Pbd Week 3

Front 1

Conjugated bile acids are dependent on Na/K transport on what area of the hepatocyte?

Back 1

Apical surface

Front 2

What does NTCP stand for?

Back 2

Na dependent taurocholic cotransporting polypeptide

Front 3

How are secondary bile acids produced?

Back 3

Bacteria in the ileum and colon deconjuagte and dehydroxylate them.

Front 4

By deconjugating band dehydroxylating bile acids they become less polar, which does what to their lipid solubility and allows for what type of absorption?

Back 4

Increases their lipid solubility and allows absorption by simple diffusion.

Front 5

Where do bile acids, bound to albumin in the plasma, leave the intestine?

Back 5

In the portal blood

Front 6

What extracts bile acids from the portal blood?

Back 6

Hepatocytes

Front 7

T/F:
In a single pass through the liver the portal blood is barely cleared of bile acid.

Back 7

False:
The portal blood is almost completely cleared of bile acid

Front 8

What controls bile acid synthesis and secretion?

Back 8

The return of bile acid to the liver

Front 9

What is the stimulation of secretion of bile acids known as?

Back 9

The choleretic effect

Front 10

T/F:
Choleretics are substances that inhibit bile acid secretion.

Back 10

False:
Choleretics are substances that enhance bile acid secretion.

Front 11

How much bile acid escapes absorption and is excreted?

Back 11

10-20%

Front 12

T/F:
Bile acid lost in feces are the only significant source of cholesterol excretion.

Back 12

True

Front 13

T/F:
High blood cholesterol is a risk factor for coronary heart disease (CHD).

Back 13

True

Front 14

Excess cholesterol in bile results in cholesterol __________.

Back 14

Excess cholesterol in bile results in cholesterol _gallstones_.

Front 15

What does the cholesterol when there is too much to be solubilized in the bile to the point of supersaturation?

Back 15

Crystals

Front 16

Where do cholesterol gallbladders form?

Back 16

In the duct system of the liver or gallbladder.

Front 17

What is the accumulation of bile salts in the blood and deficiency of bile salts in the intestinal lumen that decreases bile flow through the canaliculi?

Back 17

Cholestasis

Front 18

_______ is the degraded product of RBCs, specifically the conversion of porphyrin moiety of hemoglobin to this.

Back 18

_Bilirubin_ is the degraded product of RBCs, specifically the conversion of porphyrin moiety of hemoglobin to this.

Front 19

Bilirubin is removed by from the blood by _______ and conjugates with _________ acid to form bilirubin _________.

Back 19

Bilirubin is removed by from the blood by _hepatocytes_ and conjugates with _glucuronic_ acid to form bilirubin _glucuronides_.

Front 20

What color is bilirubin and what does it contribute to the color of?

Back 20

Its yellow and contributes to the color of bile

Front 21

What do colonic bacteria convert bilirubin to?

Back 21

Urobilinogen

Front 22

T/F:
Urobilinogen can be absorbed into the blood, excreted in the urine, or be taken up by hepatocytes and resecreted into bile.

Back 22

True

Front 23

What area does bilirubin gallstones occur in?

Back 23

Gallbladder

Front 24

What type of gallstones consist of calcium salts of unconjugated bilirubin?

Back 24

Bile pigment gallstones

Front 25

T/F:
Unconjugated bilirubin is soluble and does not form insoluble calcium salts in bile.

Back 25

False:
Conjugated bilirubin

Front 26

Why is there an elevated level of unconjugated bilirubin in bile during liver disease?

Back 26

Because hepatocytes are deficient in forming bilirubin glucuronides.

Front 27

What regulates duodenal secretions?

Back 27

Enteric neural reflexes

Front 28

What do duodenal epithelial cells secrete?

Back 28

Mucus and aqueous component (electrolyte content close to that of plasma)

Front 29

What causes the enteric neural reflex in regards to duodenal secretion?

Back 29

Chyme
Acidic so irritates and causes reflex, which in turn releases bicarb to neutralize

Front 30

How much secretion is there in one day for the small intestine?

Back 30

1500 ml/day

Front 31

What are the 3 types of cells found in the small intestine that are responsible for secretion?

Back 31

Goblet cells, columnar epithelial cells, and enterocytes

Front 32

Goblet cells line the columnar epithelial cells of the small intestine and secrete _________.

Back 32

Goblet cells line the columnar epithelial cells of the small intestine and secrete _mucous_.

Front 33

During normal digestion ________ secretion is produced by the columnar epithelial cells of the small intestine.

Back 33

During normal digestion _aqueous_ secretion is produced by the columnar epithelial cells of the small intestine.

Front 34

T/F:
Aqueous secretion is produced at a rate higher than the rate of fluid absorption by the small intestine.

Back 34

False:
Aqueous secretion is produced at a lower rate

Front 35

What cells in the small intestine produce enzymes?

Back 35

Enterocytes

Front 36

Matase, sucrase, latase, and alpha- dextrinase are all enzymes produced in the small intestine to further break down ______________.

Back 36

Matase, sucrase, latase, and alpha- dextrinase are all enzymes produced in the small intestine to further break down _disaccharides_.

Front 37

What does the enzyme, intestinal lipase, produced in the small intestine do?

Back 37

Further breakdowns fat

Front 38

T/F:
In colonic secretions, there is a mucus portion, an aqueous portion, and an enzymatic portion similiar to that of the small intestine secretions.

Back 38

False
No enzymatic portion

Front 39

The aqueous portion of the colon secretions is rich in what 2 ions?

Back 39

K and HCO3

Front 40

What stimulates colonic secretion?

Back 40

Cholinergic agents

Front 41

What is the purpose of the colon secretions?

Back 41

To protect intestinal wall from excoriation (removal of intestinal wall), bacteria, and acid and hold feces together

Front 42

What are the 3 monosaccharides?

Back 42

Glucose, fructose, and galactose

Front 43

What are the 3 disaccharides?

Back 43

Sucrose, maltose, and lactose

Front 44

Which sugars are dietary (actually ingested)? (2)

Back 44

Sucrose and lactose

Front 45

Which sugars are a result of the process of digestion in the body? (4)

Back 45

Glucose, fructose, galactose, and maltose

Front 46

T/F:
Sugar alcohols (polyois) are easily digested.

Back 46

False: not easily digested

Front 47

hydrogenated starch hydrolysates such as lactitol, maltitol, mannitol, and sorbitol are all wha kind of carbohydrates?

Back 47

Sugar alcohols (polyois)

Front 48

What were the 2 types of starches mentioned in lecture?

Back 48

Amylopectin and Amylose

Front 49

T/F:
Amylose makes up 70-80% of starches.

Back 49

False:
Amylose is 20-30%
Amylopectin is 70-80%

Front 50

Which type of starch is plant derived, easily digested, contains linear and branched glucose polymers, and is a major source of carbohydrates?

Back 50

Amylopectin

Front 51

Which starch has the ability to develope resistance, making it harder to digest?

Back 51

Amylose

Front 52

Which starch can be either natural occuring or modied and only contains linear glucose polymers?

Back 52

Amylose

Front 53

What type of carbohydrate is ingested but cannot be digested?

Back 53

Dietary fiber

Front 54

Why can humans not digest dietary fiber?

Back 54

Humans lack digestive enzymes that breakdown cellulose

Front 55

A non starchy polysaccharide that is the cellulose portion of the human diet that cannot be digested is known as which classification of carbohydrates?

Back 55

Dietary fiber

Front 56

Glycogen is a type of carbohydrate that stores ___________ in two places in the body, ___________ and __________.

Back 56

Glycogen is a type of carbohydrate that stores _glucose_ in two places in the body, _liver_ and _muscle_.

Front 57

What mechanism is responsible for the digestion of carbohydrates?

Back 57

Hydrolysis

Front 58

T/F:
The degree of cooking food that is ingested can determine the rate of digestion of carbohydrates.

Back 58

True

Front 59

What type of carbohydrates exist in the human diet? (2)

Back 59

Poly and disaccharides

Front 60

What mechanism is used to bind monosaccharides together?

Back 60

Condensation

Front 61

____________ is the returning of OH and H to disaccharides or polysarcharrides, seperating monosaccharides from eachother.

Back 61

_Hydrolysis_ is the returning of OH and H to disaccharides or polysarcharrides, seperating monosaccharides from eachother.

Front 62

Saliva contains alpha- amylase which hydrolyzes starch into what disaccharide and what monosaccharide?

Back 62

Disaccharide- maltose
Monosaccharide- glucose

Front 63

What percentage of starch is left to be digested after the hydrolyzation of starch in the mouth?

Back 63

95%

Front 64

Why is 30- 40% of starch hydrolyzed to maltose before being mixed with HCl?

Back 64

Because salivary amylase is inactivated at lower pH

Front 65

T/F:
Salivary amylase is more powerful in action than pancreatic amylase.

Back 65

False:
Pancreatic is more powerful in action than salivary

Front 66

About how long does it take for almost complete digestion, after chyme empties into the duodenum, by pancreatic amylase?

Back 66

Within 15-30 min

Front 67

What are the products of digestion of pancreatic amylase?

Back 67

Maltose and/ or small glucose polymers

Front 68

Enterocytes line the microvilli brush border relasing what intestinal epithelial enzymes? (4)

Back 68

Lactase, sucrase, maltase, and alpha- dextrinase

Front 69

What intestinal epithelial enzyme(s) breaks down maltose and glucose polymers into glucose?

Back 69

Maltase and alpha- dextrinase

Front 70

Lactase converts lactose into _______ and _________.

Back 70

Lactase converts lactose into _galactose_ and _glucose_.

Front 71

Fructose and glucose are products of _____________ broken down by the intestinal epithelial enzyme ____________.

Back 71

Fructose and glucose are products of _sucrose_ broken down by the intestinal epithelial enzyme _sucrase_.

Front 72

The digestion products of the small intestine are ______saccharides that (are/ are not) water soluble and (absorbable/ not absorbable) into portal blood.

Back 72

The digestion products of the small intestine are _mono_saccharides that ARE water soluble and ABSORBABLE into portal blood.

Front 73

What percentage of digested products in the small intestine is glucose?

Back 73

80%

Front 74

What percentage of digested products in the SI is galactose and fructose?

Back 74

20%
10% galactose and 10% fructose

Front 75

What type of transport is the absorption of glucose from the lumen into the cell and what is it dependent on which is derived by the Na ion?

Back 75

2nd active transport and depends of electrochemical gradient

Front 76

How much Na is present in the lumen?

Back 76

142 mEq/L

Front 77

With only 50 mEq/L of Na inside the cell, Na will move down its gradient into the cell by ___________ with glucose, so that Na and glucose are entering the cell simultaneously.

Back 77

With only 50 mEq/L of Na inside the cell, Na will move down its gradient into the cell by _cotransport_ with glucose, so that Na and glucose are entering the cell simultaneously.

Front 78

Glucose enters the basolateral membrane by what type of transport?

Back 78

Facilitated diffusion

Front 79

T/F:
Glucose and galactose both enter the basolateral membrane by the same transport mechanism.

Back 79

True

Front 80

Which monosaccharide present in the digestion products of the SI enters the cell by cotransport, phosphorylates to glucose, and then diffuses thru the basolateral membrane to the the capillaries?

Back 80

Fructose

Front 81

T/F:
Protein and carbohydrates are digested by the same mechanism.

Back 81

True

Front 82

Proteins exist as multiple ___________ bound by peptide linkage.

Back 82

Proteins exist as multiple _amino acids_ bound by peptide linkage.

Front 83

What pH is pepsin active at?

Back 83

2-3

Front 84

What percentage of dietary proteins are digested in the stomach by pepsin?

Back 84

10-20%

Front 85

Cheif cells excrete __________ which is then converted to _________ when parietal cells are triggered by _________ releasing HCl.

Back 85

Cheif cells excrete _pepsinogen_ which is then converted to _pepsin_ when parietal cells are triggered by _gastrin_ releasing HCl.

Front 86

The stomach digests the diestary protein _______________ which is an intracellular connective tissue found in meats.

Back 86

The stomach digests the diestary protein _collagen_ which is an intracellular connective tissue found in meats.

Front 87

What are the 4 main protein products that are digested by the stomach and small intestine?

Back 87

Amino acids, polypeptides, collagen, and elastin fibers

Front 88

Which proteolytic enzymes from pancreatic secretions are responsible fpr the splitting of proteins into small polypeptides?

Back 88

Typsin and chymotrypsin

Front 89

_______________ cleaves individual amino acids from carboxyl ends of the polypeptides.

Back 89

_Carboxypolypeptidase_ cleaves individual amino acids from carboxyl ends of the polypeptides.

Front 90

Where does most of dietary protein digestion take place?

Back 90

Small intestine

Front 91

What part of the small intestine are the enterocytes located in?

Back 91

Duodenum and jejunum

Front 92

Enterocytes are located in the brush border which contains ____________, and within their membrane _____________ are stored.

Back 92

Enterocytes are located in the brush border which contains _microvillie_, and within their membrane _peptidases_ are stored.

Front 93

There are 2 types of peptidases, _____________ and _____________, that break peptide bonds resulting in the 3 products, ________,_________and ____________.

Back 93

There are 2 types of peptidases, _aminopolypeptidase_ and _dipeptidase_, that break peptide bonds resulting in the 3 products, _tripeptides_, _dipeptides_ and _amino acids_.

Front 94

99% of digested protein products are ______________.

Back 94

99% of digested protein products are _amino acids_.

Front 95

Further digestion of peptides occur inside the cell from ____________ peptidases.

Back 95

Further digestion of peptides occur inside the cell from _cystolic_ peptidases.

Front 96

What kind of transport mechanism with Na is used in the absorption of proteins as di- and tri- peptidases and free amino acids?

Back 96

Na co-transport

Front 97

T/F:
There are 5 transporters for the absorption of proteins that are specific for amino acids.

Back 97

True

Front 98

T/F:
Fecaliths are associated with the developement of diverticular disease.

Back 98

False:
Appendicitis

Front 99

The disease resulting in chronic or recurrent diarrhea and atrophy of the villi of the small intestine that is induced by eating gluten-containing foods is _______________.

Back 99

The disease resulting in chronic or recurrent diarrhea and atrophy of the villi of the small intestine that is induced by eating gluten-containing foods is _celiac sprue_.

Front 100

T/F:
Crohn's Disease results in atrophy of villi of SI and is induced by gluten-containing foods.

Back 100

False:
Celiac Sprue

Front 101

T/F:
Cholelithiasis may occur in any part of the biliary system.

Back 101

True

Front 102

T/F:
Jaundice is the result of excessive levels of bilirubin in the plasma.

Back 102

True

Front 103

Chylomicrons leave the instestinal villi by entering the _________ (a structure) and traveling in the lymph to the systemic circulation.

Back 103

Chylomicrons leave the instestinal villi by entering the _lacteal_ (a structure) and traveling in the lymph to the systemic circulation.

Front 104

T/F:
Oxyntic cells secrete the family of proteolytic proenzymes known as the pepsinogens.

Back 104

False:
Cheif cells

Front 105

T/F:
Cholecystitis refers to the presence of gallstones in the gallbladder.

Back 105

False:
Gallstones, can be anywhere in the biliary system though gallbladder is most common site.

Front 106

T/F:
The amount of lecithin present determines the amount of cholesterol that can be dissolved in the micelles.

Back 106

True

Front 107

T/F:
The gallbladder is drained by the cystic duct.

Back 107

True

Front 108

T/F:
Primary bile acids are converted to secondary bile acids by colonic bacteria.

Back 108

False:
Bacteria in the ileum and colon deconjugate bile acids and dehydroxylate them to produce 2nd bile acids
Colonic bacteria alone converts bilirubin to urobilirubinogen

Front 109

T/F:
Intestinal villi are the very small projections on the tips of the tall columnar epithelial cells of the small intestines.

Back 109

False:
Microvilli

Front 110

T/F:
Chylomicrons are transported to the liver in the hepatic portal vein.

Back 110

False:
Transported to lymphatic system by the thoracic lymph duct.

Front 111

T/F:
Cholelithiasis is four times more common in males than in females.

Back 111

False:
Four more times common in females (fertile, forty, fat)

Front 112

T/F:
Conjugated bilirubin is not soluble and thereby form insoluble calcium salts in bile.

Back 112

False:
Unconjugated bilirubin

Front 113

T/F:
Transfusion reactions resulting in hemolysis often produce jaundice.

Back 113

True

Front 114

T/F:
Hepatocellular carcinoma can develop secondary to hepatitis B or C.

Back 114

True

Front 115

T/F:
Only 1 to 2% of ingested B12 is absorbed without the aid of intrinsic factor (IF).

Back 115

True

Front 116

T/F:
Glucose and galactose cross the brush border membrane of GI absorptive cells by cotransport with sodium.

Back 116

True

Front 117

T/F:
The large intestine absorbs the bulk of the water that enters the alimentary canal.

Back 117

False:
Small intestine, jejunum absorbs 8.6 L of water

Front 118

T/F:
Vitamin D is essential for the absorption of iron.

Back 118

False:
Vitamin C promotes absorption but doesnt mention that its essential

Front 119

T/F:
R proteins are glycoproteins that bind B12 and are found in the saliva and gastric juice.

Back 119

True

Front 120

T/F:
Transferrin irreversible binds iron in the enterocytes and serves as a binding site for iron storage in liver cells.

Back 120

False:
Serves as a binding site in the duodenum

Front 121

T/F:
Because bile acids lost into the feces are the only significant way of cholesterol excretion, drugs that promote the reabsorption of bile acids in the ileum are often used to lower the level of cholesterol in the blood.

Back 121

False:
Drugs that BLOCK the reabsorption lower cholesterol levels by synthesizes new bile acids from cholesterol to be excreted in the feces.

Front 122

What two material emulsify fat during digestion?

Back 122

Lecithin and bile salts

Front 123

What is formed to accelerate fat digestion and transport fat products to brush border of the intestinal epithelial cells?

Back 123

Micelles

Front 124

What are the 4 types of fat in the diet?

Back 124

Triglycerides, cholesterol esters, phospholipids, and cholesterol

Front 125

What is the most abundant type of fat in the diet?

Back 125

Triglycerides

Front 126

A _______________ consists of glycerol nucleus and three fatty acid side chain.

Back 126

A _triglyceride_ consists of glycerol nucleus and three fatty acid side chain.

Front 127

What type of fat in the diet is a sterol compound with no fatty acids, derived from fat, and metabolized similiar to fats?

Back 127

Cholesterol

Front 128

T/F:
A large amount of fat is digested by lingual lipase secreted in saliva.

Back 128

False:
A small amount

Front 129

What is the term for the physical breakdown of fat globules?

Back 129

Emulsification

Front 130

Where does emulsification begin?

Back 130

In the stomach, where its agitated to mix fat with products of stomach digestion

Front 131

Where does most emulsification occur?

Back 131

In the duodenum

Front 132

What substances/ material decrease interfacial tension of fats, allow break down of fats by agitation, and increase surface area?

Back 132

Lecithin and bile salts

Front 133

What are the 3 lipolytic enzymes found in pancreatic secretions that digest fats?

Back 133

Pancreatic lipase, cholesterol esterase hydrolase, and phospholipase A2

Front 134

Which lipolytic enzyme found in pancreatic secretions digests triglycerides rapidly and hydrolyzes them to free fatty acids and 2- monoglycerides?

Back 134

Pancreatic lipase

Front 135

Which lipolytic enzyme found in pancreatic secretion is used to hydrolyze fatty acid from cholesterol esters?

Back 135

Cholesterol esterase hydrolase

Front 136

___________ is found in pancreatic secretions and is a lipolytic enzyme that hydrolyzes fatty acids from phospholipids.

Back 136

_Phospholipase A2_ is found in pancreatic secretions and is a lipolytic enzyme that hydrolyzes fatty acids from phospholipids.

Front 137

What ferries fats to cell microvilli for absorption?

Back 137

Micelles

Front 138

Fats and monoglycerides enter the _____________ to form new triglycerides.

Back 138

Fats and monoglycerides enter the _endoplasmic reticulum_ to form new triglycerides.

Front 139

New triglycerides are released as ___________ which do not enter the portal system, but flow through the thoracic lymph duct through to the blood circulation.

Back 139

New triglycerides are released as _chylomicrons_ which do not enter the portal system, but flow through the thoracic lymph duct through to the blood circulation.

Front 140

What is the difference between the absorption of fats, to that of the absorption of proteins and carbohydrates?

Back 140

Fats enter the lymphatic system while proteins and carbohydrates are absorbed in the portal system.

Front 141

The absorption of water depends mainly on the absorption of ion, meaning it is ___________ to the absorption of ions.

Back 141

The absorption of water depends mainly on the absorption of ion, meaning it is _secondary_ to the absorption of ions.

Front 142

Approximately how much water enters the GI tract per day?

Back 142

9200 mL, 9.2 L

Front 143

Approximately how much water is lost in feces?

Back 143

50- 100 mL

Front 144

How much water must be absorbed based on an intake of 9.2 L of water?

Back 144

9100 mL, 9.1 L

Front 145

Where does the majority of water absorption take place?

Back 145

Small intestine
8.6L in the jejunum
Little absorption occurs in duodenum or colon (LI)

Front 146

Water absorption is by transport through the intestinal membrane by diffusion, obeying what law?

Back 146

Law of osmosis

Front 147

When will water absorb thru intestinal mucosa into the blood of the villi?

Back 147

When chyme is dilute enough

Front 148

When will water be transported from the plasma into the chyme?

Back 148

When chyme becomes hyperosmotic in contrast to the plasma

Front 149

When chyme is hyperosmotic, what happens to the cell?

Back 149

Shrinks

Front 150

Solutions are discharged from the stomach to duodenum when chyme is hyperosmotic, causing chyme to become ___________ with plasma.

Back 150

Solutions are discharged from the stomach to duodenum when chyme is hyperosmotic, causing chyme to become _isotonic_ with plasma.

Front 151

T/F:
Na and glucose have similiar absoprtion in digestion.

Back 151

True

Front 152

How is the Na gradient maintained that allows for Na to enter the cell by diffusion?

Back 152

Na/K ATPase pump, localized in basolateral membrane

Front 153

Na entering the cell by diffusion is facilitated by what two molecules?

Back 153

Glucose or amino acids

Front 154

Na entering the cell leaves chyme with an electro ___________ because Cl- tends to follow Na leaving.

Back 154

Na entering the cell leaves chyme with an electro _negativity_ because Cl- tends to follow Na leaving.

Front 155

The Na/K ATPase pump creates an electro ____________ in the paracellular spaces.

Back 155

The Na/K ATPase pump creates an electro _positivity_ in the paracellular spaces.

Front 156

Where is Cl- absorbed in the GI system?

Back 156

Duodenum and Jejunum

Front 157

T/F:
Hepatic and pancreatic bicarb are both absorbed in the same place, the duodenum and jejunum.

Back 157

True

Front 158

T/F:
Hydrogen ions secreted into the lumen in exchange for absorbed Na or hydrogen ions combining with bicarb to form carbonic acid in the lumen are two indirect absorptions of bicarb.

Back 158

True

Front 159

T/F:
Direct absorption of the bicarb ion is involved when carbonic acid forms water and carbon dioxide.

Back 159

False:
indirect

Front 160

When water remains as part of chyme and crabon dioxide is absorbed in the blood, there is ____________ absorption of bicarb.

Back 160

When water remains as part of chyme and crabon dioxide is absorbed in the blood, there is _indirect_ absorption of bicarb.

Front 161

Absorption of __________ concentrates K in the lumen causing it to flow down its gradient into the cell.

Back 161

Absorption of _water_ concentrates K in the lumen causing it to flow down its gradient into the cell.

Front 162

T/F:
Depending on K luminal concentration in the colon, it may be secreted or absorbed.

Back 162

True

Front 163

Rickets and osteoporosis are diseases related to the absorption of what ion?

Back 163

Ca

Front 164

T/F:
Ca is actively absorbed in only certain parts of the intestine.

Back 164

False:
actively absorbed in all portions of the intestine

Front 165

Which vitamin is essential for the absorption of Ca and regulates the production of intestinal membrane calcium- binding protein (IMCal)?

Back 165

Vitamin D

Front 166

Where is the intestinal membrane calcium- binding protein located?

Back 166

The brush border at the tips of the tall columnar epithelial cells of the small intestine

Front 167

What binding protein is found in the cytoplasm of absorptive cells to prevent free Ca cells in the cell?

Back 167

Calbindin (CaBP)

Front 168

Vitamin D regulates the production of ___________ and __________ which prevent free Ca ions in the cell.

Back 168

Vitamin D regulates the production of _calbindin_ and _vesicles_ which prevent free Ca ions in the cell.

Front 169

Where is the Ca/ ATPase and Na/ Ca countertransport tranporters located?

Back 169

The basolateral membranes of the absorptive cells

Front 170

The binding of what receptor allows for the release of Ca from its binding protein/ vehicles?

Back 170

IP3R

Front 171

How much iron is typically ingested per day?

Back 171

15-20 mg

Front 172

Typically how much iron is absorbed by the body?

Back 172

1-2 mg

Front 173

T/F:
Iron is absorbed by the body on a need basis.

Back 173

True

Front 174

Where is most iron absorbed?

Back 174

Duodenum of the SI

Front 175

What are the two sources of dietary iron and what food sources are they found?

Back 175

Heme- meats
Non heme- grains and vegetables

Front 176

Which source of iron is more readily absorbed?

Back 176

Heme, proteolytic enzymes allow release of heme group from protein

Front 177

___________ is heme specific, located in the brush border of the enterocytes, and mediates heme uptake into cells.

Back 177

_Heme carrier protein (HCP1)_ is heme specific, located in the brush border of the enterocytes, and mediates heme uptake into cells.

Front 178

How does the nonheme iron exist?

Back 178

In the ferric (Fe3) state

Front 179

How is nonheme iron absorbed into the enterocytes?

Back 179

By nonheme specific metal ion transporters (DMT1)

Front 180

What forms a soluble complex with nonheme iron promoting absorption by endocytosis?

Back 180

Vitamin C

Front 181

What type of transport is used for nonheme iron to cross the basolateral membrane?

Back 181

Primary active transport

Front 182

The absorption of _________ is required for protein synthesis.

Back 182

The absorption of _B12_ is required for protein synthesis.

Front 183

T/F:
Low B12 retards maturation of RBCs and result in pernicious anemia.

Back 183

True

Front 184

What is the B12 binding protein necessary for absorption of B12?

Back 184

Intrinsic factor (IF)

Front 185

Intrinsic factors is secreted by ___________ cells.

Back 185

Intrinsic factors is secreted by _parietal_ cells.

Front 186

Intrinsic factor binds with less affinity to B12 than ______________ proteins, but due to pancreatic proteases, that protein-B12 complex is _________ allowing for B12 to bind to IF.

Back 186

Intrinsic factor binds with less affinity to B12 than _R_ proteins, but due to pancreatic proteases, that protein-B12 complex is _degraded_ allowing for B12 to bind to IF.

Front 187

The brush border receptors allow for the absorption of the B12-IF complex into what portion of the small intestine?

Back 187

Ileum

Front 188

How much normal ingested B12 is absorbed without IF?

Back 188

1-2%

Front 189

How much chyme goes thru the ileocecal valve into the large intestine?

Back 189

1500 mL

Front 190

How much fluid is excreted from chyme?

Back 190

100mL

Front 191

The ________ colon is for absorbing while the _________ colon stores feces.

Back 191

The _proximal_ colon is for absorbing while the _distal_ colon stores feces.

Front 192

The colon secretes HCO3 while simultaneously absorbing _____ to neutralize acidic end products of bacterial action.

Back 192

The colon secretes HCO3 while simultaneously absorbing _Cl-_ to neutralize acidic end products of bacterial action.

Front 193

What cells of the colonic mucosa secrete mucus?

Back 193

Goblet cells

Front 194

What stimulates goblet cells in the colon?

Back 194

Cholinergic agents

Front 195

The absorption of Na and Cl ions in the colon create an osmotic gradient which causes the absorption of ___________.

Back 195

The absorption of Na and Cl ions in the colon create an osmotic gradient which causes the absorption of _water_.

Front 196

Vitamin K, Vitamin B12, thiamine, riboflavin, and various gases such as CO2, Hydrogen gas, and methane are all formed as a result of what kind of activity in the colon?

Back 196

Bacterial

Front 197

T/F:
The color of feces is determined by the food ingested.

Back 197

True

Front 198

How much of feces is water? Solid material?

Back 198

Water- 3/4
Solid material- 1/4

Front 199

The solid material of feces is mostly?

Back 199

Dead bacteria- 30%
Undigested roughage- 30%

Front 200

What derivatives of bilirubin cause the brown coloring of feces?

Back 200

Stercobilin and urobilin

Front 201

T/F:
10-20% of solid material in feces is protein, while 1-2% is fat.

Back 201

False:
1-2% is protein, 10-20% is fat