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173 notecards = 44 pages (4 cards per page)

Viewing:

digestive system

front 1

there are two groups of organs in the digestive system - what are they

back 1

the alimnetary canal (GI tract) and the accessory digestive organs

front 2

what are the organs of the alimentary canal

back 2

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

front 3

what is the function of the alimentary canal

back 3

to digest and absorb food

front 4

what are the accessory digestive organs

back 4

teeth tongue gallbladder salivary glands liver and pancreas

front 5

the digestive process contain 6 activities - what are they

back 5

1. ingestion
2. propulsion
a.deglutition
b.peristalsis
c.mass movements
3. mechanical digestion
a.mastication
b. churning
c. segmentation
4. chemical digestion
5. absorption
6. defecation

front 6

desribe peristalsis

back 6

Adjacent segments of alimentary tract organs alternately contract and relax, which moves food along the tract distally.

front 7

describe segmentation

back 7

Nonadjacent segments of alimentary tract organs alternately contract and relax, moving the food forward then backward. Food mixing and slow food propulsion occurs.

front 8

what is deglutition

back 8

swallowing

front 9

what is the Peritoneum

back 9

serous membrane of the abdominal cavity

front 10

where is the Visceral peritoneum

back 10

on external surface of most digestive organs

front 11

where is the Parietal peritoneum

back 11

lines the body wall

front 12

where is the Peritoneal cavity and what is its function

back 12

found Between the two peritoneums
the Fluid lubricates mobile organs

front 13

what is the Mesentery and what is its function

back 13

a double layer of peritoneum, Routes for blood vessels, lymphatics, and nerves
it also Holds organs in place and stores fat

front 14

where are the Retroperitoneal organs found

back 14

lie posterior to the peritoneum

front 15

Intraperitoneal (peritoneal) organs are
surrounded by what

back 15

the peritoneum

front 16

what are the Arteries of the splanchinic circulation

back 16

• Hepatic, splenic, and left gastric
• Inferior and superior mesenteric
• Hepatic portal circulation

front 17

What is the function of the arteries of the splanchnic circulation

back 17

• Drains nutrient-rich blood from digestive organs
• Delivers it to the liver for processing

front 18

What are the four basic layers of the alimentary canal

back 18

Four basic layers (tunics)
• Mucosa
• Submucosa
• Muscularis externa
• Serosa

front 19

the mucosa is found where

back 19

Lines the lumen

front 20

what is the function of the mucosa

back 20

Secretes mucus, digestive enzymes and
hormones, Absorbs end products of digestion, and Protects against infectious disease

front 21

what are the sublayers of the mucosa

back 21

Three sublayers: epithelium, lamina propria,
and muscularis mucosae

front 22

where is Stratified squamous epithelium found

back 22

the oral cavity, oropharynx, nasopharynx,
esophagus, and anal canal

front 23

where is Simple columnar epithelium found, and what are some of its functions

back 23

in the stomach, small intestine, large intestine,and rectum
• Goblet cells – secrete mucus
• Protects digestive organs from enzymes
• Eases food passage
• May secrete enzymes and hormones (e.g., in stomach and small intestine)

front 24

what is the Lamina propria composed of

back 24

Loose areolar connective tissue
• Capillaries for nourishment and absorption
• Lymphoid follicles (part of MALT)

front 25

what is the Muscularis mucosae composed of and what is its function

back 25

smooth muscle that produces local movements
of mucosa

front 26

what is the Submucosa composed of

back 26

• Dense connective tissue, Blood and lymphatic vessels, lymphoid, follicles, and submucosal nerve plexus, Muscularis externa, Inner circular and outer longitudinal layers, Myenteric nerve plexus and Sphincters in some regions

front 27

what is the function of the Submucosa

back 27

Responsible for segmentation and peristalsis

front 28

Visceral peritoneum is Replaced by what in the esophagus

back 28

the fibrous adventitia

front 29

•Retroperitoneal organs have both an ___ and a ____

back 29

an adventitia and serosa

front 30

describe the enteric nervous system

back 30

•Intrinsic nerve supply of the alimentary canal
•Submucosal nerve plexus
•Regulates glands and smooth muscle in the mucosa
•Myenteric nerve plexus
•Controls GI tract motility
•Long ANS fibers synapse with enteric plexuses
•Sympathetic impulses inhibit secretion and motility
•Parasympathetic impulses stimulate secretion and motility

front 31

the mouth is also known as

back 31

Oral (buccal) cavity

front 32

the mouth is bound by what organs

back 32

•Bounded by lips, cheeks, palate, and tongue

front 33

what type of epethelium lines the mouth

back 33

•Lined with stratified squamous epithelium

front 34

what muscles are found in the area of the mouth

back 34

Contain orbicularis oris (lips) and buccinator muscles (cheeks)

front 35

describe the Hard palate

back 35

formed by the palatine bones and palatine processes of the maxillae,Slightly corrugated to help create friction against the tongue

front 36

describe the Soft palate

back 36

fold formed mostly of skeletal muscle
Closes off the nasopharynx during swallowing
Uvula projects downward from its free edge

front 37

what is the purpose of the Tongue

back 37

Repositioning and mixing food during chewing
Formation of the bolus
Initiation of swallowing, speech, and taste
Surface bears papillae- gustatory receptor cells

front 38

where are the Extrinsic salivary glands located

back 38

(parotid, submandibular, and sublingual)

front 39

where are the intrinsic (buccal) salivary glands located

back 39

they are scattered in the oral mucosa

front 40

what is the function of saliva

back 40

Cleanses the mouth,Moistens and dissolves food chemicals, Aids in bolus formation,Contains enzymes that begin the breakdown of starch

front 41

from where is saliva secreted

back 41

Secreted by serous and mucous cells

front 42

what is saliva composed of

back 42

97–99.5% water, slightly acidic solution containing
•Electrolytes—Na+, K+, Cl–, PO4 2–, HCO3–
•Salivary amylase
•Mucin
•Metabolic wastes—urea and uric acid
•Lysozyme, IgA, defensins, and a cyanide compound protect against microorganisms

front 43

which glands continuously keep the mouth moist

back 43

Intrinsic glands

front 44

Extrinsic salivary glands produce secretions when

back 44

Ingested food stimulates chemoreceptors and mechanoreceptors in the mouth

front 45

•Salivatory nuclei in the brain stem send impulses where

back 45

along parasympathetic fibers in cranial nerves VII and IX, Strong sympathetic stimulation inhibits salivation and results in dry mouth (xerostomia)

front 46

Primary and permanent dentitions are formed by what age

back 46

21

front 47

some details about teeth

back 47

20 deciduous teeth erupt (6–24 months of age)
•Roots are resorbed, teeth fall out (6–12 years of age) as permanent teeth develop
•32 permanent teeth
•All except third molars erupt by the end of adolescence

front 48

what is the function of the Incisors

back 48

•Chisel shaped for cutting

front 49

what is the function of the canines

back 49

they are Fanglike teeth that tear or pierce

front 50

describe Premolars (bicuspids) and molars

back 50

Have broad crowns with rounded cusps for grinding or crushing

front 51

describe the structure of the tooth

back 51

Crown: the exposed part above the gingiva (gum)
•Covered by enamel—the hardest substance in the body (calcium salts and hydroxyapatite crystals)
•Root: portion embedded in the jawbone
•Connected to crown by neck
Cementum: calcified connective tissue
•Covers root and attaches it to the periodontal ligament
•Periodontal ligament
•Forms fibrous joint called a gomphosis
•Gingival sulcus: groove where gingiva borders the tooth
Dentin: bonelike material under enamel
•Maintained by odontoblasts of pulp cavity
•Pulp: connective tissue, blood vessels, and nerves
•Root canal: extends from pulp cavity to the apical foramen of the root

front 52

what are Dental caries

back 52

(cavities): gradual demineralization of enamel and dentin

front 53

how are cavities formed

back 53

caused when Dental plaque (sugar, bacteria, and debris) adheres to teeth Acid from bacteria dissolves calcium salts Proteolytic enzymes digest organic matter

front 54

how can one prevent cavities

back 54

•Prevention: daily flossing and brushing

front 55

what is Gingivitis

back 55

Plaque calcifies to form calculus (tartar), Calculus disrupts the seal between the gingivae and the teeth, Anaerobic bacteria infect gums, Infection reversible if calculus removed

front 56

describe Periodontitis

back 56

Immune cells attack intruders and body tissues, Destroy periodontal ligament, Activate osteoclasts

front 57

what are the consequences of Periodontitis

back 57

Possible tooth loss, promotion of atherosclerosis and clot formation in coronary and cerebral arteries

front 58

what is the function of the Oropharynx and laryngopharynx

back 58

•Allow passage of food, fluids, and air

front 59

what are the Oropharynx and laryngopharynx composed of

back 59

•Stratified squamous epithelium lining
•Skeletal muscle layers: inner longitudinal, outer pharyngeal constrictors

front 60

describe the esophagus

back 60

•Flat muscular tube from laryngopharynx to stomach
•Pierces diaphragm at esophageal hiatus
•Joins stomach at the cardiac orifice
•Stratified squamous epithelium lining
•Esophageal glands in submucosa secrete mucus to aid in bolus movement
•Muscularis: skeletal superiorly; smooth inferiorly
•Adventitia instead of serosa

front 61

what is the function of the mouth (digestion)

back 61

•Ingestion
•Mechanical digestion
•Mastication is partly voluntary, partly reflexive
•Chemical digestion (salivary amylase)
•Propulsion
•Deglutition (swallowing)

front 62

describe deglutition (swallowing)

back 62

Involves the tongue, soft palate, pharynx, esophagus, and 22 muscle groups
•Buccal phase
•Voluntary contraction of the tongue
•Pharyngeal-esophageal phase
•Involuntary
•Control center in the medulla and lower pons

front 63

where is the cardiac region located in the Stomach

back 63

the Cardiac region (cardia)Surrounds the cardiac orifice

front 64

where is the fundus of the stomach located

back 64

Dome-shaped region beneath the diaphragm

front 65

where is the body of the stomach

back 65

Midportion

front 66

where is the Pyloric region (antrum, pyloric canal, and pylorus)

back 66

Pylorus is continuous with the duodenum through the pyloric valve (sphincter)

front 67

where is the Greater curvature of the stomach

back 67

convex lateral surface

front 68

where is the Lesser curvature of the stomach

back 68

Concave medial surface

front 69

where is the Lesser omentum

back 69

From the liver to the lesser curvature

front 70

where is the Greater omentum located

back 70

•Drapes from greater curvature
•Anterior to the small intestine

front 71

describe the ANS nerve supply

back 71

•Sympathetic via splanchnic nerves and celiac plexus
•Parasympathetic via vagus nerve

front 72

describe the Blood supply of the stomach

back 72

•Celiac trunk
•Veins of the hepatic portal system

front 73

how many layers (tunics) are there in the stomach

back 73

Four tunics

front 74

the muscularis externa contains 3 layers of smooth muscle, describe the function

back 74

the Inner oblique layer allows stomach to churn, mix, move, physically break down food

front 75

the mucosa of the stomach is composed of what type of epithelium

back 75

Simple columnar epithelium composed of mucous cells, the Layer of mucus traps bicarbonate-rich fluid beneath it and Gastric pits lead into gastric glands

front 76

what are the cell types in the gastric glands and what are thier functions

back 76

*Mucous neck cells (secrete thin, acidic mucus)
•Parietal cells (HCl and intrinsic factor)
•Chief cells (pepsinogen)
•Enteroendocrine cells

front 77

where is most of the gastric juice produced

back 77

Glands in the fundus and body

front 78

one of the Parietal cell secretions is HCl
what is its function

back 78

pH 1.5–3.5 denatures protein in food, activates pepsin, and kills many bacteria

front 79

what is Intrinsic factor

back 79

•Glycoprotein required for absorption of vitamin B12 in small intestine

front 80

Chief cell secretions

back 80

•Inactive enzyme pepsinogen
•Activated to pepsin by HCl and by pepsin itself (a positive feedback mechanism)

front 81

•Enteroendocrine cells

back 81

•Secrete chemical messengers into the lamina propria
•Paracrines
•Serotonin (increase stomach contractions) and histamine (increase HCl secretion)
•Hormones

front 82

•Pepsin is responsible for what

back 82

protein digestion

front 83

Somatostatin does what

back 83

inhibits gastric secretion

front 84

gastrin does what

back 84

increase HCl secretion

front 85

describe the Mucosal Barrier

back 85

•Layer of bicarbonate-rich mucus
•Tight junctions between epithelial cells
•Damaged epithelial cells are quickly replaced by division of stem cells

front 86

what is Gastritis:

back 86

inflammation caused by anything that breaches the mucosal barrier

front 87

what are Peptic or gastric ulcers:

back 87

erosion of the stomach wall
•Most are caused by Helicobacter pylori bacteria

front 88

what are the Digestive Processes in the Stomach

back 88

•Physical digestion
•Denaturation of proteins
•Enzymatic digestion of proteins by pepsin (and rennin in infants)
•Secretes intrinsic factor required for absorption of vitamin B12
•Lack of intrinsic factor  pernicious anemia
•Delivers chyme to the small intestine

front 89

Regulation of Gastric Secretion occur through what sort of mechanisms

back 89

Neural and hormonal mechanisms

front 90

•Stimulatory and inhibitory events occur in three phases what are they

back 90

1.Cephalic
2.Gastric phase
3.Intestinal phase

front 91

describe the cephalic phase

back 91

few minutes prior to food entry

front 92

describe the Gastric phase

back 92

3–4 hours after food enters the stomach

front 93

describe the Intestinal phase

back 93

brief stimulatory effect as partially digested food enters the duodenum, followed by inhibitory effects (enterogastric reflex and enterogastrones)

front 94

•Peristaltic waves move toward the pylorus at the rate of what

back 94

3 per minute

front 95

•Chyme is either Delivered in ~____spurts to the _______, or __________

back 95

3 ml spurts to the duodenum, or
•Forced backward into the stomach

front 96

•Carbohydrate-rich _____ moves quickly through the _________

back 96

chyme duodenum

front 97

•Fatty chyme remains in the duodenum for how long

back 97

6 hours or more

front 98

what is the Major organ of digestion and absorption

back 98

the small intestine

front 99

describe the small intestine

back 99

•2–4 m long; from pyloric sphincter to ileocecal valve with three subdivisions
)

front 100

what are the 3 Subdivisions of the small intestine

back 100

1.Duodenum (retroperitoneal)
2.Jejunum (attached posteriorly by mesentery)
3.Ileum (attached posteriorly by mesentery

front 101

The bile duct and main pancreatic duct join where

back 101

at the hepatopancreatic ampulla - Enter the duodenum at the major duodenal papilla
and Are controlled by the hepato- pancreatic sphincter

front 102

what are some of the Structural Modifications of the duodenum

back 102

•Increase surface area of proximal part for nutrient absorption
•Circular folds (plicae circulares)which are Permanent (~1 cm deep)and force chyme to slowly spiral through lumen
•Villi
•Microvilli

front 103

describe the villi of the duodenum

back 103

Motile fingerlike extensions (~1 mm high) of the mucosa
•Villus epithelium
•Simple columnar absorptive cells (enterocytes)
•Goblet cells

front 104

describe the Microvilli of the duodenum

back 104

•Projections (brush border) of absorptive cells
•Bear brush border enzymes

front 105

explain the Intestinal crypt epithelium

back 105

•Secretory cells that produce intestinal juice
•Enteroendocrine cells
•Intraepithelial lymphocytes (IELs)
•Release cytokines that kill infected cells

front 106

describe Paneth cells

back 106

•Secrete antimicrobial agents (defensins and lysozyme)

front 107

what other cells are found in the intestinal crypts

back 107

•Stem cells

front 108

where are peyers patches found and what do they do

back 108

in ileum protect distal part against bacteria
•Duodenal (Brunner’s) glands of the duodenum secrete alkaline mucus

front 109

what do the Duodenal (Brunner’s) glands of the duodenum do

back 109

secrete alkaline mucus

front 110

describe intestinal juice and its functions

back 110

Secreted in response to distension or irritation of the mucosa
•Slightly alkaline and isotonic with blood plasma
•Largely water, enzyme-poor, but contains mucus
•Facilitates transport and absorption of nutrients

front 111

what is the largest gland in the body

back 111

the liver

front 112

describe the liver

back 112

has Four lobes—right, left, caudate, and quadrate

front 113

what is the function of the Falciform ligament

back 113

•Separates the (larger) right and (smaller) left lobes
•Suspends liver from the diaphragm and anterior abdominal wall

front 114

what is the •Round ligament (ligamentum teres)

back 114

•Remnant of fetal umbilical vein along free edge of falciform ligamen

front 115

what is the function of the Lesser omentum

back 115

it anchors liver to stomach

front 116

what are the blood vessels associated with the liver

back 116

Hepatic artery and vein at the porta hepatis

front 117

what are the Bile ducts and where are they located

back 117

•Common hepatic duct leaves the liver
•Cystic duct connects to gallbladder

front 118

how is the Bile duct formed

back 118

by the union of the common hepatic duct and the cystic duct

front 119

what are teh function of the liver Hepatocyte functions

back 119

•Process bloodborne nutrients
•Store fat-soluble vitamins
•Perform detoxification
•Produce ~900 ml bile per day

front 120

describe bile

back 120

Yellow-green, alkaline solution containing
•Bile salts: cholesterol derivatives that function in fat emulsification and absorption
•Bilirubin: pigment formed from heme
•Cholesterol, neutral fats, phospholipids, and electrolytes

front 121

what is the purpose of Enterohepatic circulation

back 121

•Recycles bile salts
•Bile salts -> duodenum -> reabsorbed from ileum-> hepatic portal blood -> liver -> secreted into bile

front 122

what is the gallbladder, where is it located and what is its function

back 122

Thin-walled muscular sac on the ventral surface of the liver
•Stores and concentrates bile by absorbing its water and ions
•Releases bile via the cystic duct, which flows into the bile duct

front 123

what is the location of the pancreas

back 123

•Mostly retroperitoneal, deep to the greater curvature of the stomach
•Head is encircled by the duodenum; tail abuts the spleen

front 124

what is the endocrine function of the pancreas

back 124

Pancreatic islets secrete insulin and glucagon

front 125

what is the exocrine function of the pancreas

back 125

•Acini (clusters of secretory cells) secrete pancreatic juice
•Zymogen granules of secretory cells contain digestive enzymes

front 126

describe the compostition of pancreatic juice

back 126

Watery alkaline solution (pH 8) neutralizes chyme
•Electrolytes (primarily HCO3–)
•Enzymes
•Amylase
•Lipases
•Nucleases (ribonuclease, deoxyribonuclease)
•Proteases (peptidases, trypsin, chymotrypsin)

front 127

Bile secretion is stimulated by

back 127

•Bile salts in enterohepatic circulation
•Secretin from intestinal cells exposed to HCl and fatty chyme

front 128

•Gallbladder contraction is stimulated by

back 128

•Cholecystokinin (CCK) from intestinal cells exposed to proteins and fat in chyme
•Vagal stimulation (minor stimulus)

front 129

•CKK also causes the hepatopancreatic sphincter to do what

back 129

relax

front 130

CCK induces the secretion of what

back 130

enzyme-rich pancreatic juice by acini

front 131

•Secretin causes secretion of what

back 131

bicarbonate-rich pancreatic juice by duct cells

front 132

•Vagal stimulation also causes release of what

back 132

pancreatic juice (minor stimulus)

front 133

Chyme from stomach contains

back 133

Partially digested carbohydrates and proteins
and Undigested fats

front 134

what are the Requirements for Digestion and Absorption in the Small Intestine

back 134

•Slow delivery of hypertonic chyme
•Delivery of bile, enzymes, and bicarbonate from the liver and pancreas
•Mixing

front 135

Motility of the Small Intestine is caused by Segmentation describe

back 135

Initiated by intrinsic pacemaker cells
•Mixes and moves contents slowly and steadily toward the ileocecal valve
•Intensity is altered by long and short reflexes
• Wanes in the late intestinal (fasting) phase

front 136

describe Peristalsis

back 136

•Initiated by motilin in the late intestinal phase
•Each wave starts distal to the previous (the migrating motility complex)
•Meal remnants, bacteria, and debris are moved to the large intestine

front 137

what are the unique features of the large intestine

back 137

Unique features
•Teniae coli
•Three bands of longitudinal smooth muscle in the muscularis
•Haustra
•Pocketlike sacs caused by the tone of the teniae coli
•Epiploic appendages
•Fat-filled pouches of visceral peritoneum

front 138

what are the Regions of the large intestine

back 138

•Cecum (pouch with attached vermiform appendix)
•Colon
•Rectum
•Anal canal

front 139

Ascending colon and descending colon are (location)

back 139

retroperitoneal

front 140

Transverse colon and sigmoid colon are anchored via

back 140

mesocolons (mesenteries)

front 141

describe the Rectum

back 141

Three rectal valves stop feces from being passed with gas

front 142

the Anal canal is what

back 142

•The last segment of the large intestine

front 143

what are the Sphincters of the anal canal

back 143

•Internal anal sphincter— smooth muscle
•External anal sphincter—skeletal muscle

front 144

describe the Large Intestine: Microscopic Anatomy

back 144

•Mucosa of simple columnar epithelium except in the anal canal (stratified squamous)
•Abundant deep crypts with goblet cells
•Superficial venous plexuses of the anal canal form hemorrhoids if inflamed

front 145

Bacterial Flora enter from where, and do what

back 145

•Enter from the small intestine or anus
•Colonize the colon
•Ferment indigestible carbohydrates
•Release irritating acids and gases
•Synthesize B complex vitamins (for cellular respiration) and vitamin K (for production of clotting proteins)

front 146

what is the function of the large intestine

back 146

Vitamins, water, and electrolytes are reclaimed
•Compaction of feces occurs
•Major function is propulsion of feces toward the anus

front 147

is the colon essential for life

back 147

no

front 148

what are Haustral contractions

back 148

•Slow segmenting movements
•Haustra sequentially contract in response to distension

front 149

what is Gastrocolic reflex

back 149

•Initiated by presence of food in the stomach
•Activates three to four slow powerful peristaltic waves per day in the colon (mass movements)

front 150

describe defecation

back 150

Mass movements force feces into rectum
•Distension initiates spinal defecation reflex
•Parasympathetic signals
•Stimulate contraction of the sigmoid colon and rectum
•Relax the internal anal sphincter
•Conscious control allows relaxation of external anal sphincter

front 151

Chemical Digestion and Absorption of Carbohydrates occurs where

back 151

the small intestine

front 152

Digestive enzymes are

back 152

Salivary amylase, pancreatic amylase, and brush border enzymes of microvilli

front 153

describe Absorption

back 153

•Enter the capillary beds in the villi
•Transported to the liver via the hepatic portal vein

front 154

Chemical Digestion and Absorption of Proteins
•Enzymes:

back 154

pepsin in the stomach

front 155

•Pancreatic proteases are

back 155

•Trypsin, chymotrypsin, and carboxypeptidase

front 156

•Brush border enzymes are

back 156

•Aminopeptidases, carboxypeptidases, and dipeptidases

front 157

chemical digestion and absorption of proteins

back 157

•Enter the capillary beds in the villi
•Transported to the liver via the hepatic portal vein

front 158

Chemical Digestion and Absorption of Lipids

back 158

•Pre-treatment—emulsification by bile salts
•Enzymes—pancreatic lipase
•Absorption of glycerol and short chain fatty acids
•Absorbed into the capillary blood in villi
•Transported via the hepatic portal vein
•Absorption of monoglycerides and fatty acids
•Cluster with bile salts and lecithin to form micelles
•Released by micelles to diffuse into epithelial cells
•Combine with proteins to form chylomicrons
•Enter lacteals and are transported to systemic circulation

front 159

Chemical Digestion and Absorption of Nucleic Acids

back 159

•Enzymes
•Pancreatic ribonuclease and deoxyribonuclease
•Absorption
•Enter the capillary beds in the villi
•Transported to the liver via the hepatic portal vein

front 160

Vitamin Absorption In small intestine

back 160

•Fat-soluble vitamins (A, D, E, and K) are carried by micelles and then diffuse into absorptive cells
•Water-soluble vitamins (vitamin C and B vitamins) are absorbed by diffusion or by passive or active transporters.
•Vitamin B12 binds with intrinsic factor, and is absorbed by endocytosis

front 161

Vitamin Absorption In large intestine

back 161

•Vitamin K and B

front 162

Electrolyte Absorption occurs where

back 162

Mostly along the length of small intestine
•Iron and calcium are absorbed in duodenum
•Na+ is coupled with absorption of glucose and amino acids
•Ionic iron is stored in mucosal cells with ferritin
•K+ diffuses in response to osmotic gradients
•Ca2+ absorption is regulated by vitamin D and parathyroid hormone (PTH)

front 163

Water Absorption

back 163

•95% is absorbed in the small intestine by osmosis
•Net osmosis occurs whenever a concentration gradient is established by active transport of solutes
•Water uptake is coupled with solute uptake

front 164

Malabsorption of Nutrients
•Causes

back 164

•Anything that interferes with delivery of bile or pancreatic juice
•Damaged intestinal mucosa (e.g., bacterial infection)

front 165

what is Gluten-sensitive enteropathy (celiac disease)

back 165

•Gluten damages the intestinal villi and brush border
•Treated by eliminating gluten from the diet (all grains but rice and corn)

front 166

GERD (heartburn)

back 166

Gastroesophageal reflux disease (GERD) is a condition in which the stomach contents (food or liquid) leak backwards from the stomach into the esophagus (the tube from the mouth to the stomach). This action can irritate the esophagus, causing heartburn and other symptoms.

front 167

hiatal hernia

back 167

Hiatal hernia is a condition in which part of the stomach sticks upward into the chest, through an opening in the diaphragm. The diaphragm is the sheet of muscle that separates the chest from the abdomen.

front 168

•gastric ulcers (Helicobacter pylori)

back 168

A hiatal hernia occurs when a portion of the stomach prolapses through the diaphragmatic esophageal hiatus. Although the existence of hiatal hernia has been described in earlier medical literature, it has come under scrutiny only in the last century or so because of its association with gastroesophageal reflux disease (GERD) and its complications. There is also an association between obesity and the presence of hiatal hernia. By far, most hiatal hernias are asymptomatic and are discovered incidentally. On rare occasion, a life-threatening complication, such as gastric volvulus or strangulation, may present acutely.

front 169

emesis

back 169

(vomiting)

front 170

•Gallstones

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A gallstone is a crystalline concretion formed within the gallbladder by accretion of bile components. These calculi are formed in the gallbladder, but may pass distally into other parts of the biliary tract such as the cystic duct, common bile duct, pancreatic duct, or the ampulla of Vater.

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•Hepatitis

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Hepatitis is swelling and inflammation of the liver. It is not a condition, but is often used to refer to a viral infection of the liver.

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•Diverticulitis

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Diverticulitis is small, bulging sacs or pouches of the inner lining of the intestine (diverticulosis) that become inflamed or infected. Most often, these pouches are in the large intestine (colon).

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•irritable bowel syndrome

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Irritable bowel syndrome (IBS) is a disorder that leads to abdominal pain and cramping, changes in bowel movements, and other symptoms.

IBS is not the same as inflammatory bowel disease (IBD), which includes Crohn's disease and ulcerative colitis. In IBS, the structure of the bowel is not abnormal