Definition
The diaphragm is a dome-shaped musculofibrous partition that separates the thoracic and abdominal cavities. The word “diaphragm” is Greek, and signifies a dividing wall or a closing or cutting off from (Mosby’s, 2008). This muscolofibrous structure is very important and if not the most important muscle in the body with regards to its main function, which is the involuntary action of breathing.
Embryological origins of the diaphragm
The diaphragm is a composite structure derived from several embryonic components. It forms during the 4th to the 10th week of embryonic life, and develops from four embryonic components, which are: septum transversum, pleuroperitoneal membranes, dorsal mesentery, and body wall (figure 1). The septum transversum forms the central tendon of the diaphragm and separates the pericardial development (ventrally) from the developing gut (dorsally). The dorsal mesentery is a double layer of peritoneum that forms the median portion of the diaphragm. The crura of the diaphragm develop from muscle fibers that grow into the dorsal mesentery during the ninth to twelfth weeks (Moore, 2008). The pleuroperitoneal membranes form the posterolateral elements of the diaphragm (peripheral muscular part of the diaphragm). Although the pleuroperitoneal membranes form large portions of the primitive diaphragm, they represent small portions of the definitive diaphragm. The fourth embryonic component, the body wall, constitutes as the peripheral part of the diaphrahm. This happens because, as the lungs and pleural cavities enlarge and invade the body wall, the tissue is divided into an outer layer that becomes the body wall, and an inner layer that forms the peripheral part of the diaphragm. The process ...
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...ssential role of Gab1 for signaling by the c-Met receptor in vivo. J Cell Biol 150: 1375-1384.
Brohmann et al. 2000. The role of Lbx1 in migration of muscle precursor cells. Curr Opin Cell Biol 12: 725-730.
Dietrich S et al. 1999. The role of SF/HGF and c-Met in the development of skeletal muscle. Development 126: 1621-1629.
Ackerman KG, Greer JJ. 2007. Development of the diaphragm and genetic mouse models of diaphragmatic defects. Am J Med Genet Part C Semin Med Genet 145c: 109-116.
Ackerman KG, Herron BJ, Vargas SO, Huang H, Tevosian SG, et al. (2005) Fog2 Is Required for Normal Diaphragm and Lung Development in Mice and Humans. PLoS Genet 1(1): e10. doi:10.1371/journal.pgen.0010010
Clugston et al. 2008. Gene expression in the developing diaphragm: significance for congenital diaphragmatic hernia. AJP- Lung Physiol vol.294. no.4 L665-L675.
Biology 2A03 Lab 4 Respiratory Gas Exchange in a Mouse Lab Manual. Winter Term 2014 (2014). Biology Department. McMaster University.
Every day we use our skeletal muscle to do simple task and without skeletal muscles, we will not be able to do anything. Szent-Gyorgyi (2011) muscle tissue contraction in rabbit’s muscles and discovered that ATP is a source for muscle contraction and not ADP. He proposed a mechanism to cellular respiration and was later used by Sir Hans Krebs to investigate the steps to glucose catabolism to make ATP. In this paper, I will be discussing the structure of muscle fibers and skeletal muscles, muscle contraction, biomechanics, and how glucose and fat are metabolized in the skeletal muscles.
The fetus begins to develop the type II alveoli at 22nd to 24th week of gestation, however these immature alveoli are incapable of supplying enough surfactant to meet the infant's respiratory needs. The fetus surfactant production begins to become adequate at the middle terminal stage of alveoli development and production becomes optimal at the 34th-to-36th week. (Porth, 1306) There are four types of surfactant produced by the type 2 alveoli known as primary surfactant proteins SP-A, SP-B, SP-C, and SP-D. SP-A and SP-D roles are inhibiting production of surfactant i...
Within skeletal muscle there are extremely small structures that form the muscle and allow contractions and movement to occur (epimysium, perimysium, endomysium, fascicles, fiber, sarcomere, sarcoplasmic reticulum and t tubules). These structures all play a role in protecting, connecting and transporting substances throughout the muscle fibers. They are also the main contributors to movement.
Healthy lung tissue is predominately soft, elastic connective tissue, designed to slide easily over the thorax with each breath. The lungs are covered with visceral pleura which glide fluidly over the parietal pleura of the thoracic cavity thanks to the serous secretion of pleural fluid (Marieb, 2006, p. 430). During inhalation, the lungs expand with air, similar to filling a balloon. The pliable latex of the balloon allows it to expand, just as the pliability of lungs and their components allows for expansion. During exhalation, the volume of air decrease causing a deflation, similar to letting air out of the balloon. However, unlike a balloon, the paired lungs are not filled with empty spaces; the bronchi enter the lungs and subdivide progressively smaller into bronchioles, a network of conducting passageways leading to the alveoli (Marieb, 2006, p. 433). Alveoli are small air sacs in the respiratory zone. The respiratory zone also consists of bronchioles and alveolar ducts, and is responsible for the exchange of oxygen and carbon dioxide (Marieb, 2006, p. 433).
VanPutte, C., Regan, J., & Russo, A. (2014). Seeley's anatomy & physiology(10th ed.). NEW YORK, NY: MCGRAW-HILL.
Mesothelioma is a very rare form of lung cancer that starts in the mesothelium. The mesothelium is made up of parietal and visceral membranes, thin layers of tissue, which surround organs and body cavities, such as the lungs or abdomen. The visceral membrane immediately surrounds the organ, and the parietal membrane is a sac covering the visceral membrane. The visceral and parietal membranes that make up the mesothelium. This fluid helps organs move easily among surrounding structures. In the case of the lung, it helps reduce friction between the lung and chest wall during normal breathing as the lung expands. The most common place for mesothelioma to develop is in the mesothelial membrane, also called the pleural lining, surrounding the lungs.
The larynx provides a passageway for air between the pharynx and the trachea. The trachea is made up of mainly cartilage which helps to keep the trachea permanently open. The trachea passes down into the thorax and connects the larynx with the bronchi, which passes to the lungs. 3. Describe the mechanisms of external respiration including the interchange of gases within the lungs.
two pleural lobes on the sides. The three main parts of it's body are called the
Here, deep in the lungs, oxygen diffuses through the alveoli walls and into the blood in the capillaries and gaseous waste products in the blood—mainly carbon dioxide—diffuse through the capillary walls and into the alveoli. But if something prevents the oxygen from reaching t...
The sarcomere is found in structures called myofibrils which make up skeletal muscle fibres. Within the sarcomere there are various different proteins. One of the most significant, myosin is found in the thick filaments of the sarcomere. Although both cells contain myosin, it is important to highlight that smooth muscle cells contain a much lower percentage of myosin compared to skeletal muscle cells. Despite this, myosin filaments in smooth muscle cells bind to actin filaments in a manner similar to that in skeletal muscle cells; although there are some differences. For instance, myosin filaments in smooth muscle cells are saturated with myosin heads so that myosin can glide over bound actin filaments over longer distances, enabling smooth muscle cells to stretch further, whilst in skeleta...
Air then travels to the bronchioles which are narrow (bronchoconstriction) due to the natural defence in keeping irritants out of the airway, causing wheezing breath sounds.(Eldridge, 2016) The air then proceeds to the alveoli, which are weakened and damaged air sacs due to the progression of the disease, that are unable to efficiently move O2 into the blood stream and gas exchange CO2 to be expelled through exhale, causing hypoxemia, lethargy, dyspnoea and high CO2 reading. (“Lung conditions - chronic obstructive pulmonary disease (COPD),”
Person, A. & Mintz, M., (2006), Anatomy and Physiology of the Respiratory Tract, Disorders of the Respiratory Tract, pp. 11-17, New Jersey: Human Press Inc.
Parker, Steve. "Chronic Pulmonary Diseases." The Human Body Book. New ed. New York: DK Pub., 2007.
The trachea, or windpipe, is a tubular organ that connects the larynx to the lungs. It is lined with special cells that produce mucus. From the trachea, air passes to the right and left lungs through their corresponding bronchi. Each bronchus divides into bronchioles, which are smaller tubes that carry air further down to the air sacs, also called