Respiratory Anatomy and Physiology Quiz

Pulmonary Anatomy and Physiology

• The pulmonary system consists of the thorax, conducting airways, respiratory airways, 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.
• Respiration is the process of gas exchange, with oxygen moving from the atmosphere into the bloodstream, and carbon dioxide moving from the bloodstream into the atmosphere.
• Knowledge of anatomy and physiology is crucial for caring for patients with pulmonary dysfunction.

Thorax

• The thorax houses the major organs of respiration, including the thoracic cage, lungs, pleura, and muscles of ventilation.
• These structures form a ventilatory pump, which powers breathing.
• The cage is composed of 12 thoracic vertebrae.
• Ribs are attached posteriorly to their corresponding vertebrae.
• Rib attachment varies anteriorly, with the first seven pairs directly connected to the sternum.
• The 8th, 9th, and 10th ribs attach to the ribs above via cartilage.
• The 11th and 12th ribs have no anterior attachment and are often called floating ribs.
• The second rib is attached to the sternum at the angle of Louis.

Lungs

• The lungs are cone-shaped organs with a total volume.
• The superior portion is called the apex, and the inferior portion is called the base.
• The apical portion of each lung is a few centimeters above the clavicle.
• The right lung is larger and heavier than the left, divided into upper, middle, and lower lobes.
• The left lung is divided into only an upper and a lower lobe.
• The lobes are divided into segments.
• Each segment has its own bronchus branching.
• Ten segments are in the right lung, and eight are in the left.

Mediastinum

• The mediastinum is the area between the two lungs.
• It contains the heart, great vessels, lymphatics, and esophagus.

Pleura

• The pleura is a thin membrane lining the outside of the lungs and the inside of the chest wall.
• The visceral pleura adheres to the lungs and extends to the hilar bronchi and into the major fissures.
• The parietal pleura lines the inner surface of the chest wall and mediastinum.
• The two pleural surfaces are separated by an airtight space containing a thin layer of lubricating fluid.
• This fluid allows the membranes to glide against each other during breathing.

Intrapleural Pressure

• Intrapleural pressure is the pressure within the pleural space.
• It is normally less than intrapulmonary pressure and atmospheric pressure.
• The normal range is 4 to -10 cm H2O during exhalation and inhalation.
• Deep inhalation can generate intrapleural pressures of 12 to -18 cm H2O.

Muscles of Ventilation

• Muscles of ventilation are controlled by the central nervous system, which stimulates their contraction and relaxation.
• Muscles that increase chest size are inhalation muscles.
• The diaphragm is the main inhalation muscle.
• It's a dome-shaped, fibromuscular septum separating the thoracic and abdominal cavities, performing approximately 80% of the work of quiet breathing.
• Its action is controlled by the phrenic nerve.
• Other inhalation muscles include the scalenes, anterior serratus, and sternocleidomastoid muscles.
• These muscles elevate the ribs and expand the chest cage.
• Exhalation is generally passive in healthy lungs, relying on diaphragm relaxation and lung recoil.
• During exercise, accessory muscles like the scalenes, sternocleidomastoid, and back muscles participate in exhalation.

Conducting Airways

• The upper airway comprises structures above the glottis.
• The lower airway comprises structures below the glottis.
• The conducting airways warm and humidify inhaled air and act as a protective barrier against foreign matter.
• The upper airway consists of the nasal cavity, nasopharynx, oropharynx, and laryngopharynx.
• The larynx consists of nine cartilages connected by ligaments and muscles.
• The most superior, largest cartilage is the thyroid cartilage (Adam's apple).
• Cricoid cartilage is the most inferior and complete cartilage ring.
• The epiglottis is a leaf-shaped cartilage that protects the lower airways during swallowing, directing food into the esophagus instead of the trachea.
• The lower airways consist of the trachea and the branching tracheobronchial tree.
• The trachea is a hollow tube supported by C-shaped cartilaginous rings and connects to the carina, a key point for bronchial branching.

Bronchial Tree

• The bronchial tree is the branching system of the trachea.
• The left bronchus is narrower than the right and angles downward toward the left lung.
• The right bronchus is wider and angles more directly downward towards the right lung.
• The right main stem bronchus is the common site for foreign object aspiration.
• Bronchi branch into smaller bronchioles, which eventually lead to clusters of alveoli.

Respiratory Bronchioles

• Respiratory bronchioles are the transition zone between conducting airways and alveolar regions.

Alveoli

• Alveoli are the functional units for gas exchange.
• Each respiratory bronchiole leads to a cluster of 10 to 16 alveoli.
• A terminal respiratory unit typically has around 100 alveolar ducts and 2000 alveoli.
• Type I alveolar epithelial cells form the gas-blood barrier and are a major component of the total alveolar surface.
• Type II alveolar epithelial cells produce pulmonary surfactant, reducing surface tension and promoting lung compliance.
• Alveolar macrophages are a crucial part of the defense system, removing foreign particles through phagocytosis.

Pulmonary Blood and Lymph Supply

• Pulmonary circulation begins at the pulmonary artery, receiving venous blood from the right heart.
• The artery branches to form capillaries surrounding the alveoli.
• After gas exchange, the blood returns to the left heart via pulmonary veins.
• The alveolar capillary membrane is thin, facilitating rapid gas exchange.
• Bronchial arteries supply blood to the tissues of the lungs themselves.
• Lymphatics circulate through the lungs, removing debris and assisting with immune responses.

Physiology of Pulmonary System

• Ventilation refers to the movement of air in and out of the lungs.
• Intrapulmonary pressure is the pressure within the alveoli.
• Intrathoracic pressure is the pressure within the pleural space.
• Inhalation occurs when intrapulmonary pressure drops below atmospheric pressure.
• Exhalation occurs when intrapulmonary pressure rises above atmospheric pressure.
• Respiratory phase involves external and internal respiration, with external respiration happening at the lung level and internal respiration happening at the tissue level.
• Diffusion is the driving factor for oxygen and carbon dioxide movement.
• The factors determining diffusion rate include gas solubility, the thickness of the alveolar-capillary membrane, and the surface area of the membrane.
• Gas transport refers to oxygen and carbon dioxide movement to and from tissue cells, using the bloodstream.
• Oxygen and carbon dioxide move into and out of the tissues by diffusion.
• Pulmonary volumes and capacities describe the various amounts and combinations of air movements.
• The work of breathing results from overcoming the elastic and resistive properties of the lungs.
• Pulmonary diseases can increase the work of breathing, affecting lung compliance, chest wall compliance, airway resistance, and lung recoil.

Test your knowledge on the structure and function of the respiratory system. This quiz covers topics like lung anatomy, pleural pressure, and the muscles involved in breathing. Perfect for students in anatomy, physiology, or medical fields.