Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Physiology > GI tract > Flashcards

GI tract Flashcards

1
Q

What organs make up the digestive system?

A

Digestive tract, salivary glands, exocrine pancreas, liver, gallbladder.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What type of muscles are found in the mouth and pharynx?

A

Striated muscle.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the main function of the mucous membrane in the digestive tract?

A

Protection, secretion, and absorption.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What does the submucosa provide in the digestive tract?

A

Elasticity and contains larger vessels and nerves.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the two layers of the muscularis externa?

A

Circular and longitudinal layers.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the function of serosa?

A

Prevents friction and suspends organs via the mesentery.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What do sphincters prevent in the GI tract?

A

Reflux between specialized compartments.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the two types of motility in the GI tract?

A

Propulsive and mixing.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the role of exocrine glands in digestion?

A

They secrete digestive juices into the lumen.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the three types of macronutrients digested in the GI tract?

A

Carbohydrates, proteins, and fats.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Where does most absorption occur in the digestive system?

A

Small intestine.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the four factors regulating digestive system function?

A

Autonomous smooth muscle function, intrinsic nerve plexuses, extrinsic nerves, GI hormones.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the cells of Cajal responsible for?

A

Generating slow-wave potentials in the GI tract.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What does the enteric nervous system regulate?

A

GI motility, secretion, and absorption.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How does sympathetic stimulation affect the GI tract?

A

It inhibits contraction and secretion.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are GI hormones produced by?

A

Endocrine cells throughout the GI tract.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the three types of GI sensory receptors?

A

Chemoreceptors, mechanoreceptors, osmoreceptors.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the function of saliva?

A

Lubricates food, starts digestion of starch, and provides oral hygiene.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Which enzyme in saliva begins starch digestion?

A

Amylase.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What triggers the conditioned salivary reflex?

A

Anticipation of food without oral stimulation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What prevents air from entering the esophagus?

A

Pharyngoesophageal sphincter.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What prevents gastric contents from regurgitating into the esophagus?

A

Gastroesophageal sphincter.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are the three main regions of the stomach?

A

Fundus, body, and antrum.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the barrier between the stomach and duodenum?

A

Pyloric sphincter.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is chyme?

A

Thick liquid mixture of food and gastric secretions.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is gastric emptying influenced by?

A

Volume of chyme, fat, acid, hypertonicity, and duodenal distension.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Which hormone inhibits antral contractions during high-fat digestion?

A

Cholecystokinin (CCK).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What are the consequences of vomiting?

A

Loss of acid, dehydration, and metabolic alkalosis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Which cells in the stomach secrete HCl?

A

Parietal cells.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Why is intrinsic factor important?

A

It is necessary for B12 absorption.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What activates pepsinogen into pepsin?

A

HCl.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What is the main role of gastrin?

A

Stimulates HCl and histamine secretion.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What protects the gastric lining?

A

Mucus and bicarbonate.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What non-nutrients are absorbed by the stomach?

A

Ethyl alcohol and aspirin.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What are the two main secretions of the pancreas?

A

Digestive enzymes and bicarbonate.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Which enzyme is essential for fat digestion?

A

Pancreatic lipase.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What are bile salts essential for?

A

Emulsifying and absorbing fats.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What organ secretes bile?

A

Liver.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What happens if bile ducts are blocked?

A

Feces become grayish white.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

What is the primary motility of the small intestine during digestion?

A

Segmentation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What is the migrating motility complex?

A

A cleaning wave between meals.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What does the ileocecal valve prevent?

A

Backward movement of contents from the large intestine to the small intestine.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Where are B12 and bile salts absorbed?

A

Terminal ileum.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

How is water absorbed in the small intestine?

A

Passively due to osmotic pressure.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

What is the function of the large intestine?

A

Drying and storage of feces.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

What initiates defecation?

A

Relaxation of internal anal sphincter and contraction of the rectum.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

What is the function of gut microbiota?

A

Digests food, maintains mucosal integrity, and supports immunity.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

What is the pH of the stomach?

A

About 2.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

What are the three phases of gastric secretion?

A

Cephalic, gastric, and intestinal.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

What is the primary component of bile?

A

Bile salts.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

What enzyme digests proteins in the stomach?

A

Pepsin.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

Which nutrient is digested by pancreatic amylase?

A

Carbohydrates.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

How are fats absorbed in the small intestine?

A

Through micelles.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

What is the function of the appendix?

A

Houses lymphocytes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

What are haustra in the large intestine?

A

Pouches formed by the colon.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

What is the gastrocolic reflex?

A

Increased motility in the large intestine after eating.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

What is the effect of secretin?

A

Stimulates bicarbonate secretion to neutralize acid.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

What is bilirubin derived from?

A

Hemoglobin degradation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

How are fat-soluble vitamins absorbed?

A

With fats in micelles.

60
Q

Which vitamin requires intrinsic factor for absorption?

A

B12.

61
Q

What is the role of hepatocytes?

A

Detoxification, nutrient processing, and bile production.

62
Q

What is the primary site for drug detoxification?

A

Liver.

63
Q

How is glucose absorbed in the small intestine?

A

Via sodium-glucose transporters (SGLT).

64
Q

What is metabolic alkalosis a consequence of?

A

Vomiting.

65
Q

What stimulates the release of CCK?

A

Fat in the duodenum.

66
Q

What is the role of tight junctions in gastric mucosa?

A

Prevents H+ penetration.

67
Q

What controls peristalsis in the esophagus?

A

Circular muscle contractions.

68
Q

What protects the esophagus from acid?

A

Mucus.

69
Q

What is the role of lysozyme in saliva?

A

Breaks down bacterial cell walls.

70
Q

What does the gallbladder store?

A

Bile.

71
Q

Which segment of the small intestine has the highest absorption?

A

Jejunum.

72
Q

How is sodium absorbed in the intestine?

A

Actively and passively.

73
Q

What triggers the simple salivary reflex?

A

Chemo- and pressure receptors in the mouth.

74
Q

What type of muscle is responsible for most of the movement in the digestive tract?

A

Smooth muscle

75
Q

Describe the two types of motility in the digestive tract.

A

Propulsive: pushes contents forward

Mixing: mixes food with digestive juices; facilitates absorption by exposing different parts of food to absorbing surfaces

76
Q

What is the function of exocrine glands in the digestive system?

A

Secrete digestive juices into the lumen

77
Q

Describe the process of how secretory cells form secretions.

A

They extract large volumes of water and raw materials from plasma to create bile salts, mucus, and enzymes

78
Q

Is the fluid used to form secretions permanently lost?

A

No, it is returned to the blood unless lost through vomiting or diarrhea

79
Q

How is the endocrine tissue of the GI tract organized compared to peripheral endocrine tissues?

A

Not in a discrete organization, but spread throughout the length of the tract

80
Q

What is the function of the signal proteins produced by the endocrine tissue of the GI tract?

A

They act as GI hormones or GI peptides

81
Q

What is the main purpose of digestion?

A

To chemically reduce complex materials into smaller, absorbable units

82
Q

Why are carbohydrates, proteins, and fats broken down during digestion?

A

Because they are too large to be absorbed from the lumen

83
Q

What are polysaccharides?

A

Long chains of sugars, making up most ingested carbs

84
Q

What are monosaccharides?

A

The simplest sugars, rarely found in the diet in their simplest form

85
Q

List three examples of monosaccharides

A

Glucose, fructose, and galactose

86
Q

How are proteins broken down during digestion?

A

Into amino acids or small polypeptides

87
Q

What is the most common form of dietary fat?

A

Triglycerides (glycerol with three fatty acid molecules)

88
Q

How are triglycerides digested?

A

Two of the fatty acids are split off, leaving a monoglyceride

89
Q

What form of fat is absorbed by the body?

A

Fatty acids

90
Q

Where does most absorption occur in the digestive system?

A

Small intestine

91
Q

What substances are transferred into the blood or lymph during absorption?

A

Nutrients, water, vitamins, and electrolytes

92
Q

List the four factors involved in regulating digestive system function.

A

Autonomous smooth muscle function
Intrinsic nerve plexuses○
Extrinsic nerves
GI hormones

93
Q

What is the basic electrical rhythm (BER)?

A

Rhythmic cycles of depolarization and repolarization in the digestive tract’s smooth muscle

94
Q

What are the pacemaker cells of the muscularis externa called?

A

Cells of Cajal

95
Q

What do the Cells of Cajal generate?

A

Slow-wave potentials

96
Q

Describe slow-wave potentials

A

Self-excitable activity in which membrane potential undergoes alternating depolarization and repolarization

97
Q

Are slow-waves action potentials?

A

No, but their peaks may trigger a volley of action potentials

98
Q

How do slow waves propagate?

A

Via gap junctions

99
Q

What happens when the muscle sheet reaches threshold?

A

It behaves as one unit

100
Q

What happens when the muscle sheet is not at threshold?

A

It oscillates between depolarization and hyperpolarization

101
Q

What are the two major nerve fiber networks that run along the length of the GI tract?

A

Submucosal plexus and myenteric plexus

102
Q

What is the function of the submucosal plexus?

A

Secretomotor innervation to the mucosa

103
Q

What is the function of the myenteric plexus?

A

Motor innervation to the muscular layer

104
Q

What is the significance of the intrinsic nerve plexuses?

A

They function as the GI system’s own nervous system, allowing for a considerable degree of self-regulation

105
Q

How many neurons are in the enteric nervous system?

A

As many as in the spinal cord

106
Q

What is the function of intrinsic afferent neurons?

A

They are sensory neurons that respond to local stimuli

107
Q

What is the function of intrinsic efferent neurons?

A

They affect motility, secretion, etc.

108
Q

What is the role of extrinsic nerves in GI tract function?

A

They regulate GI tract function by modifying motility or secretion directly or by acting on intrinsic plexuses

109
Q

How do extrinsic nerves originate?

A

From the autonomic nervous system

110
Q

What is the effect of sympathetic stimulation on the GI tract?

A

Inhibits tract contraction and secretion

111
Q

What is the effect of parasympathetic stimulation on the GI tract?

A

Enhances digestion

112
Q

Where are GI hormones produced?

A

By endocrine cells from different regions of the GI tract

113
Q

What are the influences of GI hormones on smooth muscle and gland cells?

A

They can cause both excitatory and inhibitory influences

114
Q

List the three types of sensory receptors in the GI tract wall.

A

Chemoreceptors: sensitive to lumen contents

Mechanoreceptors: sensitive to stretch or tension in the wall

Osmoreceptors: sensitive to osmolarity of luminal contents

115
Q

What happens when GI receptors are stimulated?

A

Effector actions and/or neural reflexes are initiated

116
Q

Give examples of effector cells in the GI tract

A

Smooth muscle cells (motility), exocrine cells (secretions), and endocrine cells (hormones)

117
Q

Differentiate between short and long reflexes.

A

Short reflex: located within the GI tract

Long reflex: involves the CNS

118
Q

What digestive processes occur in the mouth?

A

Digestion begins and is minimal (amylase), and no food absorption occurs

119
Q

What happens to food in the mouth?

A

It is moistened, lubricated, and made to stick together

120
Q

What is the composition of saliva?

A

99.5% water, 0.5% electrolytes and protein; no glucose and 1/7th the NaCl concentration compared to plasma

121
Q

How does the composition of saliva affect taste perception?

A

It enhances sweet and salty tastes

122
Q

What are the most important proteins in saliva?

A

Amylase and lysozyme

123
Q

What is the function of salivary amylase?

A

Begins digestion of dietary starches

124
Q

What is the function of lysozyme?

A

It is a salivary antimicrobial that breaks down bacterial cell walls

125
Q

What other antimicrobial components are found in saliva?

A

IgA antibodies and lactoferrin, which binds to iron that bacteria need

126
Q

What role does saliva play in oral hygiene?

A

It flushes food residue and foreign particles

127
Q

How does saliva contribute to dental health?

A

It is rich in bicarbonate, which neutralizes acid from food and bacteria, preventing dental caries

128
Q

How much saliva is secreted per day?

A

1-2 L

129
Q

What is the basal rate of saliva secretion?

A

0.5 mL/min

130
Q

What is the maximum rate of saliva secretion?

A

5 mL/min in response to potent stimuli

131
Q

Describe the two types of salivary reflexes that increase saliva production

A

Simple salivary reflex: oral stimulation sends an afferent impulse to the salivary center in the brainstem, increasing salivation

Conditioned salivary reflex: occurs without oral stimulation, such as the “mouth-watering” anticipation of food

132
Q

How do the sympathetic and parasympathetic nervous systems affect saliva production?

A

Both promote salivation, but with different compositions:

Parasympathetic: watery saliva rich with enzymes

Sympathetic: thick saliva rich in mucus

133
Q

Describe the pharynx and its function

A

A cavity at the rear of the throat that serves as a common passageway for the digestive and respiratory systems

134
Q

What structures are located in the pharynx?

A

Tonsils

135
Q

What initiates swallowing?

A

Motility in the pharynx leads to swallowing

136
Q

Describe the process of swallowing.

A

Pharyngeal pressure receptors send afferent impulses to the swallowing center of the brainstem, initiating the all-or-none process of swallowing

137
Q

What structures mark the beginning and end of the esophagus?

A

Sphincter muscles

138
Q

Name the sphincter muscles at each end of the esophagus and describe their functions.

A

Pharyngoesophageal sphincter (upper end): prevents air from entering the digestive tract

Gastroesophageal sphincter (lower end): stays tonically contracted, increases with inspiration, and prevents gastric contents from regurgitating

139
Q

How does food move through the esophagus?

A

Peristalsis (ringlike contractions of circular muscle) pushes the bolus between the two sphincters

140
Q

What is the purpose of esophageal secretion?

A

To protect against acid, enzymes, and sharp edges of the bolus

141
Q

List the three sections of the stomach

A

Fundus, body, and antrum

142
Q

What is the function of the pyloric sphincter?

A

It acts as a barrier between the stomach and the duodenum

143
Q

What are the three main functions of the stomach?

A

Store ingested food until it is emptied into the small intestine

Secrete HCl acid (and others)

Mix food with acid and pulverize it to produce chyme

144
Q

What is chyme?

A

A thick liquid mixture of food and gastric juices that is emptied into the duodenum

145
Q

List the four aspects of gastric motility.

A

Filling: bolus enters via the esophagus

Storage: stomach volume can increase from 50 mL to 1000 mL as deep folds flatten

Mixing: cells of Cajal in the upper fundus generate three slow waves per minute, leading to action potentials and strong antral contractions that propel chyme distally

Emptying: also facilitated by antral contraction

146
Q

Describe the process of vomiting

A

Vomiting involves the forceful expulsion of gastric contents through the oral cavity, controlled by the vomiting center of the brainstem. The major force comes from respiratory muscle contraction, especially the diaphragm and abdominal muscles

147
Q

What factors can trigger vomiting

A

Vomiting can be initiated by various stimuli, including tactile stimulation of the back of the throat, distention or irritation of the stomach and duodenum, elevated intracranial pressure, dizziness, drugs, psychogenic factors (emotions)

Physiology (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions