Digestive system Flashcards
digestive system extracts nutrients from food and –
eliminates wastes
digestive system is set up as a series of modified – to keep food and digestive enzymes sequestered from the body
tubes
digestive tract is also known as the – tract
gastrointestinal
accessory structures of the GI tract include the liver, gallbladder, and –
pancreas
three primary components of diet that require digestion are carbohydrates, proteins, and –
fats
– digestion of food by chewing
mechanical
– digestion of food by digestive enzymes
chemical
– of nutrients into the bloodstream
absorption
– of waste products
elimination
T/F: any contact of the digestive enzymes with the rest of the body could result in the self-digestion of tissues
true
digestive system is an open system that is vulnerable to –
infectious organisms
the digestive tubes are composed of – tissue layers
four
– is a mucous membrane that actually comes in contact with food
mucosa layer
mucosa layer serves as a – and protects against desiccation, abrasion, and digestive enzymes
lubricant
mucosa lack – and nerve endings
blood vessels
submucosal layer contains blood vessels, –, and nerve endings
lymphatic vessels
submucosal layer’s primary function is to support the mucosa and to – materials to the bloodstream
transport
muscularis layer is composed of two layers of – muscle that run in opposite directions
smooth
nerve endings in the submucosa serve to stimulate the muscularis to produce contractions called – that propel food through the system
peristalsis
– is a thin connective tissue layer that is found on the surface of the digestive tubing
serosa
serosa’s purpose is to – with other surfaces in contact with the GI tract
reduce friction
oral cavity > – > stomach
esophagus
small bits of stomach contents are released to the – which completes digestion with some help from secretions from liver and pancreas
small intestine
in the small intestine, nutrients are – into the bloodstream
absorbed
waste products of digestion are solidified in the – and are released after
large intestine
as food is ingested and enters the mouth, there are – sets of salivary glands that begin to secrete saliva
three
in addition to its lubricating function, saliva contains enzyme – which begins the chemical breakdown of carbohydrates such as starch
amylase
T/F: since food does not stay in the mouth for long, amylase rarely gets to complete its job in the oral cavity
true
as food is ready to be swallowed, it must pass by the –
pharynx
pharynx has one opening to the – and one to the esophagus
larynx
when food touches the pharynx, a reflex action occurs that pushes the – over to cover the glottis of the larynx
epiglottis
once in the esophagus, muscular contractions will force food toward the stomach by –
peristalsis
stomach is relatively a small, curved organ when empty but is capable of great expansion when full of food due to – in its interior lining
many folds
the top and bottom of the stomach are guarded by a –
muscular sphincter
the stomach is very unique in that it has a very – environment
acidic
T/F: the stomach must retain its own secretions
true
top sphincter opens to allow – of food to enter
bolus
once inside the stomach, food will be mixed with – to liquefy it and initiate chemical digestion of proteins
gastric juice
the hormone – signals the gastric glands of the stomach to begin producing gastric juice as well as for the stomach to tart churning
gastrin
gastric juice is composed of a mixture of – to protect the stomach lining from being digested itself
mucus
gastric juice is composed of – which is an inactive form of the enzyme that digests protein
pepsinogen
gastric juice is composed of – which is needed to activate pepsinogen
hydrochloric acid
– is the active form of pepsinogen
pepsin
hydrochloric acid secreted in the stomach provides an overall pH of –
1 to 2
unlike other enzymes, pepsin is inactive except at a – pH
low
low pH of the stomach also kills most – that entered the digestive tract with the food
infectious agents
as the food mixes with gastric juice, the resulting liquid is called –
chyme
depending on the size and nutritional content, it takes on average about – hours for the stomach to empty its contents into the small intestine
four
chyme leaves the stomach in small burst as the bottom sphincter called – opens
pyloric sphincter
small intestine is about – long
six meters
as small amounts of chyme leave the pyloric sphincter, it enters the top region of the small intestine called –
duodenum
it’s important to neutralize the acidity from gastric juice by the secretion of – from the pancreas into the small intestine
sodium bicarbonate
T/F: the duodenum also receives secretions from the liver which aids in chemical digestion in the middle and end regions of the small intestine
true
middle region of small intestine
jejunum
lower region of small intestine
ileum
liver is composed of several – of tissue and is one of the larger organs
lobes
liver produces – which emulsifies fat
bile
while bile is not an –, it helps break fats into smaller pieces so that they are more susceptible to digestion by enzymes secreted from the pancreas
enzyme
bile contains –, cholesterol, bile pigments, bile salts, and some ions
water
bile is stored in the – which is a small structure on the underside of the liver
gallbladder
bile is released into the small intestine based on signals from the hormones – and cholecystokinin (CCK) via the common bile duct as food enters the small intestine
secretin
after the absorption of nutrients, blood from the capillaries of the GI organs and spleen will travel directly to the – via the hepatic portal vein
liver
once in the liver, the – levels of blood with be regulated
glucose
when blood glucose levels get high, the liver will store the excess as glycogen under the influence of –
insulin
when blood sugar levels are low, the liver will break down glycogen to release glucose under the influence of –
glucagon
liver also packages lipids in – to allow them to travel throughout the body
lipoproteins
the – within the liver can produce enzymes to detoxify certain harmful substances
smooth ER
liver also stores vitamins A, E, D, and K which are – vitamins
fat soluble
after the regulations in the liver, the blood will leave via – and empty into the inferior vena cava before entering general circulation
hepatic veins
the type of circulation in which blood from the GI organs and spleen is moved through the liver is called – circulation
hepatic portal
pancreas secrete pancreatic juice into the – via the pancreatic duct
small intestine
pancreas has cells with endocrine functions, which are located in areas called – producing insulin and glucagon
islets of Langerhans
pancreas also has exocrine cells that produce pancreatic juice which is secreted when food enters the small intestine as signaled by the hormones secretin and –
CCK
pancreatic juice contain –, amylase, proteinases, lipase, and nucleases
bicarbonate ions
bicarbonate ions act as a – of stomach acid
neutralizer
amylase completes – that began in the oral cavity to release glucose
carbohydrate (starch) digestion
proteinases complete protein digestion that was started in the – to release amino acids
stomach
three proteinases found in pancreatic juice are –, chymotrypsin, and carboxypeptidase
trypsin
breaks down fats to fatty acids and glycerol
lipase
break down DNA and RNA into nucleotides
nuclease
it can take anywhere from – for nutrients to be absorbed from the small intestine
3-10 hours
small intestine has an internal anatomy that makes it well suited for absorption because of its tremendous –
surface area
the mucosa in the small intestine are folded into – which form the brush border
villi
villi are then further folded into microscopic –
microvilli
within each villus, there are capillaries and a – (a lymphatic capillary)
lacteal
nutrients such as glucose and other simples sugars, amino acids, vitamins, and minerals – into the capillaries within each villus, where they are carried into the bloodstream
diffuse
fat products of digestion are assembled into a triglyceride and packaged in a special coating including cholesterol, which creates a –
chylomicron
T/F: chylomicrons can diffuse into the capillaries
false
chylomicrons enter the lacteals and lymphatic fluids will carry chylomicrons to the bloodstream at the – (a merger between the two systems)
thoracic duct
water must be reclaimed by the body which in turn will – the waste products
solidify
large intestine contains a large population of normal – or harmless resident bacteria which synthesize certain vitamins
flora
large intestine has a longer width but is – than the small intestine
shorter
large intestine is about – long
1.5 meters
there are – regions of the large intestine
four
– is the small area where the large intestine connects with the small intestine on the right side of the body
cecum
an outgrowth of the cecum constitutes the –
appendix
appendix is a – structure thought to play a non crucial role in the lymphatic system
vestigial
– is the majority of the large intestine
colon
primary function of the colon
water absorption
T/F: vitamin absorption can occur in colon
true
– ultimate destination for feces in large intestine
rectum
stretching of the rectum stimulates nerves and initiates the – reflex
defecation
– receives the contents of the rectum for elimination
anal canal
– sphincter of the anal canal operates involuntarily
internal
– sphincter of the anal canal operates voluntarily
external
