Chapter 22- The Digestive System Flashcards

1
Q

What are the organs of the alimentary, or gastrointestinal, tract?

A
Oral cavity
Pharynx
Esophagus 
Stomach 
Small intestine 
Large intestine
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2
Q

What are the accessory organs of the digestive tract?

A
Teeth
Tongue
Salivary glands
Liver
Gallbladder
Pancreas
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3
Q

Basic processes of the digestive system

A
Ingestion
Secretion
Propulsion
Digestion
Absorption
Defecation
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4
Q

What is the largest serous membrane in the body and what is it composed of?

A

Peritoneal membrane

Consists of outer parietal membrane and inner visceral membrane I

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5
Q

Type of fluid that fills the peritoneal cavity between the two layers

A

Serous fluid

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6
Q

What are mesentries?

Name both of them

A

Mesenteries are folds of the peritoneum that attach the organs of the digestive system to the posterior wall of the abdomen

They are the greater and lesser omentum

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7
Q

What do we call the blood vessels that supply and drain the abdominal digestive organs?

A

Splenic circulation

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8
Q

What are the 3 main clusters of nerves from the sympathetic and parasympathetic nervous systems that serve the digestive organs?

A

Celiac plexus
Superior mesenteric plexus
Inferior mesenteric plexus

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9
Q

Describe the submucosa layer of the organs of the alimentary canal

A

Made of dense irregular connective tissue with blood/lymphatic vessels and submucosal glands

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10
Q

What is the submucosal plexus?

A

Nerves clusters of the enteric NS

Regulates secretion from and blood flow to its area of the alimentary canal

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11
Q

Describe the muscularis externa of the organs of the alimentary canal

A

Thick layer of smooth muscle

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12
Q

What is the myentric plexus?

A

Group of nerves of the enteric NS that regulates motility of the muscularis externa

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13
Q

Describe the serosa layer of the organs of the alimentary canal

A

Outer layer of connective tissue in the organs of the peritoneal cavity

It is called the adventitia for organs located outside the peritoneal cavity

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14
Q

Different forms of motility

A

Swallowing
Churning
Peristalsis
Defecation

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15
Q

Which nervous system regulates motility?

A

Nerves of the autonomic nervous system

Group of nerves known as the enteric nervous system

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16
Q

4 processes that occur at the oral cavity

A

Ingestion
Secretion
Chemical/mechanical digestion
Propulsion

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17
Q

Structural features of the oral cavity

A
Cheeks
Lips
Gums
Vestibule
Oral cavity proper
Hard/soft palate
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18
Q

Key organs of mastication

A

Teeth

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19
Q

Bony sockets where teeth are located and connective tissue that holds them in place

A

Alveoli

And

Periodontal ligament

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20
Q

3 types of teeth

A

Incisors

Canines

Premolars/molars

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21
Q

Two components of a tooth

A

Crown and root

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22
Q

What does the tongue consist of?

A

Skeletal muscle covered with a layer of stratified squamous epithelium

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23
Q

What is the lingual frenulum?

A

Thin band the attached the tongue to the floor of the oral cavity

Prevents the tongue from moving too far posteriorly

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24
Q

What is the epithelium of the tongue arranged into?

How many are there and what are they called?

A

Papillae

There are 4 kinds: filiform, fungiform, circumvallate, foliate

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25
Q

All papillae contain epithelium with sensory receptors except:

A

Filiform

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26
Q

What are the two groups of skeletal muscle that control tongue movement?

A

Extrinsic and intrinsic

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27
Q

What are the components of saliva?

A
Water
Enzymes
Mucous
Electrolytes like sodium/chloride/potassium
Salivary amylase
Lysozyme 
Bicarbonate ions
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28
Q

What is the function of saliva?

A

Moistens, lubricates and cleanses oral mucosa

Deters growth of pathogenic bacteria

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29
Q

What is salivation?

A

Process of secretion from salivary glands

Controlled by parasympathetic nervous system

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30
Q

What are the three divisions of the pharynx?

A

Nasopharynx
Oropharynx
Laryngopharynx

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31
Q

Which divisions of the pharynx are part of the alimentary canal?

A

Oropharynx and laryngopharynx

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32
Q

What is the primary function of the pharynx?

A

Propulsion in the form of swallowing

Bolus passes through pharynx and into esophagus

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33
Q

What is the opening called at the inferior end of the esophagus?

A

Gastroesophageal sphincter

Prevents food from reentering the esophagus

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34
Q

What are the primary functions of the esophagus?

A

Propulsion and a small amount of secretion of mostly mucus

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35
Q

What is deglutition?

A

Swallowing

Specialized type of propulsion that pushes a bolus from the oral cavity through the pharynx and esophagus to the stomach

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36
Q

What are the three phases of swallowing?

A

Voluntary- controlled by cerebral cortex
Pharyngeal-medulla/enteric NS
Esophageal- medulla/enteric NS

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37
Q

Summarize the voluntary phase of swallowing

A

Tongue pushes bolus toward oropharynx

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38
Q

Summarize the pharyngeal phase of swallowing

A

Bolus enters oropharynx

Soft palate and epiglottis seal off the nasopharynx and larynx

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39
Q

Summarize the esophageal phase of swallowing

A

Peristaltic waves move the bolus down the esophagus to the stomach

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40
Q

5 anatomical regions of the stomach

A
Cardia
Fundus 
Body
Pyloric antrum
Pylorus
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41
Q

What is the pyloric sphincter?

A

Sphincter that controls the flow of ingested food between the stomach and small intestine

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42
Q

What are Rugae?

A

Folds on the interior of the stomach that allow it to expand considerably

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43
Q

What is chyme?

A

Liquid that is formed from the muscles of the stomach churning and pummeling food

44
Q

What are gastric pits?

A

Deep structures in the mucosa of the stomach that contain gastric glands

45
Q

What are gastric glands?

A

Contain endocrine cells that secrete hormones into blood stream and exocrine glands that secrete gastric juice

46
Q

What is gastric juice?

A

Acidic, enzyme-containing fluid

47
Q

What are the 4 main types of cells in gastric glands?

From deep to superficial

A

Enteroendocrine cells
Chief cells
Parietal cells
Mucous neck cells

48
Q

What are enteroendocrine cells?

A

Near bottom of gastric pit, secrete hormones that influence digestion

G cells secrete the hormone gastric which stimulates secretions from parietal cells

49
Q

What are chief cells?

A

Secrete precursor enzyme pepsinogen

Becomes pepsin when encounters an acidic pH, begins protein digestion

50
Q

What are parietal cells?

A

Secrete hydrochloride acid

That acid: activated pepsinogen, destroys pathogens and produces intrinsic factor which helps us absorb B12

51
Q

What are mucous neck cells?

A

Near the top of the gastric gland

Secrete acidic mucus that prevents mucus from becoming neutralized

52
Q

3 primary functions of the stomach

A

Secretion
Propulsion
Digestion

53
Q

Three phases of gastric acid secretion during eating

A

Cephalon phase
Gastric phase
Intestinal phase

54
Q

3 actions of the stomach enabled by its motility

A

Receive food from stomach
Churn bolus into chyme
Control the rate at which chyme enters the small intestine

55
Q

Four main processes occurring in the small intestine:

A

Secretion
Digestion
Absorption
Propulsion

56
Q

What are the cells of the small intestine called?

What do they produce?

A

Enterocytes

Produce digestive enzymes, hormones and mucus

57
Q

Three divisions of the small intestine

A

Duodenum
Jejunum
Ileum

58
Q

What is the duodenum?

A

First and shortest segment of the small intestine

Houses major duodenal papilla where secretions from the gallbladder and pancreas enter the small intestine

59
Q

What are Brunner’s glands?

A

Specialized glands in the duodenal submucosa that produce alkaline mucus to protect the duodenum from the acidic chyme

60
Q

What is the jejunum?

A

Middle part of the small intestine

Most active site for chemical digestion and absorption

61
Q

What is the ileum?

A

Final segment of the small intestine

Terminates at the cecum

62
Q

What is the ileocecal?

A

Sphincter that controls the movement of materials from the ileum into the large intestine

Prevents backflow of materials

63
Q

What are the largest type of folds visible in the small intestine?

What do they do?

A

Circular folds- invoking mucosa and submucosa

Slow the movement of chyme which gives nutrients more time to be digested and absorbed

64
Q

What are villi?

A

Projections in mucosa folds that contain a layer of wnterocytes that surround a central core of blood capillaries and a lymphatic vessel

65
Q

What are lacteals?

A

Lymphatic vessels in villi

66
Q

What are intestinal crypts?

A

Indents between villi which house glands with both enteroendocrine cells and goblet cells

67
Q

What are microvilli?

A

Smallest folds found in the plasma membrane of enterocytes

Give the cells a brush border

68
Q

What is the function of the migrating motor complex?

A

To move food from the duodenum to the ileocecal valve to clear the small intestine

69
Q

Two types of movement the small intestine undergoes during eating

A

Peristalsis

Segmentation

70
Q

Nerve that regulates both peristalsis and segmentation

A

Vagus nerve

71
Q

Functions of the large intestine

A

Secretion, propulsion, defecation

Receives materials not absorbed by the small intestine

Passageway first feces to exit the body

Active in absorbing water and electrolytes

72
Q

Anatomical regions of the large intestine

A

Cecum with vermiform appendix
Colon (ascending, transverse, descending, sigmoid)
Rectum
Anal canal

73
Q

What are taeniae coli?

A

Three bands of muscle made by the gathering of the longitudinal layer of the muscularis externa of the large intestine

74
Q

What are haustra?

A

Pockets in the colon caused by constant tension bunching

75
Q

What are epiploic appendages?

A

Fat-filled pouches contained in the serosa or visceral peritoneum

76
Q

Two functional segments of the large intestine

A

Proximal and distal

77
Q

What is contained in the proximal large intestine?

A

Ascending and transverse colon

78
Q

What is contained in the distal large intestine?

A

Descending and sigmoid colon

Rectum and anal canal

79
Q

Two main types of motility in the proximal large intestine

A

Segmentation and mass movement or mass peristalsis

80
Q

Main role of distal large intestine

A

Storing fecal matter until defecation

81
Q

What NS mediates defecation?

A

Parasympathetic

Causes smooth muscle in the sigmoid colon and rectum to contract and the internal anal sphincter to relax

82
Q

Three regions of the pancreas

A

Head
Body
Tail

83
Q

What is the composition of pancreatic juice?

A

Water and multiple digestive enzymes and other proteins

84
Q

When does pancreatic secretion rise and why?

A

During eating

Rises because of parasympathetic and hormonal stimulation

85
Q

One hormonal mediator of pancreatic secretion

A

Cholecystokinin

Produced by duodenal enteroendocrine cells in response to the presence of lipids and partially digested proteins in the duodenum

86
Q

What is secretin?

A

Stimulators hormone released by duodenal cells in response to acid and lipids in the duodenum

87
Q

What are the four lines of the liver?

A

Right
Left
Caudate
Quadrate

88
Q

What is the basic unit of the liver?

A

Liver lobule

Separated by septa

Composed of heoatocytes

89
Q

What are hepatocytes?

A

Compose liver lobules

Flattened plates of cells arranged in the shape of a hexagon stacked on top of one another

90
Q

What are hepatic sinusoids?

A

Large leaky capillaries that pass between rows of hepatocytes

91
Q

What is the main function of the liver?

A

To produce bile

92
Q

What is in bike and what are it’s functions?

A

Water, electrolytes and organic compounds

Functions: required for the digestion and absorption of lipids, and it is the mechanism by which the liver excretes wastes and other substances the kidneys cannot excrete

93
Q

What does the gallbladder do and what stimulates it?

A

Stores bile

Stimulated by the hormone CCK which triggers it to contract and release bile into the cystic duct

94
Q

What from the salivary glands helps begin digestion in the mouth? What does it break down?

A

Salivary amylase

Breaks down polysaccharides into shorter oligosaccharides

95
Q

Where does chemical digestion of carbohydrates continue after the mouth? What enzyme do they encounter there? When can they be absorbed?

A

In the small intestine where they are encountered by pancreatic amylase.

They must be broken down all the way to various monosaccharides like glucose and fructose before they can be absorbed

96
Q

What transports glucose and galactose across the membrane of enterocytes in the liver?

A

Na+/glucose cotransporter

97
Q

Where does chemical digestion of proteins begin? What enzyme do they encounter there?

A

Begins in the stomach where they encounter pepsin

98
Q

What does activated pepsin digest proteins down into?

A

Smaller polypeptides
Oligopeptides
Some free amino acids

99
Q

What mist proteins be broken down to to be absorbed in the small intestine?

A

Small oligopeptides and free amino acids

100
Q

What composed 90% of the lipids taken in by the diet that consist of three fatty acid molecules and a glycerol?

A

Triglycerides

101
Q

What two enzymes break down lipids first in the stomach and then in the small intestine?

A

Gastric lipase in stomach
Emulsified by bile salts in small intestine
Digested by pancreatic lipase in small intestine

102
Q

What are the structures formed when bile salts and digested lipids stay together?

A

Micelles

103
Q

What is the process of lipid absorption?

A

Micelles escort lipids to the enterocytes plasma membrane

Lipids diffuse through the phospholipid bilayer and enter cytosol

Lipids are reassembled into triglycerides and packaged into chylomicrons

Chylomicrons are released into the interstitial fluid by exocytosis and then enter a lacteal

104
Q

What pancreatic enzymes help digestion of nucleic acids in the small intestine?

A

Nucleases

105
Q

How many liters of water enter the small intestine each day on average?

A

9 liters

106
Q

How does water absorption occur in the body?

A

Osmosis