Chapter 22 Flashcards
(124 cards)
1
Q
What are the main organs of the digestive system?
A
Mouth, esophagus, stomach, small intestine, large intestine, rectum, anus
2
Q
What are the building-block molecules of carbohydrates?
A
Monosaccharides (e.g., glucose)
3
Q
What are the building-block molecules of lipids?
A
Fatty acids and glycerol
4
Q
What are the building-block molecules of proteins?
A
Amino acids
5
Q
What are the building-block molecules of nucleic acids?
A
Nucleotides
6
Q
What are enzymes?
A
Biological catalysts, usually proteins, that speed up chemical reactions by lowering activation energy
7
Q
What is the Gastrointestinal (GI) tract?
A
A long, continuous tube from the mouth to the anus, where food is digested and waste is eliminated
8
Q
What are accessory organs in the digestive system?
A
Organs assisting digestion but outside the GI tract (e.g., liver, pancreas, gallbladder)
9
Q
What is ingestion?
A
The act of taking food into the mouth
10
Q
What is secretion in the context of the digestive system?
A
Release of substances like enzymes, acid, or mucus into the GI tract
11
Q
What is propulsion in the digestive system?
A
Movement of food along the GI tract (e.g., swallowing, peristalsis)
12
Q
What is mechanical digestion?
A
Physical breakdown of food (chewing, churning)
13
Q
What is chemical digestion?
A
Breakdown of food molecules by enzymes
14
Q
What is absorption in the digestive process?
A
Transport of digested nutrients from the GI tract into the blood or lymph
15
Q
What is defecation?
A
Elimination of indigestible waste (feces) from the body
16
Q
What is the mucosa?
A
The innermost lining layer of the GI tract
17
Q
What is the submucosa?
A
Layer beneath the mucosa containing blood vessels, nerves, and glands
18
Q
What is the muscularis externa?
A
The main smooth muscle layers responsible for GI tract movement
19
Q
What is the serosa?
A
The outermost layer of GI tract organs within the peritoneal cavity
20
Q
What is the peritoneum?
A
The serous membrane lining the abdominopelvic cavity and covering its organs
21
Q
What are mesenteries?
A
Folds of peritoneum that attach organs to the body wall and house blood vessels/nerves
22
Q
What is the primary function of the digestive system?
A
To break down food into smaller molecules that can be absorbed into the body for energy and nutrients, and to eliminate waste
23
Q
What are the two main categories of digestive system organs?
A
Gastrointestinal (GI) tract and accessory digestive organs
24
Q
What is the function of the teeth and tongue in digestion?
A
Help break down food mechanically and move it around in the mouth
25
What is the role of salivary glands?
Produce saliva to moisten food and begin digestion
26
What enzyme in saliva begins the chemical digestion of carbohydrates?
Salivary amylase
27
What is the pharynx?
The part of the throat behind the mouth and nasal cavity, serving as a passageway for both food and air
28
What is the esophagus?
The muscular tube connecting the pharynx with the stomach
29
What is deglutition?
The act of swallowing
30
What are the two main types of digestion that begin in the oral cavity?
Mechanical digestion and chemical digestion
31
What structure serves as a common passageway for both food/liquid and air?
The pharynx
32
What is the primary function of the esophagus?
To transport food from the pharynx to the stomach via muscular contractions called peristalsis
33
What are the main differences between primary and secondary dentition?
Primary: 20 teeth; Secondary: 32 teeth
* Primary: 8 incisors, 4 canines, 8 molars
* Secondary: 8 incisors, 4 canines, 8 premolars, 12 molars
34
What is the function of the liver in the digestive system?
Makes bile, a substance needed to break down fats
35
What does the gallbladder do?
Stores bile made by the liver and squirts it into the intestine when needed
36
What is the primary role of the pancreas in digestion?
Makes powerful digestive juices (enzymes) that break down proteins, fats, and carbohydrates
37
What happens to dietary fiber in the digestive system?
It passes through the GI tract with minimal breakdown and absorption
38
What is the composition of primary dentition?
8 incisors, 4 canines, 8 molars
## Footnote
Does not include premolars.
39
What is the composition of secondary dentition?
8 incisors, 4 canines, 8 premolars, 12 molars (including 4 third molars)
## Footnote
Also known as wisdom teeth.
40
At what age do primary teeth typically begin to erupt?
Around 6 months of age.
41
By what age are all primary teeth usually present?
By age 2-3 years.
42
At what age do secondary teeth typically begin to erupt?
Around age 6.
43
What is the size and appearance difference between primary and secondary teeth?
Primary teeth are generally smaller and appear whiter compared to secondary teeth.
44
Describe the structural differences between primary and secondary teeth.
Primary teeth have thinner enamel and dentin, larger pulp chambers, and shorter, more flared roots.
45
What is the lifespan and function of primary teeth?
Primary teeth are naturally shed to make way for permanent teeth and are crucial for chewing, speech development, and acting as space holders.
46
What are the three major pairs of salivary glands?
* Parotid Glands
* Submandibular Glands
* Sublingual Glands
47
What is the contribution of the Parotid Glands to saliva?
Primarily produce a watery, serous secretion rich in enzymes, especially salivary amylase.
48
What is the contribution of the Submandibular Glands to saliva?
Produce a mixed secretion of serous fluid and mucus, predominantly serous.
49
What is the contribution of the Sublingual Glands to saliva?
Primarily produce a viscous, mucous secretion acting mainly as a lubricant.
50
What is the process of swallowing also known as?
Deglutition.
51
Identify the mucosal epithelium of the esophagus.
Non-keratinized stratified squamous epithelium.
52
What muscle type is found in the upper third of the esophagus?
Primarily skeletal muscle.
53
What muscle type is found in the lower third of the esophagus?
Primarily smooth muscle.
54
What is the outer layer of the esophagus called?
Adventitia.
55
What is the primary function of the esophagus?
Transport (propulsion) of a food bolus from the pharynx to the stomach.
56
What are rugae in the stomach?
Folds or wrinkles in the stomach lining when the stomach is empty.
57
What is chyme?
The semi-liquid, acidic mixture of partially digested food and gastric secretions formed in the stomach.
58
What are gastric pits?
Small depressions on the surface of the stomach mucosa that are openings for gastric glands.
59
What do parietal cells secrete?
Hydrochloric acid (HCl) and intrinsic factor.
60
What do chief cells secrete?
Pepsinogen and a small amount of gastric lipase.
61
What is the role of gastrin?
Stimulates gastric acid secretion and motility.
62
What triggers the cephalic phase of gastric regulation?
Sensory stimuli like the sight, smell, taste, or thought of food.
63
What occurs during the gastric phase of gastric regulation?
Initiated by the arrival of food in the stomach, involving stretch receptors and chemical stimuli.
64
What is the enterogastric reflex?
A neural reflex originating in the duodenum that inhibits gastric emptying and secretion.
65
What is the importance of the extra oblique layer of smooth muscle in the stomach?
Allows for vigorous churning and mixing of food.
66
What are the three types of gastric gland cells?
* Parietal Cells
* Chief Cells
* Enteroendocrine Cells
67
What is the role of intrinsic factor secreted by parietal cells?
Essential for the absorption of vitamin B12 in the small intestine.
68
What factors assist with turning off stomach acid production?
* Low stomach pH
* Somatostatin
* Enterogastric nerve reflex
* Intestinal hormones (like secretin and CCK)
* Sympathetic nervous system activity
69
What is the duodenum?
The first and shortest segment of the small intestine.
70
What is the duodenum?
The first and shortest segment of the small intestine, receiving chyme from the stomach and digestive juices from the pancreas and liver.
71
What is the jejunum?
The middle section of the small intestine, located between the duodenum and ileum, where most chemical digestion and nutrient absorption occur.
72
What is the ileum?
The final and longest section of the small intestine, extending to the large intestine, primarily absorbing vitamin B12, bile salts, and remaining nutrients.
73
What is the function of the ileocecal valve?
A sphincter muscle located at the junction of the ileum and the cecum that controls the flow of chyme.
74
Define villi.
Finger-like projections lining the mucosa of the small intestine that increase the surface area available for nutrient absorption.
75
What are microvilli?
Tiny projections of the plasma membrane on the surface of absorptive cells (enterocytes) lining the villi, further maximizing surface area.
76
What is the brush border?
The collective term for the microvilli on the apical surface of small intestine epithelial cells, resembling a brush; also contains digestive enzymes.
77
What are intestinal crypts?
Glands located in the pits between villi in the small intestinal lining, containing secretory and stem cells.
78
What is segmentation in the small intestine?
The primary type of smooth muscle contraction involving localized, ring-like contractions that mix chyme with digestive juices and facilitate absorption.
79
What is the main job of the small intestine?
It's the primary site for finishing chemical digestion and absorbing most nutrients, water, and electrolytes from food.
80
List three structures that greatly increase the small intestine's surface area for absorption.
* Circular folds (plicae circulares)
* Villi
* Microvilli (forming the brush border)
81
Is it accurate to state that the majority of digestion and absorption occurs in the small intestine?
Yes, that statement is highly accurate.
82
What are the three main features that increase the small intestine's surface area for absorption?
* Circular folds
* Villi
* Microvilli
83
What is the role of circular muscles in the small intestine?
To mix (segmentation) and squeeze behind food (peristalsis).
84
What is the role of longitudinal muscles in the small intestine?
To shorten segments, propelling food forward (peristalsis).
85
What is the function of the large intestine?
Absorbing water and electrolytes, housing gut bacteria that produce certain vitamins, forming and storing feces, and eliminating feces (defecation).
86
What are haustra?
Pouches or sacculations of the colon formed by the contraction of the longitudinal muscle bands called taeniae coli.
87
What is mass movement in the large intestine?
Strong, wave-like contractions that move fecal matter through the large intestine, typically occurring a few times a day.
88
What is feces?
Waste matter discharged from the bowels after food has been digested.
89
What is the function of the internal anal sphincter?
This inner ring is made of smooth muscle and is under involuntary control, maintaining continence without conscious effort.
90
What is the function of the external anal sphincter?
This outer ring is made of skeletal muscle and is under voluntary control via the somatic nervous system.
91
What causes the 'pocketed' appearance of the large intestine?
The 'pocketed' appearance is created by haustra, formed because the taeniae coli are shorter than the rest of the colon wall.
92
What is the importance of normal bacterial flora in the large intestine?
Gut bacteria synthesize essential vitamins, ferment indigestible carbohydrates, help train the immune system, and prevent harmful bacteria from growing.
93
What are acini in the pancreas?
Clusters of exocrine cells in the pancreas that synthesize and secrete digestive enzymes.
94
What is the main pancreatic duct?
The primary duct draining pancreatic juice from the pancreas into the duodenum.
95
What are the main components of pancreatic juice?
* Bicarbonate ions (HCO3−)
* Digestive enzymes
96
What is the function of bile?
Essential for emulsifying fats during digestion.
97
Where is bile produced and stored?
Bile is produced in the liver and stored in the gallbladder.
98
What regulates the flow of bile and pancreatic juice into the duodenum?
The hepatopancreatic sphincter (Sphincter of Oddi).
99
Where does bile originate and its function?
Bile originates in the liver and its function is to emulsify fats.
100
What are the main components of pancreatic juice?
Main components of pancreatic juice include:
* Bicarbonate ions
* Digestive enzymes (Pancreatic amylase, Pancreatic lipase, Proteases, Nucleases)
101
What is the role of bicarbonate ions in pancreatic juice?
Neutralize acidic chyme from the stomach, creating an alkaline environment.
102
What does pancreatic amylase digest?
Starches (carbohydrates).
103
What does pancreatic lipase digest?
Fats (triglycerides).
104
What do proteases digest?
Proteins.
105
What do nucleases digest?
Nucleic acids (DNA, RNA).
106
What is the relationship between the gallbladder and the liver?
The liver produces bile, which is stored in the gallbladder and released into the small intestine.
107
What are other functions of the liver besides bile production?
Other functions of the liver include:
* Nutrient metabolism
* Detoxification
* Excretion
108
What is emulsification?
The process of breaking large fat globules into smaller droplets.
109
What are micelles?
Small spherical aggregates of bile salts surrounding digested lipids.
110
What are chylomicrons?
Lipoprotein particles formed within intestinal cells to package absorbed fats.
111
What is the main difference between lipid digestion and carbohydrate/protein digestion?
Lipid digestion requires emulsification by bile salts.
112
How are water and electrolytes absorbed from the intestines?
Water is absorbed via osmosis; electrolytes are absorbed through active transport and cotransport.
113
What are the main organs of the digestive system?
Main organs of the digestive system include:
* Mouth
* Esophagus
* Stomach
* Small Intestine
* Large Intestine
* Rectum/Anus
114
What are the building-block molecules of carbohydrates?
Simple sugars (like glucose).
115
What are the building-block molecules of lipids?
Fatty acids and glycerol.
116
What are the building-block molecules of proteins?
Amino acids.
117
What are the building-block molecules of nucleic acids?
Nucleotides.
118
What are enzymes?
Biological catalysts that speed up chemical reactions.
119
True or False: Bile is produced in the gallbladder.
False.
120
Fill in the blank: The main enzyme from the pancreas that breaks down dietary fats is _______.
Pancreatic lipase.
121
What is the role of brush border enzymes in digestion?
Complete the digestion of carbohydrates and proteins.
122
How are amino acids absorbed in the small intestine?
Amino acids are absorbed through the intestinal cell membrane.
123
What is the function of trypsin?
A major protein-digesting enzyme produced by the pancreas.
124
What is the importance of bile salts during digestion?
They aid in emulsification of fats.
