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90 terms

Ch. 25 Digestive System

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Ingestion
intake of food
digestion
breakdown of molecules
absorption
uptake nutrients into blood/lymph
defecation
elimination of undigested material
rennin
a milk protein digesting enzyme in children uncommon in adults
vestibule
area between lips and teeth
churning action of stomach
layer of smooth muscle
accessory organs
teeth, tongue, liver, gallbladder, pancreas, salivary glands
tongue
mixes the food in the mouth
visceral peritoneum
serosa of stomach and intestines
parietal
serosa of abdominal wall
lesser omentum
attaches stomach to the liver
greater omentum
covers small intestines like an apron
mesentery of small intestine
holds many blood vessels; suspends small intestine from posterior body wall
tongue
sensitive, muscular maipulator of food
hard and soft palate
-uvula is here
-allow breathing and chewing at the same time
hard and soft palate
anterosuperior boundary of oral cavity
amylase
begins starch digestion
salivation
gum chewing is a mechanical stimulus to help prevent dry mouth
esophagus
-food chute
-straight muscular tube 25-30 cm long
pharynx
common passageway for food and air
stomach
mechanically breaks up food particles, liquifies the food and begins chemical digestion of protein and fat
chyme
soupy mixture from the stomach
pylorus
opening to duodenum (pyloric sphincter)
mucous cells
secrete muscus and consist of folds called rugae
HCl acid and intrinsic factor
gastrin causes an increase hormonal response
functions of hydrochloric acid
activates enzymes pepsin and lingual lipase
pepsin
-chief cell, protein digestion
-secreted as pepsinogen (an inactive zymogen)
-HCl converts it to pepsin (active form)
-pepsin then activates more pepsinogen
lipase
-digests butterfat of milk in infants (Rennin)
-comes from the pancreas
cephalic phase
vagus nerve stimulates gastric secretion and motility just with sight, smell, taste or thought of food (psychological)
liver secretion
causes liver to increase bile output
cholecystokinin
causes release of bile
gallbladder
-sac on underside of liver
-stores and concentrates bile
bile
-yellow-green fluid containing minerals, bile acids, cholesterol, bile pigments and phospholipids
-between meals, it is concentrated by factor of 20
pancreas
-protein digesting enzymes amylase and nucleases
-pancreatic juice into duodenum
hormone control by
cholecystokinin and secretin
small intestine
nearly all chemical digestion and nutrient absorption occurs here
lleocecal valve
separates small intestine from large
plicae circularis
circular folds of small intestine; up to 10mm tall
villi
-fingerlike projections 1 mm tall
-contain blood vessels and lymphatics
microvilli
-1 micron tall
-brush border on cells
-brush border enzymes for final stages of digestion
peyer patches
-populations of lymphocytes to fight pathogens
-also known as collection of lymphatic tissue
intestinal motility
intestinal juice, bile and pancreatic juice
digestion
occurs as food is broken down both chemically and mechanically
mesentery
structure that suspends the small intestine from the posterior body wall
oral cavity, stomach
two anatomical regions involved in the physical breakdown of food
three extensions/modifications of the peritoneum
greater omentum, lesser omentum, mesentery
esophagus
literally a food chute, no digestion or absorption occurs
rugae
folds of the stomach mucosa
haustra
saclike outpocketings of the large intestine wall
microvilli
projections of the plasma membrane of a cell that increase the cells surface area
ileocecal valve
prevents food from moving back into the small intestine once it has entered the large intestine
small intestine
organ responsible for most food and water absorption
colon
organ primarily involved in water absorption and feces formation
appendix
blind sac hanging from the initial part of the colon
stomach
organ in which protein digestion begins
lesser omentum
membrane attached to the lesser curvature of the stomach
small intestine
organ in which the stomach empties
pyloric sphincter
sphincter, controlling the movement of food from the stomach into the duodenum
soft palate
uvula hangs from its posterior edge
small intestine
organ that receives pancreatic juices and bile
parietal peritoneum
serosa of the abdominal cavity wall
anal canal
region containing 2 sphincters, through which feces are expelled from the body
hard palate
anterosuperior boundary of the oral cavity; supported by bone
ingestion
eating
propulsion
includes swallowing, segmentation and peristalsis
mechanical digestion
chewing, churning
chemical digestion
enzymatic breakdown
absorption
transport of nutrients from lumen to blood
defecation
elimination of feces
salivary amylase
starch digestion begins in the mouth when ___ is ducted in by the salivary glands
hormonal stimulus
gastrin, which prods the stomach glands to produce more enzymes and HCl represents a ___
psychological stimulus
the fact that the mere thought of a relished food can make your mouth water is an example of ___
mechanical stimulus
many people chew gum to increase saliva formation when their mouth is dry. This is an example of ___
pepsin
protein foods are largely acted on in the stomach by ___
HCl
for the stomach protein-digesting enzymes to become active, ___ is needed
mucus
since living cells of the stomach are largely protein, it is amazing that they are not digested by the activity of stomach enzymes. The most important means of stomach protection is the ___ it produces
rennin
a milk protein-digesting enzyme found in children but uncommon in adults
churning
the third layer of smooth muscle found in the stomach wall allows mixing and mechanical breakdown by ___
brush border enzymes
important intestinal enzymes
bicarbonate-rich fluid
the small intestine is protected from the corrosive action of hydrochloric acid in chyme by ___, which is ducted in by the pancreas
lipases
the pancreas produces protein-digesting enzymes, amylase and nucleases. It is the only important source of ___
bile
a nonenzyme substance that causes fat to be dispersed into smaller globules
cholecystokinin and secretin
these two hormones stimulate the pancreas to release its secretions
gastrin
this hormone stimulates increased production of gastric juice
cholecystokinin
this hormone causes the gallbladder to release stored bile
secretin
this hormone causes the liver to increase its output of bile
fructose, galactose, glucose
the building blocks of carbohydrates are monosaccharides, or simple sugars. The three common simple sugars in our diet are __, __, __
fatty acids
fats are broken down to two types of building blocks, __ and glycerol
glucose
of the simple sugars, ___ is most important because it is the sugar referred to as "blood sugar"