These are among the most memorable experience of teaching and often criticized or cited as a trauma, dissections are nonetheless a remarkable observation exercise the many pedagogical virtues. In these four articles entitled "Chronic Dissecting" I will return to the TP of Animal Biology of L2 UPPA.
TP4: Digestive system of white mice.
A biological model must
"This is undoubtedly the mammal in the pluscontribué the progress of science" is what is said about the sourisblanche, Mus musculus in our textbooks. Certainly from my point of view, the mammal which has contributed to science Lepley is Man (we will ignore mickey, minus and mouse cortex and other gifted) ... But still, how expliquerl'incroyable contribution of this rodent before the advent of scienceétait considered a scourge of granaries ...
First breeding mouse is economical, with low volume occupied, and a consumption of 5 g of food per day only. More lareproduction is easy and fast with 5 to 15 litters per year, each donnantnaissance a dozen mice or mice parfemelle fifty year! This ability to reproduce rapidly unedurée associated with short life is a strategy r : it's actually a glibness offset by the number one natural mortality (predation, starvation etc..) Important. It contrasts this strategy to the strategy K (long life, large animals, breeding in small numbers). Other criteria, the mouse is an excellent représentantdes mammals (50% of mammal species are rodents), and with saproximité Man is sufficient for many studies (99% of genes in common). Last, the amount of accumulated knowledge about the species, DELANCE allows virtually any type of study, for example séquençagedu the mouse genome was completed in 2003.)
glands of the digestive tract.
The digestive tract consists of the esophagus and stomach del'intestin, can not alone provide all of the digestion. Enumeration gleanings say annexes complement the device. The liver estla more massive, it secretes bile : This yellowish liquid pH basiqueest rich bile salts whose main role is to favoriserl'absorption and enzymatic digestion of lipids. Bile acts as a detergent faitcomme allowing the formation of small lipid droplets (Emulsion, as in salad dressing) which will act lesenzymes. Bile, produced in continuous talks liver is released into the hepatic duct before joining the gallbladder, sonlieu storage via the cystic duct. When digéréspénètrent food in the gut hormone, cholecystokinin (CCK) lacontraction of the gallbladder. The bile then goes back into lecanal before joining the cystic bile duct that opens dansl'intestin.
Another glands of the gut is the pancreas quilibère pancreatic juice rich in enzymes of all kinds - proteolytic (trypsin, chimotrypsine, carboxypeptidases)-glycolytic (α-amylase), lipolytic (lipase). Mice is a body bounded diffusmal present in the mesentery after the stomach. Finally spleen purple no digestive role, she is involved in ladestruction formed elements of blood (red blood cells for example), Quedan and immune function.
[The liver up on this This dissection 4-5 unequal lobes, observed in the stomach below the esophagus before (drawn on the left side) and follow the duodenum (first part of the small intestine in the upper right). Most strikingly, the gallbladder orange linked below by the cystic duct to common bile duct which joins the intestine to the right. Finally the diffuse pancreas is pinned down in the stomach with the spleen on the left.]
The qualities of a good drawing
Dissection of the mice presenting no particular difficulty, I'm going to focus this time on the quality criteria dessinscientifique. Firstly this method of representation is intended to make comtede reality, and therefore observations made during dissection, and this sansler idealize. So it's a teaching tool for working Lesens observation and memorization of the observed structures.
To make a good drawing, it must already be large etremplir much of the leaf. The line should be fine and well marked for continuous maissuffisamment delimit the structures. The proportions sontégalement an essential point to be successful we must not hesitate àcomparer size items between them in reality and in the drawing. Uneautre trick is to take data points (length of a pin ...) see measurements with a ruler. Finally it should give a bit of realism for all not just a schema. Thus it will add up to little details, pieces of muscle cut, remains on the gut mesentery etc. . It may also apply where their shade différentséléments texture to properly différentsorganes distinguish between them.
Once the drawing is finished it should be captioned endisposant legends all on the same side with a line return rectilignele finest possible. A title as complete as possible will make the final latouche in the bottom of the drawing.
Thanks to all the students for their contributions to these articles - Good luck for the revisions.
Sources:
- Wikipedia http://fr.wikipedia.org/wiki/Mus_musculus
http://fr.wikipedia.org/wiki/Tube_digestif - The site of Emmanuelle Van Noppen: Scientific illustrator: http:// www.illustration-animaliere.be/index.php/dessin-scientifique
- Lab Animal Biology - Zoology Embryology Histology, 3rd edition. Andrew Beaumont, Pierre Cassier. Editions Dunod 502p.
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