Introduction and Anatomy of Lungs, Airways and Blood Supply Flashcards
What are the main components of the airway system?
Nasal cavity
Pharynx
Larynx
Trachea
Bronchi (primary, secondary, tertiary)
Bronchioles
Alveolar ducts and sacs
What is the structure and function of the trachea?
Structure: A rigid tube made of cartilage rings
Function: Carries air from the larynx to the bronchi, ensures airway patency
What are bronchi and bronchioles?
Bronchi: Larger airways branching from the trachea into the lungs
Bronchioles: Smaller airways that branch from the bronchi and lead to the alveoli
What are the anatomical features of the lungs?
Right lung (3 lobes: superior, middle, inferior)
Left lung (2 lobes: superior, inferior)
Apex (top part of the lung)
Base (bottom part of the lung)
Hilum (area where blood vessels, airways, and nerves enter/exit)
What is the role of alveoli in the lungs?
Tiny air sacs where gas exchange (oxygen and carbon dioxide) occurs
Located at the ends of the bronchioles
How are the lungs protected anatomically?
Surrounded by pleura (double-layered membrane)
The ribs and sternum provide external protection
Diaphragm helps with respiration
What is the function of the pleura?
Visceral pleura: Covers the lungs
Parietal pleura: Lines the chest wall
Pleural cavity: Contains pleural fluid to reduce friction during breathing
What is the significance of the diaphragm in lung anatomy?
A muscle that separates the thoracic cavity from the abdominal cavity
Plays a key role in breathing by contracting and relaxing to allow lung expansion and compression
What is the role of the respiratory bronchioles?
Transition from conducting airways to gas exchange areas
Have some alveoli on their walls, where gas exchange begins
What are the different classes of airways in the respiratory system?
Conducting Zone:
Nasal cavity
Pharynx
Larynx
Trachea
Bronchi (primary, secondary, tertiary)
Bronchioles
Respiratory Zone:
Respiratory bronchioles
Alveolar ducts
Alveolar sacs
Alveoli (where gas exchange occurs)
What is the function of the conducting zone of the airways?
Transports air to the respiratory zone
Filters, warms, and moistens air before it reaches the lungs
Includes larger airways (nose to bronchioles)
What is the function of the respiratory zone?
Site of gas exchange between air and blood
Includes smaller airways (respiratory bronchioles to alveoli)
What are the two types of alveolar cells?
Type I alveolar cells:
Structure: Thin, flat cells
Function: Facilitate gas exchange across the alveolar membrane
Type II alveolar cells:
Structure: Cuboidal cells
Function: Produce surfactant, which reduces surface tension in the alveoli and prevents collapse
What is the role of Type I alveolar cells?
Form the majority of the alveolar surface
Allow for efficient gas exchange by creating a thin barrier for oxygen and carbon dioxide to diffuse across
What is the function of Type II alveolar cells?
Secrete surfactant, which reduces the surface tension within the alveoli
Help to repair and regenerate the alveolar lining after injury
How do Type I and Type II alveolar cells work together?
Type I cells enable gas exchange by forming the thin alveolar wall.
Type II cells maintain the alveolar environment and prevent collapse by producing surfactant.
What is the primary function of the respiratory system?
To facilitate gas exchange (oxygen and carbon dioxide) between the air and the bloodstream.
How does the respiratory system help with oxygen supply to the body?
The respiratory system delivers oxygen from the air to the lungs, where it diffuses into the blood and is transported to tissues and organs.
How does the respiratory system remove carbon dioxide from the body?
It transports carbon dioxide (a waste product of metabolism) from the bloodstream to the lungs, where it is exhaled into the air.
What role does the respiratory system play in regulating blood pH?
By controlling the levels of carbon dioxide in the blood, the respiratory system helps maintain the pH balance of the body. Increased CO2 lowers pH (making it more acidic), and exhaling CO2 helps return pH to normal levels.
How does the respiratory system contribute to temperature regulation?
The respiratory system helps regulate body temperature by warming or cooling the air as it is inhaled and exhaled, contributing to overall homeostasis.
How does the respiratory system protect the body from harmful particles?
The respiratory system filters and traps foreign particles, dust, and pathogens using mucus and cilia in the airways. The mucociliary escalator helps move these particles out of the respiratory tract.
How does the respiratory system contribute to vocalization?
The vocal cords in the larynx vibrate as air passes through, allowing for sound production, which is essential for speech and other vocalizations.
What role does the respiratory system play in fluid balance?
The respiratory system helps in regulating fluid balance by influencing the amount of water vapor lost through exhalation, especially in dry or humid environments.
What is pulmonary circulation?
Pulmonary circulation is the movement of blood from the heart to the lungs and back to the heart.
It involves the right side of the heart pumping deoxygenated blood to the lungs for oxygenation.
What is systemic circulation?
Systemic circulation is the movement of oxygenated blood from the heart to the rest of the body and back.
It involves the left side of the heart pumping oxygen-rich blood to tissues and organs, and deoxygenated blood returning to the heart.
What side of the heart is involved in pulmonary circulation?
The right side of the heart (right atrium and right ventricle) pumps deoxygenated blood to the lungs via the pulmonary arteries.
What side of the heart is involved in systemic circulation?
The left side of the heart (left atrium and left ventricle) pumps oxygenated blood to the body via the aorta.
What is the main function of pulmonary circulation?
The main function is to exchange gases (oxygen and carbon dioxide) in the lungs, oxygenating the blood and removing carbon dioxide.
What is the main function of systemic circulation?
The main function is to deliver oxygen and nutrients to body tissues and organs and return deoxygenated blood back to the heart.
What types of blood vessels are involved in pulmonary circulation?
Pulmonary arteries (carry deoxygenated blood from the heart to the lungs)
Pulmonary veins (carry oxygenated blood from the lungs back to the heart)
What types of blood vessels are involved in systemic circulation?
Arteries (carry oxygenated blood from the heart to the body)
Veins (carry deoxygenated blood from the body back to the heart)
How does blood pressure compare between pulmonary and systemic circulation?
Pulmonary circulation has lower blood pressure compared to systemic circulation.
Systemic circulation requires higher pressure to pump blood throughout the entire body.
What is the primary point of gas exchange between the respiratory and cardiovascular systems?
The alveoli in the lungs are the primary site where oxygen from the air is exchanged for carbon dioxide from the blood.
How does oxygen move from the alveoli to the blood?
Oxygen diffuses across the thin walls of the alveolar sacs into the capillaries surrounding the alveoli, where it binds to hemoglobin in red blood cells.
How does carbon dioxide move from the blood to the alveoli?
Carbon dioxide in the blood diffuses from the capillaries into the alveolar sacs, where it is expelled from the body during exhalation.
What is the role of the pulmonary capillaries in gas exchange?
Pulmonary capillaries surround the alveoli and facilitate the exchange of gases (oxygen and carbon dioxide) between the blood and the alveolar air.
What occurs at the interface between the alveolar and capillary membranes?
Oxygen moves from the alveoli (where the oxygen concentration is high) into the capillaries (where the oxygen concentration is low).
Carbon dioxide moves from the capillaries (where the CO2 concentration is high) into the alveoli (where the CO2 concentration is low).
Where does oxygenated blood go after leaving the lungs?
Oxygenated blood from the pulmonary capillaries enters the pulmonary veins, which carry it to the left atrium of the heart, from where it is pumped to the rest of the body through systemic circulation.
Where does deoxygenated blood come from before reaching the lungs?
Deoxygenated blood from the body returns to the right atrium of the heart, is pumped into the right ventricle, and then travels through the pulmonary arteries to the lungs for gas exchange.
What factors affect the efficiency of gas exchange in the lungs?
The thickness of the alveolar-capillary membrane
The surface area of the alveoli
The concentration gradient of oxygen and carbon dioxide between the blood and alveolar air
What is the process by which gases are exchanged between the alveoli and blood vessels?
Diffusion is the process where gases move from areas of high concentration to areas of low concentration. Oxygen diffuses into the blood, and carbon dioxide diffuses into the alveoli.
What is the general pattern of resistance to airflow in the respiratory tree?
Resistance to airflow is highest in the larger airways (such as the trachea and primary bronchi) and decreases significantly as the airways become smaller (in bronchioles and alveolar ducts).
Why is resistance to airflow highest in the large airways?
The larger airways have a smaller total cross-sectional area, leading to higher resistance according to Poiseuille’s law (resistance is inversely proportional to the fourth power of the radius).
How does the total cross-sectional area affect airflow resistance in the respiratory tree?
As the airways branch into smaller bronchi and bronchioles, the total cross-sectional area increases dramatically. This larger area reduces the resistance to airflow, even though individual airway radii are smaller.
How does airway diameter influence resistance to airflow?
Resistance is directly proportional to the length of the airway and inversely proportional to the fourth power of the radius (diameter). A small decrease in airway diameter results in a large increase in resistance.Why does resistance decrease in the smaller airways despite their smaller diameters?
Why does resistance decrease in the smaller airways despite their smaller diameters?
The total cross-sectional area of the smaller airways (such as bronchioles) increases significantly compared to the larger airways. This compensates for their smaller individual diameters, leading to lower overall resistance.
How does airflow behave in the trachea and large bronchi compared to smaller airways?
In the trachea and large bronchi, airflow is mostly turbulent, which increases resistance.
In smaller airways, airflow is mostly laminar (smooth), which reduces resistance.
What role does the autonomic nervous system play in airway resistance?
The autonomic nervous system can constrict or dilate the airways. Bronchoconstriction (e.g., in asthma) increases airway resistance, while bronchodilation (e.g., during exercise) reduces resistance and increases airflow.
How does airway resistance affect breathing?
Higher resistance (such as during bronchoconstriction or obstruction) requires greater effort to breathe and can reduce airflow, leading to difficulty in inhalation and exhalation. Lower resistance allows for easier and more efficient breathing.
How does the overall structure of the respiratory tree impact airflow resistance?
The branching structure of the respiratory tree increases the total cross-sectional area as airways get smaller, which reduces resistance. Despite the smaller individual airway diameters, the large total cross-sectional area of the smaller airways ensures minimal overall resistance to airflow.
What is the impact of pathological conditions (e.g., asthma) on airway resistance?
Conditions like asthma can cause inflammation, bronchoconstriction, and mucus production, which reduce the diameter of the airways, increasing resistance and making breathing more difficult.
