Digestive Flashcards
what is the alimentary canal
the digestive tract (food enters the body and solid waste is expelled)
what is the average length of the alimentary canal
about 40ft long
what is the length of the small intestine
15ft
what is the length of the colon
3ft
what is the average time of transit for food through the body
about 40 hours
what would stall the transit of food
opiates or other medications, state of health, type of food eaten
where does absorption of nutrients occur
in the small intestine
how many external layers are in the alimentary canal
4, mucosa, submucosa, muscularis, and serosa
what is the mucosa layer of the alimentary canal
the innermost epithelial layer, high turnover, single layer
what is the submucosa layer of the alimentary canal
just external to the mucosa, contains blood vessels, nerves, glands, and lymphatic vessels
what is the muscularis layer of the alimentary canal
it is smooth muscle, circular and longitudinal, autonomic, constant movement, surrounds the submucosa
what is the serous layer of the alimentary canal
the outermost layer of the tube, lined by a serous membrane- peritoneum
what is the “second brain”
the digestive system, it has about as many neurons as the brain
why is a perforating ulcer life threatening
digestive juices and food enter the abdomen
what are serous membranes
they secrete lubricating fluids
what are the 4 types of serous membranes
peritoneum, mesentery, omentum, and retroperitoneum
what is pertioneum
a serous membrane that lines the walls of the abdominal cavity, single layer (visceral and parietal)
what is mesentery
a double layer of peritoneum, connects the intestines to the dorsal abdominal wall
what is the omentum
4 layers (double the mesentery), support and cushioning
what is retroperitoneum
the space between the peritoneum and the posterior abdominal wall that contains the kidneys
what is the esophagus
muscular tube which food passes from the pharynx to the stomach
what pushes food down the esophagus
peristalsis not gravity
what is the default position of a sphincter
closed- open when activated (autonomically controlled)
where is the cardiac sphincter
between the esophagus and the stomach
what is GERD
gastroesophageal reflux disease- leakage back into the esophagus
how much can the stomach normally hold
about 1 liter
what is the function of the stomach
it is mainly a holding tank, it does start digesting the tough stuff/proteins
what is the acid level in the stomach
about 2.0 pH very strong
what protects the stomach from the strong acid produced
a heavy mucous layer is secreted
why do people develop stomach ulcers
it is a high risk area, lots of turnover
where is the pyloric sphincter
between the stomach and small intestine
what is an ulcer
discontinuity or break in a membrane, not caused by stress
what is the duodenum
the first section of the small intestine
what does the duodenum do
it adds sodium bicarbonate to neutralize stomach acid and begins to digest food
where is the gall bladder
under the liver and connects to the duodenum
what is bile
dark green, yellowish brown fluid produced by the liver to aid in digestion of lipids in the small intestine
what does the pancreas do
produces enzymes that are going to be dumped into the small intestine to help with digestion
what does the liver do
detoxifies, protein synthesis, and produces bile
what is hepatitis
liver inflammation, can be caused by alcoholism or drug abuse
what is cirrhosis
scaring of the liver due to chronic inflammation
what is a side effect of cirrhosis
jaundice (yellow pigmentation of the skin, can be seen on sclera)
what does the small intestine do
constant peristalsis, adds water and enzymes, main job is absorbing nutrients
how big is the small intestine diameter
about 1 in
what happens if the small intestine gets twisted
it will become ischemic and die
where is the ileocecal valve
from small intestine to the large intestine
what do intestinal villi and microvilli do
located in the intestinal wall to increase surface area and increase absorption
what is the hepatic portal system
a system of veins that direct blood from the gastrointestinal tract to the liver
what are the 4 parts of the colon
ascending, transverse, descending, and sigmoid
how big is the diameter of the colon
3 in
does the colon do peristalsis
no, it only has weak muscles to massage what is inside
what is the main job of the colon
to reabsorb the water that the small intestine added
how does the colon move the waste
through ambulation (walking)
how much of the feces is bacteria
about 2/3 (alive and dead)
where is the cecum
the beginning of the colon, it is a blind area/dead end
where is the rectum
the final straight portion of the large intestine, temporary storage point for feces
where is the appendix
at the junction of the small and large intestine, in the lower right abdomen (4in long)
who typically gets their gall bladders removed
late 20 year old females
what happens to the bile after the gall bladder is removed
it is constantly released as a steady stream (eating fatty foods is problematic)
