Section 7: Salivary and Gastric Secretion and Esophageal and Gastric Motility Flashcards Preview

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Flashcards in Section 7: Salivary and Gastric Secretion and Esophageal and Gastric Motility Deck (214):
1

Cell types of salivary gland:

serous, acinar, and mucous cells

2

Functions of saliva:

protects and digests

3

Protective aspects of saliva:

mucus, HCO3-, and antibacterial enzymes

4

Digestive aspects of saliva;

alpha-amylase, Lingual lipase (neither are essential for digestion)

5

True or False? Alpha-amylase is essential for digestion while lingual lipase is not.

F. neither are essential

6

What type of glands are salivary glands?

exocrine

7

Surface epithelial cells of the salivary glands produce:

0.5 to 1.0 L, most productive gland of the body, isotonic NaCl, NaHC03, KCl

8

True or False? Saliva is always hypertonic.

F. Hypotonic (a solution in which normal cells will increase in volume)

9

pH of saliva at rest and when stimulated:

6 vs. 9

10

mOsm/L of saliva at rest and when stimulated:

575 vs. 200 mOsm/L

11

ion concentrations in plasma, most to least:

Na+, Cl-, HCO3-, K+

12

Ion concentration in saliva when stimulated, most to least:

Na+, HCO3-, Cl-, K+

13

What are the two components of the model of salivary secretion?

acinar cells produce primary secretion and duct cells modify secretion

14

Functional unit of any salivary gland:

The "Salivon", blind end set of epithelial cells, acing region, smooth muscle cells to contract secretions

15

Ion concentration in saliva when not stimulated, most to least:

K+, Cl-, Na+, HCO3-

16

What is found in the end piece of a salivary gland?

amylase-containg primary secretion, nearly isotonic total he plasma)

17

Where does modification of ionic content take place in the salivary gland?

Striated and excretory ducts

18

What types of secretions are released from acing cells?

Plasma-like

19

What drives Cl- secretion into the acing lumen through apical-membrane Cl- channels?

Cl- electrochemical gradient created by large intracellular stores

20

What happened to the acing fluid as it flows through the ducts?

modified

21

What are absorbed and what are secreted in the salivary gland duct between Na+, Cl-, K+, and HCO3-?

unstimulated absorption: Na+ and Cl-, unstimulated secretion: K+, and stimulated secretion: HCO3-

22

Unstimulated absorption of ___ occurs in the salivary gland duct.

Na+ and Cl-

23

Unstimulated secretion of ___ occurs in the salivary gland duct.

K+

24

Stimulated secretion of ___ occurs in the salivary gland duct.

HCO3-

25

What nerve enters the Otic Ganglion?

Jacobson's nerve and Tympanic Plexus

26

Parasympathetic input from fibers of this nucleus stimulates the parotid gland to produce vasodilation and secrete saliva.

inferior salivatory

27

What nerve innervates the submandibular ganglion?

facial nerve

28

What is the innervation to the parotid gland?

Auriculotemporal branch of the trigeminal nerve

29

Parasympathetic perganglionic fibers to the major salivary glands

Facial and glossopharyngeal nerves

30

Sympathetic preganglionic nerves originate here that supply the major salivary glands:

the cervical ganglion, postganglionic fibers from this extend to the gland in the periarterial spaces

31

What aspects of the salivary glands do the parasympathetic and sympathetic mediates regulate?

blood flow, ductular smooth muscle activity, growth, and metabolism (all know salivary gland functions)

32

From what vertebral level does the superior cervical ganglion arise?

T1-T3

33

Nervous control of salivary secretions:

psyche, taste, smell, food, chewing, and pain

34

How do taste, smell, food, chewing, and pain exert nervous control over the CNS?

via oral mechanical and chemical receptors

35

Which nucleus in the medulla controls salivary secretion?

salivary nucleus

36

Sympathetic receptors that control salivary secretion:

B-adrenergic receptors and alpha-adrenergic receptors

37

Parasympathetic receptors controlling salivary secretion:

cholinergic receptors

38

Where are cholinergic receptors located?

acing cells and duct cells

39

When is sympathetic innervation to the salivary secretions activated?

fear stimuli, "fight or flight", scared spit-less

40

When is parasympathetic innervation to the salivary secretions activated?

meal stimuli

41

Attributes of salivary content with sympathetic nervous input:

low volume, high viscosity, high protein concentration, and very high mucin concentration

42

Attributes of salivary content with parasympathetic nervous input:

High volume, low viscosity, low protein concentration, and very low mucin concentration

43

Sjogren Syndrome:

chronic progressive autoimmune disease, antibodies to salivary and lacrimal gland cells, immunologic injury to acini reduces secretion, expression of Cl-/HCO3- exchanger in ducts is lost, dry mouth, keratoconjunctivitis, can lead to difficulty chewing, caries, difficulty with continuous speech, oral ulcers

44

True or False? There are significant levels of secretions in the esophagus.

F.

45

Gastic juices:

H+, water, pepsinogens, intrinsic factor (for B12 absortption)

46

Functions of acid:

kill bacteria, break chemical bonds in food, activate pepsinogen

47

Secreted volume of acid:

2-3 L/day

48

Name of stomach mucosa:

oxyntic gland mucosa

49

In which stomach chamber are oxyntic gland mucosa:

cardia/ corpus or body

50

True or False? Gastrin is released into the blood stream.

T

51

Gastric gland is aka:

Oxyntic gland

52

Mucous neck cells:

3.0 ml/min when stimulated, isotonic, HCl, KCl, IF

53

Oxyntic cells are aka:

parietal cells

54

Functions of duct cells:

modification of secretion s it flows into oral cavity

55

Why do we need bicarbonate in our saliva?

acid producing bacteria

56

Exocrine glands release where?

Outside the body, the lumen of ducts

57

Amount of flow of salivary secretions when maximally stimulated per minute

40 ml/min

58

F. Concentrations of Na, HCO3-, Cl-, and K+ all increase with stimulation of salivary glands.

K+ decreases

59

True or False? The osmotic content of saliva is low regardless of stimulation.

T

60

True or False? Secretions from the endpience are osmotically similar to the interstitial fluid by the end of the duct.

F

61

Is the change in osmolarity of secretions from the end piece an active or passive process?

passive

62

Acing cells producew

Interstiial fluid like secretions

63

The Na/K pump is always located on this side of the cell

basolateral membrane

64

Which ion is being recycled on the basolateral membrane of the acing cell?

K

65

Acetylcholine binds this type of receptor on the basolateral membrane of acing cells:

M3 receptors

66

What can move through the tight junctions in response to Cl- entering the lumen from the acing cells?

Na+ and water

67

ENac:

distal tubule of kidney and apical side of ductal cells of salivary glands

68

H/ K exchangers are located on which membrane of the ductal cells of the salivary gland?

apical

69

When is the H/ K exchanger most effective?

when plasma-like NaCl flow is slow

70

how to get Cl- out of the lumen and into he interstitial space?

CFTR channels and the Cl- channels on the basolateral side

71

Duct cells are capable of secretion lots of:

bicarbonate

72

What channels reduces sodium concentration in the plasma-like NaCl fluid flowing past duct cells of salivary gland?

ENac

73

As fluid flow rate increases:

bicarbonate concentration increases, M3 receptor is stimulated and Cl- is lost via CFTR (actively pumping bicarbonate into fluid)

74

True or False? The m3 receptor requires ATP.

F. It is an active process but does not require ATP

75

Stimulation of what receptor leads to he activation of bicarbonate channels?

M3 receptors on the basolateral membrane of the ductal cell

76

Sympathetic component to the glands:

norepinephrine release, nothing to do with a meal

77

Acetylcholine is released onto what cells to control the salivary gland?

duct or acinar cells

78

Cholinergic receptors are __ receptors.

M3 receptors

79

Why not to salivate when scared:

you may aspirate saliva and kill you if being chased by a lion

80

Affect of nonfunctioning Cl-?HCO3- exchanger:

dry mouth and eyes

81

special tube that carries food and medicine to the stomach through the nose:

nasogastric tube (NG tube)

82

What can elicit the same gastric juice composition as a meal/

histamine

83

How is the Na concentration affected when secretory rate increases?

decreases

84

2 mechanisms for H+ secretion from parietal cells:

increases in surface area and membranes H+ pump activated

85

The stomach is capable of producing a H+ gradient of ___ times.

1 million

86

pH range of gastric secretions:

1 to 7

87

Is the gastrointestinal tract electrically negative or positive in relation o the plasma?

negative

88

List the stimuli for acid secretion:

Vagal stimulation, G-cells of antrum, in sub-epithelial space

89

True or False? All methods for stimulating acid secretion increase calcium levels directly.

F. vagal stimulation and G-cells of antrum do,the in sub-epithelials space activates adenylyl cyclase first which converts ATP to cAMP

90

To what does histamine bind in the stimulation of acid secretion?

unique H2 receptors

91

Which pump is turned on in the secretion of acid?

gastric hydrogen ion pump

92

What enzyme stimulates he secretory cells of the stomach folicular be functionally active?

gastrin

93

2 stage process of food digestion:

initial absorption of digested food hen liberation of gastrin into the circulatory system to stimulate cellular activity

94

Method to extract gastrin:

trichloroacetic acid in acetone

95

Pharmacological inhibitors of acid secretion and what they act on:

atropine, vagal stimulation (vagal stimulation), omeprazole ( H+/ K+ exchanger, cimetidine (an H2 receptor blocker)

96

3 phases of acid secretion:

cephalic phase, gastric phase, intestinal phase

97

3 chemical stimuli in food digeston:

Gastrin, Acetylcholine, Histamine

98

Method for studying processes related to cephalic phase

sham feeding: eaten food is diverted by gastric or esophageal catheter so it can't accumulate, stopping food processing. (In humans: food is tasted by not swallowed)

99

What, in the lumen of the stomach, inhibits gastrin release?

H+ (pH

100

How does food affect the pH of the stomach?

raises the pH, stops inhibition of gastrin release by H+

101

What does distension trigger?

the vast-vagal reflex (check)

102

Substances in the lumen that stimulate parietal cels or G cells

amino acids, protein, caffeine, calcium, ethanol

103

Two hours after a meal;

food gone, pH decreases (under 3) H+ inhibits gastrin release, vagal stimulation is gone, enterogastrones released by the duodenum inhibit parietal cells and G cells

104

3 enterogastronse:

secretin, CCK, and GIP

105

Symptoms of GERDs:

burning sensation radiating up from the sternum to the throat (commonly referred to heartburn)

106

Treatment of GERDs:

Antacids (mild symptoms), h2 receptor blockers, Na+/K+ ATPase blockers

107

3 basic salts used in the treatment of GERDs:

magnesium, calcium, and aluminum - with hydroxide or bicarbonate ions

108

Examples of H2 blockers:

cimetidine, Zantac (ranitidine)

109

What is a gastric (peptide) ulcer?

sore in the wall of the stomach

110

This bacterium is responsible for most gastric ulcers:

helicobacter pylori

111

How do you treat Helicobcater pylori:

antibiotics

112

Where in the stomach does Helicobcater pylori?

Where bicarbonate is released from surface cells in the stomach.

113

True or False? Smooth muscle pushes food to the back of the oral cavity.

F. skeletal muscle

114

What happens in the complex reflex involving the nerve coordination of skeletal muscle?

close the epiglottis, opens the upper esophageal sphincter, and propels food into the esophagus

115

What is the last voluntary act in processing food until the analysis end of the gastrointestinal tract?

swallowing

116

Where is the junction of smooth and striated muscle?

just below the upper sphincter of esophagus

117

True or False? The peristaltic wave is due to spontaneous muscle activity.

F

118

What activates a reflex stimulation via the vagus for the secondary peristaltic wave?

stretch receptors in the esophagus

119

To where do the stretch receptors in the esophagus feed back to?

vagal nuclei in the brain stem

120

What relaxes to let food pass into the stomach?

the lower sphincter of the esophagus

121

Neurotransmitter for the relaxation of LES:

VIP and NO (inhibitory motor neurons)

122

Functions of the stomach:

secretes acid, intrinsic factor, pepsinogen, store food and mix food

123

True or False? The storage of food is involved in motility/

T

124

Factors that can relax LEX:

alcohol, coffee, chocolate

125

Factors that can open the LES:

large meal or pregnancy (baby pushing on stomach?)

126

stomach resting volume:

100 ml

127

What controls receptive relaxation:

Purigenic reflex and CCK: fats in the small intestines triggers CCK which triggers relaxation

128

vagotomy:

surgery to cut one or more branches of vagus, typically to reduce the rate of gastric secretion (e.g., in treating peptic ulcers).

129

Origin of basal secretion:

surface cells

130

Origin of stimulates secretions:

parietal cells

131

Composition of basal secretions:

NaCl, NaHCO3-, KCl, Isotonic H2O

132

Composition of stimulated secretions:

HCl, NaCl, KCl, Isotonic H20

133

What stops inhibition of gastrin release by H+?

food raising the pH of stomach

134

gastrointestinal tract reflex circuits where afferent and efferent fibers of the vagus nerve coordinate responses to gut stimuli via the dorsal vagal complex in the brain:

Vagovagal reflex

135

Which complex in the brain coordinates responses to gut stimuli?

dorsal vagal complex

136

On which cells does Acetylcholine act in the stomach?

parietal and G cells (probably more)

137

A hormone released from intestinal endocrine cells which stimulates gastric acid secretion in the stomach, hypothesised to exist in humans:

Entero-oxyntin

138

Intestinal endocrine cells activate:

"entero-oxytonin"

139

2 stimuli that can lead to the release of acid from parietal cells:

gastrin and absorbed amino acids

140

Stimulus for the gastric phase:

distention

141

Stimulus for the intestinal phase:

digested protein

142

Stimulus for all phases:

gastrin and Acetylcholine

143

Distention triggers:

local reflexes and vagus nerve

144

Vagus nerve triggers the release of:

GRP or Ach

145

Examples of H +/K+ ATPase blockers:

Prilosec (omeprazole), Nexium (esomeprazole)

146

H. pylori can live at what pH level?

7

147

reflex where gastric fundus dilates when food passes down pharynx and esophagus:

Receptive relaxation

148

The opening of this can lead to heartburn:

LES (lower esophageal sphincter

149

At what stomach volumes does the pressure increase sharply?

about 1500 ml

150

At what stomach volume does the intraluminal pressure really start to increase?

800 ml

151

In what type of muscle are the pacemaker cells found?

longitudinal

152

In which portion of the stomach does spontaneous muscle activity start?

mid-stomach

153

Is there peristalsis in the actual stomach?

yes

154

True or False? The peristaltic wave decreases in speed as it moves down the stomach.

F. accelerates

155

Main functions of gastric peristalsis:

mix food with a little food pushed out

156

What controls gastic peristalsis?

Vagal stiulation via Acetylcholine and gastrin

157

Percent of test meal remaining in stomach, greatest to least:

oleate meal, acid meal, saline meal

158

How does deviation from isotonicity effect vagal stimulation?

lowers it

159

True or False? Fats increase CCK activity.

F. decrease

160

Does acid inhibit or increase purigenic stimulation?

inhibit

161

Vomiting is aka:

emesis

162

Where is the vomiting center in the brain?

pons-medulla junction

163

How are the proximal GI organs involved in vomiting innervated?

cranial nerves

164

How are the diaphragm and abdominal muscles involved in vomiting innervated?

spinal cord

165

Physiological changes during vomiting:

hypersalivation, larynx and hyoid bone are drawn forward, soft palate rises, glottis closes, esophagus dilates, cardiac sphincter releases, fundus becomes flaccid, diaphragm contracts sharply, abdominal muscles and incisor anglers contract, gastric contents forced into esophagus and expelled

166

Which organ describe most of the work of digestion?

pancreas

167

How long does it take for food to be propelled to the stomach?

8 seconds

168

How long does food stay in the stomach?

about 2 hrs

169

Why do we need B12?

red blood cell formation intrinsic factor to bind to it

170

What type of bacterial does not get killed in the stomach?

H. pylori

171

Total body water:

about 40L

172

Gastric glands are located?

bottom of stomach/ antrum

173

Surface epithelial cells secrete this in h unstimulated state:

sodium chloride and bicarbonate

174

How can you increase the HCl secretion of the parietal cells?

histamine or food

175

True or False? Surface cells change their rate of production when stimulated by histamine.

F.

176

How do both Cl- and K+ concentrations change with histamine concentration?

they don't change much

177

Secretions from these cells dominate in the basal state:

surface cells

178

What are secretion in the stimulated state dominated by?

H+

179

True or False? Secretion of H+ is an active process.

T. 1 million times gradient

180

The stomach is the only site of this active transporter:

K+/ H+ pump, always in the same place on the cell (luminal/ apical side)

181

Source of acid in the parietal cell to create HCl

CO2, metaboolic byproduct

182

What enzyme is used to make HCl out of CO2 in the parietal cells?

carbonic anhydrase

183

Overall reaction in parietal cells

H and some K through tight junctions, lumen inalways negative, leak some K down its gardent, HCl solution and lots of water goes with it

184

True or False? Equal parts of bicarbonate and hydrogen are produced in the parietal cell.

T

185

Why does the large increase in bicarbonate in from parietal cells not change overall body pH?

movement of hydrogen from the pancreas

186

True or False? Vagal stimulation initiates the actions of both Acetylcholine and G-cells of the antrum to lead to acid secretion.

T

187

What happens at the molecular level to turn on the Gastric Hydrogen ion pump?

phosphorylation

188

What receptors are blocked with atropine?

M3

189

True or False? There are M3 receptors in the salivary gland.

T, in the eyes as well (they will jitter)

190

How does atropine help with ulcers?

reduces acid secretion, but effected other systems

191

True or False? Histamine is always there so you will always have acid secretion.

T. just a little of the other two will produce a lot of secretion

192

Antihistamine affect on acid secretions in the stomach.

Nothing, because this is the only place that H2 receptors are found

193

pylorus:

mucosa of the antrum of the stomach

194

True or False? Blocking the H2 receptor will have a minimal effect on overall acid secretion.

F. Big effect

195

Na/K blocker:

Oubain

196

True or False? Omeprazole will block all acid secretion.

T

197

True or False? Many digestive enzymes don't like an acidic environment.

T

198

What nerve produces acid in the stomach?

vagus, anything that stimulates the vagal nuclei (the stimulates the enteric plexus)

199

_ of the 3 agonists are released by the vagus.

2

200

Which food source is especially basic?

protein

201

What neurotransmitter is involved on both sides of the vago-vagal reflex?

Acetylcholine

202

3 stimuli of the parietal cells:

gastrin, entero-oxyntin and amino acids

203

3 hormones are released to inhibit acid secretion from this part of the GI tract:

duodenum

204

True or False? Increased calcium consumption can lead to the formation of acid.

T

205

GERD can lead to:

ulcers

206

True or False? Ulcers can be caused by stress.

F. (not directly at least)

207

True or False? H. pylori will die in the lumen of the stomach.

T

208

True or False? The pH at the level of the mucus secreting cells in the stomach is neutral.

T

209

What cells release pepsinogen?

chief cells

210

When, in swallowing, does the lower sphincter of the esophagus open?

right after food is pushed form the pharynx and past the upper sphincter of the esophagus

211

Pressure in the stomach does not raise significantly until:

1,500 ml of volume filled

212

How is the intraluminal pressure altered with a vagotmoy?

pressure begins to rise at a much lower stomach volume, almost linearly

213

What prevents food from entering the small intestines too quickly?

greater concentration of GAP junctions need the antrum of the stomach which speed contraction ahead of the wave. This prevents the forward progression of the bolus.

214

Function of hyper salivation before vomiting:

neutralize the acidic pH of the gastric contents...?