Anatomy of the respiratory system:
The pharynx serves as a passageway for both air and food, leading to the
larynx which is responsible for sound production.
● The epiglottis: a flap of elastic cartilage, prevents food and liquid
from entering the trachea during swallowing by covering the glottis.
● The movement of the pharynx and larynx during swallowing is
crucial for directing food to the esophagus.
● The larynx contains vocal cords that vibrate which are essential for
speech.
● Damage to the larynx can lead to voice disorders and loss of voice.
Trachea & Bronchial Tree:
The tracheas is a tube that connects the larynx to the bronchi, supported
by C-shaped cartilaginous rings.
● The carina is the ridge at the tracheal bifurcation, and its distortion
can indicate serious conditions like carcinoma. (cancer).
● The trachea branches into right and left primary bronchi, which
further divide into the secondary and tertiary bronchi, which then
further divides to bronchioles.
● The extensive branches form the bronchial tree, which facilitates air
distribution to the alveoli.
● The alveoli are the primary sites for gas exchange, surrounded by a
rich capillary network.
Structure of the Lungs:
The right lung has three lobes, while the left lung has two lobes,
accommodating to the heart's position.
● Each lung is encased in a double pleural membrane, the parietal
pleura lines the thoracic cavity, and the visceral pleura covers the
lungs.
● The intrapleural space between these membranes contains pleural
fluid, reducing friction during breathing.
● The pleural membranes play a role in maintaining lung inflation and
preventing collapse.
● Understanding lung anatomy is crucial for diagnosing respiratory
diseases.
Histology and Mechanics of Breathing;
, Alveolar structure and function
- The alveoli are lined with two types of cells: Type I (simple squamous
epithelial cells) Type II (surfactant-producing cells).
● Type I cells facilitate gas exchange due to their thin structure ,
while type II cells produce surfactant to reduce surface
tension.
● Surfactant prevents alveolar collapse during exhalation,
ensuring efficient gas exchange.
● A deficiency in surfactant can lead to respiratory distress
syndrome, particularly in premature infants.
● The balance of these cell types is critical for maintaining
healthy lung function.
Breathing Mechanics:
Breathing involves two main phases: inspiration and expiration, regulated
by neural signals.
● During inspiration, the diaphragm contracts and moves downward,
while intercostal muscles elevate the rib cage, expanding the
thoracic cavity.
● The pressure difference created allows air to flow into the lungs,
driven by higher atmospheric pressure compared to alveolar
pressure.
● Expiration is primarily passive, relying on elastic recoil of lung
tissues and the chest wall, with no muscular contraction required.
● Conditions like pneumothorax disrupt normal breathing mechanics,
leading to lung collapse. This occurs when intrapleural pressure
becomes equal to atmospheric pressure (4mmHg = 0mmHg) and
occurs when air enters the pleural cavity from a stab or gunshot
wound causing the lungs to collapse
● A hemothorax is the introduction of blood. Treatment includes
inserting a chest tube to remove the air or blood to allow it to
reinflate.
Chemoreceptors: Found in the carotid and aortic bodies (neck at the
bifurcation of the common carotid arteries and arch of the aorta).
These monitor oxygen supply and increases in H+ concentrations.
The cells of these receptors communicate with afferent nerve fibers
passing through the brain stem. They provide excitatory input to the
medullary inspiratory neurons. The Carotid input is the predominant
chemoreceptor involved in control of respiration.
The pharynx serves as a passageway for both air and food, leading to the
larynx which is responsible for sound production.
● The epiglottis: a flap of elastic cartilage, prevents food and liquid
from entering the trachea during swallowing by covering the glottis.
● The movement of the pharynx and larynx during swallowing is
crucial for directing food to the esophagus.
● The larynx contains vocal cords that vibrate which are essential for
speech.
● Damage to the larynx can lead to voice disorders and loss of voice.
Trachea & Bronchial Tree:
The tracheas is a tube that connects the larynx to the bronchi, supported
by C-shaped cartilaginous rings.
● The carina is the ridge at the tracheal bifurcation, and its distortion
can indicate serious conditions like carcinoma. (cancer).
● The trachea branches into right and left primary bronchi, which
further divide into the secondary and tertiary bronchi, which then
further divides to bronchioles.
● The extensive branches form the bronchial tree, which facilitates air
distribution to the alveoli.
● The alveoli are the primary sites for gas exchange, surrounded by a
rich capillary network.
Structure of the Lungs:
The right lung has three lobes, while the left lung has two lobes,
accommodating to the heart's position.
● Each lung is encased in a double pleural membrane, the parietal
pleura lines the thoracic cavity, and the visceral pleura covers the
lungs.
● The intrapleural space between these membranes contains pleural
fluid, reducing friction during breathing.
● The pleural membranes play a role in maintaining lung inflation and
preventing collapse.
● Understanding lung anatomy is crucial for diagnosing respiratory
diseases.
Histology and Mechanics of Breathing;
, Alveolar structure and function
- The alveoli are lined with two types of cells: Type I (simple squamous
epithelial cells) Type II (surfactant-producing cells).
● Type I cells facilitate gas exchange due to their thin structure ,
while type II cells produce surfactant to reduce surface
tension.
● Surfactant prevents alveolar collapse during exhalation,
ensuring efficient gas exchange.
● A deficiency in surfactant can lead to respiratory distress
syndrome, particularly in premature infants.
● The balance of these cell types is critical for maintaining
healthy lung function.
Breathing Mechanics:
Breathing involves two main phases: inspiration and expiration, regulated
by neural signals.
● During inspiration, the diaphragm contracts and moves downward,
while intercostal muscles elevate the rib cage, expanding the
thoracic cavity.
● The pressure difference created allows air to flow into the lungs,
driven by higher atmospheric pressure compared to alveolar
pressure.
● Expiration is primarily passive, relying on elastic recoil of lung
tissues and the chest wall, with no muscular contraction required.
● Conditions like pneumothorax disrupt normal breathing mechanics,
leading to lung collapse. This occurs when intrapleural pressure
becomes equal to atmospheric pressure (4mmHg = 0mmHg) and
occurs when air enters the pleural cavity from a stab or gunshot
wound causing the lungs to collapse
● A hemothorax is the introduction of blood. Treatment includes
inserting a chest tube to remove the air or blood to allow it to
reinflate.
Chemoreceptors: Found in the carotid and aortic bodies (neck at the
bifurcation of the common carotid arteries and arch of the aorta).
These monitor oxygen supply and increases in H+ concentrations.
The cells of these receptors communicate with afferent nerve fibers
passing through the brain stem. They provide excitatory input to the
medullary inspiratory neurons. The Carotid input is the predominant
chemoreceptor involved in control of respiration.
