Digestive System Flashcards
Digestive System (161 cards)
1
Q
The digestive system is divided into organs of
A
The alimentary canal and accessory organs
2
Q
What are other names of the alimentary canal
A
GI Tract or digestive tract
3
Q
Literally refers to the stomach through anal canal
A
GI Tract
4
Q
What subset of the abdominal cavity are the digestive organs in?
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Peritoneal cavity
5
Q
What is the name of the membrane that surrounds the digestive organs
A
Peritoneal membrane.
6
Q
parts of the peritoneal membrane that attach the organs to the body wall.
A
Mesentery
7
Q
Name an organ that loses its mesentery
A
Pancreas
8
Q
What is mechanical breakdown
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Manipulating food to cause physical change
9
Q
Examples of mechanical breakdown include
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Chewing, churning, emulsification of fats by bile
10
Q
Chemical breakdown resulting in chemical change. Usually breaking chemical bonds assisted by an enzyme.
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Chemical digestion
11
Q
Breaking down a protein molecule into an amino acid is an example of what type of digestive change?
A
Chemical Change
12
Q
What is the point of digesting food?
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So we can absorb its basic molecules.
13
Q
What part of the parotineal membrane portion lines the cavity?
A
pariteal portion
14
Q
What part of the paritoneal membrane covers the digestive organs
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visecreal portion
15
Q
Organs like the pancreas that lose their mesentery and are more attached to the posterior body wall are called
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Retroperotineal
16
Q
Outer membrane made of tough connective tissue and a surface epithilium
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Serosa
17
Q
two layers of smooth muscle through most of the tract- longitudinal and circular
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Muscularis externa
18
Q
The connective tissue layer, numerous blood vessles, glands, nerves etc
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Submucosa
19
Q
What kind of tissue is the submucosa made of?
A
Connective tissue
20
Q
What kind of layer is the muscularis externa made of?
A
two layers of smooth muscle (circular and longitudinal)
21
Q
What is the underlying layer in the mucosa composed of connective tissue
A
Lamnia propria
22
Q
An inner layer with absorptive epithelial cells. A thin layer of smooth muscle is also present in some of the tract
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Mucosa
23
Q
Building blocks molecules
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Monomers
24
Q
Moves food through the digestive tract
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muscularis externa
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What two ways does the muscularis externa move food along the tract
Segmentation and peristalsis
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Wave like milking motion
Peristalsis
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Constricts the tube into segments, pushing material from one segment to the next
Segmentation
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Which organ may do segmentation and peristalsis
The small intestine
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Helps keep food out of the nasopharynx, extends down from soft palate.
The uvula
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How do small molecules get across the plasma membrane?
Using transport proteins
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Are dissacharides able to get transported across the plasma?
No, they can be too large
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What organ is good at breaking down macromolecules to their smallest pars?
Small intestine
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How does the small intestine break down molecules to their smallest parts?
The enzymes of the small intestine are able to do this
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What are the layers of the digestive tract?
Serosa, Muscularis extern, submucosa, mucosa
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Further reinforces the GI Tract tube and and secretes a small amount of lubricating fluid. This is the outermost layer
Serosa
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besides vessels and nerves, lymphatic tissue tissue may be found here.
submucosa
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Teeth and tongue
Mechanical digestion
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amylase from salivary glands
Chemical digestion
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Where does mechanical and chemical digestion occur?
In the mouth
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Made of the palatine process of the maxilla and palatine bone
Hard palate
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Consists of muscle and epithelial covering
Soft palate
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lined with non-keratinized stratified squamous epithelium, and has a great deal of skeletal muscle
The mouth
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Are there living cells of the enamel coating of the teeth?
No because it is so dense
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What are the main anatomical features of the teeth?
Crown (above the gum, neck and root
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What supplies the tooth with blood vessles and nerves?
Root canal
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Amalayse begins the process of
Starch digestion
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water, salivary amalayse, and mucous is secreted by what glands into the mouth? What is the purpose of this?
salivary glands. The purpose is to moisten and lubricate food to make it easier to chew and swallow.
48
What cells produce the watery secretions with amylase?
Serous cells
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What cells produce mucous?
Mucous cells
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Why can some lipid digestion begin in the mouth ?
Because small amounts of salivary lipase are produced.
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Secrete a mixture of enzymes, water and mucous
Buccal glands
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Ducts open near upper molars, secrete mostly enzymes and water
Parotid glands
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Skeletal muscle of the oropharynx and laryngopharynx do what with food?
push is back into the esophagus
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Where does an abrupt change in epithelium from stratified squamous to simple columnar occur?
gastroesophageal junction.
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Which region of the stomach is where the esophagus attaches?
The cardiac region
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Bulge above the point of attachment to the esophagus
Fundus
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The area that tappers down to the small intestine
pyloric region
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keeps food from moving into the intestine until liquified
pyloric sphincter
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Deep folds in the lining of the stomach
Gastric pits
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Chief cells which produce pepsinogen, pariteal cells which produce HCL
Gastric gland cells
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Why doesnt the acid of HCL destroy the stomach lining?
Mucous protects the lining. Fairly rapid mitosis allows the stomach lining to replace itself every few days.
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Unlike most of the GI, this has a third layer of muscle in the muscularis externa. An oblique layer that allows churning
The stomach
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The inside curve of the stomach
Lesser curvature
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The outside curve of the stomach
The greater curvature
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Why doesnt the chief cell directly produce pepsin
Pepsin would digest the cells own proteins.
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Chops up large proteins into smaller polypeptide fragments
Pepsin
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The small intestine consists of the
duodenum, jejunum, and ileum
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First half of the remainder of the small intestine
jejunum
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Second half of the remainder of the small intestine
ileum
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First part that loops under the stomach and is behind part of the colon
duodenum
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What is the main pancreatic duct connected to?
The duodenum
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produces mainly digestive enzymes and bicarbonate ions to neutralize the acidc chyme coming from the stomach
The pancreas
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indirectly stimulates bicarbonate ion release
Acidic chyme in the duodenum
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indirectly stimulates enzyme release
Nutrient rich chyme
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Modified for digestion and absorption
Small intestine
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Examples of enzymes that break down small peptide chains into individual amino acids
aminopeptidase and dipeptidase
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Examples of enzymes that break down small polysaccharides and dissacharides into simple sugars
Glucoamylase, sucrase, and lactase
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easily absorbed through the plasma membrane, however, they are converted into triglycerides in the ER, and processed into chylomicron vesicles by the Golgi apparatus.
Large fatty acids and monoglycerides
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he pocket of large intestine below this point of attachment
The cecum
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regulates flow of material into the large intestine.
ileocecal valve
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What make up most of the large intestine?
The colon
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Where is waste stored?
the rectum- part of the large intestine
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What helps regulate waste elimination?
The anal sphincters
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At the end of the anal canal the epithelium changes to
Stratified squamous
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mainly absorbs water to solidify wastes, but “commensal” bacteria found inside also break down molecules and produce some vitamins such as vitamin K. These vitamins and some electrolytes are also absorbed.
Large intestine
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stretch receptors in the rectum initiating a spinal reflex that stimulates contraction of muscle in the wall of the rectum, and relaxation of the internal (involuntary) anal sphincter.
defecation reflex
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arguably the largest organ in the body, with functions that overlap into several systems.It is made of large right and left lobes, and smaller quadrate and caudate lobes.
The liver
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protein catylst that help break down the major classes of macromolecules
Enzymes
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Works best at slightly acidic to netural pH but does work to some degree under a slightly more broad range of pH's and temperatures.
Salivary amylase
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Works for up to an hour in the stomach, until pH drops to low and the enzyme is destroyed by HCL and pepsin
Salivary amylase `
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requires a slightly alkaline pH (7.5-8.0) and temperatures around 37iC in order to be effective.
Pancreatic amylase
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finish the job of digesting carbohydrates down to monosaccharides.
Brush boarder enzymes
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requires an acidic pH to work, which is usually the pH in the stomach within an hour after eating due to HCl.
pepsin
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not an enzyme, but a surfactant that breaks up big fat globules into small ones.
Bile
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controlled by the nervous system mainly through the parasympathetic division of the autonomic nervous system. This includes diverse input from the CNS as well as simple local reflexes.
Digestion
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controlled through a system of hormones secreted by endocrine tissues in the digestive tract. These hormones are mainly secreted in response to chemical stimuli.
Digestion
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food molecules and pH changes may locally stimulate contraction of smooth muscle in parts of the GI tract.
Short reflex
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stimulate saliva release
The facial and glossopharyngeal nerves
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Mostly mechanoreceptors stimulate the salivatory nuclei in the brain stem.
Salivary glands
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Which organ does mainly local control or short reflexes?
Small intestine
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These organs deliver most of their secretions to the small intestine. They are mostly controlled by hormones
the liver, gallbladder, and pancreas
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What inhibit parasympathetic stimulation of the stomach.
Sympathetic stimulation, low stomach pH, as well as psychological (cerebrum) and emotional factors
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Chemoreceptors in the stomach detecting food chemicals and higher pH stimulate the release this hormone
gastrin from g cells
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stimulates gastric gland secretion, and relaxation of the ileocecal valve.
Gastrin
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Acidic, nutrient-rich chyme in the duodenum triggers release of the hormones
CCK (cholecystokinin) and secretin
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stimulates gallbladder contraction
CCK
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Stimulates faster bile production in the liver
secretin
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A hormone made by the stomach
Gastrin
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stimulates the pancreas to release bicarbonate into the duodenum to neutralize the acid.
Secretin
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a hormone made by the duodenum.
secretin
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cck is a hormone made by the
duodenum
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The presence of food, particularly lipid-rich food, entering the duodenum triggers release of
cck
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Nutrients absorbed by the GI tract are used 2 ways
anabolism and catabolism
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building up larger molecules: amino acids into proteins; glucose to glycogen; glycerol and fatty acids to lipids.
anabolism
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breaking down molecules for energy: sugars and glycerol into glycolysis; amino acids and fatty acids into acetyl CoA.
catabolism
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Enzyme system in cytoplasm breaks down glucose and obtains 2 ATP (aka anaerobic respiration).
glycolysis
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What are the 3 salivary glands?
parotid glands, submandibular gland, and sunlingual gland.
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These combined secretions make it easier to chew most food and swallow it as a small rounded bolus.
submandibular gland and sunlingual gland
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gland located below the mandible
submanibular gland
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Gland located below the tongue
sunlingual gland
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modified bone which surrounds a pulp cavity
dentin
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Most of the dentin and pulp lies below the gum line and forms the
root
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The enamel lies mostly above the gum line and forms most of the
crown
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transition area at the gum line
neck
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The permanent set of teeth differ from the deciduous teeth by having
biscups and third molars (wisdom teeth)
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composed of stratified squamous epithelium and voluntary muscles involved in swallowing.
pharynx
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Special lymph nodes also located in the pharynx
tonsils
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Does the cardiac sphincter remain closed or open?
closed except when swallowing which is important for keeping acid from the stomach from leaking upward into the esophagus.
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sac-like organ where food will be liquefied into chyme ("kime") and stored for gradual release into the small intestine.
stomach
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Mechanical breakdown in the form of churning occurs due to the muscular action from a
third oblique layer of smooth muscle
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What assists chemical digestion?
pepsin and HCL
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Produces pepsinogen and pariteal cells
chief cells found in gastric pits
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What is the inactive form of pepsin?
pepsinogen
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When does pepsinogen convert into active pepsin ?
when it is attacked by the acid of the stomach
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converts CO2 into carbonic acid which dissociates to provide a source of H+
carbonic anhydrase
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Chyme from the stomach, bile from the liver/gallbladder, and pancreatic secretions (several enzymes and bicarbonate) all pout into
the duodenum
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Full of blood vessles and nerves in the mouth
pulp cavity
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modified bone matrix which is so dense that is crowds out cells. This is why damaged teeth can not heal as bones.
enamel
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when the tongue pushes food toward the oropharynx, starting a reflex that constricts pharyngeal muscles in order from top to bottom, which pushes the bolus of food toward the esophagus.
initiation of swallowing
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composed of stratified squamous epithelium and voluntary skeletal muscle in its superior portion, but gradually transitions into smooth muscle near the stomach. This seems to allow for voluntary initiation of swallowing along with the pharyngeal muscles, but at some point the involuntary aspect of swallowing takes over.
esophagus
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How does the stomach protect itself from acidic chyme?
Rapid mitosis and and numerous mucous globlete cells
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Most lipid digestion occurs in the
small intestine
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What are the divisions of thte stomach?
fundus, body, and plyroic region
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Why does chemical digestion take place?Q
Because of lipase, amylase, and proteases from the pancreas.
145
Nearly all of the nutrients should be absorbed from the digested food by the time it exits the
ileum
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What makes up the large intestine?
cecum, colon, and rectum, (sometimes the anal canal)
147
Blind pouch with the appendix at its end
cecum
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Nearly square in all shape, framing abdominal cavity.
colon
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Found on the right side of the colon
Ascending colon
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brings waste products across the superior portion of the abdominal cavity,
Transverse colon
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Runs down the left side of the body
desceding colon
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squiggles through the pelvic cavity, finally connecting to the rectum
Sigmoid colon
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Major function of the colon is
water absorption
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The microscopic bile ducts from the lobules eventually merge to form
Hepatic duct
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The hepatic duct and merges with the gallbladder's cystic duct to become
the common bile duct
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small sac-like organ tucked up under the liver.
gallbladder
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both break down starches in different parts of the digestive tract.
salivary amylase and pancreatic amylase
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Numerous small ducts from the clumps of acinar cells merge to form the
main pancreatic duct
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pancreatic duct merges with the bile duct from the liver/gallbladder to form the
hepato-pancreatic duct.
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r example of portal circulation.
blood supply to and from the liver
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inhibit gastrin release
cck and secretine
