup and view all the answers

What is the primary characteristic of the walls of bronchioles?

<p>They have no connective tissue or cartilage (D)</p> Signup and view all the answers

What process helps keep the alveoli clean and sterile?

<p>Phagocytosis (D)</p> Signup and view all the answers

What is the primary role of the pulmonary artery?

<p>To transport deoxygenated blood to the lungs (B)</p> Signup and view all the answers

During gas exchange, why does oxygen diffuse from the alveoli into the blood?

<p>Higher concentration of oxygen in the alveoli (D)</p> Signup and view all the answers

How does the capillary blood Pco2 level change after gas exchange?

<p>Decreases (A)</p> Signup and view all the answers

What is the thickness of the alveolar-capillary membrane critical for diffusion?

<p>0.5 micron (B)</p> Signup and view all the answers

What is a typical characteristic of blood entering the pulmonary capillaries?

<p>High Pco2 and low Po2 (B)</p> Signup and view all the answers

Where does blood go after gas exchange in the alveoli?

<p>To the left side of the heart (A)</p> Signup and view all the answers

What role does physiological shunting play in the pulmonary circulation?

<p>It mixes oxygenated and deoxygenated blood (D)</p> Signup and view all the answers

Which of these structures branches off from the aorta to perfuse the left side of the thorax?

<p>Bronchial arteries (A)</p> Signup and view all the answers

How does the diffusion of gases across the alveolar-capillary membrane occur?

<p>Based on concentration gradients (A)</p> Signup and view all the answers

Flashcards

Carina location

The carina (where the trachea branches into the two main bronchi) is roughly at the level of the aortic arch, fifth thoracic vertebra, or slightly below the angle of Louis.

Trachea structure

The trachea is made of C-shaped cartilaginous rings, which support its structure and prevent collapse, especially during inhalation and exhalation.

Right bronchus angle

The right main stem bronchus angles about 20-30 degrees from the midline.

Left bronchus angle

The left main stem bronchus angles about 45-55 degrees from the midline, positioned above the heart.

Signup and view all the flashcards

Aspiration risk

Foreign objects are more likely to enter the right main stem bronchus due to its wider angle and gravitational pull.

Signup and view all the flashcards

Bronchial generations

The branching of the airway creates different generations of bronchi (main stem, lobar, segmental, then smaller bronchi).

Signup and view all the flashcards

Bronchioles structure

Bronchioles are the smallest airways in the lungs and lack cartilage or connective tissue in their walls.

Signup and view all the flashcards

Alveoli function

Alveoli are tiny air sacs at the end of the airways where gas exchange takes place. Clusters of 10-16 alveoli are found at the ends of the alveolar ducts.

Signup and view all the flashcards

Pulmonary Circulation: Start

The pulmonary circulatory system begins with the pulmonary artery, which receives deoxygenated blood from the right side of the heart.

Signup and view all the flashcards

Pulmonary Circulation: Pathway

Pulmonary artery branches into smaller vessels, forming capillaries that surround the alveoli where gas exchange occurs.

Signup and view all the flashcards

Pulmonary Circulation: Return

After gas exchange, oxygenated blood travels back to the left side of the heart through the pulmonary veins.

Signup and view all the flashcards

Alveolar Capillary Membrane: Structure

The alveolar-capillary membrane, less than 0.5 microns thick, is composed of several layers: alveolar epithelium, basement membranes, interstitial space, and capillary endothelium.

Signup and view all the flashcards

Alveolar Capillary Membrane: Function

The membrane allows easy diffusion of oxygen and carbon dioxide due to its thinness, acting as a barrier to other substances.

Signup and view all the flashcards

Gas Exchange: Direction

Oxygen diffuses from alveoli (higher concentration) into the blood (lower concentration), while carbon dioxide moves from blood (higher concentration) into alveoli.

Signup and view all the flashcards

Gas Exchange: Equilibrium

Diffusion stops when the partial pressures of oxygen and carbon dioxide in the alveoli and blood equilibrate.

Signup and view all the flashcards

Bronchial Arteries: Supply

Bronchial arteries, branching from the aorta and other major arteries, supply blood to the structures of the lungs, including the airways.

Signup and view all the flashcards

Alveoli: The Gas Exchange Hub

Alveoli are tiny air sacs in your lungs where oxygen from the air you breathe enters your bloodstream, and carbon dioxide from your blood is released into the air to be exhaled.

Signup and view all the flashcards

Type I Alveolar Cells: Thin Walls

These cells make up the majority of the alveolar surface and have thin walls to allow easy gas exchange between the air and your blood.

Signup and view all the flashcards

Type II Alveolar Cells: Surfactant Makers

These cells produce a special substance called surfactant, which helps keep the alveoli open and prevents them from collapsing.

Signup and view all the flashcards

Surfactant: Keeping Alveoli Open

A substance made by type II alveolar cells. It helps reduce surface tension in the alveoli, making it easier for your lungs to expand and contract.

Signup and view all the flashcards

Alveolar Macrophages: Lung Cleaners

These cells act like tiny vacuum cleaners, engulfing and removing harmful particles that you inhale.

Signup and view all the flashcards

What are Alveolar Macrophages?

They are specialized cells in your lungs that come from bone marrow and are released into the bloodstream. Once in the lungs, they become macrophages and are involved in immune defense.

Signup and view all the flashcards

Alveolar Epithelial Cells: Roles in Gas Exchange

These cells are crucial for gas exchange in your lungs. Type I cells form the thin barrier, and Type II cells produce surfactant.

Signup and view all the flashcards

Why is Surfactant Important?

Surfactant plays a key role in preventing the collapse of alveoli, making it easier for your lungs to expand and contract. Without it, breathing would be difficult.

Signup and view all the flashcards

Lymphatic Circulation

The lymphatic system in the lungs is crucial for removing foreign particles, debris, and excess fluid, aiding in immunity and keeping the alveoli clear.

Signup and view all the flashcards

Lymphatic Vessel Location

Lymphatic vessels in the lungs follow the pulmonary blood vessels and airways down to the terminal bronchioles, also found in lung tissue and pleural membranes.

Signup and view all the flashcards

Lymphatic Drainage

Lymphatic fluid from the lungs eventually drains into the lymph nodes located near the lung's main opening (hilum).

Signup and view all the flashcards

Air Movement

Air flow in and out of the lungs depends on the difference between the pressure inside the lungs (intrapulmonary) and the pressure outside (atmospheric).

Signup and view all the flashcards

Inhalation vs. Exhalation

Inhalation is air moving into the lungs, driven by a lower intrapulmonary pressure than atmospheric. Exhalation is air moving out, driven by higher intrapulmonary pressure.

Signup and view all the flashcards

External Respiration

Oxygen from inhaled air moves into the blood, while carbon dioxide from the blood moves into the air, happening in the tiny air sacs (alveoli) and capillaries.

Signup and view all the flashcards

Internal Respiration

Oxygen from the blood moves into the body's tissues, while carbon dioxide from the tissues moves into the blood, happening at the capillaries and cells.

Signup and view all the flashcards

Pressure Gradient for Ventilation

Ventilation relies on a pressure difference between the air outside the lungs (atmospheric), the air inside the lungs (intrapulmonary), and the pressure within the chest cavity (intrathoracic).

Signup and view all the flashcards

Pulmonary Surfactant - Decreasing Factors

Smoking and inhaling smoke are detrimental to the lungs and can decrease the production of pulmonary surfactant, a substance crucial for keeping the alveoli open.

Signup and view all the flashcards

Work of Breathing - Increase

Various factors increase the work required for breathing, making it more difficult to take in air. These factors include decreased lung compliance (the ability of the lungs to expand), increased airway resistance, and decreased lung recoil (the tendency of the lungs to return to their original size).

Signup and view all the flashcards

Accessory Muscles - Increased Work

When breathing becomes labored, the body calls upon accessory muscles to help with the effort. These muscles, such as the scalenes, sternocleidomastoid, and back muscles, are usually only activated during strenuous activity, but become apparent when breathing is difficult.

Signup and view all the flashcards

Tidal Volume

The amount of air you inhale and exhale during a normal breath.

Signup and view all the flashcards

Inspiratory Reserve Volume

The maximum amount of air you can inhale after a normal breath.

Signup and view all the flashcards

Expiratory Reserve Volume

The maximum amount of air you can exhale after a normal breath.

Signup and view all the flashcards

Residual Volume

The air remaining in the lungs after a forceful exhale.

Signup and view all the flashcards

Inspiratory Capacity

The total amount of air you can inhale starting from a relaxed exhale.

Signup and view all the flashcards

Diffusion

The movement of molecules from an area of high concentration to an area of low concentration.

Signup and view all the flashcards

Driving pressure

The difference in concentration of a gas between two areas, causing diffusion.

Signup and view all the flashcards

Oxygen Diffusion in Lungs

Oxygen moves from the alveoli (high concentration) into the pulmonary capillaries (low concentration) due to driving pressure.

Signup and view all the flashcards

Carbon Dioxide Diffusion in Lungs

Carbon dioxide moves from the pulmonary capillaries (high concentration) into the alveoli (low concentration) due to driving pressure.

Signup and view all the flashcards

Factors Affecting Diffusion Rate

The thickness of the alveolar-capillary membrane and the surface area of the membrane influence the rate of diffusion.

Signup and view all the flashcards

Diffusion Coefficient

A measure of how easily a gas diffuses, determined by its solubility.

Signup and view all the flashcards

Gas Transport: Bloodstream

Oxygen and carbon dioxide are transported by the bloodstream, powered by the heart's pumping action (cardiac output).

Signup and view all the flashcards

Tissue Level Gas Exchange

Oxygen and carbon dioxide move into and out of cells at the tissue level by diffusion.

Signup and view all the flashcards

Oblique Fissure

A diagonal groove that divides the upper and middle lobes from the lower lobe in each lung.

Signup and view all the flashcards

Lung Lobes

Large sections within each lung, separated by fissures. The right lung has three lobes (upper, middle, lower), while the left lung has two lobes (upper, lower).

Signup and view all the flashcards

Mediastinum: What's inside?

The space between the lungs that houses vital organs like the heart, major blood vessels, lymph nodes, and the esophagus.

Signup and view all the flashcards

Pleura: Double-Layered Membrane

A thin membrane surrounding the lungs, with a visceral layer adhering to the lung surface and a parietal layer lining the chest wall. It creates a fluid-filled space for smooth breathing.

Signup and view all the flashcards

Intrapleural Pressure

The pressure within the pleural space. It's normally lower than atmospheric pressure and intrapulmonary pressure, helping the lungs expand.

Signup and view all the flashcards

Muscles of Ventilation

Muscles responsible for air movement in and out of the lungs. Inhalation muscles expand the chest cavity, while exhalation muscles decrease it.

Signup and view all the flashcards

Diaphragm: Key Inhalation Muscle

A dome-shaped muscle separating the chest and abdomen. It contracts and flattens during inhalation, increasing chest volume and drawing air in.

Signup and view all the flashcards

Diaphragm's Role in Breathing

During normal breathing, the diaphragm contracts and flattens, pushing down on the abdominal organs, which helps expand the chest cavity and draw air into the lungs. It's responsible for about 80% of the work of inhalation.

Signup and view all the flashcards

Phrenic Nerve's Function

The phrenic nerve sends signals from the medulla (in the brain) to the diaphragm, controlling its contractions and therefore our breathing.

Signup and view all the flashcards

What happens during exhalation?

Exhalation is a passive event during normal breathing. The diaphragm relaxes and moves back up, reducing the chest cavity volume and pushing air out.

Signup and view all the flashcards

Why do we need accessory muscles for breathing?

During exercise or when breathing is labored, we use accessory muscles to increase inhale effort. These muscles help to raise the rib cage, expanding the chest further.

Signup and view all the flashcards

What is the purpose of the conducting airways?

The airways (trachea and bronchi) act like a system of tubes, responsible for bringing air into the lungs. They warm, humidify, and filter the incoming air to protect the delicate lung tissue.

Signup and view all the flashcards

How do the upper and lower airways differ?

The upper airway includes all the structures above the glottis (voice box), while the lower airway includes all the structures below the glottis, leading to the lungs.

Signup and view all the flashcards

What is the C3-C5 injury impact?

Because the phrenic nerve comes from the cervical nerves C3-C5, injuries to this region cause difficulty breathing by affecting the diaphragm's function.

Signup and view all the flashcards

What muscles help with inhalation?

Besides the diaphragm, other muscles like the external intercostal muscles, scalenes, and sternocleidomastoids help raise the rib cage, expanding the chest for deeper breaths. These muscles are most active during exercise or effortful breathing.

Signup and view all the flashcards

What is the difference between normal and active exhalation?

Normal exhalation is mostly passive, relying on the diaphragm relaxation. However, during exercise or labored breathing, exhalation becomes more active, requiring the help of accessory muscles to push air out more forcefully.

Signup and view all the flashcards

Inspiration (Inhalation)

The process of breathing in air. The muscles of ventilation contract, expanding the thorax and lungs. This lowers intrapulmonary pressure, allowing air to flow into the lungs.

Signup and view all the flashcards

Expiration (Exhalation)

The process of breathing out air. The muscles of ventilation relax, the thorax contracts, and the lungs are compressed. This raises intrapulmonary pressure, forcing air out of the lungs.

Signup and view all the flashcards

Work of Breathing

The effort required to overcome the elastic and resistive forces within the lungs and airways to move air in and out.

Signup and view all the flashcards

Elastic Properties of Lungs

Forces that cause the lungs to spring back to their resting shape. These include lung recoil, chest wall recoil, and surface tension of the alveoli.

Signup and view all the flashcards

Resistive Properties of Lungs

Forces that oppose airflow. Primarily determined by airway resistance, which is the friction of air moving through the airways.

Signup and view all the flashcards

Right Main Stem Bronchus

The right main stem bronchus is wider and shorter, angling at 20-30 degrees from the midline. Foreign objects are more likely to be aspirated into this bronchus.

Signup and view all the flashcards

Left Main Stem Bronchus

The left main stem bronchus is narrower and longer, angling at 45-55 degrees from the midline, positioned above the heart.

Signup and view all the flashcards

What are Bronchioles?

Bronchioles are the smallest airways branching from the bronchi, lacking cartilage and connective tissue. They conduct air to the alveoli.

Signup and view all the flashcards

What are Alveoli?

Alveoli are tiny air sacs at the end of the bronchioles where gas exchange takes place. They are clustered together, with 2000 alveoli per respiratory unit.

Signup and view all the flashcards

Respiratory Airways

Respiratory airways include respiratory bronchioles and alveoli, where gas exchange occurs, forming the transition zone of the lungs.

Signup and view all the flashcards

What are Respiratory Bronchioles?

Respiratory bronchioles represent the transitional zone in the lungs, acting as gas exchange units. Alveoli branch off from these bronchioles.

Signup and view all the flashcards

What is Aspiration?

Aspiration is the inhalation of foreign objects, such as food or liquids, into the respiratory tract.

Signup and view all the flashcards

Physiological Shunting

The left atrium normally contains pure oxygenated blood, with a hemoglobin saturation level of 100%.

Signup and view all the flashcards

Study Notes

Pulmonary Anatomy and Physiology

  • The pulmonary system comprises the thorax, conducting airways, respiratory airways, and pulmonary blood and lymph supply.
  • The primary functions of the pulmonary system are ventilation and respiration.
  • Ventilation is the movement of air in and out of the lungs, involving oxygen uptake and carbon dioxide release.
  • Respiration is the process of gas exchange, where oxygen is taken into the bloodstream and carbon dioxide is expelled.
  • A strong understanding of anatomy and physiology is critical for patient care in cases of pulmonary dysfunction.

Thorax

  • The thorax houses the major organs of respiration and is a cone-shaped structure with a rigid frame.
  • The framework features 12 thoracic vertebrae, ribs, and the sternum.
  • Ribs are attached to the vertebrae posteriorly and, in the anterior portion, their attachment varies. The first seven pairs are directly linked to the sternum while the 8th, 9th, and 10th attach to the ribs above by cartilage. The 11th and 12th, also referred to as floating ribs, lack anterior attachment.
  • The second rib attaches to the sternum at the angle of Louis, a notable ridge beneath the suprasternal notch.
  • The thorax's components form a ventilatory pump, the mechanism for breathing.

Lungs

  • Lungs are cone-shaped organs, with an apex (superior portion) and a base (inferior portion).
  • The apex of each lung extends a few centimeters above the clavicle.
  • The right lung, larger and heavier than the left, is divided into three lobes (upper, middle, and lower).
  • The left lung is divided into two lobes (upper and lower).
  • Fissures divide the lobes. Lobes are further separated into segments (a total of 18). Each has its own bronchus branching. Ten segments are found in the right lung, and eight in the left.

Mediastinum

  • The mediastinum sits between the lungs, encompassing the heart, great vessels, lymphatics, and esophagus.

Pleura

  • The pleura is a thin membrane that lines the outside of the lungs and the inside of the chest wall.
  • The visceral pleura attaches to the lungs, extending to the hilar bronchi and major fissures.
  • The parietal pleura lines the inner chest wall and mediastinum.
  • An airtight space exists between these pleural membranes, containing a lubricating fluid.
  • The pleural membranes glide over each other without friction during breathing.

Intrapleural Pressure

  • Intrapleural pressure is the pressure within the pleural space. It's less than intrapulmonary and atmospheric pressure.
  • Under normal conditions, it ranges from 4 to -10 cm H₂O during inhalation and exhalation.
  • Deep inhalation can create intrapleural pressure of 12 to -18 cm H₂O.

Muscles of Ventilation

  • The central nervous system governs the muscles of ventilation through nerve impulses that cause their contraction and relaxation.
  • Muscles that expand the chest are called inhalatory muscles, and those that reduce chest size are called exhalatory muscles.
  • The diaphragm is the principal inspiratory muscle; during quiet breathing, it contributes to about 80% of the work involved. This dome-shaped fibromuscular structure separates the thoracic and abdominal cavities.
  • Accessory muscles such as the sternocleidomastoid, scalene, and pectoral muscles aid in breathing, particularly during exercise.
  • Exhalation in healthy individuals is usually passive and requires minimal energy.

Conducting Airways

  • The conducting airways (upper and lower) warm and moisten inhaled air.
  • They also function as a protective barrier against foreign particles entering the gas exchange areas.
  • The upper airways comprise structures above the glottis (nose, mouth, pharynx).
  • The lower airways are below the glottis (larynx, trachea, bronchi).

Larynx

  • The larynx, or voice box, consists of nine cartilages, six of which are paired and three are unpaired.
  • The unpaired cartilages—thyroid (Adam's apple), cricoid, and epiglottis—are crucial.
  • The epiglottis is a leaf-shaped cartilage that prevents food from entering the trachea during swallowing.
  • The vocal cords regulate the airflow and are responsible for voice production.

Trachea

  • The trachea is the windpipe, roughly 11 cm long and 2.5 cm in diameter.
  • It's a hollow tube, supported by C-shaped cartilaginous rings, and connects the larynx to the bronchi branching at the carina.
  • The trachea divides into two main bronchi.

Bronchial Tree

  • The bronchial tree has sequentially branching structures within the lungs.
  • Bronchi split into progressively smaller structures such as lobar, segmental, and subsegmental bronchi.
  • Finally, they divide into bronchioles, then to alveolar ducts and alveoli.
  • The right main bronchus is wider and angles more directly downward compared to the left, placing the right lung as more vulnerable to aspirated foreign bodies.
  • The characteristics of increasing branching and decreasing tube diameter throughout the bronchial tree are key to understanding respiratory physiology.

Respiratory Airway

  • The respiratory bronchioles connect conducting airways to gas exchange units (alveoli).

Alveoli

  • Alveoli are the primary site of gas exchange in the lungs. Hundreds of millions of clustered alveoli give enormous surface area for gas diffusion.
  • Alveolar walls contain specialized cells (type I and type II alveolar epithelial cells and alveolar macrophages). Each terminal respiratory unit contains approximately 100 alveolar ducts and 2000 alveoli.
  • Type I cells form the majority of the alveolar wall and are pivotal to forming the gas-blood barrier.

Alveolar-Capillary Membrane

  • The alveolar-capillary membrane is a very thin structure separating the alveoli from the capillaries, enabling efficient gas exchange. Its thinness facilitates the rapid transfer of both oxygen and carbon dioxide across its membrane.
  • Factors like thickness of the membrane and the surface area affect the rate of diffusion.

Pulmonary Circulation

  • The pulmonary circulatory system begins at the pulmonary artery and ends at the pulmonary veins.
  • Venous blood from the right heart enters the pulmonary artery, which branches into smaller vessels leading to the alveolar capillaries surrounding the alveoli.
  • After gas exchange, oxygenated blood returns to the left heart via the pulmonary veins.

Work of Breathing

  • The work of breathing is the amount of effort required to overcome the lung's elastic and resistive properties aided by the muscles of inhalation and exhalation to achieve the necessary mechanical actions.
  • Lung recoil, chest wall compliance, and surface tension are key elastic determinants of the work of breathing.
  • Airway resistance and the presence of pathologies are key in influencing the work of breathing.
  • During normal quiet breathing, the work required is relatively low (less than 1% to 2%). However, the work load increases during heavier work or presence of pathologies.

Pulmonary Volumes and Capacities

  • Measures of the volume of air that can be exchanged throughout varying respiratory actions and stages.
  • Key measurements such as tidal volume (amount of air exchanged during a normal breath), inspiratory reserve volume (maximal inspiration after a normal breath), expiratory reserve volume (maximal expiration after a normal breath), and residual volume (air remaining after a maximal expiration) dictate the lungs' capacity for breathing.

Respiration

  • Respiration encompasses external respiration (gas exchange in the lungs) and internal respiration (gas exchange at the tissue level).
  • Diffusion is the primary mechanism of gas transport, moving gases across the thin alveolar-capillary membrane down a pressure gradient.
  • Factors influencing the diffusion rate include the membrane's thickness and surface area, and the diffusion coefficient of each gas.

Gas Transport

  • Gas transport refers to the movement of oxygen and carbon dioxide between the lungs and tissues.
  • The blood stream moves these gases throughout the body.
  • At the tissue level, oxygen and carbon dioxide diffuse across membranes and move into and out of cells as needed.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Related Documents

Anatomy and Physiology PDF

Description

Dive into the fascinating world of human anatomy with this quiz focusing on the alveoli and their functions. Explore questions related to gas exchange, epithelial cells, and the structure of the respiratory system. Perfect for students studying human physiology or preparing for exams.

More Like This

Surfactant and Alveoli Function Quiz
3 questions

Surfactant and Alveoli Function Quiz

CheerfulRockCrystal avatar
CheerfulRockCrystal
Gas Exchange and Cellular Respiration Overview
7 questions

Gas Exchange and Cellular Respiration Overview

InvulnerableGold2463 avatar
InvulnerableGold2463
Respiratory System Functions Quiz
57 questions

Respiratory System Functions Quiz

CharmingSpessartine2714 avatar
CharmingSpessartine2714
Trocas Gasosas e Alvéolos Pulmonares
7 questions

Trocas Gasosas e Alvéolos Pulmonares

WellRegardedNobility4103 avatar
WellRegardedNobility4103
Use Quizgecko on...
Browser
Open
Browser
Browser