exam 3: chapter 37 Flashcards
what are the components of swallowing?
esophagus
peristalsis
upper esophageal sphincter
lower esophageal sphincter
what are the functions of the components of swallowing?
○ Esophagus
■ Hollow, muscular tube
■ Connects oropharynx to the stomach
○ Peristalsis: muscle movement automatic
■ Involuntary constriction and relaxation that pushes content down the digestive tract
○ Upper esophageal sphincter (UES)
■ Keeps air from entering the esophagus during respiration
○ Lower esophageal sphincter (LES)
■ Prevents regurgitation from the stomach and caustic injury to the esophagus
describe what happens at the oropharyngeal/upper esophageal and esophageal phases
Phases
■ Oropharyngeal/upper esophageal
● Food formed into bolus and forced toward pharynx
● Pharynx contracts
● Respiration inhibited and epiglottis slides down
● UES closed
■ Esophageal
● Food bolus enters esophagus
● Esophagus relaxes
● UES opens
● Peristalsis occurs to move food down to LES
● Food bolus enters stomach
describe the Digestive/absorptive anatomy/ structures (as food moves through)
○ Stomach:
■ Stores food, secretes digestive juices, mixes food with the juices, and propels partially digested food (chyme)
● Mucus coats and protects from H.pylori
● Intrinsic factor - aids in absorbing vitamin B12
● Gastroferrin (iron) - facilitates small intestinal absorption of iron
■ Receives food bolus per LES
■ Intestinal digestion and absorption is initiated in stomach
● Actions of gastric hydrochloric acid and pepsin (breaks down protein)
○ Small intestine:
■ Three segments
● Duodenum
● Jejunum
● Ileum
○ Ileocecal valve: attaches small intestine to large intestine
■ Peritoneum
● Parietal-lines the walls of the cavity (entire abdomen)
● Visceral wraps around the abdominal organs (stomach, liver, spleen, SI/LI
■ Intestinal digestion and absorption continues in proximal portion of small intestine
● Action of pancreatic enzymes, intestinal enzymes, and bile salts
○ Carbohydrate breakdown
○ Protein degraded
○ Fats emulsified
○ Large intestine
■ Cecum
● Pouch that receives chyme from ileum
■ Colon
● Ascending
● Transverse
● Descending
● Sigmoid
■ Fecal mass massaged
■ Water absorbed
■ Peristaltic movements promote the emptying of the colon
■ Gastrocolic reflex
● Causes the fecal mass to pass rapidly into the sigmoid colon and rectum
■ Defecation reflex
● Stimulated by the movement of feces into the sigmoid colon and rectum
■ Rectum
■ Anus
what are the functions of the liver?
○ Bile is produced in the liver
○ Stores blood
○ Hemostatic functions
■ Synthesizes clotting factors
● Bile salts are needed for reabsorption of fats, vitamin K absorption depends on adequate bile production in the liver
○ Metabolism of nutrients
■ Fats
■ Proteins
■ Carbohydrates
○ Metabolic detoxification
○ Storage of minerals and vitamins
○ Functions:
■ Storage
■ Degradation/ breakdown
■ Metabolism
■ Synthesis
the liver is divided into
Divided into right and left lobes
■ Right lobe further divided into 2 additional lobes
what are the functions of the gallbladder
○ It’s primary function is to store and concentrate bile
○ Bile:
■ An alkaline, bitter-tasting, yellowish-green fluid that contains bile salts, cholesterol, bilirubin, electrolytes, and water
■ Formed by hepatocytes and stored in the gallbladder
what is the immune role of the digestive system
○ Major role in immune defenses by killing many microorganisms
■ Antibodies (IgA)
■ Peyer patches (collection of lymphocytes, plasma cells, and macrophages) produce immunoglobulin A as a component of the gut-associated lymph tissue in the small intestine
○ Numbers of bacteria increases from proximc to distal GI tract
■ Highest in colon
○ Antibiotics affect gut biome
what are the functions of the exocrine pancreas and the related outcomes of malfunction
○ Involved in digestion and is composed of acinar cells that secrete enzymes and networks of ducts that secrete alkaline fluids to assist in digestion
■ Enzymes
● Hydrolyze proteins, carbohydrates, and fats
■ Trypsin inhibitor
● Prevents the activation of proteolytic enzymes while they are in the pancreas
_________is defined as waves of sequential contractions of the gastrointestinal muscles
a. peristalsis
b. anorexia
c. retching
d. hematemesis
a. peristalsis
the functional unit of the small intestine:
a. villi
b. perietal cells
c. hepatocytes
d. kuppfer cells
a. villi
motilin (stimulates; inhibits) gastric emptying; while secretin (stimulates, inhibits) gastric emptying
a. inhibits, stimulates
b. stimulates; inhibits
b. stimulates; inhibits
which structure controls the flow of digested material from the terminal ileum into the large intestine?
a. mucosal barrier
b. duodenum
c. ileocecal valve (spincter)
d. peritoneum
c. ileocecal valve (sphincter)
________ is necessary for the intestinal absorption of B12; while _________ facilitates the absorption of iron in the small intestine
a. gastroferrin; intrinsic factor
b. intrinsic factor; gastroferrin
c. histamine; gastrin
d. secretin; gastroferrin
b. intrinsic factor; gastroferrin
The small intestine is compromised of which of the following segments?
a. jejunum
b. ascending colon
c. ileum
d. duodenum
a. jejunum
c. ileum
d. duodenum
