A few fun breathing facts from my current biology lab.
1. What are the structural adaptations of the nasal cavity that allow it to carry out its functions?
Nasal hairs act as a filter to keep dust and dirt out of the nasal passages. Loss of nasal hair due to alopecia areata has been linked to increased severity of asthma, seasonal allergy and atopic dermatitis.
In humans, as with most mammals, the nose is the primary organ for smelling. The air flows over structures called turbinates in the nasal cavity. The turbulence caused by this disruption slows the air and directs it toward the olfactory epithelium. At the surface of the olfactory epithelium, odor molecules carried by the air contact olfactory receptor neurons which translate the features of the odor molecule into electrical impulses in the brain.
The shape of the nose is determined by the ethmoid bone and the nasal septum. The septum consists mostly of cartilage. It separates the nostrils.
The ethmoid bone is a cubical bone in the skull that separates the nasal cavity from the brain. It is located at the roof of the nose, between the two orbits. It is lightweight due to its spongy construction. The ethmoid bone consists of four parts: the horizontal Cribriform plate or lamina cribrosa, the vertical Perpendicular plate or lamina perpendicularis, which is part of the nasal septum, and the two lateral masses or labyrinths.
The ethmoid bone is very delicate and is easily injured by a sharp upward blow to the nose. The force of such a blow can drive bone fragments through the cribiform plate into the meninges or brain tissue. Such injuries cause leakage of cerebrospinal fluid into the nasal cavity and the brain. Blows to the head can also shear off the olfactory nerves that pass though the ethmoid bone and cause anosmia, an irreversible loss of the sense of smell. This not only eliminates certain aesthetic pleasures, but can also be dangerous. A person who cannot smell would be unable to detect smoke, gas, or spoiled food.
The nasal septum separates the left and right airways in the nose, dividing the two nostrils. It is composed of the ethmoid bone, vomer bone and the quadrangular.
A turbinate, or nasal conchae, is a long, narrow and curled bone shelf shaped like an elongated sea-shell which protrudes into the breathing passage of the nose. Turbinate bone refers to any of the scrolled spongy bones of the nasal passages in humans and other vertebrates. The turbinates divide the nasal airway into three groove-like air passages, and are responsible for forcing inhaled air to flow in a steady, regular pattern around the largest possible surface of cilia and climate controlling tissue.
The turbinates are located laterally in the nasal cavities. They curl medially and downwards into the nasal airway. Each pair is comprised of one turbinate in either side of the nasal cavity, divided by the septum.
The inferior turbinates are the largest turbinates. They are approximately three inches long, and are responsible for the majority of airflow direction, humidification, heating, and filtering of air inhaled through the nose.
The middle turbinates are usually around 2.5 inches long. They project downwards over the openings of the maxillary and ethmoid sinuses, and act as buffers to protect the sinuses from coming in direct contact with pressurized nasal airflow. Most inhaled air travels between the inferior turbinate and the middle turbinate.
The superior turbinates are smaller structures, connected to the middle turbinates by nerve endings. They protect the olfactory bulb.
The turbinates comprise most of the mucosal tissue of the nose. They are enriched with airflow pressure and temperature sensing nerve receptors linked to the trigeminal nerve route. They are responsible for filtration, heating and humidification of air inhaled through the nose. As air passes over the turbinate tissues it is heated to body temperature, humidified by up to 98% water saturation, and filtered.
The respiratory epithelium which covers the Lamina propria of the turbinates is part of the body’s first line of immunological defense. The respiratory epithelium is partially comprised of mucus producing goblet cells. This secreted mucus covers the nasal cavities and traps air-borne particles larger than 2 to 3 micrometers. The respiratory epithelium also serves as a means of access to the lymphatic system.
Information primarily gathered from http://www.wikipedia.org
2. What are the structural adaptations of the larynx that allow it to carry out its functions?
The larynx is mainly composed of cartilage bound by ligaments and muscle. At the front is the thyroid cartilage. This cartilage forms the Adam's apple. The inferior horns of the thyroid cartilage rest on the ring-shaped cricoid cartilage which connects the larynx to the trachea. Above the larynx is the hyoid bone, by which the larynx is connected to the jaw and skull. These muscles move the larynx during swallowing. The epiglottis consists of cartilage extending upwards behind the back of the tongue and projects down through the hyoid bone. It connects to the thyroid cartilage just beneath the thyroid notch. The space defined by these main cartilages is divided into the supraglottis and the glottis.
The glottis is defined as the space between the vocal cords, which are located at the upper rim of the cricoid cartilage. They attach to the thyroid cartilage at the front, and to the Arytenoid cartilages at the back. These are two roughly tetrahedral cartilages responsible for adduction and abduction of the vocal cords. The vocal cords are muscular masses coated with a mucous membrane which protects much of the respiratory tract from foreign particles. Their inner edges contain the vocal ligament.
The supraglottis is the portion of the pharynx above the glottis. It contains the ventricle of the larynx or laryngeal sinus, the ventricular folds or false vocal cords, the epiglottis, and the aryepiglottal folds. These are two folds of connective tissue that connect the epiglottis to the arytenoid cartilages. Muscles in the aryepiglottal folds have the ability to pull the epiglottis down, sealing the larynx and protecting the trachea below from foreign objects.
3. What are the structural adaptations of the trachea that allow it to carry out its functions?
The trachea, or windpipe, is a tube extending from the larynx to the bronchi, carrying air to the lungs. It is lined with ciliated cells which push particles out, and cartilage rings which reinforce the trachea and prevent it from collapsing on itself during breathing. These numerous cartilaginous half-rings, located one above the other along the trachea, have open ends adjacent to the esophagus. The rings are connected by muscular and fibrous tissue, and they are lined inside with a ciliated mucous membrane.
4. What are the structural adaptations of the alveoli that allow it to carry out its functions?
The alveoli consist of an epithelial layer and extracellular matrix surrounded by capillaries. In some alveolar walls, there are pores between alveoli. The alveoli are composed of Type I cells that form the structure of an alveolar wall, and Type II cells that secrete surfactant to lower the surface tension of water. The lungs contain about 300 million alveoli, each wrapped in a fine mesh of capillaries.
5. Compare the function of the conducting and respiratory zones.
The Conducting zone consists of the mouth, nose, pharynx, larynx, trachea, bronchi
The Respiratory zone consists of the respiratory bronchioles and alveoli.
The conducting zone warms the incoming air and removes pathogens and debris from it before it enters the respiratory zone. In the respiratory zone, oxygen is uploaded into the erythrocytes from the alveoli and transported throughout the body. Erythrocytes which have traveled through the body return to download carbon dioxide, which is then expelled from the body via the conducting zones.
1. What are the structural adaptations of the nasal cavity that allow it to carry out its functions?
Nasal hairs act as a filter to keep dust and dirt out of the nasal passages. Loss of nasal hair due to alopecia areata has been linked to increased severity of asthma, seasonal allergy and atopic dermatitis.
In humans, as with most mammals, the nose is the primary organ for smelling. The air flows over structures called turbinates in the nasal cavity. The turbulence caused by this disruption slows the air and directs it toward the olfactory epithelium. At the surface of the olfactory epithelium, odor molecules carried by the air contact olfactory receptor neurons which translate the features of the odor molecule into electrical impulses in the brain.
The shape of the nose is determined by the ethmoid bone and the nasal septum. The septum consists mostly of cartilage. It separates the nostrils.
The ethmoid bone is a cubical bone in the skull that separates the nasal cavity from the brain. It is located at the roof of the nose, between the two orbits. It is lightweight due to its spongy construction. The ethmoid bone consists of four parts: the horizontal Cribriform plate or lamina cribrosa, the vertical Perpendicular plate or lamina perpendicularis, which is part of the nasal septum, and the two lateral masses or labyrinths.
The ethmoid bone is very delicate and is easily injured by a sharp upward blow to the nose. The force of such a blow can drive bone fragments through the cribiform plate into the meninges or brain tissue. Such injuries cause leakage of cerebrospinal fluid into the nasal cavity and the brain. Blows to the head can also shear off the olfactory nerves that pass though the ethmoid bone and cause anosmia, an irreversible loss of the sense of smell. This not only eliminates certain aesthetic pleasures, but can also be dangerous. A person who cannot smell would be unable to detect smoke, gas, or spoiled food.
The nasal septum separates the left and right airways in the nose, dividing the two nostrils. It is composed of the ethmoid bone, vomer bone and the quadrangular.
A turbinate, or nasal conchae, is a long, narrow and curled bone shelf shaped like an elongated sea-shell which protrudes into the breathing passage of the nose. Turbinate bone refers to any of the scrolled spongy bones of the nasal passages in humans and other vertebrates. The turbinates divide the nasal airway into three groove-like air passages, and are responsible for forcing inhaled air to flow in a steady, regular pattern around the largest possible surface of cilia and climate controlling tissue.
The turbinates are located laterally in the nasal cavities. They curl medially and downwards into the nasal airway. Each pair is comprised of one turbinate in either side of the nasal cavity, divided by the septum.
The inferior turbinates are the largest turbinates. They are approximately three inches long, and are responsible for the majority of airflow direction, humidification, heating, and filtering of air inhaled through the nose.
The middle turbinates are usually around 2.5 inches long. They project downwards over the openings of the maxillary and ethmoid sinuses, and act as buffers to protect the sinuses from coming in direct contact with pressurized nasal airflow. Most inhaled air travels between the inferior turbinate and the middle turbinate.
The superior turbinates are smaller structures, connected to the middle turbinates by nerve endings. They protect the olfactory bulb.
The turbinates comprise most of the mucosal tissue of the nose. They are enriched with airflow pressure and temperature sensing nerve receptors linked to the trigeminal nerve route. They are responsible for filtration, heating and humidification of air inhaled through the nose. As air passes over the turbinate tissues it is heated to body temperature, humidified by up to 98% water saturation, and filtered.
The respiratory epithelium which covers the Lamina propria of the turbinates is part of the body’s first line of immunological defense. The respiratory epithelium is partially comprised of mucus producing goblet cells. This secreted mucus covers the nasal cavities and traps air-borne particles larger than 2 to 3 micrometers. The respiratory epithelium also serves as a means of access to the lymphatic system.
Information primarily gathered from http://www.wikipedia.org
2. What are the structural adaptations of the larynx that allow it to carry out its functions?
The larynx is mainly composed of cartilage bound by ligaments and muscle. At the front is the thyroid cartilage. This cartilage forms the Adam's apple. The inferior horns of the thyroid cartilage rest on the ring-shaped cricoid cartilage which connects the larynx to the trachea. Above the larynx is the hyoid bone, by which the larynx is connected to the jaw and skull. These muscles move the larynx during swallowing. The epiglottis consists of cartilage extending upwards behind the back of the tongue and projects down through the hyoid bone. It connects to the thyroid cartilage just beneath the thyroid notch. The space defined by these main cartilages is divided into the supraglottis and the glottis.
The glottis is defined as the space between the vocal cords, which are located at the upper rim of the cricoid cartilage. They attach to the thyroid cartilage at the front, and to the Arytenoid cartilages at the back. These are two roughly tetrahedral cartilages responsible for adduction and abduction of the vocal cords. The vocal cords are muscular masses coated with a mucous membrane which protects much of the respiratory tract from foreign particles. Their inner edges contain the vocal ligament.
The supraglottis is the portion of the pharynx above the glottis. It contains the ventricle of the larynx or laryngeal sinus, the ventricular folds or false vocal cords, the epiglottis, and the aryepiglottal folds. These are two folds of connective tissue that connect the epiglottis to the arytenoid cartilages. Muscles in the aryepiglottal folds have the ability to pull the epiglottis down, sealing the larynx and protecting the trachea below from foreign objects.
3. What are the structural adaptations of the trachea that allow it to carry out its functions?
The trachea, or windpipe, is a tube extending from the larynx to the bronchi, carrying air to the lungs. It is lined with ciliated cells which push particles out, and cartilage rings which reinforce the trachea and prevent it from collapsing on itself during breathing. These numerous cartilaginous half-rings, located one above the other along the trachea, have open ends adjacent to the esophagus. The rings are connected by muscular and fibrous tissue, and they are lined inside with a ciliated mucous membrane.
4. What are the structural adaptations of the alveoli that allow it to carry out its functions?
The alveoli consist of an epithelial layer and extracellular matrix surrounded by capillaries. In some alveolar walls, there are pores between alveoli. The alveoli are composed of Type I cells that form the structure of an alveolar wall, and Type II cells that secrete surfactant to lower the surface tension of water. The lungs contain about 300 million alveoli, each wrapped in a fine mesh of capillaries.
5. Compare the function of the conducting and respiratory zones.
The Conducting zone consists of the mouth, nose, pharynx, larynx, trachea, bronchi
The Respiratory zone consists of the respiratory bronchioles and alveoli.
The conducting zone warms the incoming air and removes pathogens and debris from it before it enters the respiratory zone. In the respiratory zone, oxygen is uploaded into the erythrocytes from the alveoli and transported throughout the body. Erythrocytes which have traveled through the body return to download carbon dioxide, which is then expelled from the body via the conducting zones.
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