ผลต่างระหว่างรุ่นของ "กะบังลม"

| Name = กะบังลม<br />(Diaphragm)

| Latin = diaphragma

| GraySubject = 117

| GrayPage = 404

| Image = Respiratory system.svg

| Caption = อวัยวะระบบทางเดินหายใจ ('''กะบังลม'''อยู่ด้านล่างของภาพ)

| Artery = [[Pericardiacophrenic artery]], [[Musculophrenic artery]], [[Inferior phrenic arteries]]

| Vein = [[Superior phrenic vein]], [[Inferior phrenic vein]]

| Nerve = [[Phrenic nerve|phrenic]] and lower [[intercostal nerves]]

| Lymph =

| Action = [[Respiration (physiology)|respiration]]

| Precursor = [[septum transversum]], pleuroperitoneal folds, body wall <ref>{{EmbryologyUNC|mslimb|012}}</ref>

| MeshName = Diaphragm

| MeshNumber = A02.633.567.900.300

| DorlandsPre = d_15

| DorlandsSuf = 12293509

| lumbar || aponeurotic arches, named the [[lumbocostal arches]], and from the [[lumbar vertebrae]] by two pillars or crura.

The diaphragm is innervated by the [[phrenic nerve]] which is formed from the [[cervical nerves]] [[Cervical spinal nerve 3|C3]], [[Cervical spinal nerve 4|C4]], and [[Cervical spinal nerve 5|C5]]. A useful mnemonic to remember this is, "C-3, 4, 5 keep the diaphragm alive"

| two lesser aperture of [[right crus of diaphragm|right crus]] || || greater and lesser [[right splanchnic nerves]]

| three lesser aperture of [[left crus of diaphragm|left crus]] || || greater and lesser [[left splanchnic nerves]] and the [[hemiazygos vein]]

| behind the diaphragm, under the [[medial lumbocostal arches]] || || [[sympathetic trunk]]

| areolar tissue between the sternal and costal parts (see also [[foramina of Morgagni]]) || || the [[superior epigastric branch]] of the [[internal mammary artery]] and some [[lymphatics]] from the abdominal wall and convex surface of the [[liver]]

| areolar tissue between the fibers springing from the medial and [[lateral lumbocostal arch]]es || || This interval is less constant; when this interval exists, the upper and back part of the [[kidney]] is separated from the [[pleura]] by [[areolar tissue]] only.

[[ไฟล์:Diaphragm Arthur Keith 1.jpg|thumb|300 px|Diaphragm and pleural cavities in amphibian (left), bird (center), mammal (right). a, [[mandible]]; b, [[genio-hyoid]]; c, [[hyoid]]; d, [[sterno-hyoid]]; e, [[Human sternum|sternum]]; f, [[pericardium]]; g, [[septum transversum]]; h, [[rectus abdominis]]; i, [[abdominal cavity]]; j, [[pubis (bone)|pubis]]; k, [[esophagus]]; l, [[Vertebrate trachea|trachea]]; m, cervical limiting membrane of abdominal cavity; n, dorsal wall of body; o, [[lung]]; o', [[Bird anatomy#Respiratory system|air-sac]].<ref name="Keith">{{cite book|url=http://books.google.com/books?id=2ecDAAAAYAAJ|title=The nature of the mammalian diaphragm and pleural cavities|author=Arthur Keith, M.D.|journal=Journal of Anatomy and Physiology|year=1905}}</ref>]]

* [[Aortic hiatus]] = 12 letters = T12

* [[Oesophagus]] = 10 letters = T10

* [[Vena cava]] = 8 letters = T8

The existence of some membrane separating the pharynx from the stomach can be traced widely among the [[chordate]]s. Thus [[amphioxus]] possesses an [[atrium (alveoli)|atrium]] by which water exits the pharynx, which has been argued (and disputed) to be homologous to structures in [[ascidian]]s and [[hagfish]]es.<ref>{{cite journal|url=http://dev.biologists.org/cgi/reprint/126/6/1295.pdf|title=Characterization of an amphioxus paired box gene, AmphiPax2/5/8|author=Zbynek Kozmik et al.|year=1999|journal=Development|volume=126|issue=6|pages=1295–1304|pmid=10021347}}</ref> The urochordate epicardium separates digestive organs from the pharynx and heart, but the anus returns to the upper compartment to discharge wastes through an outgoing siphon.

Thus the diaphragm emerges in the context of a body plan that separated an upper feeding compartment from a lower digestive tract, but the point at which it originates is a matter of definition. Structures in fish, amphibians, reptiles, and birds have been called diaphragms, but it has been argued that these structures are not [[homologous]]. For instance, the alligator diaphragmaticus muscle does not insert on the [[esophagus]] and does not affect pressure of the lower esophageal sphincter.<ref>{{cite journal|doi=10.1242/jeb.01746|url=http://jeb.biologists.org/cgi/content/full/208/16/3047|title=Structure and function of the esophagus of the American alligator (''Alligator mississippiensis'')|author=T. J. Uriona et al.|journal=Journal of Experimental Biology|year=2005|volume=208|issue=Pt 16|pages=3047–3053|pmid=16081603}}</ref> The lungs are located in the abdominal compartment of amphibians and reptiles, so that contraction of the diaphragm expels air from the lungs rather than drawing it into them. In birds and mammals, lungs are located above the diaphragm. The presence of an exceptionally well-preserved fossil of [[Sinosauropteryx]], with lungs located beneath the diaphragm as in crocodiles, has been used to argue that dinosaurs could not have sustained an active warm-blooded physiology, or that birds could not have evolved from dinosaurs.<ref>{{cite web|url=http://cas.bellarmine.edu/tietjen/images/lung_fossils_suggest_dinos_breat.htm|title=Lung fossils suggest that dinos breathed in cold blood}}</ref> An explanation for this state of affairs is that lungs originated beneath the diaphragm, but as the demands for respiration increased in warm-blooded birds and mammals, natural selection came to favor the [[parallel evolution]] of the herniation of the lungs from the abdominal cavity in both lineages.<ref name="Keith" /> However, birds do not have diaphragms. They do not breathe in the same way as mammals, and do not rely on creating a negative pressure in the thoracic cavity, at least not to the same extent. They rely on a rocking motion of the keel of the sternum to create local areas of reduced pressure to supply thin, membranous airsacs cranially and caudally to the fixed-volume, non-expansive lungs. A complicated system of valves and air sacs cycles air constantly over the absorption surfaces of the lungs so allowing maximal efficiency of gaseous exchange. Thus, birds do not have the reciprocal tidal breathing flow of mammals. On careful dissection, around eight air sacs can be clearly seen. They extend quite far caudally into the abdomen.<ref>Dyce, Sack and Wensing in ''Textbook of Veterinary Anatomy''; '''2002''' (3rd Edn); Saunders, Philiadelphia</ref>

The right crus of the diaphragm is part of the lower esophageal sphincter (LES), which separates the thoracic and abdominal parts of the esophagus. A ''[[hiatal hernia]],'' in which the abdominal esophagus or even the fundus of the stomach rises up through the esophageal hiatus into the thoracic cavity, can result from a tear or weakness in the diaphragm. Weakness may also result from injury to the neck at levels C3, C4, C5 which can result in altered tone of either half of the diaphragm. Both general weakness of the LES and hiatal hernia can cause "acid reflux," also known as [[gastroesophageal reflux disease]] u(GERD).

The thoracic diaphragm develops embryologically beginning in the third week after fertilization with two processes known as transverse folding and longitudinal folding. The [[septum transversum]], the primitive central tendon of the diaphragm, originates at the rostral pole of the [[embryo]] and is relocated during longitudinal folding to the ventral thoracic region. Transverse folding brings the body wall anteriorly to enclose the gut and body cavities. The pleuroperitoneal membrane and body wall myoblasts, from somatic lateral plate mesoderm, meet the septum transversum to close off the pericardio-peritoneal canals on either side of the presumptive esophagus, forming a barrier that separates the peritoneal and pleuropericardial cavities. Furthermore, dorsal mesenchyme surrounding the presumptive esophagus form the muscular crura of the diaphragm.

Because the earliest element of the embryological diaphragm, the septum transversum, forms in the cervical region, the [[phrenic nerve]] that innervates the diaphragm originates from the cervical spinal cord (C3,4, and 5). As the septum transversum descends inferiorly, the phrenic nerve follows, accounting for its circuitous route from the upper cervical vertebrae, around the [[pericardium]], finally to innervate the diaphragm.

Failure of one of the pleuroperitoneal membrane to form of a competent barrier between cavities can result in [[congenital diaphragmatic hernia]]. This condition is present in 1 out of 2,000 births. A large herniation has a mortality rate of 3/4 and requires immediate surgical repair.