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Chapter 26

The Respiratory System

The respiratory system includes both upper and lower respiratory organs. The upper respiratory organs consist of the nose and nasal cavity, paranasal …
The nose is the primary passageway for air entering the respiratory system. Its visible part, the external nose, is supported by the frontal bone, nasal …
The pharynx or throat is about a 13 cm long tube extending from the internal nares down to the cricoid cartilage of the larynx. It can be divided into the …
The larynx or voice box connects the laryngopharynx with the trachea. It includes unpaired thyroid cartilage, cricoid cartilage, and the epiglottis, as …
The trachea or windpipe begins at the larynx and extends into the mediastinum, bifurcating into two main bronchi in the mid-thorax region. The tracheal …
At the carina, located at the upper boundary of the fifth thoracic vertebra, the trachea splits into the right and left primary bronchi, each leading to …
Within a pulmonary lobule, the terminal bronchioles branch into microscopic respiratory bronchioles, which conduct air to the respiratory zone of the …
Enclosed within the ribcage, the lungs are cone-shaped organs in the thoracic cavity. Their apex lies beneath the clavicle, and the base sits on the …
The pleura or pleural membrane is a double-layered serous membrane enclosing the lungs. The right and left lungs are enveloped by their respective …
Healthy respiration in humans requires proper air pressure levels in different respiratory organs. These pressures are expressed relative to the …
Respiration is a rhythmic process of alternating inhalation and exhalation. During quiet inhalation, the thoracic cavity expands due to a decrease in the …
Exhalation — the process of expelling air — during quiet breathing in healthy individuals relies on the elasticity of the lungs rather than …
Breathing is influenced by the alternating pressure difference between the external environment and the lungs, alveolar surface tension, lung compliance, …
Respiratory volumes define the varying amounts of air that enter and exit the lungs, while respiratory capacities are combinations of respiratory …
Inhaled air contains a mixture of different gases like nitrogen, oxygen, and carbon dioxide, among others. Dalton's law is fundamental to …
External respiration involves the exchange of oxygen and carbon dioxide between alveoli and pulmonary capillaries in the lungs. This gas exchange always …
Blood primarily transports oxygen bound to hemoglobin in RBCs, with a small percentage dissolved in the plasma due to its low solubility in the blood. …
Carbon dioxide is transported from tissues to the lungs in three ways. About 7-10% travels dissolved in plasma. Over 20% is bound to hemoglobin, forming …
Hypoxia is a condition where body tissues don't receive an adequate oxygen supply. It may be categorized into four distinct types. Anemic hypoxia …
Groups of neurons in the brainstem called the respiratory centers mediate the regulation of respiration. The two primary centers are the medullary …
CO2, O2, and H+ ion levels affect the rate of respiration. These changes are detected by the central chemoreceptors in the brain stem, and the peripheral …
The human body responds to various stimuli to regulate the breathing rate via receptors present in respiratory organs. Physical and chemical irritants in …
Hyperventilation is a condition where the rate and depth of breathing exceed the body's need to remove CO2, often occurring during anxiety attacks. …
Chronic Obstructive Pulmonary Disease, or COPD, is defined as a diverse lung condition marked by persistent and progressive respiratory symptoms such as …
Some major pulmonary disorders include asthma, tuberculosis, and lung cancer. Asthma is a chronic ailment marked by airway inflammation and obstruction. …
In this protocol, two deep breathing patterns were shown to 15 participants to determine an easy yet effective method of breathing exercise for future …
An adipocyte-produced hormone leptin is a potent respiratory stimulant, which may play an important role in defending respiratory function in obesity. The …
There is increasing interest in the use of the forced oscillation technique (FOT) or oscillometry to characterize respiratory mechanics in healthy and …