Digestive System Flashcards
Ingestion occurs
when food enters oral cavity
Digestion and propulsion
Breaking food into nutrient molecules
Propelling food along digestive tract
Absorption
Movement of nutrients into the bloodstream
Defecation
Elimination of indigestible waste
three subdivision of the pharynx
- nasopharynx
- oropharynx
- laryngopharynx
esophagus conducts food by
peristalsis to the stomach
espohagus is located _________ to the trachea
posterior
the stomach is a c-shaped organ located on the _______ side of the abdominal cavity
left
food enters at the ______________ from the esophagus
cardioesophageal sphincter
food empties into the small intestine at the ________
pyloric sphincter valve
internal fold of the mucosa present of the stomach
rugae
gastric glands secrete ____________, including _________, which is needed for _________ absorption in the small intestine
gastric juice, intrinsic factor, vitamin B12 absorption in the small intestine
Parietal cells produce
hydrochloric acid
Functions of the stomach
- temporary storage tank for food
- mechanical digestion
- chemical breakdown of protein
- delivers chyme to the small intestine
- production of intrinsic factor
stomach delivers _____ to the small intestine
chyme
small intestine parts
- duodenum
- jejunum
- ileum
the bile duct and the main pancreatic duct join the ________ via and opening called as __________
duodenum, hepatopancreatic ampulla
Pancreatic ducts carry enzymes to the ______
Pancreatic ducts, duodenum
_______ carries bile, formed by the _____
Bile duct , liver
fingerlike projections formed by the mucosa
villi
tiny projections of the plasma membrane
microvilli
_________ produce alkaline mucus to lubricate the passage of feces.
Goblet cells, lubricate
masticate
chew
Three pairs of salivary glands empty secretions into the mouth
- parotid glands
- sublingual glands
- submandibular glands
function of saliva
helps to moisten and bind food together into a mass called a bolus
saliva contains ________ to begin ________
salivary amylase, starch digestion
chemical digestion in the small intestine relies on the _________ and _______
liver and pancreas.
liver located on the ______ side of the body under the __________
right, diaphragm
liver connected to the gallbladder via
hepatic duct
bile is produced by
cells in the liver
bile leaves the liver through _________ and enter the _______ through the _________
common hepatic duct, duodenum, bile duct
Function of bile
emulsify fats by physically breaking large fat gobules into smaller ones
What are gallstones
gallstones are crystallized cholesterol, which can cause blockages
When no digestion is occuring, bile backs up the ________ for storage in the gallbladder.
cystic duct
the pancreas lies ________ in the retroperitoneum behind the _______.
transversely, stomach
function of pancreas
produces a wide spectrum of digestive enzymes that break down all categories of food . It secretes enzyme into the duodenum
Alkaline fluid introduced with enzymes from the pancreas ______________
neutralizes acid chyme coming from the stomach
is pancreatic fluid alkaline or acidic?
alkaline
hormones produced by the pancreas
Insulin and Glucagon
Ingestion
placing of food into the mouth
propulsion
movement of foods from one region of the digestive system to another
Peristalsis
alternating waves of contraction and relaxation that squeezes food along the GI tract
Segmentation
movement of materials back and forth to foster mixing in the small intestine
Examples of mechanical breakdown
mixing of food in the mouth by tongue
churning of food in the stomach
segmentation in the small intestine
Mechanical digestion prepares food for _________
further degradation by enzymes
type of food breakdown
1) mechanical breakdown
2) digestion
Digestion occurs when enzymes
chemically break down large molecules into their building blocks
carbohydrates are broken to
monosaccharides
proteins are broken to
amino acids
fats are broken to
fatty acids and glycerol
digestion of carbohydrates happens in the
mouth and small intestine
enzymes and source that digest carbohydrates
- salivary amylase
- pancreatic amylase
describe what happens during absorption of carbohydrates
The monosaccharides , glucose , galactose and fructose enter the capillary blood blood in the villi and are transported to the liver via the hepatic portal vein
Examples of brush border enzymes in small intestine
glucoamylase, lactase, maltase, and sucrase
diGESTION of proteins happens in the
stomach, small intestine
enzymes and sources that digest proteins
- pepsin (stomach galnds ) in the presence of HCL
- pancreatic enxymes (trypsin, carboxypeptidase)
- brush border enzymes (aminopeptidase, carboxypeptidase)
Describe what happens during absorption of proteins
amino acids enter the capillary blood in the villi and are transported to the liver via the hepatic portal vein
Digestion of fats occurs in the
small intestine
enzymes and source that digest fats
- emulsified by the detergent action of bile salts from the liver
- pancreatic lipase
describe what happens during absorption of fats
fatty acids and monoglycerides enter the lacteals of the villi and are transported to the systematic circulation via the lymph in the thoracic duct.
Glycerol and short-chain fatty acids are absorbed into the capillary blood in the villi and transported to the liver via the hepatic portal vein
End products of digestion are absorbed in the ________ or______
blood, lymph
food must enter ______ cells and then into _____ or __________
mucosal, blood or lymph capillaries
Defecation
Elimination of indigestible substances from the GI tract in the form of feces
Describe activites occuring in the mouth
- Food ingestion and breakdown happens in the mouth.
- When foods are placed into the mouth, it is physically broken down by chewing.
- When the food is mixed with saliva, which is released in response to mechanical pressure and psychic stimuli
- salivary amylase begins starch digestion
- no food absorption occurs in the mouth
Activities occuring in the pharynx
-swallowing and food propulsion
function of pharynx
pharynx functions in swallowing (deglutition)
functions of esophagus
serves as passageways to the stomach
___________________ causes the release of the hormone gastrin
Presence of food or rising pH
Gastric juice is regulated by
neural and hormonal factor
Gastrin causes stomach glands to produce
protein-digesting enzymes
mucus
HCL
The acidic pH activates ______ to ______ for protein digestion
pepsinogen to pepsin
acidic pH provides a _________ _______________ for microorganism
hostile environment
protein digestive enzymes in the stomach
- pepsin- an active protein-digesting enzyme
- rennin - works on digesting milk protein in infants
Describe what happens in the stomach
Food breakdown occurs in the stomach.
Gastric juice is regulated by neural and hormonal factors
Presence of food or rising pH causes the release of the hormone gastrin
Gastrin causes stomach glands to produce protein-digesting enzymes, mucus and hydrochloric acid
Hydrochloric acids make the stomach contents very acidic which activates pepsinogen for protein digestion and provides a hostile environment for microorganisms
Enzymes such as pepsin and rennin will digest proteins
Alcohol and aspirin are virtually the only items absorbed in the stomach
Waves of peristalsis occur from the fundus to the pylorus, forcing food past the pyloric sphincter
The pylorus meters out chyme into the small intestine
Peristaltic waves close the pyloric sphincter, forcing content back into the stomach.
Hydrochloric acid makes the stomach contents very acidic which
- activates pepsinogen to pepsin for protein digestion
- provides a hostile environment for microorganisms
Peristalsis
Waves of peristalsis occur from the fundus to the pylorus, forcing food past the pyloric sphincter
Grinding
The pylorus meters out chyme into the small intestine
Retropulsion
Peristaltic waves close the pyloric sphincter, forcing content back into the stomach.
Intestinal enzymes from the brush border function to
break double sugars into simple sugars
complete some protein digestion
Alkaline content in the small intestine ______________________________.
neutralizes acidic chyme and provides the proper environment for the pancreatic enzymes to operate
Describe what happens in the small intestine
- Intestinal enzymes from brush border function to break double sugars into simple sugars. Complete some protein digestion.
- Intestinal enzymes and pancreatic enzymes help to complete digestion of all food groups
- Pancreatic enzymes play the major role in the digestion of fats, proteins, and carbohydrates
- Alkaline content neutralizes acidic chyme and provides the proper environment for the pancreatic enzymes to operate
- Water is absorbed along the length of the small intestine
- Most substances are absorbed by active transport through cell membranes
- Lipids are absorbed by diffusion
- Substances are transported to the liver by the hepatic portal vein or lymph
Are there any digestive enzymes produced in the large intestine ?
no
Predict the effect on digestion if the pancreas is unable to make and release pancreatic juices ?
Pancreatic juices are rich in both enzymes and bicarbonate. Without the enzyme-rich pancreatic juice, starch digestion will be incomplete, about half of protein digestion will not occur, all of fat digestion will cease, and nucleic acid digestion will not occur. Bircarbonate-rich pancreatic juice helps neutralize the acidic chyme entering the small intestine from the stomach. Without the alkaline environment in the small intestine, enzymatic activity would not occur.
