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Terminal Bronchioles
The bronchioles or bronchioli (pronounced ''bron-kee-oh-lee'') are the smaller branches of the bronchial airways in the lower respiratory tract. They include the terminal bronchioles, and finally the respiratory bronchioles that mark the start of the respiratory zone delivering air to the gas exchanging units of the alveoli. The bronchioles no longer contain the cartilage that is found in the bronchi, or glands in their submucosa. Structure The pulmonary lobule is the portion of the lung ventilated by one bronchiole. Bronchioles are approximately 1 mm or less in diameter and their walls consist of ciliated cuboidal epithelium and a layer of smooth muscle. Bronchioles divide into even smaller bronchioles, called ''terminal'', which are 0.5 mm or less in diameter. Terminal bronchioles in turn divide into smaller respiratory bronchioles which divide into alveolar ducts. Terminal bronchioles mark the end of the conducting division of air flow in the respiratory s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pulmonary Alveolus
A pulmonary alveolus (plural: alveoli, from Latin ''alveolus'', "little cavity"), also known as an air sac or air space, is one of millions of hollow, distensible cup-shaped cavities in the lungs where oxygen is exchanged for carbon dioxide. Alveoli make up the functional tissue of the mammalian lungs known as the lung parenchyma, which takes up 90 percent of the total lung volume. Alveoli are first located in the respiratory bronchioles that mark the beginning of the respiratory zone. They are located sparsely in these bronchioles, line the walls of the alveolar ducts, and are more numerous in the blind-ended alveolar sacs. The acini are the basic units of respiration, with gas exchange taking place in all the alveoli present. The alveolar membrane is the gas exchange surface, surrounded by a network of capillaries. Across the membrane oxygen is diffused into the capillaries and carbon dioxide released from the capillaries into the alveoli to be breathed out. Alveoli are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epinephrine
Adrenaline, also known as epinephrine, is a hormone and medication which is involved in regulating visceral functions (e.g., respiration). It appears as a white microcrystalline granule. Adrenaline is normally produced by the adrenal glands and by a small number of neurons in the medulla oblongata. It plays an essential role in the fight-or-flight response by increasing blood flow to muscles, heart output by acting on the SA node, pupil dilation response, and blood sugar level. It does this by binding to alpha and beta receptors. It is found in many animals, including humans, and some single-celled organisms. It has also been isolated from the plant ''Scoparia dulcis'' found in Northern Vietnam. Medical uses As a medication, it is used to treat several conditions, including allergic reaction anaphylaxis, cardiac arrest, and superficial bleeding. Inhaled adrenaline may be used to improve the symptoms of croup. It may also be used for asthma when other treatments are not ef ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Simple Cuboidal Epithelium
Simple cuboidal epithelium is a type of epithelium that consists of a single layer of cuboidal (cube-like) cells which have large, spherical and central nuclei. Simple cuboidal epithelium is found on the surface of ovaries, the lining of nephrons, the walls of the renal tubules, parts of the eye and thyroid, and in salivary glands. On these surfaces, the cells perform secretion and filtration. Location Simple cuboidal cells are also found in renal tubules of nephrons, glandular ducts, and thyroid follicles. Simple cuboidal cells are found in single rows with their spherical nuclei in the center of the cells and are directly attached to the basal surface. Simple ciliated cuboidal cells are also present in the respiratory bronchioles. Germinal cuboidal epithelial lines the ovaries and seminiferous tubules of testes. They undergo meiosis to form gametes A gamete (; , ultimately ) is a haploid cell that fuses with another haploid cell during fertilization in organisms that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Simple Columnar Epithelium
Simple columnar epithelium is a single layer of columnar epithelial cells which are tall and slender with oval-shaped nuclei located in the basal region, attached to the basement membrane. In humans, simple columnar epithelium lines most organs of the digestive tract including the stomach, and intestines. Simple columnar epithelium also lines the uterus. Structure Simple columnar epithelium is further divided into two categories: ciliated and non-ciliated (glandular). The ciliated part of the simple columnar epithelium has tiny hairs which help move mucus and other substances up the respiratory tract. The shape of the simple columnar epithelium cells are tall and narrow giving a column like appearance. the apical surfaces of the tissue face the lumen of organs while the basal side faces the basement membrane. the nuclei are located closer along the basal side of the cell. Absorptive columnar epithelium is characterized as having a striated boarder on its apical side, this ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Club Cell
Club cells, also known as bronchiolar exocrine cells, and formerly known as Clara cells, are low columnar/cuboidal cells with short microvilli, found in the small airways (bronchioles) of the lungs. Club cells are found in the ciliated simple epithelium. These cells may secrete glycosaminoglycans to protect the bronchiole lining. Bronchiolar cells gradually increase in number as the number of goblet cells decrease. One of the main functions of club cells is to protect the bronchiolar epithelium. They do this by secreting a small variety of products, including club cell secretory protein uteroglobin, and a solution similar in composition to pulmonary surfactant. They are also responsible for detoxifying harmful substances inhaled into the lungs. Club cells accomplish this with cytochrome P450 enzymes found in their smooth endoplasmic reticulum. Club cells also act as a stem cell, multiplying and differentiating into ciliated cells to regenerate the bronchiolar epithelium. Function ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hyaline Cartilage
Hyaline cartilage is the glass-like (hyaline) and translucent cartilage found on many joint surfaces. It is also most commonly found in the ribs, nose, larynx, and trachea. Hyaline cartilage is pearl-gray in color, with a firm consistency and has a considerable amount of collagen. It contains no nerves or blood vessels, and its structure is relatively simple. Structure Hyaline cartilage is covered externally by a fibrous membrane known as the perichondrium or, when it's along articulating surfaces, the synovial membrane. This membrane contains vessels that provide the cartilage with nutrition through diffusion. Hyaline cartilage matrix is primarily made of type II collagen and chondroitin sulphate, both of which are also found in elastic cartilage. Hyaline cartilage exists on the sternal ends of the ribs, in the larynx, trachea, and bronchi, and on the articulating surfaces of bones. It gives the structures a definite but pliable form. The presence of collagen fibres make ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bronchopulmonary Segment
A bronchopulmonary segment is a portion of lung supplied by a specific segmental bronchus and its vessels. These arteries branch from the pulmonary and bronchial arteries, and run together through the center of the segment. Veins and lymphatic vessels drain along the edges of the segment. The segments are separated from each other by layers of connective tissue that forms them into discrete anatomical and functional units. This separation means that a bronchopulmonary segment can be surgically removed without affecting the function of the others. There are ten bronchopulmonary segments in the right lung: three in the superior lobe, two in the middle lobe, and five in the inferior lobe. Some of the segments may fuse in the left lung to form usually eight to nine segments (four to five in the upper lobe and four to five in the lower lobe. The delineation of the bronchopulmonary segments was made by Chevalier Jackson and John Franklin Huber at Temple University Hospital. Right l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Segmental Bronchi
A bronchus is a passage or airway in the lower respiratory tract that conducts air into the lungs. The first or primary bronchi pronounced (BRAN-KAI) to branch from the trachea at the carina are the right main bronchus and the left main bronchus. These are the widest bronchi, and enter the right lung, and the left lung at each hilum. The main bronchi branch into narrower secondary bronchi or lobar bronchi, and these branch into narrower tertiary bronchi or segmental bronchi. Further divisions of the segmental bronchi are known as 4th order, 5th order, and 6th order segmental bronchi, or grouped together as subsegmental bronchi. The bronchi, when too narrow to be supported by cartilage, are known as bronchioles. No gas exchange takes place in the bronchi. Structure The trachea (windpipe) divides at the carina into two main or primary bronchi, the left bronchus and the right bronchus. The carina of the trachea is located at the level of the sternal angle and the fifth thoracic verte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lobar Bronchi
A bronchus is a passage or airway in the lower respiratory tract that conducts air into the lungs. The first or primary bronchi pronounced (BRAN-KAI) to branch from the trachea at the carina are the right main bronchus and the left main bronchus. These are the widest bronchi, and enter the right lung, and the left lung at each hilum. The main bronchi branch into narrower secondary bronchi or lobar bronchi, and these branch into narrower tertiary bronchi or segmental bronchi. Further divisions of the segmental bronchi are known as 4th order, 5th order, and 6th order segmental bronchi, or grouped together as subsegmental bronchi. The bronchi, when too narrow to be supported by cartilage, are known as bronchioles. No gas exchange takes place in the bronchi. Structure The trachea (windpipe) divides at the carina into two main or primary bronchi, the left bronchus and the right bronchus. The carina of the trachea is located at the level of the sternal angle and the fifth thoracic verte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trachea
The trachea, also known as the windpipe, is a cartilaginous tube that connects the larynx to the bronchi of the lungs, allowing the passage of air, and so is present in almost all air- breathing animals with lungs. The trachea extends from the larynx and branches into the two primary bronchi. At the top of the trachea the cricoid cartilage attaches it to the larynx. The trachea is formed by a number of horseshoe-shaped rings, joined together vertically by overlying ligaments, and by the trachealis muscle at their ends. The epiglottis closes the opening to the larynx during swallowing. The trachea begins to form in the second month of embryo development, becoming longer and more fixed in its position over time. It is epithelium lined with column-shaped cells that have hair-like extensions called cilia, with scattered goblet cells that produce protective mucins. The trachea can be affected by inflammation or infection, usually as a result of a viral illness affecting othe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parasympathetic Nervous System
The parasympathetic nervous system (PSNS) is one of the three divisions of the autonomic nervous system, the others being the sympathetic nervous system and the enteric nervous system. The enteric nervous system is sometimes considered part of the autonomic nervous system, and sometimes considered an independent system. The autonomic nervous system is responsible for regulating the body's unconscious actions. The parasympathetic system is responsible for stimulation of "rest-and-digest" or "feed and breed" activities that occur when the body is at rest, especially after eating, including sexual arousal, salivation, lacrimation (tears), urination, digestion, and defecation. Its action is described as being complementary to that of the sympathetic nervous system, which is responsible for stimulating activities associated with the fight-or-flight response. Nerve fibres of the parasympathetic nervous system arise from the central nervous system. Specific nerves include sev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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