Digestive System Anatomy Flashcards
Beaumont + Alex St. Marten initial shooting
-Beaumont was called to a trading store where Alex St. Marten was shot
-a gun had fallen and hit him in the abdomen
-wasn’t enough tissue to close the hole —> Beaumont sutured the holes around it and thought St. Marten was going to die
-St. Marten lived so over time they realized that the hole would be closed when he was moving around or would close if he moved a certain way- flap that developed
-discovered the hole opened to the stomach
Beaumont + St. Marten
-Beaumont paid St. Marten to participate in studies —> first time people realized that it was something in the stomach that would change when they ate rather than their food
-Beaumont used a string attached to foods to pull out @ different stages to see how they were digested
-St. Marten outlived Beaumont after Beaumont fell on icy steps and St. Marten’s wife refused to let researchers look at his body
pathway of blood from heart
blood comes from the left ventricle —> arch of aorta —> thoracic aorta —> through the diaphragm —> hiatus —> abdominal aorta
pathway of blood to the heart
superior messenteric artery that feeds gut and drops to the portal vein that goes to the liver —> inferior vena cava —> heart
digestive system
-alimentary canal- tubular space that develops through the body that opens to the outside world
-throughway in the body
-certain things built in to prevent infection
- 40 ft long tube from mouth to anus
structures that are tagged onto tube to address different foods and assist in digestion
liver, pancreas, salivary glands, and gallbladder (designed not to produce anything but stores extra bile)
mechanical portion of digestion
-chewing (mastication) and hydrolysis (fluid from saliva)
-swallow food- trachea with soft tissue —> behind it is the esophagus and has to push forward for soft tissue
-increasing surface area to break food down for chemicals and enzymes surrounding the food
oral cavity
-upper extent- roof of mouth or the hard palate
-posterior is the soft palate (uvula)
-inferior extent- tongue and gutter of the mouth
-laterally- cheeks and inferior of mouth
what is the process of chewing?
clamping teeth up and down to chew, your tongue is moving food where it needs to be chewed, and don’t bite down on your tongue
musculature of the lateral side of the face
-temporalis- extends up the temporal line and goes to the tendonis portion that attaches to the front condyle part of the jaw Ex. when people are talking/chewing, you can see the temporalis moving in bald people
-massetter- really strong jawline in addition to the bone
-buccinator- movement of food around the mouth and compression of oral cavity
Ex. infants have pronounce bucchal fat pad to help with feeding —> volume of oral cavity has to be low to help with suction
-not a lot of flexibility in the mouth
dizzy gillespie
circle breathing- train themselves to exhale and blow in a horn and continue to exhale based on already expelled air —> able to fill the oral cavity with air and let recoil tension of the mouth muscles recoil to let air out and keep a single note for a long time
teeth
-32 teeth with 16 on each jaw
-3rd molar can be troublesome given how far back it is
-jaw continues to move as you get older and teeth in the front get pushed together
tongue
-surface of the tongue has roughness with fungiform papillae and conical papillae
-innervated differences and play a role in how food tastes
Ex. Rini’s sense of smell has decreased over the years and it’s closely tied to the sense of taste —> can taste sensation of food but not perceive it
-parotid duct comes into the orbicularis oris and opens up to the 2nd molar and every once in awhile you can palpate it
-tongue meets the floor of the mouth —> sublingual ducts
-in frenulum tissue @ the base are submandibular ducts
salivary glands
-saliva dumps from the parotid gland into the oral cavity
-sublingual gland is in the floor of the mouth and submandibular gland is under the ramus of the jaw
-saliva has ptyalin in it, a starch decomposer
swallowing
-buccinator has to compress cheeks and oral cavity needs to be made small
-hyloid bone and thyroid cartilage raise up in position as you swallow —> push the food back in mouth
-series of muscles contract that bring soft palate up and closes nasal cavity —> don’t want the food to go down the eustachian tube since the mucosa is ciliated
-you want the soft palate to go up and close off the nasopharynx
-tongue elevates and epiglottis flaps back to allow food to go down esophagus and not trachea
-food in esophagus with constrictor muscles that milks material down and also gravity pushes it down
-strong coughing reflex to cough up liquid or food —> can happen when slightly stimulated and pushing out air to make chest cavity small quickly to force sensation away
what is the heimlich not good for?
isn’t great for anything that is self-sealing like peanut butter —> blows open a hole in the pb but as you push out the hole closes
what lines the abdomen?
abdomen is lined by type of tissue called mesothelium that makes up the peritoneum (very similar tissue lining thoracic cavity)
peritoneal cavity
-space between wall of abdomen and all of the stuff protruding into space
(GI tract)
-space between visceral and parietal peritoneum
-closed in males since there is no reason for space but open in females from fallopian tubes
peritoneum
-made up of the mesothelium
-reflects on itself and becomes mesentery (2 layer sheet of mesothelium) and goes out to invest in organs of the digestive tract —> all of the arteries and veins go through here
mesocolon
part of the mesentary that attaches the colon to the abdominal wall
visceral peritoneum
peritoneum on the organs
parietal peritoneum
outer layer of the peritoneum
is the small intestine in the abdominal cavity?
technically yes, but no since it is covered by the same covering as the rest of the space —> intraperitoneal
intraperitoneal
-covered by peritoneum and connected to the back wall by mesentery
-stomach, spleen, liver, first and fourth parts of duodenum, jejunum, illeum, transverse colon, sigmoid colon, appendix, and tail of pancreas
retroperitoneal
-behind peritoneal proper and includes the kidney, ascending/descending colon, rectum, aorta, and vena cava —> adhered to the back wall
-abdominal organs that are not suspended by the mesentery and lie between the abdominal wall and parietal peritoneum
what are the 2 main areas of the peritoneal cavity?
- greater sac
- lesser sac
connected through the epiploic foramen between the abdomen proper and the space back there
greater sac
most of what we see in the abdomen
lesser sac
small area behind the stomach
peritonitis
-infection of the peritoneal cavity
-if it gets into the lesser sac, it can be difficult to treat with antibiotics
-when you hear of peritonitis or sepsis or insult to space, it can get bad quickly since you have a warm, moist space, and contact with the tissue
-sometimes will have to treat through pumping antibiotics into the peritoneal cavity
fallopian tubes in women
in females, you have opening to outside with fallopian tubes coming up from the uterus out to ovary —> space between the ovary and end of fallopian tube is a place for infectious material to enter into the peritoneal cavity
toxic shock syndrome
caused by use of tampons and infectious material is introduced by the fallopian tubes —> presented late since it is often misdiagnosed
septic shock
trauma from punctured perforated valve or appendicitis or GI surgery on bowel —> have to be super careful that everything is sutured and will often take turkey baster to flush out the bowels and ensure the infectious material doesn’t get into the peritoneal cavity
path to sphincter
mouth —> pharynx —> esophagus —> sphincter to stomach —> sphincter
what are the 3 parts of the small intestine?
- duodenum- first portion
- jujonum- next two thirds
- illeum- final third
illeum attaches to the colon (large intestine)- widening area is called the secum and begins moving through first with ascending colon, transverse colon then descending colon then sigmoid colon then rectum
what are the 2 areas of the colon?
- hepatic near liver
- splenic near spleen
what is the path food will travel?
esophagus —> stomach —> small intestine (duodenum, jejunum, illeum) —> ascending colon —> transverse colon —> descending colon —> sigmoid colon —> rectum
what does the cardiac sphincter do?
dumps into the duodenum and travels from retroperitoneal to intraperitoneal
pancreas
head is in the C part of the duodenum
stomach
-covered with folds called rugi with pits that produce HCl
-esophagus is @ the top and goes through esophageal hiatus close to the diaphragmatic hiatus
-1st sphincter is the cardiac sphincter that prevents food from reflexing back from the stomach
-pyloris- opens selectively to the duodenum since you do not want all the dumping of the acidic material into the small intestine
duodenum
openings for pancreatic ducts that pump pancreatic juice
coeliac trunk
branches into left gastric artery that goes to the lesser curvature of the stomach and right common hepatic artery
gastroduodenal branch
comes around the greater curvature of the stomach and meets the splenic artery which feeds the spleen
splenic artery
looks like a corkscrew and is a beefy vessel since the spleen is well profused
common cystic artery and cystic proper
supply the dome of the gallbladder
GERD
-highly acidic environment in the stomach
-any problem with the cardiac sphincter closing off you can get reflux of the acidic material into the distal esophagus
-can start to erode the esophagus if chronic and could be precursor to esophageal cancer
fundus hernia in the thoracic cavity
repair with fundoplication- go into the body and pull fundus down and wrap it on itself to create a knot and prevent the stomach from going through the hiatus then suture the hiatus to tighten it
types of bariatric surgery
lap band, gastric bypass, and vertical gastric sleeve
lap band
take inflatable band around the stomach and can regulate how big the stomach expands
gastric bypass
surgically take a section of the fundus and create a new gastric pouch then disconnect the small intestine and reconnect somewhere else
vertical gastric sleeve
-new stomach with reduced volume
-have to be careful who gets approved —> if someone doesn’t follow the diet, they can easily bring in calories and gain weight
-can be very effective when it works
pancreatic cancer
-usually diagnosed very late when the digestion is off
-treatment can be effective if caught early enough
whipple procedure
-can be treatment of pancreatic cancer
-remove head of the pancreas and duodenum to reroute the small intestine to serve as the pancreatic duct
greater oomentum
double sheath of peritoneum that hangs down —> reduces the friction in small intestine and migrates over to the site of trauma in abdominal wall
what happens when someone gets their gallbladder removed?
bile has strong influence of emulsification of fats —> have to be careful how much gets taken in
illeum
-goes into the large intestine @ cecum
-when nothing is in the cecum, angle opens up and when the cecum is full, the angle is closed
superior messenteric artery
-the entire digestive tract is supplied by superior messenteric artery with the exception of the final third of rectum, which is supplied by the inferior messenteric artery
why do physicians use suppositories?
allow for blood to be picked up and bypass the portal system to go right to the systemic system
first pass effect
dump something into the digestive tract it is either a) metabolized or b) pulled into systemic circulation through the liver
hemorrhoids
-venous drainage of the anus and rectum —> pressure of veins is increased by blockage further up
-blood cannot flow up freely
