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Histology Spring 2020 > Digestive System > Flashcards

Digestive System Flashcards

1
Q

Place the following in the correct order of how to build an organism (least complex to most complex level of organization): cells, chemicals, tissues, organs, organ systems, organism

A

Chemicals to cells to tissues to organs to organ systems to organism

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2
Q

T/F Digestive efficiency of a food type increases with increasing amount of refractory material in food.

A

False

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3
Q

Rank the following in the order of hardness (>): enamel, cementum, dentin

A

Enamel>Dentin>Cementum

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4
Q

The ____ make dentin. Dentin is made in step ____?

A

odontoblasts, step 2

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5
Q

Hypsodont teeth are found in all of the following animals except:
Dogs, horses, cows, rabbits

A

dogs

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6
Q

Salivary secretions are modified in?

A

striated ducts

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7
Q

T/F Sensory receptors located in GI smooth muscle respond to stretch and tension

A

True

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8
Q

T/F Neurocrines are released by varicosities of sensory fibers

A

False

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9
Q

Equine veterinarians will often encounter horses affected by an alkaloid toxin called slaframine. Slaframine is produced by a mold (Rhizoctonia leguminicola) found in moldy red clover. The horse seems particularly sensitive and can lose as much as 40 L of saliva/day. The toxin is generally destroyed by exposure to stomach acid, so its effects are restricted to the salivary glands. Cows and sheep can also be affected by this mold. This toxin acts on which salivary gland receptors causing extreme salivation and drooling?

A

Muscarinic

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10
Q

Which of the following statments is TRUE regarding the sympathetic nervous system?

a. Postganglionic nerve cell bodies (ganglia) are within the wall of the target organ
b. Postganglionic receptors are nicotinic and muscarinic
c. Preganglionic neurons are adrenergic
d. Preganglionic neurons have short axons

A

d. Preganglionic neurons have short axons

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11
Q

The interstitial cells of Cajal (ICC) are:

A

modified smooth muscle cells capable of generating only slow waves

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12
Q

An animal is presented to you with aspiration pneumonia (the result of food material entering the lower respiratory tract). Which of the following lesions would be a likely cause?

a. Loss of myenteric plexus function in the pharynx and upper esophagus.
b. loss of slow-wave activity in the pharynx and upper esophagus
c. A lesion in the brainstem
d. A lesion in the trachea

A

c. A lesion in the brainstem

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13
Q

Conditions in the duodenum, such as low pH or high fat concentration, can reflexively inhibit gastric emptying. Which reflex arc is involved in this inhibition?

a. Parasympathetic nervous system
b. GI enteric nervous system
c. GI endocrine system
d. All the above

A

d. All the above

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14
Q

Which of the following best describes the motility of the fundus/body of the monogastric stomach?

a. rhythmic segmentation
b. adaptive relaxation
c. Peristalsis
d. Retropulsion

A

b. Adaptive relaxation

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15
Q

Colonic “pacemakers”:

A

shift in their sites under the influence of the ENS

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16
Q

Inhibition of the enzyme carbonic anhydrase is likely to have what effect on gastric pH?

A

increase gastric pH

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17
Q

Which of the following is not a potential stimulus for gastric acid secretion?

a. Norepinephrine secretion resulting from stimulation of sympathetic nerves
b. vagal nerve activity resulting from the sight of food
c. The presence of undigested protein in the pyloric antrum
d. Acetylcholine release stimulated by gastric stretch receptors acting on nerves of the ENS
e. Histamine release from cells in the gastric mucosa

A

a. Norepinephrine secretion resulting from stimulation of sympathetic nerves

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18
Q

Which of the following is not a natural ligand for receptors in the pancreas?

a. Cholecystokinin (CCK)
b. Acetylcholine (Ach)
c. Gastrin
d. Secretin

A

c. Gastrin

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19
Q

T/F Pancreatic proteases (trypsin and chymotrypsin) are stored as zymogens.

A

True

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20
Q

How could a bile stone lodged in the common bile duct induce vomiting?

A

Visceral afferents from outside the gastrointestinal tract

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21
Q

Which statement about the tight junctions is FALSE?

a. Tight junctions encircle the enterocyte near its apical end
b. Tight junctions from the dividing line between the apical membrane and basolateral membrane
c. Tight junctions are impermeable to water
d. Tight junctions separate the lateral space from the intestinal lumen
e. Tight junctions are the only points that attach enterocytes together

A

c. Tight junctions are impermeable to water

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22
Q

Which of the following molecules is consumed during the process of hydrolytic digestion?
Glucose, Alanine, Dipeptides, Fatty acids, Water

A

Water

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23
Q

The Na, K ATPase pump is the mechanism by which?

a. Exterior of cells is kept electrically negative with respect to the ICF
b. Concentration of sodium is kept very low in the intracellular fluid
c. Concentration of potassium is kept very low in the intracellular fluid
d. Concentration of sodium kept very high in the intracellular fluid

A

b. Concentration of sodium is kept very low in the intracellular fluid

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24
Q

T/F Transcellular absorption refers to movement of materials through the tight junctions

A

False

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25
Q

Crypt cell Cl- secretion is accomplished by?

A

Coupled Na/Cl transport-basolateral membrane, Cl moves through chloride channel in apical membrane into lumen

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26
Q

T/F Regarding Na absorption: As H+ is exchanged for Na+, HCO3- concentrations build up in the cell and the resulting transcellular HCO3- gradient drives the action of the Cl-/HCO3- exchanger.

A

True

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27
Q

T/F Right sided heart failure will cause a decrease in pressure in the thoracic and abdominal portions of the caudal vena cava.

A

False

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28
Q

Where are chylomicrons absorbed?

A

Lamina propria lymphatic capillaries (lacteals)

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29
Q

In which of the following respects is fermentative digestion different from glandular digestion?

A

Substrates are more extensively altered in fermentative digestion than in glandular digestion.

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30
Q

The three VFAs- acetate, propionate, and butyrate are:

A

Net reaction products of the fermentative action of the entire rumen biomass

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31
Q

Matching protein and energy availability in the rumen is an important nutritional goal in feeding ruminants. Which of the following statements is FALSE regarding diets well matched in available protein and energy?

a. Results in the most efficient use of energy for microbial growth
b. Results in maximal delivery of protein to the host
c. Results in minimal breakdown of protein in the rumen
d. Results in loss of a minimal amount of dietary amino acids because of formation of excess ammonia.
e. Results in optimal rumen ammonia concentrations

A

c. Results in minimal breakdown of protein in the rumen

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32
Q

T/F Energy and nitrogen are derived from either glucose or peptide.

A

False

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33
Q

T/F Digestibility is decreased by chopping or grinding of forages because the duration of exposure to microbial action is reduced as a result of rapid passage of feed through the rumen.

A

True

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34
Q

Papillary growth in the rumen is stimulated by which VFAs

A

Butyrate and propionate

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35
Q

T/F The rates of fermentation/molecular mechanisms of VFA production in the hindgut of the horse are similar to the rumen of the cow.

A

True

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36
Q

T/F Increasing particle size has a relatively small effect on the movement of particles out the the cecum. However, as particle size increases, there is significant retention of material in the colon and slow passage to the feces.

A

True

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37
Q

T/F In the rooster, the epithelium of the seminiferous tubules is arranged into narrow columns of cells that undergo spermatogenesis independently.

A

True

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38
Q

In what follicle size would you expect to see the highest progesterone levels?

A

F1

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39
Q

Which of the following is FALSE regarding vertebrate digestive system evolution?

a. Fruits contain an intermediate content of refractory material
b. Anus develops from the blastopore in deuterostomes
c. structural and functional features of vertebrate GI tracts reflect electrolyte chemistry content
d. Multicellular organisms utilize extracellular digestion to obtain nutrients
e. Decreasing the amount of refractory material increases digestive efficiency

A

c. structural and functional features of vertebrate GI tracts reflect electrolyte chemistry content

40
Q

Histology is focused at the following levels of organism organization:

A

cells, tissues, organs

41
Q

T/F Your patient has a normal physical exam and blood test values are within the reference ranges. As the DVM, you conclude your patient is healthy (homeostasis is occurring in the body).

A

True

42
Q

T/F The primary prehension mechanism in the horse is the tongue.

A

False

43
Q

Brachydont teeth problems require local/general anesthesia due to close proximity of?

A

pulp cavity

44
Q

The ____ make enamel. Enamel is made in step ____ of brachydont tooth formation.

A

Ameloblasts, Step 2

45
Q

Which of the following is FALSE regarding hypsodont teeth in the horse?

a. short root
b. tall crown
c. Mandible and maxilla alignment allows for even teeth wear
d. Enamel>dentin>cementum (hardness

A

c. Mandible and maxilla alignment allows for even teeth wear

46
Q

T/F Salivary secretions are modified in the striated ducts. Simple columnar duct epithelium provides Na and Cl reabsorption as well as K and HCO3- secretion into the duct lumen.

A

True

47
Q

Premolars and molars are responsible for:

A

Grinding and increasing the surface area of food= mechanical digestion

48
Q

ENS nerve plexuses contain sensory receptors located in
GI smooth muscle that?
a. Respond to stretch and tension
b. Control GI motility and secretion
c. Respond to chemical stimulation (acid, glucose, amino acids)
d. Respond to osmotic stimuli

A

a. Respond to stretch and tension

49
Q

What is the structure and functions of the ENS (enteric nervous system) myenteric plexus?

A

located between inner circular and outer longitudinal smooth muscle layers. Controls GI motility

50
Q

T/F the motor fibers of the ENS communicate with vascular muscle, and glands via direct synaptic transmission of Ach (acetylcholine).

A

False

51
Q

Parasympathetic preganglionic neurons are located?

a. Prevertebral ganglia
b. Paravertebral ganglia
c. T1-T13 and L1-L4
d. Brainstem and L1-L4
e. Brainstem and S1-S3

A

e. Brainstem and S1-S3

52
Q

Which statement is TRUE regarding the ANS (autonomic nervous system) mechanoreceptors and chemoreceptors?

a. X (vagus n.) efferent nerve fibers monitor normal to day changes in smooth muscle tension and chemical conditions in the GI lumen
b. X (vagus n.) afferent nerve fibers signals overdistension of gut wall, stretching of mesenteric attachments, or noxious chemicals in the GI lumen
c. Splanchnic sympathetic afferent nerve fibers signals overdistention of gut wall, stretching of mesenteric attachments, or noxious chemicals in the GI lumen
d. Splanchnic sympathetic efferent nerve fibers monitor normal day to day changes in smooth muscle tension and chemical conditions in the GI lumen

A

a. X (vagus n.) efferent nerve fibers monitor normal to day changes in smooth muscle tension and chemical conditions in the GI lumen

53
Q

T/F Enteroendocrine cells (EECs) communicate by: Endocrine signaling, paracrine signaling, afferent nerves, and efferent nerves.

A

True

54
Q

Which of the following is FALSE regarding enterochromaffin cells and 5-HT (serotonin)?

a. Type of enteroendocrine cell (EEC)
b. Released upon platelet activation during inflammation
c. Largest quantitiy is stored in platelets
d. Leads to decreased stimulation of myenteric neurons to increase GI motility
e. Serve as important chemoreceptors within the gut with serotonin serving as the signaling molecule linking these chemosensory cells to afferent neurons of the ENS

A

d. Leads to decreased stimulation of myenteric neurons to increase GI motility

55
Q

T/F Esophageal peristalsis begins with contraction of inner circular and relaxation of longitudinal smooth muscle to increase lumen size. This is followed by contraction of outer longitudinal and relaxation of inner circular smooth muscle to decrease lumen size.

A

False

56
Q

Which of the following statements is not consistent with interstitial cells of Cajal (ICC).

a. Connected to each other and to the smooth muscle mass by tight junctions
b. Movement of ions leads to the propagation of waves of partial cell membrane depolarization across large numbers of smooth muscle cells.
c. Forms a cellular network around the submucosal plexus in the space between the circular and longitudinal muscle layer.
d. ICC determines origin and direction of propagation of slow waves
e. Exhibit rhythmical and spontaneous oscillation in their transmembrane and electrical potentials

A

c. Forms a cellular network around the submucosal plexus in the space between the circular and longitudinal muscle layer.

57
Q

Which of the following is FALSE regarding slow waves, action potentials, and smooth muscle contractions?

a. Slow waves occur at the same frequency in all portions of the GI tract
b. Amplitude and frequency of the slow waves can be modulated by the ENS
c. When slow waves pass over an area of smooth muscle and smooth muscle action potentials are superimposed on the slow waves, smooth muscle contracts.
d. Excitatory molecules elevate the baseline and cause smooth muscle contraction
e. Inhibitory molecules lower the baseline and cause smooth muscle relaxation

A

a. Slow waves occur at the same frequency in all portions of the GI tract

58
Q

Which statement is FALSE regarding the migrating motility complex (MMC)?

a. Housekeeping function of small intestine
b. Impedes the migration of bacteria from the ileum to the duodenum
c. Begins in the duodenum as groups of slow waves that stimulate intense action potentials and smooth muscle contraction.
d. Meal consumption stimulates the MMC

A

d. Meal consumption stimulates the MMC

59
Q

T/F Afferent receptors of the enterogastric reflex are located in the gastric mucosa and are activated by low, pH, high osmolality, and the presence of fat

A

False

60
Q

All of the following are TRUE regarding colon motility and pacemakers EXCEPT?

a. Segmentation- mixing, circulates over absorptive surfaces
b. Tonic contraction- impedes ingesta movement, Ileocecal sphincter and colonic pacemaker
c. Colonic slow wave activity originates in the ICCs
d. Colonic ENS cannot shift the site of origin of slow waves and the direction of propagation
e. Peristalsis is responsible for propulsion.

A

d. Colonic ENS cannot shift the site of origin of slow waves and the direction of propagation

61
Q

Vomiting causes a loss of water and electrolytes. Can dehydration occur? Type of acid-base imbalance?

A

Yes. Metabolic alkalosis

62
Q

T/F Gastric acid secretion is maximally stimulated by parietal cell receptor binding of acetylcholine (ACh), gastrin, and histamine.

A

True

63
Q

NSAIDS cause a decrease in prostaglandin synthesis leading to the inability of surface mucous cells to secrete mucus leading to gastric ulceration. How does a proton pump inhibitor (ppi) help when added to clinical management plan?

A

Inhibits H, K ATPase pump

64
Q

T/F The luminal surface of centroacinar cells have a chloride-bicarbonate exchange protein that transports bicarbonate (HCO3-) into the cell in exchange for chloride (Cl-). This mechanism increases the bicarbonate concentration of pancreatic fluid.

A

False

65
Q

When receptor binding sites on the surfaces of pancreatic acinar, centroacinar, or duct cells are occupied by ligands, pancreatic secretions are stimulated. What are the receptors?

A

Ach (acetylcholine), cck (cholecystokinin), secretin

66
Q

Emeric drugs will directly stimulate _____ to induce vomiting?

A

Chemoreceptor trigger zone

67
Q

Emulsification provided by bile acids function to?

A

Increase surface area by solubilizing products of fat digestion

68
Q

T/F Pancreatitis is caused by premature activation of pancreatic lipases that are stored as zymogens.

A

False

69
Q

Which of the following is FALSE regarding structures responsible for increasing the surface area of the small intestine?
Villi, Microvilli, Crypts, Pilicae circularis

A

Crypts

70
Q

Chemical digestion of carbohydrates, proteins, and fats is accomplished through the action of digestive enzymes. Amylase works through the process of hydrolysis which cleaves?

A

Glycosidic bonds

71
Q

T/F Trypsinogen is activated to trypsin during the luminal phase of protein digestion by enterokinase.

A

True

72
Q

Membrane bound digestive enzymes are synthesized within the enterocytes and subsequently transported to the luminal surface of the ____ membrane.

A

Apical

73
Q

Na cotransport with glucose is an example of what type of transport?

A

Secondary active transport

74
Q

T/F Passive transport occurs only through paracellular absorption.

A

False

75
Q

Na is NOT absorbed from the small intestinal lumen into the enterocytes by this mechanism.

a. Na/H antiport
b. Na/ HCO3- antiport
c. Na cotransport proteins
d. Simple diffusion

A

b. Na/ HCO3- antiport

76
Q

T/F K absorption is directly coupled to water absorption.

A

True

77
Q

The regulated process of water and electrolyte secretion from the _____ ensures the continual availability of water and sodium in the gut lumen.

A

Crypt cells

78
Q

T/F Blood passes through capillaries in the lamina propria of small intestine villi with a low arterial hydrostatic pressure and the sinusoidal capillaries of liver with a high arterial hydrostatic pressure.

A

False

79
Q

Villus length is determined by the rate at which?

A

Villus epithelial cells are lost at the tips and crypt epithelial cells replace villi tips

80
Q

Regarding chylomicrons, the phospholipid and cholesterol are arranged with hydrophobic ends facing the core lipids and hydrophilic ends facing the surface. This arrangement of surface lipids makes the chylomicron?

A

Water soluble

81
Q

T/F Most cases of hypersecretory diarrhea result from inappropriate secretion from the small intestinal crypts. Hypersecretion can be stimulated by enterotoxins.

A

True

82
Q

Cellulases are produced by?

A

Microbes

83
Q

T/F Within the microbes, glucose enters the glycolytic pathway producing volatile fatty acids (acetate, butyrate, and proprionate) which contain chemical energy.

A

True

84
Q

T/F Glucose and peptide represent the available dietary carbohydrate and protein to the microbes for fermentation.

A

True

85
Q

Protein is produced in the rumen from nonprotein sources such as urea. Urea excretion occurs by absorption of urea into the rumen from the blood or by excretion into ____?

A

Salivary glands

86
Q

All of the following are considered primary contractions of the rumen EXCEPT?

a. Cranial moving contraction that starts in the caudal dorsal blind sac and continues over and dorsal sac
b. Cranial moving contraction of the dorsal sac serves to mix the dorsal sac ingesta, creating a mass of tangled forage fibers representing a large collection of relatively recently swallowed material
c. Material in the dorsal portion of the reticulum, including the recently swallowed bolus of feed, is washed back into the rumen by this flow of liquid ingesta
d. Caudal moving contraction of the dorsal sac follows the reticular contraction, continuing to move the recently swallowed bolus and other material further back into the dorsal sac.

A

a. Cranial moving contraction that starts in the caudal dorsal blind sac and continues over and dorsal sac

87
Q

T/F During regurgitation, there is a positive pressure created in the thorax allowing bolus movement into esophagus

A

False

88
Q

This structure contains broad longitudinal folds or leaves maximizing mucosal surface area, possible VFA and HCO3- absorption, and contains finely ground ingesta.

A

Omasum

89
Q

T/F VFAs, electrolytes, and water are initially absorbed through the stratum corneum and pass through intracellular channels to the cells of the stratum spinosum and stratum basale, from which the absorbed substances are passed into the intercellular spaces before entering the capillaries.

A

False

90
Q

T/F In contract to ruminants, horses do not have an efficient means of recovering the microbial protein synthesized in the hindgut, and most of it passes out in the feces.

A

True

91
Q

The squeezing action of the pelvic flexure in the equine mimics the action of the pylorus in selectively retaining relatively____ particulate matter while allowing liquid and ___ particles to pass.

A

Large, small

92
Q

Which of the following statements is FALSE?

a. Na absorption accompanies VFA absorption and bicarbonate is generated in the lumen.
b. Absorption of VFA and Na leads to osmotic absorption of water
c. Molecular mechanisms of VFA absorption in the equine colon is completely different when compared to the cow rumen

A

c. Molecular mechanisms of VFA absorption in the equine colon is completely different when compared to the cow rumen

93
Q

T/F Sperm is viable at body temperature in the rooster.

A

True

94
Q

T/F FSH stimulation leads to follicular development and estrogen/androgen release from F1 ovarian follicles.

A

False

95
Q

T/F Yolk and lipoproteins are produced in the hen’s liver. These products are transported through the hen’s blood supply to the oocyte.

A

True

96
Q

T/F The ventriculus contains keratinoid, a very thick layer of smooth muscle, and functions to grind material to increase surface area.

A

True

97
Q

T/F The cloaca is subdivided into three regions (coprodeum, urodeum, and proctodeum) and has antiperistaltic activity.

A

True

Histology Spring 2020 (4 decks)

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