Introduction and Anatomy of Lungs, Airways and Blood Supply

Question 1

What are the main components of the airway system?

Answer 1

Nasal cavity
Pharynx
Larynx
Trachea
Bronchi (primary, secondary, tertiary)
Bronchioles
Alveolar ducts and sacs

Question 2

What is the structure and function of the trachea?

Answer 2

Structure: A rigid tube made of cartilage rings
Function: Carries air from the larynx to the bronchi, ensures airway patency

Question 3

What are bronchi and bronchioles?

Answer 3

Bronchi: Larger airways branching from the trachea into the lungs
Bronchioles: Smaller airways that branch from the bronchi and lead to the alveoli

Question 4

What are the anatomical features of the lungs?

Answer 4

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)

Question 5

What is the role of alveoli in the lungs?

Answer 5

Tiny air sacs where gas exchange (oxygen and carbon dioxide) occurs
Located at the ends of the bronchioles

Question 6

How are the lungs protected anatomically?

Answer 6

Surrounded by pleura (double-layered membrane)
The ribs and sternum provide external protection
Diaphragm helps with respiration

Question 7

What is the function of the pleura?

Answer 7

Visceral pleura: Covers the lungs
Parietal pleura: Lines the chest wall
Pleural cavity: Contains pleural fluid to reduce friction during breathing

Question 8

What is the significance of the diaphragm in lung anatomy?

Answer 8

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

Question 9

What is the role of the respiratory bronchioles?

Answer 9

Transition from conducting airways to gas exchange areas
Have some alveoli on their walls, where gas exchange begins

Question 10

What are the different classes of airways in the respiratory system?

Answer 10

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)

Question 11

What is the function of the conducting zone of the airways?

Answer 11

Transports air to the respiratory zone
Filters, warms, and moistens air before it reaches the lungs
Includes larger airways (nose to bronchioles)

Question 12

What is the function of the respiratory zone?

Answer 12

Site of gas exchange between air and blood
Includes smaller airways (respiratory bronchioles to alveoli)

Question 13

What are the two types of alveolar cells?

Answer 13

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

Question 14

What is the role of Type I alveolar cells?

Answer 14

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

Question 15

What is the function of Type II alveolar cells?

Answer 15

Secrete surfactant, which reduces the surface tension within the alveoli
Help to repair and regenerate the alveolar lining after injury

Question 16

How do Type I and Type II alveolar cells work together?

Answer 16

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.

Question 17

What is the primary function of the respiratory system?

Answer 17

To facilitate gas exchange (oxygen and carbon dioxide) between the air and the bloodstream.

Question 18

How does the respiratory system help with oxygen supply to the body?

Answer 18

The respiratory system delivers oxygen from the air to the lungs, where it diffuses into the blood and is transported to tissues and organs.

Question 19

How does the respiratory system remove carbon dioxide from the body?

Answer 19

It transports carbon dioxide (a waste product of metabolism) from the bloodstream to the lungs, where it is exhaled into the air.

Question 20

What role does the respiratory system play in regulating blood pH?

Answer 20

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.

Question 21

How does the respiratory system contribute to temperature regulation?

Answer 21

The respiratory system helps regulate body temperature by warming or cooling the air as it is inhaled and exhaled, contributing to overall homeostasis.

Question 22

How does the respiratory system protect the body from harmful particles?

Answer 22

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.

Question 23

How does the respiratory system contribute to vocalization?

Answer 23

The vocal cords in the larynx vibrate as air passes through, allowing for sound production, which is essential for speech and other vocalizations.

Question 24

What role does the respiratory system play in fluid balance?

Answer 24

The respiratory system helps in regulating fluid balance by influencing the amount of water vapor lost through exhalation, especially in dry or humid environments.

Question 25

What is pulmonary circulation?

Answer 25

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.

Question 26

What is systemic circulation?

Answer 26

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.

Question 27

What side of the heart is involved in pulmonary circulation?

Answer 27

The right side of the heart (right atrium and right ventricle) pumps deoxygenated blood to the lungs via the pulmonary arteries.

Question 28

What side of the heart is involved in systemic circulation?

Answer 28

The left side of the heart (left atrium and left ventricle) pumps oxygenated blood to the body via the aorta.

Question 29

What is the main function of pulmonary circulation?

Answer 29

The main function is to exchange gases (oxygen and carbon dioxide) in the lungs, oxygenating the blood and removing carbon dioxide.

Question 30

What is the main function of systemic circulation?

Answer 30

The main function is to deliver oxygen and nutrients to body tissues and organs and return deoxygenated blood back to the heart.

Question 31

What types of blood vessels are involved in pulmonary circulation?

Answer 31

Pulmonary arteries (carry deoxygenated blood from the heart to the lungs) Pulmonary veins (carry oxygenated blood from the lungs back to the heart)

Question 32

What types of blood vessels are involved in systemic circulation?

Answer 32

Arteries (carry oxygenated blood from the heart to the body) Veins (carry deoxygenated blood from the body back to the heart)

Question 33

How does blood pressure compare between pulmonary and systemic circulation?

Answer 33

Pulmonary circulation has lower blood pressure compared to systemic circulation. Systemic circulation requires higher pressure to pump blood throughout the entire body.

Question 34

What is the primary point of gas exchange between the respiratory and cardiovascular systems?

Answer 34

The alveoli in the lungs are the primary site where oxygen from the air is exchanged for carbon dioxide from the blood.

Question 35

How does oxygen move from the alveoli to the blood?

Answer 35

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.

Question 36

How does carbon dioxide move from the blood to the alveoli?

Answer 36

Carbon dioxide in the blood diffuses from the capillaries into the alveolar sacs, where it is expelled from the body during exhalation.

Question 37

What is the role of the pulmonary capillaries in gas exchange?

Answer 37

Pulmonary capillaries surround the alveoli and facilitate the exchange of gases (oxygen and carbon dioxide) between the blood and the alveolar air.

Question 38

What occurs at the interface between the alveolar and capillary membranes?

Answer 38

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).

Question 39

Where does oxygenated blood go after leaving the lungs?

Answer 39

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.

Question 40

Where does deoxygenated blood come from before reaching the lungs?

Answer 40

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.

Question 41

What factors affect the efficiency of gas exchange in the lungs?

Answer 41

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

Question 42

What is the process by which gases are exchanged between the alveoli and blood vessels?

Answer 42

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.

Question 43

What is the general pattern of resistance to airflow in the respiratory tree?

Answer 43

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).

Question 44

Why is resistance to airflow highest in the large airways?

Answer 44

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).

Question 45

How does the total cross-sectional area affect airflow resistance in the respiratory tree?

Answer 45

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.

Question 46

How does airway diameter influence resistance to airflow?

Answer 46

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?

Question 47

Why does resistance decrease in the smaller airways despite their smaller diameters?

Answer 47

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.

Question 48

How does airflow behave in the trachea and large bronchi compared to smaller airways?

Answer 48

In the trachea and large bronchi, airflow is mostly turbulent, which increases resistance. In smaller airways, airflow is mostly laminar (smooth), which reduces resistance.

Question 49

What role does the autonomic nervous system play in airway resistance?

Answer 49

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.

Question 50

How does airway resistance affect breathing?

Answer 50

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.

Question 51

How does the overall structure of the respiratory tree impact airflow resistance?

Answer 51

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.

Question 52

What is the impact of pathological conditions (e.g., asthma) on airway resistance?

Answer 52

Conditions like asthma can cause inflammation, bronchoconstriction, and mucus production, which reduce the diameter of the airways, increasing resistance and making breathing more difficult.