Digestive System

describe the three stages of metabolism

(1) digestion, transport absorbed nutrients to tissue cells via blood (2) anabolic pathways within the cells cytoplasm, where nutrients are built into cellular molecules-or- catabolic pathways, where nutrients are broken down to simpler form (3) catabolic pathway within the mitochondria of cells, which completes the breakdown of newly digested or stored foods. this produces CO2 and water and harvests large amounts of ATP.

A mucosal barrier of the stomach is created by what four factors?

(1) thick coating of mucus on stomach wall (2) epithelial cells of mucosa are joined together by tight junctions that prevent gastric juices from leaking into tissue (3) where protective mucus is absent, plasma membrane is impermeable to HCl (4) stomach surface epithelium is completely renewed every 3-6 days

the syloric region of the stomach acts as a "dynamic filter" allowing only liquids and small particles to pass through the barely open pyloric valve. only (?) of chyme goes through the sphincter at a time. the rest of the chyme is propelled back into the stomach for further mixing to break up solids. the more food in the stomach, the more vigorous the stomach mixing and emptying

3 ml

How many ATP molecules are formed during aerobic respiration?

36-38

the substrate level phosphorylation is the conversion of (?) to (?). this occurs after one step of glycolysis and after one turn of the Krebs cycle.

ADP to ATP

most foods are used as metabolic fuels. they are oxidized and transformed into (?)

ATP

nutrients absorbed by active transport are driven by (?), through the villi and into the capillary blood.

ATP

the (?) are located in the duodenum only. these glands produce alkaline (bicarbonate rich) mucus. it neutralizes the acidic chyme moving in from the stomach

Brunner's glands

the large intestine contains (?) which breaks down cellulose, synthesizes vitamin K, B12, Thiamine and Riboflavin

E. coli bacteria

the (?) cycle breaks down acetyl CoA. its carbon atoms are liberated to CO2 and its hydrogen atom is removed and delivered to the electron transport chain

Krebs cycle

the oxidative phosphorylation is the (?) which releases ATP

Krebs cycle

the (?) are aggregates of lymph nodules that increase in abundance toward an end of the small intestine. this is due to the high bacteria content of the chyme as it comes to the end of the ileum. each lymph nodule is a clot of macrophages.

Peyer's patches

only small quantities of water, glucose, salts, alcohol and lipid soluble drugs are (?) within the stomach.

absorbed

(?) is the passage of digested end products (plus vitamin, minerals and water) from the GI tract into the blood or lymph. this occurs by products entering mucosal cells by active or passive transport processes.

absorption

proteins, broken down to amino acids, are absorbed by (?).

active transport

carbohydrates (simple sugars) are absorbed by (?) or (?).

active transport and facilitated diffusion

(?) is when food fuels (glucose) are broken down within the cells and some the energy released is captured to form ATP.

aerobic repiration

another name for the digestive tract is the (?) canal. it is approx a 30 ft long tube.

alimentary canal

The pancreas secretes a broad spectrum of hormones and digestive enzymes capable of digesting (?).

all food groups

the (?) rule of protein is that "all amino acids needed to make a particular protein must be present in a cell at the same time and in sufficient amounts." If not, proteins cannot be stored and are therefore used for energy or converted into carbs or fats.

all-or-none

during primary metabolism, nutrients are incorporated into cellular molecules by a process called (?). or nutrients may be broken down via glycolysis by the process called (?)

anabolic/ catabolic

the pancreas also secretes (?) which neutralizes stomach acid.

biarbonate

the duodenum recieves (?) from the liver and (?) from the pancreas at the hepatopancreatic ampulla

bile/ pancreatic juices

chemical digestion of (?) first occurs in the mouth, with salivary amylase breaking down starch and glycogen. the small intestine continues the chemical digestion process by use of pancreatic amylase and secreting intestinal enzymes.

carbohydrates

Pancreatic amylase breaks down (?), pancreatic lipase breaks down (?) trypsin, chymotrypsin and carboxypeptides each break down a specific type of (?)

carbohydrates/ fats/ protein

each villi of the small intestine contains 2 blood capillaries, a venous and artery and a lymph capillary. the venous capillary absorb the breakdown of (?) and (?), whereas the lymph capillary (lacteal) absorbs (?)

carbohydrates; protein; fat

the (?) sphincter controls the chyme from re-entering the esophagus

cardiac

when gastric juices are secreted in response to the parasympathetic reflexes triggered by sight, taste, smell and thought, the (?) phase is occurring

cephalic phase

name the three phases of gastric secretion

cephalic phase, gastric phase, intestinal phase

when complex food molecules are broken down to their monomers (chemical building blocks) by the enzymes secreted by various glands, (?) digestion is occurring.

chemical

bile is releases when the gall bladder us stimulates by the hormone (?), secrete by the small intestine

cholecystokinin

in the stomach, food transported by the esophagus is mixed with gastric juices and converted to a creamy paste called (?)

chyme

the (?) duct combines secretions from the lover, gall bladder and pancreas and delivers them to the duodenum

common bile duct

the (?) glands secrete intestinal juice t/o the entire small intestine. this secretion is a watery mixture containing mucus that serves as a carrier fluid for absorption of nutrients and chyme

crypts of Lieberkuhm (intestinal glands)

the small intestine completes (?) and is the most important absorbong organ. very little absorbable material reaches its distal end

digestion

when stimulates, receptors initiate reflexes to activate or inhibit glands that secrete (?) juices into lumen, or mix lumen contents and move them along the length of tract by stimulating (?) of GI tract walls.

digestive juices/ smooth muscle

the stomach usually empties completely within 4 hours after a meal. however, the rate of gastric emptying depends on the contents of the (?)

duodenum

in what two regions does most of the absorption occur within the GI tract?

duodenum and jejunum

the small intestine is divided into what three secretions?

duodenum,jejunum,ileum

(?) cells release the hormones gastrin, intestinal gastrin, enterogastrones, secretin and cholecystokinin. These hormones diffuse into the blood capillaries and influence several digestive system target organs.

enteroendocrine cells

when there is a high fat content in the intestine, the hormone (?) is released which causes a decrease in gastric juice secretion, which inhibits peristalsis. this process gives the small intestine more time to break down the fat.

enterogastrone

bile breaks up (?) into tiny particles so they are more accessible to digestive enzymes. It also creates a salty environment, which enzymes prefer.

fat

carbs moves thru the duodenum rapidly, however (?) are digested more slowly and can remain in the stomach for six or more hours

fats

fats are broken down into (?) and (?) by pancreatic enzymes. they enter the epithelial cell, where the E.R. uses the fatty acids to synthesize triglycerides. Fatty globules combine with protein to form chylomicrons.

fatty acids and glycerol

The (?) is a storage organ for bile between meals to concentrate it.

gall bladder

bile is a major vehicle for cholesterol excretion from the body. bile slats keep the cholesterol dissolved within the bile. too much cholesterol or too few bile salts can lead to crystallization of cholesterol, forming (?) which obstruct the flow of bile from the gall bladder.

gall stones

(?) is formed from the combination of pepsinogen. HCl, pepsin< mucus, intrinsic factor and gastric lipase, and is secreted into the lumen of the stomach via gastric glands and pits

gastric juice

when the food within the stomach stimulates release of more gastrin into the blood, which in turn stimulates secretion of gastric juices, the (?) phase is occurring.

gastric phase

persistent damage to underlying tissues can cause erosions of the stomach wall called (?)

gastric ulcers

ATP is formed from what three processes within aerobic respiration?

glcolysis, Krebs cycle, electron transport chain

when the stored glucose has diminished and the blood glucose levels have declined, (?) occurs, which is the process of forming new sugar from noncarbohydrate molecule. (ex. glycerol and amino acids are converted to glucose.)

gluconeogenesis

During carbohydrate metabolism, when there are already high ATP level, (?) occurs, which is the conversion of glucose into glygogen for storage or for liver and skeletal muscle

glycogenesis

during carbohydrate metabolism, when blood glucose drops, (?) occurs, which is the break down of glycogen to release glucose.

glycogenolysis

the pits of the colon are heavily covered with (?) which secrete mucus to protect it's lining and to hold the fecal material together.

goblet cells

parietal cells release (?)

hydrochloric acid and intrinsic factor (glycoprotein required for absorption of B12 in the small intestine)

by the time the chyme reaches the (?) its major absorptive role is reclaiming bile salts to be recycled back to the liver for further secretion.

ileum

describe the six activities of the digestion process

ingestion, propulsion, mechanical digestion, chemical digestion, absorption, defecation

when the duodenum is filled with chyme, the internal pressure increases which stimulates wall receptors and triggers enterogastric reflexes, which inhibits (?)

inhibits the parasympathetic NS from acting on stomach, which inhibits peristalsis, which causes the stomach to move slower, which causes the intestines to fill less rapidly

as food enters the small intestine, cells in the intestinal mucosa release intestinal gastrin, which promotes secretion of gastric juices within the stomach, this phase is called (?)

intestinal phase

blockage of bile ducts prevents bile salts and bile pigments from entering the intestine. the result f this is (?) due to yellow bile pigment accumulating in the blood and eventually depositing into the skin.

jaundice

chylomicrons are absorbed by the (?). the smooth muscle contractions cause the lymph capillary to transport chylomoicrons into the blood stream, which then goes to adipose tissue.

lacteal

the chemical breakdown of lipids begins in the small intestine where pancreas secretes fat digesting enzymes called (?). Large fat globules are formed and broken up in the duodenum by the use of bile salts. the globules form fatty droplets.

lipase

The (?) produces bile for export to the duodenum.

liver

chewing, mixing food with saliva using the tongue, churning food within the stomach, segmentation (rhythmic local constrictions) of the intestines are all examples of (?) digestion.

mechanical digestion

once inside the cell, nutrients become involved in biochemical reactions to maintain the homeostasis of life. This process is called (?)

metabolism

the (?) also called "Brush Border", amplifies the absorptive surface and contains enzymes which complete the final stages of digestion of carbs and proteins in the small intestines

microvilli

name the six regions of the true digestive tract

mouth, pharynx, esophagus, stomach, small intestines, large intestine

when the pancreas secretes (?) it is breaking down nucleic acid which becomes sugar, phosphate, and nucleotide (base, which mostly goes to uric acid)

nucleases

chemical digestion of proteins begins in the stomach with the digestive enzyme (?). The small intestine secretes pancreatic enzymes and then intestinal enzymes reduce proteins down to their amino acids.

pepsin

chief cells secrete (?)

pepsinogen (protein digesting enzyme)

swallowing is an example of propulsion within the pharynx (process of moving food through the alimentary canal) What is the form of propulsion that occurs within the remainder of the digestive tract?

peristalsis

the (?) of the small intestine, force the chyme to spiral through the lumen to continually mix with the intestinal juices and to slow its movement. this allows for full nutrient absorption

plica circularis

the digestion process of the pharynx and esophagus is (?), accomplished by the act of swallowing and serving as conduits to pass food from mouth to stomach. food is rolled into a mass called the bolus.

propulsion

(?) digestion is initiated in the stomach and is the only type of enzymatic digestion that occurs in the stomach.

protein

the (?) sphincter performs as a valve which controls stomach emptying.

pyloric sphincter

glycolysis breaks glucose down to (?) and (?)

pyruvic acid and acetyl CoA

Name the four functions of the digestive system

receiving, transporting, digesting, and absorbing food

the salivary glands contains the first digestive enzyme, (?) which breaks down carbohydrates into sugars (starch into glucose)

salivary amlase

the hormone (?) is secreted from the duodenal walls which causes the pancreas to secrete bicarbonate ion to neutralize acid entering the intestine

secretin

the stretching of the organ wall by food products, osmolarity (solute concentration) pH of the food contents and presence of substrates and end products of digestion are all(?) which alert sensors located in the walls of GI tract organs to initiate reflexes.

stimuli

the (?) is a temporary "storage tank" for food, where the chemical breakdown of proteins begins.

stomach

the chemical breakdown of nucleic acids is to break down the acid into nucleotides and the nucleotides are then broken up by intestinal brush border enzymes. these enzymes release the (?), (?) and (?) from the nucleotide.

sugar, phosphate, base

name the three functions of the tongue

taste, initiate swallow reflex, chewing

name the six accessory digestive organs

tongue, teeth, salivary glands, liver, gull bladder, pancreas

gastric secretion is regulated by neural control from the (?), of which it's impulse stimulates hormonal control by release of the hormone (?) into the blood

vagus nerve of the parasympathetic NS/ gastrin

the (?) contains the absorpative columnar cells. it also contains the lactgeal and a line of smooth muscle which allows it to lengthen and shorten, increasing the amount of contact with the nutrients.

villi

(?) is the most abundant substance in chyme. 80-95% of it is absorbed in the small intestine by osmosis.

water

the main function of the large intestine is to absorb (?) electrolytes. it eliminates all that can't be absorbed by the small intestine

water, electrolytes

at the end of the ilieum, all that remains is (?), (?) and (?). these remaining items are then transferred to the large intestines.

water, indigestible food materials (cellulose) and bacteria