ch 25 and 26 practice test Flashcards
- digestive process begins with the ingestion of food
- starting in the mouth the mechanical and chemical breakdown of food is referred to as digestion
- once foods are broken down into chemical monomers the digestive system moves nutrients from the GI tract into the cells of the body via absorption
- indigestable residues along with some of the non-reabsorbed secretion of digestive organs, undergo compaction
- the final step requires defecation where the fecal matter resulting from compaction is excreted from the body
accessory organ
- gallbladder
- salivary gland
- tooth
- liver
part of the digestive tract
- colon
- duodenum
- buccal cavity
- rectum
- ileum
- jejunum
parts of the buccal cavity
- foliate papillae
- gingivae
- submandibular ducts
- labial frenulum
parts of the stomach
- gastric pits
- fundus
- gastric rugae
- pylorus
- greater curvature
- three muscle layers
function of hydrochloric acid
- converts iron to an absorbable form
- activates pepsin and lingual lipase
- destroys most ingested pathogens
- breaks up connective tissues and cell walls of plants
function of pepsin
- digests proteins
- auocatalytic
- active form of a zymogen
function of gastric lipase
- digests fat in the stomach
function of intrinsic factor
- essential to the absorption of vitamin B12
- dysfunction could causes pernicious anemia
- during the gastric phase food stretched the stomach and activates myenteric and vagovagal reflexes
- these reflexes stimulate gastric secretions
- these secretion include gastrin, pepsinogen, and HCl
- these process will continue in a positive feedback cycle until the phase is complete
- small peptides buffer stomach acid so the pH does not fall excessively low
carbohydrate
- salivary amylase
- maltase
- sucrase
lipid
- lingual lipase
- pancreatic lipase
- gastric lipase
protein
- pepsin
- chymotrypsin
- carboxypeptidase
- the absorption of carbs from the intestinal lumen occurs directly through secondary active transport
- sodium-potassium pumps in the basal membrane work to actively transport sodium out the cell towards the interstitium while cotransporting potassium to the intracellular fluid
- with a declining intracellular concentration of sodium, sodium now diffuses from the intestinal lumen to the ICF of the epithelium
- the luminal diffusion of sodium to the ICF is coupled with glucose and galactose cotransport into the cell
what is the outermost layer of the digestive tract
serosa
in which direction do the peristalic contraction of the stomach’s smooth muscle move contents
from the body to the pyloric region
what is the mechanical and chemical breakdown of food called
digestion
which of the hormones does NOT inhibit gastric gland secretions
gastrin
which occurs during the gastric phase of gastric secretion
- gastric secretion begins
- the secretion of hydrochloric acid and pepsin is stimulated
- gastric secretion and motility is stimulated in response to food increasing the pH of the stomach’s contents
which inhibits the secretion of the gastric glands
duodenal pH of less than two
the medulla oblongata controls gastric secretion by utilizing the parasympathetic branch of the nervous system and the endocrine system
false
distention of the stomach activates a direct stimulatory effect on the gastric glands
true
in the parietal cells the enzyme carbonic anhydrase causes a reaction between
carbon dioxide
water
ions exchange molecules in the plasma membrane of the parietal cells exchange ____ ions going out for _ ions coming in
bicarbonate
chloride
hydrochloric acid is formed when
hydrogen ions and chloride ions join in the duct of the gastric gland
in the parietal cell carbonic acid dissociates into a bicarbonate ion and a hydrogen ion
true
the carbonic acid ion is joined to a hydrogen ion by the enzyme carbonic anhydrase
false
which does NOT stimulate the secretion of HCl in the stomach
secretin
secretin is released from the duodenum in response to
hydrochloric acid in chyme
which enzymes is produces by the stomach
pepsin
gastric function to increase the production of HCl in the stomach
true
as long as there is chyme in the duodenum it will continue to stimulate gastric secretion
false
uptake of nutrient molecules into the body’s own tissues is called
absorption
an ex of chemical digestion is the breakdown of
nucleic acids into nucleotides
which is not an accessory organ of digestion
spleen
____ is a hormone whereas ____ is an enzyme
secretun
pepsin
which is not normally found in saliva
protease
HCl is secreted by
parietal cells
pepsin is secreted as a zymogen
so it acts only in the stomach lumen and does not digest intracellular proteins
which of the following enzymes at the lowest pH
pepsin
pancreatic enzymes are secreted in response to a hormone called
cholecystokinin (CCK)
contact digestion takes place in/at the
brush border of the small intestine
in which organ does protein digestion begin
D. stomach
where does most nutrient absorption occur
F. small intestines
where do mass movements occur
E. large intestine
in which layer is the muscularis mucosae found
F
which layer is controlled by the plexus at A?
D
in which layer is the lamina propria found
F
which region is examined with a sigmoidoscope
G.
where is the hepatic flexure
C
which regions are retroperitoneal
B and F
