Chapter 35 - Jejunum and ileum Flashcards
What is the approximate average length of the equine small intestine?
A) 10 meters
B) 20 meters
C) 25 meters
D) 30 meters
C) 25 meters
Where is the duodenojejunal flexure located in the horse?
A) Right side of the ventral abdomen
B) Left side of the dorsal abdomen
C) Right side of the dorsal abdomen
D) Left side of the ventral abdomen
B) Left side of the dorsal abdomen
What is the range of the length of the jejunum in adult horses?
A) 10 to 20 meters
B) 17 to 28 meters
C) 5 to 15 meters
D) 20 to 30 meters
B) 17 to 28 meters
Which artery provides the arterial supply to the jejunum?
A) Caudal mesenteric artery
B) Ileocecocolic artery
C) Cranial mesenteric artery
D) Ileal artery
C) Cranial mesenteric artery
What structure allows the jejunum to have significant mobility?
A) The length of the jejunum
B) The long mesojejunum
C) The ileocecal fold
D) The vasa recta
B) The long mesojejunum
Which of the following structures does NOT form part of the ileal papilla in horses?
A) Inner circular muscle layer
B) Central longitudinal muscle layer
C) Outer layer from the circular muscle of the cecum
D) Inner longitudinal muscle layer
D) Cranial mesenteric artery
What is the length of the ileum in adult horses?
A) 0.5 meters
B) 0.7 meters
C) 1.0 meter
D) 1.5 meters
B) 0.7 meters
Which of the following best describes the role of the venous network at the ileocecal junction?
A) It functions as a true sphincter
B) It contributes to the sphincter mechanism
C) It is most engorged when the ileum is discharging its contents
D) It prevents reflux of cecal contents into the ileum
C) It is most engorged when the ileum is discharging its contents
Which artery branches off to supply the ileum?
A) Jejunal artery
B) Caudal mesenteric artery
C) Cranial mesenteric artery
D) Ileal artery
D) Ileal artery
Which of the following is NOT a component of the vascular arcade in the jejunum?
A) Major jejunal vessel
B) Arcuate vessel
C) Vasa recta
D) Ileal artery
D) Ileal artery
Which statement is correct regarding the ileal orifice?
A) It is located at the cecal base
B) It lacks an annular fold
C) It is surrounded by cecal musculature
D) It has a true sphincter
C) It is surrounded by cecal musculature
What happens to the ileal papilla when the cecum is active?
A) It becomes less prominent
B) It remains unchanged
C) It contracts and closes
D) It becomes more prominent
D) It becomes more prominent
Where does the majority of digestion and nutrient absorption occur in the equine small intestine?
A) In the ileum
B) In the lower half of the small intestine
C) In the upper half of the small intestine
D) In the large intestine
C) In the upper half of the small intestine
What unique feature is found on the epithelial surface of the equine small intestine?
A) Plicae circulares
B) Mucosal folds
C) Villi
D) Rugae
C) Villi
What type of cells makes up the majority of the small intestinal epithelial cells?
A) Paneth cells
B) Enteroendocrine cells
C) Goblet cells
D) Enterocytes
D) Enterocytes
How many crypts of Lieberkühn typically surround each villus in the equine small intestine?
A) 2 to 4
B) 4 to 6
C) 6 to 9
D) 10 to 12
C) 6 to 9
Which statement is TRUE about the turnover time of enterocytes on the villus?
A) They have a turnover time of 1 day
B) They turnover every 2 to 3 days
C) They remain for 7 to 10 days
D) They do not undergo turnover
B) They turnover every 2 to 3 days
Which of the following is NOT a feature of the mature enterocyte’s apical surface?
A) Microvilli
B) Brush border membrane
C) Tight junctions
D) Mucosal folds
D) Mucosal folds
Which type of cells in the small intestine is primarily responsible for surface digestion and active transport of nutrients?
A) Paneth cells
B) Enteroendocrine cells
C) Mature enterocytes
D) Undifferentiated columnar cells
C) Mature enterocytes
What function do tight junctions between enterocytes serve?
A) They allow large molecules to pass through
B) They restrict the transmucosal flux of large molecules
C) They prevent the absorption of water
D) They help in nutrient absorption directly
B) They restrict the transmucosal flux of large molecules
What happens to the intercellular space during water absorption in the small intestine?
A) It shrinks
B) It expands
C) It remains unchanged
D) It becomes impermeable
B) It expands
Where are the enzymes responsible for the final digestion of carbohydrates and proteins located?
A) Within the crypts of Lieberkühn
B) In the brush border membrane of microvilli
C) In the paracellular channel
D) In the intercellular space
B) In the brush border membrane of microvilli
What triggers the release of secretin in the duodenum?
A) Presence of fat
B) Presence of protein
C) Presence of hydrogen ions
D) Presence of carbohydrates
C) Presence of hydrogen ions
What is the primary role of bicarbonate (HCO3−) secreted in the proximal small intestine?
A) To digest carbohydrates
B) To stimulate bile production
C) To neutralize hydrogen ions
D) To activate pancreatic enzymes
C) To neutralize hydrogen ions
Which cells in the duodenal mucosa release cholecystokinin (CCK)?
A) S-cells
B) Parietal cells
C) I-cells
D) G-cells
C) I-cells
Which pancreatic enzyme requires activation by the brush border enzyme enterokinase?
A) Amylase
B) Lipase
C) Trypsinogen
D) Chymotrypsinogen
C) Trypsinogen
Which of the following is a unique feature of the equine pancreatic secretion?
A) High concentration of bicarbonate
B) High enzymatic content
C) Continuous secretion even at rest
D) High concentration of sodium ions
C) Continuous secretion even at rest
How does the concentration of bicarbonate (HCO3−) in equine pancreatic secretion compare to that in other animals?
A) It is higher
B) It is similar
C) It is lower
D) It is negligible
C) It is lower
What is the significance of the chloride ion (Cl−) in equine pancreatic secretion?
A) It is exchanged with HCO3− in the terminal ileum
B) It is a cofactor for enzyme activation
C) It inhibits bile acid secretion
D) It is primarily involved in nutrient absorption
A) It is exchanged with HCO3− in the terminal ileum
Which statement is TRUE regarding nutrient digestion and absorption in horses?
A) It is less efficient than in other species
B) Horses ferment starches only in the large intestine
C) Lipase activity is particularly high compared to other enzymes
D) Starch digestibility is independent of botanical origin
C) Lipase activity is particularly high compared to other enzymes
Which acids combine with glycine and taurine to form conjugated bile salts in the liver?
A) Acetic acid and butyric acid
B) Cholic acid and chenodeoxycholic acid
C) Lactic acid and pyruvic acid
D) Palmitic acid and stearic acid
B) Cholic acid and chenodeoxycholic acid
What percentage of bile salts are reabsorbed by the small intestinal mucosa?
A) 70%
B) 80%
C) 90%
D) 94%
D) 94%
Which process describes the reabsorption and resecretion of bile salts by the liver?
A) Passive diffusion
B) Endocytosis
C) Enterohepatic circulation
D) Osmosis
C) Enterohepatic circulation
Which part of the small intestine is critical for the active transport of bile salts?
A) Duodenum
B) Jejunum
C) Ileum
D) Cecum
C) Ileum
What is the effect of ileal resection on bile salt loss through feces in horses?
A) It significantly increases bile salt loss
B) It decreases bile salt loss
C) It does not increase bile salt loss compared to jejunal resection
D) It stops bile salt loss completely
C) It does not increase bile salt loss compared to jejunal resection
Why can passive absorption in the jejunum preserve enterohepatic circulation of bile salts?
A) Because bile salts are at their highest concentration in the jejunum
B) Because the jejunum has a special enzyme for bile absorption
C) Because the jejunum produces bile salts
D) Because bile salts are not absorbed elsewhere in the intestine
A) Because bile salts are at their highest concentration in the jejunum
Which pancreatic enzyme is NOT directly involved in the digestion of protein?
A) Trypsin
B) Chymotrypsin
C) Carboxypeptidase
D) Amylase
D) Amylase
Where does most water absorption occur in the equine small intestine?
A) Proximal third
B) Middle third
C) Distal third
D) Water is not absorbed in the small intestine
C) Distal third
Which part of the gastrointestinal tract absorbs the bulk of intestinal water?
A) Small intestine
B) Large intestine
C) Stomach
D) Esophagus
B) Large intestine
Which of the following is TRUE about the transcellular movement of Na+ in the small intestine?
A) It is a passive process
B) It involves the Na+/K+–ATPase pump
C) It does not require energy
D) It is driven by water transport
B) It involves the Na+/K+–ATPase pump
What is the main function of the Na+/K+–ATPase pump in the small intestine?
A) To passively transport Na+ into the cell
B) To generate energy for Cl− transport
C) To actively transport Na+ out of the cell
D) To create an osmotic gradient for water absorption
C) To actively transport Na+ out of the cell
How is Cl− transported into the cell across the apical membrane?
A) By passive diffusion
B) By secondary active transport
C) By simple diffusion
D) By primary active transport
B) By secondary active transport
Which process is energized by the Na+ gradient in the small intestine?
A) Uptake of water
B) Secretion of digestive enzymes
C) Uptake of glucose and amino acids
D) Release of bicarbonate
C) Uptake of glucose and amino acids
What primarily drives water transport in the small intestine?
A) Active transport
B) Osmotic gradient
C) Electrochemical gradient
D) Chemical gradient
B) Osmotic gradient
Where does water accumulated in the intercellular space move next?
A) Into the lumen
B) Toward the capillary bed
C) Toward the central lacteal
D) Into the cell
B) Toward the capillary bed
What is the effect of the tight junctions between enterocytes in the jejunum?
A) They allow free passage of ions and water
B) They completely block ion and water movement
C) They restrict backflow of absorbed water and electrolytes
D) They facilitate active transport of nutrients
C) They restrict backflow of absorbed water and electrolytes
What is the mechanism called when net water movement from lumen to plasma drags permeant ions and low–molecular weight substances with it?
A) Active transport
B) Solvent drag
C) Facilitated diffusion
D) Osmosis
B) Solvent drag
In which structure does fluid absorbed by the intestinal epithelium initially accumulate?
A) Capillary bed
B) Intercellular space
C) Central lacteal of the villus
D) Crypts of Lieberkühn
C) Central lacteal of the villus
Which factor primarily influences ion and fluid transport in the proximal bowel?
A) Osmotic gradient alone
B) Active Na+ transport only
C) Starling forces
D) Chemical gradients
C) Starling forces
What is the role of solvent drag in the small intestine?
A) It blocks ion movement
B) It enhances nutrient absorption by dragging ions with water
C) It decreases water absorption
D) It prevents water from leaving the lumen
B) It enhances nutrient absorption by dragging ions with water
Which structure is involved in moving absorbed fluid from the villus to deeper lymphatics?
A) Central lacteal
B) Basolateral membrane
C) Tight junction
D) Capillary bed
A) Central lacteal
Which of the following monosaccharides are produced by the hydrolysis of starch digestion products by brush border enzymes in horses?
A) D-ribose, D-mannose, D-glucose
B) D-glucose, D-fructose, D-galactose
C) D-glucose, D-sucrose, D-maltose
D) D-glucose, D-lactose, D-fructose
B) D-glucose, D-fructose, D-galactose
How does sucrase activity in the proximal small intestine of horses on a grass-based diet compare to other nonruminants?
A) It is lower
B) It is higher
C) It is comparable
D) It is absent
C) It is comparable
Which enzyme has a constant distribution along the equine small intestine and higher activity than in other species?
A) Lactase
B) Sucrase
C) Maltase
D) Amylase
C) Maltase
What is TRUE about lactase activity in the equine small intestine?
A) It is highest in the duodenum
B) It increases with maturity
C) It is higher in the jejunum than other parts of the small intestine
D) It remains constant throughout life
C) It is higher in the jejunum than other parts of the small intestine
Which transporter is responsible for the uptake of D-glucose and D-galactose in the small intestine of horses?
A) GLUT5
B) SGLT1
C) GLUT2
D) Na+/K+–ATPase
B) SGLT1
Which part of the equine small intestine is the major site of D-glucose uptake via SGLT1?
A) Ileum
B) Duodenum
C) Jejunum
D) Cecum
B) Duodenum
How does fructose enter enterocytes in the equine small intestine?
A) Via active transport
B) Via facilitated diffusion through GLUT5
C) Via passive diffusion
D) Via SGLT1 cotransport
B) Via facilitated diffusion through GLUT5
Which transporter is responsible for moving monosaccharides out of the enterocytes into the portal venous system?
A) SGLT1
B) GLUT5
C) GLUT2
D) Na+/K+–ATPase
C) GLUT2
How does an increase in soluble carbohydrates (like oats, corn, or barley) in the diet affect glucose transport in the equine small intestine?
A) It decreases glucose transport rates
B) It increases glucose transport rates and SGLT1 expression
C) It increases disaccharidase activity
D) It decreases SGLT1 expression in the duodenum
B) It increases glucose transport rates and SGLT1 expression
What happens to SGLT1 expression in the ileum when a horse’s diet is gradually switched from low to high hydrolyzable carbohydrates?
A) It remains the same
B) It decreases
C) It increases three to five times
D) It decreases in the duodenum
C) It increases three to five times
Which dietary transition can help reduce the risk of diet-induced colic in horses?
A) A sudden increase in hydrolyzable carbohydrates
B) A gradual switch to a high-carbohydrate diet
C) A decrease in fiber intake
D) A switch from grass-based diet to low-carbohydrate feed immediately
B) A gradual switch to a high-carbohydrate diet
Which statement is TRUE about GLUT5 in horses?
A) It is a Na+-dependent transporter
B) It has high affinity but low capacity
C) It is most active in the ileum
D) It facilitates fructose transport
D) It facilitates fructose transport
What is the impact on disaccharidase activity when horses switch from a pasture forage diet to a diet high in soluble carbohydrates?
A) It increases significantly
B) It decreases
C) It remains unaffected
D) It stops altogether
C) It remains unaffected
Which of the following monosaccharides are produced by the hydrolysis of starch digestion products by brush border enzymes in horses?
A) D-ribose, D-mannose, D-glucose
B) D-glucose, D-fructose, D-galactose
C) D-glucose, D-sucrose, D-maltose
D) D-glucose, D-lactose, D-fructose
B) D-glucose, D-fructose, D-galactose
How does sucrase activity in the proximal small intestine of horses on a grass-based diet compare to other nonruminants?
A) It is lower
B) It is higher
C) It is comparable
D) It is absent
C) It is comparable (Correct Answer)
Which enzyme has a constant distribution along the equine small intestine and higher activity than in other species?
A) Lactase
B) Sucrase
C) Maltase
D) Amylase
C) Maltase
What is TRUE about lactase activity in the equine small intestine?
A) It is highest in the duodenum
B) It increases with maturity
C) It is higher in the jejunum than other parts of the small intestine
D) It remains constant throughout life
C) It is higher in the jejunum than other parts of the small intestine
Which transporter is responsible for the uptake of D-glucose and D-galactose in the small intestine of horses?
A) GLUT5
B) SGLT1
C) GLUT2
D) Na+/K+–ATPase
B) SGLT1
Which part of the equine small intestine is the major site of D-glucose uptake via SGLT1?
A) Ileum
B) Duodenum
C) Jejunum
D) Cecum
B) Duodenum
How does fructose enter enterocytes in the equine small intestine?
A) Via active transport
B) Via facilitated diffusion through GLUT5
C) Via passive diffusion
D) Via SGLT1 cotransport
B) Via facilitated diffusion through GLUT5
Which transporter is responsible for moving monosaccharides out of the enterocytes into the portal venous system?
A) SGLT1
B) GLUT5
C) GLUT2
D) Na+/K+–ATPase
C) GLUT2
How does an increase in soluble carbohydrates (like oats, corn, or barley) in the diet affect glucose transport in the equine small intestine?
A) It decreases glucose transport rates
B) It increases glucose transport rates and SGLT1 expression
C) It increases disaccharidase activity
D) It decreases SGLT1 expression in the duodenum
B) It increases glucose transport rates and SGLT1 expression
What happens to SGLT1 expression in the ileum when a horse’s diet is gradually switched from low to high hydrolyzable carbohydrates?
A) It remains the same
B) It decreases
C) It increases three to five times
D) It decreases in the duodenum
C) It increases three to five times
Which dietary transition can help reduce the risk of diet-induced colic in horses?
A) A sudden increase in hydrolyzable carbohydrates
B) A gradual switch to a high-carbohydrate diet
C) A decrease in fiber intake
D) A switch from grass-based diet to low-carbohydrate feed immediately
B) A gradual switch to a high-carbohydrate diet
Which statement is TRUE about GLUT5 in horses?
A) It is a Na+-dependent transporter
B) It has high affinity but low capacity
C) It is most active in the ileum
D) It facilitates fructose transport
D) It facilitates fructose transport
What is the impact on disaccharidase activity when horses switch from a pasture forage diet to a diet high in soluble carbohydrates?
A) It increases significantly
B) It decreases
C) It remains unaffected
D) It stops altogether
C) It remains unaffected
What role do brush border oligopeptidases play in protein digestion in the small intestine of horses?
A) They convert proteins into large peptides
B) They hydrolyze small neutral peptides into dipeptides, tripeptides, or amino acids
C) They activate pancreatic peptidases
D) They transport peptides into the portal blood
B) They hydrolyze small neutral peptides into dipeptides, tripeptides, or amino acids
After peptides are transported into the enterocyte, how are they processed?
A) They are packaged into chylomicrons
B) They are converted into fatty acids
C) They are hydrolyzed into amino acids by cytoplasmic oligopeptidases
D) They are excreted directly into the lumen
C) They are hydrolyzed into amino acids by cytoplasmic oligopeptidases
Which of the following statements about amino acid transport in the equine intestine is TRUE?
A) All amino acids are Na+-dependent for transport
B) Amino acid transport systems are uniform in their specificity
C) Some amino acid transport systems are Na+-dependent while others are not
D) Only dipeptides and tripeptides are Na+-dependent for transport
C) Some amino acid transport systems are Na+-dependent while others are not
What is required for the transport of small peptides in the equine jejunum?
A) Na+
B) H+
C) K+
D) Cl-
B) H+
How do long-chain fatty acids and 2-monoglycerides reach the enterocyte membrane for absorption?
A) They diffuse directly through the lumen
B) They form mixed micelles with bile acids
C) They are actively transported by GLUT5
D) They bind to amino acids
B) They form mixed micelles with bile acids
What is the fate of long-chain fatty acids and 2-monoglycerides once they enter the mucosal cells?
A) They are broken down into amino acids
B) They are converted into glucose
C) They are reesterified and form chylomicrons
D) They are directly absorbed into the blood
C) They are reesterified and form chylomicrons
How is fat digestion in horses affected by the composition and concentration of dietary fat?
A) Fat digestion is highest in forage-based diets
B) Fat digestion decreases with increasing dietary fat
C) Fat digestion is lowest for forages and highest with added triglycerides
D) Fat digestion is unaffected by dietary composition
C) Fat digestion is lowest for forages and highest with added triglycerides
How can the lipolytic activity in horses be upregulated?
A) By decreasing dietary fat intake
B) By gradually increasing dietary fat through supplementation
C) By increasing fiber intake
D) By reducing dietary triglycerides
B) By gradually increasing dietary fat through supplementation
Why might horses require greater supplementation with fat-soluble vitamins during growth and pregnancy?
A) They have reduced fat digestion during these periods
B) They have increased demand for energy
C) Lipolytic activity increases with dietary fat, necessitating higher intake of fat-soluble vitamins
D) They lose fat-soluble vitamins in the feces
C) Lipolytic activity increases with dietary fat, necessitating higher intake of fat-soluble vitamins
What effect does adding fat to the diet of horses have on fat digestion?
A) It decreases the residence time of fat in the small intestine
B) It reduces the digestibility of fat
C) It increases fat digestibility through delayed gastric emptying
D) It inhibits fiber digestion in the large intestine
C) It increases fat digestibility through delayed gastric emptying
What does the term “micellar solubilization” refer to in the context of fat digestion?
A) The breakdown of fats into amino acids
B) The formation of mixed micelles that facilitate lipid absorption
C) The conversion of triglycerides into monosaccharides
D) The passive diffusion of fatty acids across the brush border
B) The formation of mixed micelles that facilitate lipid absorption
What happens to absorbed ferrous iron in the enterocyte if iron stores in the body are low?
A) It binds to apoferritin and is stored
B) It is released into the circulation via transferrin receptors
C) It is excreted into the intestinal lumen
D) It is converted to ferritin and stored in the liver
B) It is released into the circulation via transferrin receptors
What is the role of apoferritin in iron regulation within the enterocyte?
A) It transports iron across the basolateral membrane
B) It binds to absorbed ferrous iron to form ferritin
C) It activates transferrin receptors
D) It facilitates iron absorption from the lumen
B) It binds to absorbed ferrous iron to form ferritin
Where is the highest flux of calcium absorption in the horse’s small intestine?
A) Jejunum
B) Duodenum
C) Ileum
D) Colon
B) Duodenum
What effect does a high concentration of dietary magnesium have on calcium absorption?
A) It enhances calcium absorption
B) It decreases calcium absorption through competition
C) It has no effect on calcium absorption
D) It increases calcium-binding protein activity
B) It decreases calcium absorption through competition
Which vitamin regulates the specific calcium-binding protein that facilitates calcium transport in enterocytes?
A) Vitamin A
B) Vitamin D
C) Vitamin E
D) Vitamin K
B) Vitamin D
Where does magnesium absorption primarily occur in the equine digestive tract?
A) Stomach
B) Proximal small intestine
C) Distal small intestine
D) Large intestine
B) Proximal small intestine
What is the primary determinant of intestinal water and electrolyte secretion in horses?
A) Na+ absorption by crypt cells
B) K+ secretion by villi
C) Cl− secretion by crypt cells
D) Mg2+ absorption by enterocytes
C) Cl− secretion by crypt cells
Which cells are thought to act as pacemakers for generating electrical slow waves in the equine small intestine?
A) Enterocytes
B) Myenteric plexus neurons
C) Interstitial cells of Cajal (iCC)
D) Crypt cells
C) Interstitial cells of Cajal (iCC)
What is the function of mucus secreted by Brunner glands in the equine small intestine?
A) To aid in the absorption of nutrients
B) To neutralize acidic chyme
C) To protect the duodenal wall from gastric secretions
D) To stimulate peristalsis
C) To protect the duodenal wall from gastric secretions
In horses, where is the density of interstitial cells of Cajal (iCC) highest?
A) In the duodenum
B) In the jejunum
C) In the ileocecal junction
D) In the colon
C) In the ileocecal junction
Which phase of the migrating motor complex (MMC) is characterized by no action potentials and slow waves only?
A) Phase I
B) Phase II
C) Phase III
D) Phase IV
A) Phase I
What is the primary role of the migrating motor complex (MMC) during the interdigestive state?
A) To enhance nutrient absorption
B) To increase gastric emptying
C) To reduce bacterial colonization in the small intestine
D) To slow down peristalsis
C) To reduce bacterial colonization in the small intestine
What neural components are involved in the control of motor events in the small intestine?
A) Vagus nerve and sympathetic nervous system
B) Enteric nervous system
C) Both A and B
D) None of the above
C) Both A and B
Which plexus in the enteric nervous system is primarily responsible for innervating the longitudinal muscle and the outer lamella of circular muscle?
A) Submucosal (Meissner) plexus
B) Myenteric (Auerbach) plexus
C) Intrinsic plexus
D) Sympathetic plexus
B) Myenteric (Auerbach) plexus
What role does motilin play in the gastrointestinal system?
A) Stimulates the release of digestive enzymes
B) Regulates the interdigestive migrating motor complex (MMC)
C) Inhibits intestinal contractions
D) Promotes absorption of nutrients
B) Regulates the interdigestive migrating motor complex (MMC)
Where can the migrating action potential complex (mAPC) be recorded in ponies?
A) Jejunum only
B) Ileum only
C) Both jejunum and ileum
D) Neither jejunum nor ileum
B) Ileum only
What is the effect of withholding food for 24 hours on the ileal migrating action potential complex (mAPC) in ponies?
A) Increases frequency of mAPC
B) Decreases frequency of mAPC
C) Increases slow-wave frequency
D) Decreases conduction velocity of spike bursts
B) Decreases frequency of mAPC
Which neurotransmitter decreases ileal and cecal activity but increases ileal sphincter tone?
A) Serotonin
B) Epinephrine
C) Acetylcholine
D) Dopamine
B) Epinephrine
Which drug does NOT significantly affect duodenal motility in horses?
A) Xylazine
B) Butorphanol
C) Acepromazine
D) Detomidine
C) Acepromazine
What happens to myoelectric activity in the horse’s ileum after small intestinal resection and anastomosis?
A) Increases in frequency
B) Stops aboral progression of the MMC
C) Enhances motility
D) Remains unaffected
B) Stops aboral progression of the MMC
Which neurotransmitter receptor type is responsible for increasing ileal sphincter tone?
A) β-adrenergic receptors
B) α1-adrenergic receptors
C) H1 receptors
D) M3 muscarinic receptors
B) α1-adrenergic receptors
How does fasting affect motility in the equine jejunum and large intestine?
A) Increases motility
B) Decreases motility
C) Has no effect on motility
D) Increases sensitivity to acetylcholine
B) Decreases motility
What is the primary function of the ileal papilla in the horse?
A) To increase nutrient absorption
B) To prevent reflux of cecal contents
C) To stimulate bile secretion
D) To enhance peristalsis in the ileum
B) To prevent reflux of cecal contents
Which substance increases ileal peristalsis in ponies?
A) Bile acids
B) Luminal fatty acids
C) Lipids
D) Intraluminal short-chain fatty acids
B) Luminal fatty acids
What percentage range of all colic cases treated at veterinary hospitals is attributed to small intestinal diseases?
A) 10% to 20%
B) 25% to 64%
C) 70% to 90%
D) Less than 10%
B) 25% to 64%
What is the median percentage of colic cases due to small intestinal diseases in veterinary hospitals?
A) 10%
B) 25%
C) 34%
D) 50%
C) 34%
In what percentage of small intestinal obstructions is the ileum involved?
A) 10% to 20%
B) 25% to 30%
C) 41% to 46%
D) 50% to 60%
C) 41% to 46%
What percentage range of small intestinal colics are caused by strangulating lesions?
A) 10% to 30%
B) 31% to 50%
C) 58% to 85%
D) 90% to 100%
C) 58% to 85%
What is the remaining percentage of small intestinal colics caused by nonstrangulating obstructions?
A) 10% to 30%
B) 15% to 42%
C) 50% to 70%
D) 85% to 100%
B) 15% to 42%
What is the most common cause of nonstrangulating obstruction of the equine small intestine?
A) Strangulating obstruction
B) Ileal impaction
C) Gastric rupture
D) Cecal impaction
B) Ileal impaction