152 Questions
What accessory organs supply secretions to the digestive tract for digestion
All of the above
The digestive tract can be described as
A hollow, tube-like structure extending from the mouth to the anus
Materials within the lumen of the GI tract are, strictly speaking _________
Outside the body
Function of the oral cavity in order; _________, __________, _________ __________(add comma after each answer)
Prehension, mastication, chemical digestion
What is the mechanical breakdown of food, the process also increases surface area for exposure to digestive enzymes
Mastication
What provides the enzymes for initial chemicla breakdown of food
Saliva
What salivary enzyme is present in omnivores
Both A and B
What does amylase break down
Starches
Degluitition is the act of
Swallowing
Name the parts of the stomach cranial to caudal, add a comma after each part
Fundus, body, pyloric antrum, pylorus
What inhibits muscle activity of the fundus
Gastrin by the G cells of the antrum
This part of the stomach relaxes with swallowing but also contracts to help mix food
Body
What moves food in the stomach
Peristalsis
What is involved in peristalsis
Both A and C
What does the longitudinal muscle layer in the body of the stomach do
Propels food from cardia to antrum
What is the role of the circular muscle layer in the body of the stomach
Mixes and grinds
Where does the circular muscle layer maintain constant tone during stomach contractions
Pylorus
What maintains constant tone during stomach contractions
Circular muscle layer in the pylorus of the stomach
What prevents the stomach from pushing contents into duodenum too quickly
Enterogastric reflex
What is inhibited by factors causing distention of the small intestine or increased acidity in the duodenum
Stomach contractions
Stomach contractions can be inhibited by what
Factors causing distension in the small intestines or increased acidity in the duodenum
What does excess stomach acid in the duodenum do
Stimulate release of the hormone secretin from the duodenum
Produces pepsinogen
Chief cells
Secretes mucous
Mucus cells
Secretes hydrochloric acid (HCI)
Parietal cells
Prehension of food is carried out with
All of the above
What is the term for the mechanical grinding and breakdown of food
Mastication
Digestive tract functions, for beginning to end
Prehension, mastication, digestion, absorption, elimination
Saliva provides enzymes for the secondary chemical breakdown of food
False
Saliva provides enzymes for initial chemical breakdown of food
True
Breaks down lipids
Lipase
Mastication and saliva work together to _________
Both B and C
Which gastric glands of the GI tract secrete intrinsic factor
Both A and B
Why is the secretion/production of intrinsic factor important
Necessary for absorption of vitamin B12
Which of the following can slow gastric emptying by stimulating the release of hormone cholecytoskinin (CKK)
Large amounts of fats or proteins in duodenum
Which of the following decreases contractions of gastric fundus, body and antrum
Both A and C
Which of the following hormones causes the fundus to relax and inhibits peristalsis of gastric body and antrum resulting in slowing of gastric emptying
Secretin
Transports food from pharynx to stomach
Esophagus
Movement of a food bolus is a coordinated effort between what muscle layers
Outer longitudinal and inner circular muscle layers
Which of the following moves the food bolus towards the stomach
Relaxation of the longitudinal muscle and contraction of the circular muscles
The relaxation and contraction of the longitudinal and circular muscle layers is referred to as _________
Peristalsis
What happens when the peristaltic wave reaches the lower end of the esophagus
Longitudinal muscles shorten and the circular muscles relax
The esophagus enters the stomach at an angle to allow the stomach to _______________
Form a natural fold which acts as a valve to close the distal portion of the esophagus
The salivary gland ducts secrete saliva when they are stimulated by
The parasympathetic nervous system
Relaxes with swallowing and allows filling
Fundus
Secretion of gastrin by the G cells of the antrum inhibit muscle activity of the fundus which allows ___________
Both B and C
What allows relaxation and filling of the fundus and stimulation of mixing activity in the pyloric antrum
Secretion of gastrin by the G cells of the antrum
Propels food towards pylorus
Both A and B
Grinding and mixing activity in the pyloric antrum is stimulated by
Both A and B
When G cells secrete the hormone gastrin, the antrum begins to distend with food, what happens next
The parietal cells are stimulated, releasing HCI
Pepsin and HCI are secreted into
The lumen of the stomach
Gastrin is a hormone that is secreted
Into the blood
What forces liquid food (chyme) through the duodenum
Antral contractions
Antral contractions force liquid food (chyme) through
to the duodenum first, and solids/semisolids are retained in the stomach
Helps regulate stomach acid production
All of the above
Gastrin secreted by G cells
Stimulates both parietal and chief cells
Acetylcholine from cholinergic neurons
Stimulates mainly parietal cells
Histamine secreted by ECL cells
Mainly stimulates parietal cells
What results in the correct amount of hydrogen and chloride secretion
All of the above
Blocking any of the receptors that regulate stomach acid production will not cause a decrease in the production of stomach acid
False
Blocking any of the receptors that regulate stomach acid production will cause a decrease in the production of stomach acid
True
Match to its best description
Contractions of smooth muscle in the walls of the GI tract that crush, mix and propel its contents = Motility Breakdown of food, via mechanical and chemical means, into smaller soluble particles = Digestion Delivery of enzymes, mucus and ions into the lumen of the GI tract = Secretion Transport of water, ions and nutrients from the lumen, across the epithelium and into blood = Absorption
Chemical digestion of proteins
Starts in the stomach
Digestion of starch by salivary amylase
Occurs in the stomach and is continued in the small intestine by pancreatic amylase
Prostaglandins, (PGE & PGI) reduce stomach acid by inhibiting gastrin release from chief cells
False
Prostaglandins, (PGE & PGI) increase stomach acid by stimulating gastrin release from G cells
False
Prostaglandins, (PGE & PGI) reduce stomach acid by inhibiting gastrin release from G cells
True
Prostaglandins, (PGE & PGI) do NOT directly inhibit parietal cells
False
Prostaglandins, (PGE & PGI) may directly inhibit parietal cells
True
Prostaglandins, (PGE & PGI) stimulate potassium ion production
False
Prostaglandins, (PGE & PGI) stimulate bicarbonate ion production
True
Prostoglandins in the GI
Both A and C
Prostaglandins, (like PGE & PGI) can enhance blood flow to the liver
False
Prostaglandins, (PGE & PGI) can enhance blood flow to the stomach
True
Prostaglandins, (PGE & PGI) destabilizes lysosomes w/in gastric cells
False
Prostaglandins, (PGE & PGI) stabilize lysosomes w/in gastric cells
True
Prostaglandins, (PGE & PGI) stabilize macrophages in gastric cells
False
Prostoglandins (like PGE & PGI) regulate parietal and chief cell activity
False
Prostaglandins, (PGE & PGI) regulate macrophage and mast cell activity
True
Macrophage and mast cell activity in the stomach is regulated by
Both A and C
The macrophages and mast cells in the stomach serve to
Repair damage done to the epithelial lining caused by breaks in the mucus barrier
Rumination is described as
The regurgitation of chewed food for rechewing
Regurgitation of chewed food for rechewing is termed ____________
Rumination
Increased mechanical breakdown of plant material results in
Both A and C
What part of the ruminant stomach is the true stomach
Abomasum
The abomasum is considered the
The true stomach
The forestomach has
3 compartments
What type of epithelium is the forestomach made up of
Stratified squamous epithelium, nonglandular
Match the following
Smallest compartment, located cranial to the rumen and lies against the diaphragm on the median plane = Reticulum Takes up most of the left side of the abdominal cavity and extends from diaphragm to pelvis when it gets full = Rumen True stomach = Abomasum On the right side of the abdominal cavity, is reduced in camelids (or absent alltogether) = Omasum
Which is located cranial to the rumen and lies against the diaphragm on the median plane
Reticulum
Has honey comb appearance
Luminal surface of the reticulum
The luminal surface of the rumen has a honeycomb appearance and it _____________
Increases surface area of the absorptive surface
Which of the following contracts with the rumen in a coordinated manner
Reticulum
Primary contractions are termed
Reticulorumen contractions
Primary contractions (reticulorumen contractions) refer to
The mixing of contents back and forth between the rumen and the reticulum
Primary contractions serve to
Both A and B
What allows carbon dioxide and methane gas to be expelled
Eructation
Fermentative digestion is anaerobic
True
Fermentative digestion is aerobic
False
Fermentative digestion happens via _____________
Both A and B
During fermentative digestion; what do cellulase enzymes do
All of the above
What is fermentative digestion reliant on
bacteria, protozoa and fungi from the rumen and reticulum
Cellulose, hemicellulose, and pectin are _________
Complex carbohydrates
The rumination process involves four steps, what is the first
Regurgitation
VFAs like proprionic acid are absorbed and converted in the ____________ into _________
Liver, glucose
VFAs other than proprionic acid are used to produce _______
Both A and B
Microbial breakdown of proteins yield peptides and amino acids that are _______________________
Both B and C
Microbial breakdown of proteins _____
Yields peptides and amino acids
Ruminant liver converts ammonia to ___________
Urea
Ruminant liver converts ammonia to area that is secreted into the __________
Both B and C
The ruminant liver converts ammonia to urea that is secreted into the rumen to _____________
Supply the microbes with nitrogen
Urea is secreted into the saliva via _________
Bloodstream
When urea is secreted into the rumen what does it do
Supplies microbes with nitrogen
When microbes are digested they provide a small fraction of the source of protein for the ruminant
False
When microbes are digested they provide the major source of protein for the ruminant
True
The rumen provides
Both B and C
Ingesta moves into the ________ from the _________ in response to ____________________________
omasum, reticulum, reticulorumen contractions
_______ __________ are left at the top of the rumen and ________ are pushed into the __________ by primary contractions
Smaller particles, liquid, omasum
The inner surface of the omasum has ___________
Many folds, like plies or leaves
What is the function of the folds (plies or leaves) of the omasum
Increased absorptive surface area
The inner surface of the omasum has many folds for increased absorption of
Water and salts
At birth _________ and ________ are small and essentially ___________ with little to no __________ ___________ occurring while young are on a milk diet
rumen, reticulum, nonfunctional, fermentative digestion
How long does the development of rumen and reticulum take in calves
3 months depending on the diet fed
The act of suckling causes milk to bypass the rumen and reticulum via ___________
Both A and B
What would happen if the reticular groove folds didnt fold in and enter the omasum directly
Both B and C
What happens if the rumen pH is decreased
Production of lactic acid that causes acidosis which inhibits normal bacterial growth
Abomasum in young ruminants secretes the enzyme _______
Rennin
Rennin
Both A and C
Milk protein remain in the abomasum for longer due to rennin and are broken down by
Pepsin
The small intestine is made up of the
Duodenum, jejunum, ileum
What happens in the small intestine
Both B and C
What is the role of the large intestine
Fluid and electrolyte reabsorption, storage of feces
What are the componetns of the large intestine
Cecum, colon, rectum
Absorption of intestinal contents and consistency of stool depend partly on
Balance between perisalsis and segmental contractions
Match
Complex reflex response in which feces is evacuated from the terminal colon and rectum = Defecation Voluntary motor impulses to external sphincter muscle are inhibited allowing the external sphincter to relax = During defecation Filters materials absorbed from the GI tract before they reach the systemic circulation = Liver Exocrine and endocrine functions = Pancreas
Match
Enzyme produced in the saliva = Amylase Breakdown proteins into amino acids and dipeptides = Proteases Breaks down some of the protein chains into polypeptides = Gastric pepsin Penetrate bile acid coating and digest the fat molecule = Pancreatic lipases
Trypsinogen is converted to trypsin by the enzyme
Enteropeptidase
Enteropepcinogen is secreted in response to
CKK secretion
Pancreatic enzymes are released as inactive precursors (proenzymes), the key precursor and activator is ______ which converts into __________ and activates more trypsinogen as well as ______________________
Trypsinogen, trypsin, other pancreatic enzyme precursors
Chemical digestion of protein occurs at ___________ by __________ embedded in the cell membrane
brush border, peptidases
Pancreatic enzymes are released as
Inactive precursors
Match
Stomach breaks globules into droplets via agitation of the antrum = Emulsification Bile salts secreted into the duodenum via the livers bile duct attach to the droplets so they cannot form into globules again = Micelle formation Secretes bicarbonate into the duodenum to neutralize stomach acid = Pancreas Largest organ in the body besides the skin = Liver
___________ is released by ____________, secreted into __________ that merge to form _______ that form the _____________ leading to the _________ where bile is stored
Bile, hepatic cells, bile ductules, ducts, hepatic duct, gallbladder
Blood proteins are produced in the liver, which of the following is the primary protein
Albumin
CKK causes gallbladder contraction, forcing bile into the duodenum
Via the common bile duct
Release of the hormone cholecytoskinin _____________ intestinal motility and ________ gastric motility
Stimulates, decreases
Excess stomach acid in the duodenum stimulates the release of homone __________ from the duodenum
Secretin
MAATCH
Coordinated contractions of longitudinal and circular muscle layer = Peristalsis Mix intestinal contents; random, localized contractions of circular muscl elayer = Segmental contractions Electrolytes, water, and vitamins can be absorbed intact = Small intestinal digestion Stimulation of stretch receptors in rectum, partial relaxation of internal sphincter of anus = Defecaton
Fermentative digestion is
Anaerobic
The antrum has gastric glands with mucous cells
True
The antrum has gastric glands with mast cells
False
Gastric glands in the fundus and body of the stomach
Mucous cells, chief cells and parietal cells
Test your knowledge of the accessory organs that supply secretions to the digestive tract and their functions in digestion. Explore the mechanical and chemical processes involved in breaking down food in the digestive system.
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