L43 - Anatomy of Gastrointestinal System PDF

L43- ANATOMY OF GASTROINTESTINAL SYSTEM Dr.Pugazhandhi Bakthavatchalam Assistant Professor of Anatomy and Physiology, AUACAS, American University of Antigua  LEARNING OUTCOMES 2 At the end of this session the student would be able to:  Quadrants and regions of abdomen  Abdomin...

L43- ANATOMY OF GASTROINTESTINAL SYSTEM Dr.Pugazhandhi Bakthavatchalam Assistant Professor of Anatomy and Physiology, AUACAS, American University of Antigua  LEARNING OUTCOMES 2 At the end of this session the student would be able to:  Quadrants and regions of abdomen  Abdominal incissions  Abdominal Organs  Peritoneum and its functions 19-Nov-24 QUADRANTS AND REGIONS OF ABDOMEN TRANSUMBILICAL PLANE- intervertebral disc between III & IV Lumbar vertebra 3 19-Nov-24  Transpyloric plane -a horizontal plane through the ninth costal cartilages and the body of the LI vertebra  Subcostal plane - through the lower edge of the costal margin (tenth costal cartilage) and the body of the LIII vertebra  Umbilicus- disc between the LIII and LIV vertebrae  Supracristal plane- a horizontal plane through the highest point on the iliac crests and spine and body of the LIV vertebra  Transtubercular plane-a plane through the tubercles of the crest of the ilium 4 19-Nov-24 and the body of the LV vertebra.  liver and gallbladder are in the right upper quadrant  stomach and spleen are in the left upper quadrant  cecum and appendix are in the right lower quadrant  end of the descending colon and sigmoid colon are in the left lower quadrant 5 19-Nov-24  ABDOMINAL INCISSIONS  Median or Midline Incisions: made along the length of the linea alba from the xiphoid process to pubic symphysis  Paramedian Incisions/(lateral to the median plane): made in a sagittal plane and may extend from the costal margin to the pubic hairline After the incision passes through the anterior layer of the rectus sheath, the muscle is freed and retracted laterally to prevent tension and injury to the vessels and nerves. 6 19-Nov-24 https://www.studyblue.com/notes/note/n/unit- 3/deck/12565579 7 19-Nov-24  ABDOMINAL OESOPHAGUS  Emerges through the right crus of the diaphragm, usually at the level of vertebra T10  Passes from the esophageal hiatus  Terminates by opening into the cardiac end of the stomach at level of T11 vertebra about 2.5cm to the left of the median plane 8 19-Nov-24  STOMACH Most dilated part of the gastrointestinal tract SITUATION:  With moderated gastric contents the stomach occupies the epigastric, left hypochondriac and umbilical region PRESENTING PARTS:  2 orifices- cardiac & pyloric  2 curvatures- lesser & greater  2 surfaces- antero-superior & postero- inferior  3 subdivisions- fundus, body & pylorus - (pylorus- pyloric antrum & pyloric canal) 9 19-Nov-24  SMALL INTESTINE  longest part of the gastrointestinal tract  Extends from the pyloric orifice of the stomach to the ileoceacal junction  Consists of: a. proximal(fixed) part- duodenum b. distal(mobile) part- jejunum & ileum  Total length- 6.5 metres 10 19-Nov-24  Duodenum: C-shaped structure, adjacent to the head of the pancreas, is above the level of the umbilicus  Jejunum: represents the proximal two-fifths. It is mostly in the left upper quadrant of the abdomen  Ileum: represents distal three-fifths of the small intestine and is mostly in the right lower quadrant 11 19-Nov-24 LARGE INTESTINE  Extends from the distal end of the ileum to the anus, a distance of approximately 1.5 m  Consists of the cecum, appendix, colon, rectum, and anal canal 12 19-Nov-24 LIVER  Largest visceral organ in the body  Primarily located in the right hypochondrium and epigastric region, extending into the left hypochondrium 13 19-Nov-24  PANCREAS  Lies mostly posterior to the stomach  Extends across the posterior abdominal wall from the duodenum, on the right, to the spleen, on the left  Consists of a head, uncinate process, neck, body, and tail 14 19-Nov-24  SPLEEN  Lies against the diaphragm, in the area of rib IX to rib X on the left side (left hypochondrium) 15 19-Nov-24  PERITONEUM  Is a large serous membrane lining the abdominal cavity  Externally lined by fibrous tissue which gives strength & internally by mesothelial cells  Peritoneum is in the form of a closed sac invaginated by a number of viscera  Is divided into Outer or parietal layer Inner or visceral layer And folds of peritoneum by which the viscera are suspended 16 19-Nov-24 STUDENTS GRACE ANATOMY TEXTBOOK  Parietal peritoneum: Lines the inner surface of the abdominal and pelvic walls and lower surface of the diaphragm Is loosely attached to the walls & can be easily stripped off  Visceral peritoneum: Lines the outer surface of the viscera & is firmly attached to it & cannot be stripped 17 19-Nov-24 STUDENTS GRACE ANATOMY TEXTBOOK  PERITONEAL FOLDS  Peritoneal folds within the peritoneal cavity: Many organs of the abdomen are suspended by the folds of peritoneum, such organs are mobile Some organs are fixed and immobile They rest directly on the posterior abdominal wall & may be covered by peritoneum on one side, they are called retroperitoneal organs Apart from allowing mobility, the peritoneal folds provide pathways for the passage of vessels, nerves & lymphatics 18 19-Nov-24  Peritoneal folds are given various names: The folds suspending the small intestine is called mesentery Folds suspending part of the colon is called mesocolon Folds attached to the stomach are called omenta(cover) In some areas double layered fold of peritoneum connect organs to the abdominal wall or http://www.easynotecards.com/print_list/2621 to each other, such folds are8?fs=0&dis=1&pi=on called ligaments 19 19-Nov-24  GREATER OMENTUM  Is a large fold of peritoneum which hangs down from the greater curvature of the stomach  Covers the loops of intestines  Is made up of 4 layers, all of which are fused together to form a thin membrane containing fat ,small arteries & veins.  Contents : Right and left gastro-epiploic vessels Fat https://www.studyblue.com/notes/note/n/unit- 3/deck/12565579 20 19-Nov-24  FUNCTIONS OF GREATER OMENTUM  Storehouse of fat 21  Protects the peritoneal cavity against the infection because of the macrophages in it  Collections of macrophages form small, dense patches, known as milky spots which are visible to the naked eye  It also limits the spread of infection by moving to the site of infection and sealing it off from the surrounding areas  On this account the greater omentum is also known as the policeman of the abdomen 19-Nov-24  LESSER OMENTUM  Is a fold of peritoneum which extends from the lesser curvature of stomach & the first 2cm of duodenum to the liver  The portion of lesser omentum between the duodenum and liver is called hepato-duodenal ligament  Behind the lesser omentum there lies a part of the lesser sac  The lesser omentum has a right free margin behind which there is the Epiploic foramen  The greater and lesser sac communicates through this foramen NETTER ATLAS OF ANATOMY 22 19-Nov-24  REFERENCES  Drake R.L., Gray’s Anatomy for Students, 2nd Edition, 2009, Churchill Livingstone  Moore, Clinically Oriented Anatomy, 6th Edition, 2009, Lippincott Williams & Wilkins  Textbook of Medical Physiology – Guyton & Hall  Medical Physiology – R.K Marya  Essentials of Physiology for Dental Students. K Sembulingam and Prema Sembulingam ,2016, four Edition , Jaypee Brothers Medical Publishers.  Human Physiology. Stuart Ira Fox., TWELFTH EDITION,2017. Published by McGraw-Hill 23 19-Nov-24