abdominal cavity organization and digestion Flashcards
ingestion
the process of taking food, drink, or another substance into the body by swallowing or absorbing it.
mechanical processing
physically breaking the food into smaller pieces
digestion
the process of breaking down food by mechanical and enzymatic action in the alimentary canal into substances that can be used by the body.
secretion
a process by which substances are produced and discharged from a cell, gland, or organ for a particular function in the organism or for excretion.
absorption
the movement of nutrients, water and electrolytes from the lumen of the small intestine into the cell, then into the blood.
compaction
this is the removal of water from the fecal matter in the large intestine to prepare it for defication
excretion
eliminating or expelling waste matter.
defication
discharge of feces from the body.
peristalsis
A wave of smooth muscle contractions that propels materials along the lumen of a tube such as the digestive tract, the ureters, or the ductus deferens.
segmentation
churn and fragment the materials; mixing it with the digestive secretions
sphincters
regions along the digestive tract that are thickened areas of muscular circular layer
- they constrict and restrict the movement of things and ensure one way movement through the lumen
mucosa
the inner lining of the digestive tract
- a mucus membrane made of the epithelium
- a layer of loose connective tissue covered by an epithelium moistened by glandular secretions
circular folds
a series of ring-shaped projections in the intestinal lining of the small intestine
- these are permanent and do not disappear when the intestine fills up (opposite of the gastric folds in the stomach)
- these are lined with villi which are subsequently lined with microvilli
submucosa
a layer of areolar connective tissue superficial to the mucosa but deep to the muscularis mucosa
-has large blood vessels and lymphatic vessels running through it
muscular layer
(muscularis externa)
- this is a double layer of smooth muscle fibers that are arranged in internal circular and external longitudinal layers
- this is responsible for mechanically processing and propelling the materials along the digestive tract
myenteric neural plexis
- this coordinates the movements of the smooth muscle
- this is between the two layers of smooth muscle in the muscular layer
- contains parasympathetic ganglia and sympathetic post ganglionic fibers
parasympathetic ganglia role in the myenteric neural plexus
- this increases muscular tone and stimulates contraction
sympathetic post ganglionic fibers role in the myenteric neural plexus
these decrease muscular tone and promote relaxation
serosa
a serous membrane that covers the muscular layer
- this doesnt surround the muscular layer of the pharynx, esophagus, and rectum
- these are surrounded by an adventitia
adventitia
this is a dense network of collagen fibers that surrounds the muscular layer of pharynx, esophagus, and rectum
- this attaches the digestive tract to adjacent structures and the fibers are continuous with those around it
peritoneum
this is a serous membrane with two parts
-lines your abdominal wall and covers most of the organs in your abdomen
visceral peritoneum
-this is the layer that is on the abdominal organ
parietal peritoneum
this is the layer that lines the abdominal walls
peritoneal cavity
a potential space between the parietal peritoneum and visceral peritoneum
intraperitoneal organ
organs within the peritoneal cavity, in that they are compleetly surrounded on all sides by the visceral peritoneum
retroperitoneal organ
organs covered by the parietal peritonum on their anterior surface only
- they lie outside of the peritoneal cavity
- typically don’t develop from the embryonic gut
ex. kidneys, ureters, and abdominal arota
secondarily retroperitoneal organ
organs of the digestive tract that form as intraperitoneal organs and become retroperitoneal
- shift occurs during embryonic development when the visceral peritoneum fuses with opposing parietal peritoneum
ex. pancreas and two distal thirds of the duodenum
mesentery
fused double sheets of perioneal membrane
- in the peritoneal cavity, most regions of the digestive tract are suspended by sheets of serious membrane that connect the visceral and parietal peritoneum layers
- stabalize the position of the attached organs and prevent entanglement during digestive movements or changes in body postion
lesser omentum
small pocket of mesentery that connects the lesser curvature of the stomach to the liver
greater omentum
a large fold of the dorsal mesentery of the stomach that hangs in front of the intestines
- loose connective tissue
- has a loose layer of adipose tissue
mesentery proper
a double layer of serous membrane that supports and stabalizes the position of the organ
- allows for routes for blood vessels/nerves/lymph vessels
- provides stability but allows certain independant movements
mesocolon
the mesentary that supports the large intestine
what are the four lobes of the liver
- right
- left
- caudate
- quadrate
liver lobule
these are arranged in a series of irregular plates arranged like the spokes of a wheel
-hepatic sinusoids surround the plates of hepatocytes
hepatic sinusoids
highly fenestrated capillaries that the hepatic portal vein and hepatic artery proper drain into
- the fenestrations allow substances to pass through and enter circulation
- the sinusoids drain into the central vein
hepatocytes
these are the liver cells
bile
- this is a substance produced in the liver
- this is mostly water and has small amounts of ions, bilirubin, and lipids called bile salts
- these are what make the breakdown of lipids to be possible
- stored in the gall bladder
- aids in the transportation of cholesterol out of the body
hepatic portal system
a series of veins that carry blood from the capillaries of the stomach, intestine, spleen, and pancreas to capillaries in the liver
hepatic portal vein
this is what brings blood from the digestive system intestinal capillaries
hepatic artery proper
this brings 1/3 of the normal hepatic blood flow (the rest comes from the hepatic portal vein)
-this is supplying oxygen rich blood to the
central vein
- veins found at the center of hepatic lobules
- They receive the blood mixed in the liver sinusoids and return it to circulation via the hepatic veins
stellate macrophages
- these engulf pathogens, cell debris, and damaged blood cells
- these store iron, lipids, and heavy metals that are absorbed in the digestive tract
- these are within the liver
gall bladder
- this stores the bile that is made from the liver and not needed immediately
- water is absorbed from the bile while it is stored here which causes the bile to become more concentrated
- this is on the inferior side of the liver
cystic duct
this is the duct that allows bile to drain out of the gall bladder
- it merges with the common hepatic duct to make the common bile duct
common bile duct
this is the duct that forms from the mergence of the cystic duct and the common hepatic duct
- this duct travels down and transports bile to the hepatopancreatic ampulla
pancreas
- a mixed gland that contains exocrine and endocrine portions
- is lumpy and has nodular texture
- a large gland behind the stomach which secretes digestive enzymes into the duodenum
- contains the islets of Langerhans which secrete insulin and glucagon into the blood
pancreatic duct
delivers the enzymes and buffers into the lumen of the SI and it meets up with the common bile duct at the heptopancreatic ampulla
pancreatic acini
these are the cells of the exocine pancreas
- they produce the pancreatic juice
pancreatic juice
the mixture of buffers and digestice enzymes that are discharged into the duodenum
biliary apparatus
Structures concerned with secretion and excretion of bile; includes liver, gallbladder, and hepatic, cystic, and common bile ducts.
- the right and left hepatic ducts
- Common hepatic duct
- Common bile duct
- Pancreatic duct
- Hepatopancreatic ampulla
common hepatic duct
this is the duct that allows bile to leave the liver
- it is formed by the mergence of the left and right hepatic ducts
the left and right hepatic ducts
- these drain bile from the right functional lobe of the liver and left functional lobe of the liver
- these merge to form the common hepatic duct
hepatopancreatic ampulla
this is a widening where the common bile duct and the pancreatic duct merge prior to entering the duodenum
umbilical region
this is the center region
- this is over where the belly button is
epigastric region
this is the top center region
-this is directly over the umbillical region
hypogastric region
this is the bottom center region on the abdomen
- this is below the umbilical region
right and left hypochondriac region
- these are the left and right regions that are on the top row
- think about the fact that they are by the ribs and the ribs are held by cartilage
right and left lumbar regions
- these are the left and right regions in the middle row
- think about the fact that they are near the lumbar spine
right and left inguinal regions
- these are the left and right regions on the bottom row
- think about the fact that they are near the inguinal ligament
forgut
esophagus, stomach, gall bladder, liver, spleen, duodenum (1st and 2nd parts)
midgut
duodenum (3rd and 4th parts), jejunum, ileum, cecum, appendix, ascending colon, transverse colon (proximal 1/3)
hindgut
transverse colon (distal 1/3), descending and sigmoid colon, rectum
what are some of the protections that the digestive tract has to protect itself
- there are chemicals that are secreted that counter the harsh chemicals that are used to break down food
- the epithelium lining is replaces very frequently
- there is GALT to combat incoming pathogens
GALT
gut associated lymphatic tissue
pirus patches
esophageal hiatus
this is an opening in the diaphragm that the esophagus is able to pass through to get to the stomach
superior innervation of the the esophagus
this is somatic
- the upper part is composed of skeletal muscle and we can control when it contracts
- deciding to swallow
inferior innervation of the the esophagus
this is innervated by the esophageal plexus
- the inferior esophagus is smooth muscle and this is under parasympathetic and sympathetic control
parasympathetic control over the inferior esophagus is from what nerve(s)
- this is innervated with the vagus nerve
sympathetic control over the inferior esophagus
- traveling through the post ganglionic sympathetic pathway and fibers travel superiorly in the sympathetic chain
- these synapse within the chain in the middle or inferior cervical ganglion and leave and enter the esophageal plexus
what do mucus glands do for the esophagus
these secrete mucus to help lubricate the food being swallowed
- the ones in the inferior region secrete a bicarbonate based mucus that leads protection from the acidic contents of the stomach
describe the muscularis externa of the esophagus
- the superior 1/3: skeletal muscle
- middle 1/3: mix of smooth and skeletal muscle
- inferior 1/3: smooth muscle
describe the way the epithelium changed throughout the esophagus
- it begins as stratified squamous non-keritinized epithelium
- it changed to simple columnar epithelium near the junction between the esophagus and the stomach
- as it gets closer to the stomach, it becomes more cuboidal and then eventually columnar
superior esophageal sphincter
this is a junction of the pharynx and the esophagus
- not very prominent or strong
- regulates what enters esophagus as we swallow
esophageal glands proper
- these are superior in the esophagus
- secrete substances that lubricate and help protect from mechanical stresses as food passed through
esophageal cardiac glands
these are closer to the stomach
- these secrete basic substances
- secrete these substances that protect against the harsh chemicals of stomach (this is why the epithelial cells switch to columnar because those are specialized for secretion)
inferior esophageal sphincter
- this is the junction of the esophagus and the stomach
- this regulates the passage of food into the stomach and helps prevent he regurgitation of stomach acid back into the esophagus
what does the diaphragm do for protection
this helps support the lower esophageal sphincter
esophageal plexus
this is where the nerve fibers pass through that are innervating the esophagus
esophageal branches of the aorta
these are the arteries that supply the esophagus with oxygen rich blood
greater curvature
this is the lateral side of the stomach
stomach
- this is where the bolus is turned into chyme
- lines with simple columnar epithelium
- it is intraperitoneal
- stores food for 4 hours
- has limited absorption of nutrients (alcohol and some drugs)
- performs physical and chemical digestion
lesser curvature
this is the medial side of the stomach
rugae
- coiled sections of tissue that exist in the mucosal and submucosal layers of the stomach.
- allow for expansion of the stomach after the consumption of foods and liquids.
chyme
the digestive contents that leave the stomach and enter the small intestine
surface mucus cell
- these produce an alkaline fluid with mucus
- a protective layer over the surface of the epithelium
- these are on the surface facing the lumen and not in the gastric pits
mucus neck cells
- these secrete acidic fluid with mucin
- these are in the neck of the gastric pit
- the fluid attaches to the bolus and lubricates the contents of the stomach, not the stomach itself
parietal cell
releases intrinsic factor and hydochorlic acid
- these are within the gastric glands of the gastric pits
intrinsic factor
this assists in the absorption of vitamin B 12 in the small intestine
- this becomes active once it travels with the chyme into the small intestine
- vit B12 is really important for the making of RBC
what does HCL do
this helps kill microorganisms
- helps breakdown the plant cell walls and breaks down the connective tissue in meat and it denatures proteins
enteroendocrine cells
- these are within the gastric gland of the pit
- these release gastrin
- this is released when food enters the stomach
gastrin
- this stimulates the parietal cells and chief cells to secrete their substances and the smooth muscle in the muscle wall to churn to get mechanical digestion
cheif cells
these are within the gastric gland of the pit
- secretes pepsinogen and gastric lipase
pepsinogen
- this is an inactive coenzyme that gets activated by HCl to become pepsin
gastric lipase
- helps to digest fat
- really mostly active in infants
superior mesenteric vein
- is a blood vessel that drains blood from the small intestine (jejunum and ileum)
- its termination behind the neck of the pancreas, the superior mesenteric vein combines with the splenic vein to form the hepatic portal vein.
inferior mesenteric vein
a blood vessel that drains blood from the large intestine.
- It usually terminates when reaching the splenic vein, which goes on to form the portal vein with the superior mesenteric vein
gastric and splenic veins
these drain the stomach and lower esophagus
celiac trunk
- a major artery that supplies the foregut of the gastrointestinal tract
- this branches of the descending aorta
- this branches into the left gastric artery, the splenic artery, and the common hepatic artery
superior mesenteric artery
supplies arterial blood to the organs of the midgut
- a branch off of the descending aorta
inferior mesenteric artery
- supplies the hind gut
supplying the large intestine from the distal transverse colon to the upper part of the anal canal
what causes gastric ulcers
- caused by excessive acid or if the epithelium is not replaced at a fast enough rate
- caused by taking too many NSAIDs or H. Pylorie bacteria
- sores of the mucosea exposed to gastric secretions
small intestine
- where most nutrient absorption occurs here
- this is where chemical digestion is finished
- has three sections
circular folds
slow the passage of food along the intestines and afford an increased surface for absorption. They are covered with small finger-like projections called villi.
what are things that increase the surface area
- the circular folds which are covered by villi which are covered by absorptive enterocytes which have microvilli across them
enteroendocrine cells
these secrete hormones to the gall bladder and the pancreas to cause the secretion of substances to aid in digestion
what do the pyrus patches do in the small intestine
these allow for a quick immune response if there is a pathogen that is absorbed
duodenal papilla
this is where bile and pancreatic secretions enter the duodenum
- this is between the 2nd and 3rd parts of the duodenum
what is the importance of the 2nd and 3rd part of the division of the duodenum
this is the division of the forgut and the midgut
duodenum
the first part of the small intestine immediately beyond the stomach
Duodenojejunal fissure
the border between the duodenum and the jejunum
jejunum
- middle portion of the small intestine
- primary region for chemical digestion and nutrient absorption
ileum
- this is the last segment of the small intestine
- ends at the ileocecal valve
Ileocecal valve
this separates the small intestine (ileum) and the large intestine
- this is a sphincter
alpha cells
these are cells within the pancreatic islets
- they secrete glucagon
beta cells
these are cells within the pancreatic islets
- they secrete insulin
large intestine
- absorption of water
compacts and solidifies undigestible wastes into feces
-stores feces until defecation
-has mass peristaltic movements
teniae coil
this is the line that runs the length of the large intestine
- there are three of these and they lead to the shortening of the large intestine
haustra
the bulges of the large intestine that are created from the shortening of the large intestine from the teniae coil
omental appendices
globs of fat hanging off the LI
- we do not know the function of these
- are a good identifying structure of the LI
what are the different parts of the large intestine
- Cecum
- Ascending colon
- Right colic flexure
- Transverse colon
- Left colic flexure
- Descending colon
- Sigmoid colon
- Rectum
Transverse mesocolon
- the part of the mesocolon (the mesentery) that supports the transverse colon
rectal valves
3 transverse fold that ensure fecal matter is retained within the rectum when someone is passing gas
anal canal
- this is the last 3 cm of the large intestine
anal sinuses
these secrete mucin for lubrication during defecation
anal columns
a number of vertical folds, produced by an infolding of the mucous membrane and some of the muscular tissue in the upper half of the lumen of the anal canal
internal anal sphincter
- this is smooth muscle
- this is under parasympathetic and sympathetic control
external anal sphincter
- this is skeletal muscle
- this is under voluntary control
parasympathetic innervation of the anal canal and internal sphincter
- this stimulates the contraction of the rectal walls and relaxes the internal anal sphincter
sympathetic innervation of the anal canal and internal sphincter
- this causes constriction of the internal anal sphincter
