AP1 Module 3 Flashcards
1
Q
Pepsinogen
stomach. roles throughout the gastrointestinal tract
A
Pepsinogen (a pro-enzyme) is secreted by the** chief cells** in the stomach. Hydrochloric acid converts the inactive pepsinogen (secreted by the chief cells) into the active enzyme pepsin, which begins the breakdown of proteins. Mucus protects the stomach lining from the hydrochloric acid and pepsinogens. The muscularis externa churns and mixes the food, breaking it into smaller pieces. The smaller pieces allow for more surface area of the food to be exposed to the enzymes in the stomach to form chyme.
ogen means that it is a pre-enzyme (not ready yet) can.t make any activi
2
Q
Ingestion
digestive system
A
is when food enters the mouth.
3
Q
Peptides
roles throughout the gastrointestinal tract
small intestine
A
which result from the first step in protein digestion, are digested by peptidases to amino acids
4
Q
Pharynx
A
connects the mouth to the esophagus . made up of three parts: the nasopharynx , oropharynx, and laryngopharynx. The pharynx has two types of skeletal muscles: a circumferential outer layer and an inner longitudinal layer. These two layers of muscles contract alternatively causing peristalsis which squeezes food into the esophagus.
5
Q
Cellular respiration
ATP reaction
A
Cellular respiration is an aerobic process (oxygen must be present) used by cells to produce energy. Respiration takes place inside and around the double membrane-enclosed organelle known as the mitochondria.
6
Q
The stomach has two purposes
A
- it is a temporary storage area for food. Usually, the stomach stores up to two liters of partially digested food. The stomach wall contains rugae.
- mechanical food breakdown.
7
Q
Esophageal Hiatus
A
The esophageal hiatus is the opening in the diaphragm through which the esophagus passes from the thoracic to the abdominal cavity. It is one of three apertures in the diaphragm and is located in the right crus.
8
Q
ascending colon
large intestine parts
A
which runs along the right side of the abdomen superiorly. The right colic (hepatic) flexure connects the ascending colon to the transverse colon.
third
9
Q
vitamins
A
Fat-soluble vitamins are stored in body fat. Ingestion of excessive amounts of fat-soluble vitamins can be problematic.
10
Q
large intestine
Misc fun facts
A
The large intestine’s major function is to propel wastes from the body (see Figure 3.24). The large intestine also reabsorbs some water and electrolytes. About 1.5 liters of water enter the digestive tract daily because of eating and drinking, and an additional 8.5 liters enter the digestive tract each day carrying the various substances secreted by the digestive glands. About 95% of this water is absorbed by the small intestine, and much of the remaining portion is absorbed into cells in the wall of the colon. When materials pass through the colon too quickly, excess water is not reabsorbed, and diarrhea will result. Extreme or prolonged diarrhea can lead to serious dehydration and electrolyte loss. Vitamin K and certain B vitamins, all produced by intestinal bacteria, are also absorbed by the cells in the wall of the colon.
11
Q
ingestion
roles throughout the gastrointestinal tract
A
starting with the mouth. occurs when food enters the mouth. The mouth is also where digestion begins, both mechanical and chemical. Chemically, saliva is released by the salivary glands (note the locations of the parotid, sublingual, and submandibular glands in Figure 3.27 below).
12
Q
vitamins
A
Water-soluble vitamins are not able to be stored in the body and are excreted in urine.
13
Q
digestive system
high level
A
The digestive system has four main roles that it performs: ingestion, digestion, absorption, and defecation.
14
Q
Ascending, Transverse, Descending Colon
A
15
Q
Digestion
digestive system
A
Digestion or food breakdown occurs when food is moved, mixed, and exposed to enzymes along the gastrointestinal tract. Digestion can be divided into two parts:
1. mechanical digestion
2. chemical digestion.
16
Q
Hormones that cause satiety (decrease hunger)
A
Leptin, Serotonin, Cholecystokinin (CCK)
17
Q
satiety
Basic physiological responses
A
satiety is the satisfied feeling of being full after eating
The GI tract itself contributes to the feeling of satiety.
18
Q
Anus
A
Anus, terminal opening of the anal canal, the portion of the digestive tract through which fecal material is excreted.
19
Q
chyme
stomach
A
The stomach contents are called chyme, which is a thick, soupy consistency.
Chyme stimulates the small intestine to secrete two hormones: cholecystokinin and secretin.
20
Q
muscularis externa
esophagus
muscular tube, containing four layers of tissue of the same types found in the stomach, small intestine, and large intestine.
A
The third layer is the muscularis externa made of two layers of muscle: the outer longitudinal fibers and inner circumferential fibers.
21
Q
ATP
A
In summary, cells require ATP to survive. Under aerobic conditions (in the presence of oxygen), the complete catabolism of glucose yields 2 ATP from glycolysis, 2 ATP from the TCA cycle and 34 ATP from the electron transport system, for a total of 38 ATP from a single glucose molecule. The summation of these metabolic processes is shown in Figure 3.32 below.
22
Q
adenosine triphosphate or ATP
A
The most widely used form of energy in the cells is adenosine triphosphate or ATP
23
Q
Mesentery
A
The mesentery is a fold of membrane that attaches the intestine to the wall around the stomach area and holds it in place
24
Q
Ileum
A
section of the small intestine the ileum (see Figure 3.20) is the third section. The ileum is slightly longer than the jejunum. Goes to the ileocecal valve (controls the entrance to the large intestine).
25
lacteal
| Each **villus** contains blood vessels and a lymphatic vessel
Sugars and amino acids enter villi cells, and then are absorbed through the capillary beds present inside the villi. ugars and amino acids enter villi cells, and then are absorbed through the capillary beds present inside the villi. The nutrients are carried into the hepatic portal circulation (of the liver) before entering general blood circulation. Molecules that are too large to enter blood capillaries, such as glycerol and fatty acids, are transported into lacteals. For example, fatty acids enter villi cells and are reassembled into fat molecules (triglycerides). The newly packaged fat molecule moves into the lacteals, eventually connecting to general blood circulation at the thoracic duct.
| lacteal vessel. with vessels (atery in red, vein in blue) for nutrient a
26
Palate
Palate: The roof of the mouth. The front portion is bony (hard palate), and the back portion is muscular (soft palate).
27
tooth
| crown
is the visible portion of the tooth and lies above the gum line.
28
body
| stomach
which is the wider midportion located between the fundus and fourth part, which is the funnel-shaped pyloric region.
| third part
29
stomach
| roles throughout the gastrointestinal tract
Once in the stomach, mechanical and chemical breakdown of food continues with the secretion of digestive juices. Very little to no nutrient absorption occurs in the stomach. The stomach’s main function is for mechanical and chemical breakdown of food. The hormone gastrin stimulates the stomach to secrete gastric juices, which contains: pepsinogens, mucus, and hydrochloric acid.
30
tooth
| neck
is located within the upper portion of the gums (gingiva)
31
Figure 3.28
32
parietal cells
| stomach. roles throughout the gastrointestinal tract
The **parietal cells** (located in the wall of the stomach body) secrete hydrochloric acid, generating a pH of 1.3-3.5. This very acidic pH kills many of the bacteria ingested along with food. In addition, the low pH stops the activity of salivary amylase. The secretion of hydrochloric acid is essential in the activation of pepsin.
33
Anabolism
Anabolism is the set of reactions in which smaller molecules are combined to make larger, more complex molecules.
34
tongue
1. is a muscle. it attaches to other structures so it can contract for movement. The tongue’s attachments are the hyoid bone, the mandible, and the lingual frenulum. grips the food and constantly repositions it between the teeth, forming it into a compact mass called a **bolus.**
2. It contains papillae. three types of **papillae** that help to grip food on the tongue: circumvallate, fungiform, and filiform. Circumvallate and fungiform papillae both contain **taste buds**. Taste buds are chemical receptors that are stimulated by the chemical composition of food. They are found primarily on the tongue as well as on the surface of the mouth and the wall of the pharynx.
35
Lipid metabolism
**Lipid metabolism **occurs in the liver by a process known as beta-oxidation. Lipids are used by the body primarily during low energy activities. Lipid metabolism yields twice the amount of ATP than when a carbohydrate or protein is broken down. A fat molecule is broken down in the mitochondria to form acetic acid. Acetic acid is further catabolized by the TCA cycle to carbon dioxide forming some ATP molecules. The electron transport chain (as described above) then converts hydrogen atoms to water. This process releases energy, which is used to add phosphate to ADP to form ATP in the same way.
36
serosa
| esophagus
## Footnote
muscular tube, containing four layers of tissue of the same types found in the stomach, small intestine, and large intestine.
Finally, the fourth and outermost layer is the **serosa** made up of cells that make serous fluid.
37
Electron transport system
| ATP reaction
electron transport system also referred to as the electron transport chain, is a continuation of cellular respiration. In some organisms this process can proceed either aerobically (with oxygen) or anaerobically (without oxygen). In humans, this process is carried out under aerobic conditions. As electrons are transferred from NADH/FADH2 to terminal electron acceptors (O2; aerobic respiration), energy is released and captured by electron acceptor proteins located in the inner membrane of mitochondria. Electrons are then passed down a chain of electron acceptors (thus the name) causing protons (H+; positive charge) to be pumped out of the membrane. This causes a strong differential across the inner mitochondrial membrane, which forms the **proton motive force**. The proton motive force drives H+ back through the ATP synthase complex, also located in the membrane, resulting in the production of up to 34 molecules of ATP.
38
Peristalsis
| stomach. roles throughout the gastrointestinal tract
Peristalsis moves the food toward the small intestine where the pyloric sphincter controls the slow release of chyme into the duodenum
39
Hormones
Hormones also influence our feelings of hunger or satiety. The human body produces a variety of hormones that work together to balance our hunger and satiety.
Hormones are compounds secreted into the bloodstream by one type of cell that acts to control the function of another type of cell. The list below outlines several types of hormones related to hunger and satiety.
40
stomach
is a backward C-shaped organ located along the left side of the abdomen below the diaphragm. Food enters the stomach from the esophagus via the cardiac sphincter, also known as the lower esophageal sphincter (LES) or the gastroesophageal sphincter. Food exits the stomach via the pyloric sphincter into the small intestine.
41
small intestine
Absorption continues along the small intestine until almost all products of digestion have been complete. The epithelial cells of the villi produce intestinal enzymes, which remain attached to the plasma membrane of microvilli. These enzymes complete the digestion of peptides and sugars.
| When food reaches the end of the small intestine, digestion is complete
## Footnote
Bacteria, undigested food, and water remain by the time chyme reaches the end of the small intestine.
42
cecum
| large intestine parts
is the entrance to the large intestine through the ileocecal valve.
| first
43
liver
| Accessory Organs
has numerous functions, including three that are important in digestion.
1. it produces **bile**. it is stored in the **gallbladder**
2. the liver stores glucose as **glycogen**
3. the liver produces** urea** from amino groups that are removed from excess amino acids.
44
Carbohydrates
Carbohydrates are classified as starches and sugars. Milk and fruits, such as apples or peaches, contain sugar. Grains such as wheat and vegetables such as potatoes contain starches.
| major biochemical categories of food that the body needs in large amount
45
teeth
| There are four different types
accommodate both a vegetable and meat diet. One-half of each jaw has two chisel-shaped incisors for biting; one pointed canine for tearing; two increasingly flat pre-molars for grinding; and three flat molars for crushing.
46
large intestine
As food continues to move along the gastrointestinal tract, it comes to the large intestine . This organ extends from the ileocecal valve to the anus. Muscular contractions move the food contents (chyme) through the large intestine (colon) to be excreted as feces. The large intestine has eight parts:
| What remains of the food enters the large intestine by the ileocecal val
47
hypothalamus
The hypothalamus (see Figure 3.29) is a region of the brain that plays a role in hunger, satiety, and the feeling of “being full”.
The amount of nutrients in the blood begin to decline if a person has not eaten in a long period of time. This drop stimulates the feeding center in the hypothalamus and signals the body to feel “hungry” and desire to eat. When the nutrient level of the blood begins to rise, the satiety center is activated and the desire to continue to eat declines. The hypothalamus is constantly processing signals from a variety of nerves throughout the body that influence food intake. If a portion of the hypothalamus is damaged or destroyed, from certain chemicals, trauma, surgery, or cancers, the regulation of hunger and satiety can be lost. In such an instance, the body no longer receives signals to stop eating and weight gain is almost certain.
48
accessory digestive organs
teeth, tongue, gall bladder, salivary glands, liver, and pancreas
49
Fundus
The fundus is a dome-shaped part of the stomach that stores gas from digestion
| The second part is the fundus, which is dome-shaped top of the stomach j
50
Absorption
| digestive system
is the process of moving digested food into the bloodstream.
51
Dentin
| tooth
Dentin or dentine is a layer of material that lies immediately underneath the enamel of the tooth. It is one of the four major components of the tooth which comprises: The outer hard enamel. The dentin underneath the enamel. The dental pulp that lies soft and encased within the dentin
52
Plicae Circulares
The small intestine is the site of terminal food digestion, nutrient absorption, and endocrine secretion. The lining of the small intestine consists of a series of permanent spiral or circular folds, termed the plicae circulares, which amplify the organ's surface area, promoting efficient nutrient absorption.
53
amino acids
There are nine amino acids called **essential amino acids **required in an adult human diet (with ten required in an infant’s diet). They are called essential amino acids because the body is unable to make these amino acids. Complete proteins contain all nine essential amino acids but incomplete proteins do not.
54
mechanical digestion
| Digestion - two parts
occurs when food is physically broken down into smaller pieces. This occurs when the teeth chew food, when the stomach churns and mixes food, and as food is moved and squeezed along the gastrointestinal tract
55
Epiglottis
a flap of elastic cartilage that covers the larynx when swallowing food or liquid
56
Esophagus
extends from the pharynx to the stomach, travelling through an opening in the diaphragm on its way to the stomach (see Figure 3.13). It is a muscular tube, containing four layers of tissue of the same types found in the stomach, small intestine, and large intestine.
57
chyme
| enters the duodenum
proteins and carbohydrates are only partially digested, and fat digestion still needs to be carried out. Considerably more digestive activity is required before these nutrients can be absorbed through the intestinal wall.
58
Cardiac region/sphincter
The lower esophageal sphincter (LES), also known as the cardiac sphincter, is an involuntary sphincter located at the bottom of the esophagus, where it connects with the stomach.
59
mucus protects
| stomach
As with the rest of the digestive tract, a thick layer of **mucus protects the wall of the stomach **and the first part of the duodenum. In a circumstance where gastric juice does penetrate the mucus, pepsin starts to digest the stomach or duodenal lining and an ulcer results
60
autonamic neurvos system
| peristalsis. swallowing
controls contractions of alimentary canal that moves swallowed food down the esophogus, turns the stomach and move cyme down the small/large intestines
61
tongue
A freely movable muscular organ that lies partly in the floor of the mouth and partly in the pharynx. It is the organ of taste and contributes also to chewing, swallowing, and speech.
62
adenosine diphosphate or ADP
If a phosphate group is removed from ATP it becomes adenosine diphosphate or ADP. Thus, ATP has energy to donate, while ADP can accept energy (phosphate group) to become ATP.
63
amylase
an enzyme, or special protein, that helps you digest carbohydrates. Most of the amylase in your body is made by your pancreas and salivary glands.
| which digest starch
64
ATP
| high level reaction
1.) Glycolysis
2.) Cellular respiration
3. 3.3 The electron transport system
65
human digestive organs can be divided into two main groups. Name them
(1) those of the alimentary canal
(2) the accessory digestive organs
66
Incisor
Incisors are teeth at the front of the upper and lower jaws used to scrape or tear food objects into smaller particles.
67
Villi
a small slender often vascular process: such as.
a. one of the minute finger-shaped processes of the mucous membrane of the small intestine that serve in the absorption of nutriment.
68
Leptin
| key hormones
Leptin is produced by adipose tissue (fat cells). The role of leptin is to alert the brain to turn off the hunger center in the brain and activate the satiety center when consuming a meal.
69
Protein metabolism
Protein metabolism only takes place when carbohydrates and fats are unavailable to the body. Proteins are the building blocks for the cells and saved as a last resort. When proteins must be used to form ATP, the amino group is removed from the protein to form ammonia. The remainder of the protein molecule enters the TCA cycle, forming some carbon dioxide and ATP. Hydrogen atoms formed during the TCA cycle are converted to water. This releases energy, which is used to add phosphate to ADP to form ATP. Ammonia is harmful to the body and must be converted to a different form. Ammonia is combined with carbon dioxide in the liver to make urea. Urea is then excreted from the body in urine
70
descending colon
| large intestine parts
The descending colon runs along the left side of the abdomen superiorly to the sigmoid colon.
| fifth
71
peritoneum
The stomach is covered by peritoneum (a serous membrane), called the **lesser omentum** and the **greater omentum**
72
small intestine
is specialized for absorption. Molecules are absorbed by the huge number of villi (singular, villus) that line the intestinal wall
73
Aspiration
Coughing is the body’s way of preventing **aspiration** of food or liquid into the lungs. Aspiration of food or liquid into the lungs can cause aspiration pneumonia.
74
Canine
The canines, also called cuspid or eye-teeth, are the longest teeth, located in the corners of the mouth.
75
Defecation
| digestive system
is the excretion of indigestible food from the anus.
76
pancreas
| Accessory Organs
lies deep in the abdominal wall. The **pancreas** sends pancreatic juice into the duodenum by way of the pancreatic duct. Pancreatic juice contains **sodium bicarbonate**, which neutralizes the chyme and makes the pH of the small intestine slightly basic. Pancreatic juice also contains digestive enzymes that act on every major component of food. Pancreatic amylase digests starch to maltose; trypsin and other enzymes digest protein to peptides; and lipase digests fat droplets to glycerol and fatty acids. The enzymes travel by way of the pancreatic duct to the hepatopancreatic ampulla into the duodenum of the small intestine (see Figure 3.26).
77
submucosa
| cross section view of the layers found in the alimentary canal
The second layer is the **submucosa**; this layer contains blood and lymph vessels, lymph nodes, nerves, and mucous glands.
| muscular tube, containing four layers of tissue of the same types found
78
Hunger
| Basic physiological responses
Hunger is the internal drive to find and eat food and is often experienced as a negative sensation such as churning, growling, or a painful sensation in the stomach.
79
muscularis externa
| esophagus
## Footnote
muscular tube, containing four layers of tissue of the same types found in the stomach, small intestine, and large intestine.
The third layer is the muscularis externa made of two layers of muscle: the outer longitudinal fibers and inner circumferential fibers.
80
pyloric region
| stomach
fourth part, which is the funnel-shaped
| fourth part
81
small intestine
| villi
The nutrients are carried into the hepatic portal circulation (of the liver) before entering general blood circulation. Molecules that are too large to enter blood capillaries, such as glycerol and fatty acids, are transported into lacteals. For example, fatty acids enter villi cells and are reassembled into fat molecules (triglycerides). The newly packaged fat molecule moves into the lacteals, eventually connecting to general blood circulation at the thoracic duct.
82
mandible
the movable, lower mandible contains the lower arch of teeth.
83
salivary amylase
| roles throughout the gastrointestinal tract. First food entering mouth.
The enzyme salivary amylase contained in the saliva begins the chemical breakdown of starches. Mechanically, the food is broken down into smaller physical pieces by both the teeth and tongue.
| Chewing on food within the mouth the salivary glands secret the amylase
84
Pyloric region/sphincter
At the base of the stomach is a narrow opening controlled by a valve. Relaxation of the sphincter causes a small quantity of chyme to pass through the opening into the duodenum, the first part of the small intestine. When chyme enters the duodenum, it sets off a reflex that causes the muscles of the sphincter to contract and close the opening temporarily. Then the sphincter relaxes again and allows more chyme to enter. The slow process allows chyme to enter the small intestine for thorough digestion.
| which is a thick, soupy consistency.
85
villus
| small intestine is specialized for absorption
Each villus contains blood vessels and a lymphatic vessel called a lacteal.
86
Bicarbonate
| Pancreatic juice includes
Bicarbonate, which is also contained in the pancreatic juice, neutralizes the acidic chyme.
87
proteins
| complete proteins
Examples of complete proteins are meat, poultry, eggs, milk, dairy products, and soybeans.
| major biochemical categories of food that the body needs in large amount
88
Maltose
| roles throughout the gastrointestinal tract
## Footnote
small intestine
Maltose, which results from the first step in starch digestion, is digested by maltase to glucose. Other disaccharides, each of which is acted upon by a specific enzyme, are digested in the small intestine.
89
cardia
| stomach
where the food enters from the esophagus
| first part
90
Rectum
| Dam near killed him
The last 20 cm of the large intestine is the **rectum**, which terminates in an external opening, the anus. Digestive wastes (feces) eventually leave the body through the rectum and anus. Feces are about 75% water and 25% solid matter. Almost one-third of this solid matter is made up of intestinal bacteria. The remainder is undigested plant material, fats, waste products (such as bile pigments), inorganic material, mucus, and dead cells from the intestinal lining.
91
internal sphincter
| anal canal
The anal canal has an **involuntary smooth muscle internal sphincter** and a voluntary skeletal muscle external sphincter (Figure 3.23). These sphincters open and close the anus during defecation to discharge solid waste material called feces.
92
Catabolism
Catabolism is the set of reactions in which larger molecules are broken down to be used as energy sources for the body. For instance, the anabolic process is often used during growth and repair phases of the cell. The above processes require a great deal of energy in order to carry out the required reactions for life.
93
anal canal
| large intestine parts
the anal canal where feces are expelled through the anus, the end of the gastrointestinal tract.
| eigth
94
Buccal Cavity
The buccal cavity (also known as the mouth or oral cavity) refers to the space at the beginning of the alimentary canal, spanning from the lips to the back of the throat. It serves various important functions, primarily in the process of digestion and communication.
95
Vitamins
Vitamins are needed in the diet to maintain growth and good cellular health. No one food includes all the vitamins needed by the body. This is one reason that humans need to eat a balanced diet that consists of a variety of different foods.
96
Muscularis
| cross section view of the layers found in the alimentary canal
The muscularis mucosae is the deepest layer of mucosa, lying next to the submucosa. It consists of an outer longitudinal and inner circular layer of smooth muscle cells. It is a fairly thin layer, being only 3 to 10 cells thick, extending into the circular folds
97
ulcer
| stomach or duodenal lining
An ulcer is an open sore in the wall caused by the gradual disintegration of tissues.
| In a circumstance where gastric juice does penetrate the mucus, pepsin
## Footnote
**duodenal ulcers **- pepsin starts to digest the stomach or duodenal lining and an ulcer results.
98
Minerals
Minerals are inorganic compounds that, like vitamins, are not used as fuel in metabolic reactions but are combined with other nutrients to form necessary body substances. Humans need the following seven minerals in their diets: calcium, chloride, magnesium, phosphorus, potassium, sodium, and sulfur. There are twelve other minerals needed in trace amounts. Foods such as milk, some meats, legumes, and vegetables are the best sources of minerals. No one food contains all the minerals that are needed by the human body. Therefore, it is necessary to eat a balanced diet with a variety of foods.
99
fundus
| stomach
which is dome-shaped top of the stomach just under the diaphragm
| second part
100
Ghrelin
| key hormones
Ghrelin is produced by the stomach and has the opposite role. Ghrelin travels to the brain and stimulates the hunger center as it deactivates the satiety center. Ideally, leptin and ghrelin work together to balance hunger and satiety.
101
Rugae
| stomach
are folds within the stomach wall, which allows the stomach to expand when it is full
102
transverse colon
| large intestine parts
runs across the abdomen. The left colic (splenic) flexure connects the transverse colon to the descending colon.
| forth
103
Metabolism
Metabolism is a set of chemical reactions that are essential for the body to sustain life.
104
maxilla
The upper arch of teeth is located within the maxilla
105
Cholecystokinin
| Chyme stimulates the small intestine to secrete two hormones: cholecysto
causes the gallbladder to secrete bile.
| Both hormones cause the pancreas to secrete its juices.
106
ulcer
| continueing effect
Once a hole is formed, gastric juice enters other areas in the abdominal region, causing bleeding or damage to other organs. Ulcers also occur from the overuse of drugs, such as NSAIDs (nonsteroidal anti-inflammatory drugs) and aspirin. NSAIDs damage the mucosal lining of the stomach.
107
peristalsis
is the involuntary contraction and relaxation of longitudinal and circular muscles throughout the digestive tract, allowing for the propulsion of contents beginning in the pharynx and ending in the anus.
| No ingestion, digestion, absorption, or defecation takes place in the p
## Footnote
one large wave can push bolus down the esphagus.
In the intestin chyme is push with smaller waves and more regular. rythmic wave like patterns
108
Secretin
| Chyme stimulates the small intestine to secrete two hormones: cholecysto
causes the liver to secrete bile.
| Both hormones cause the pancreas to secrete its juices.
109
Right/Left Colic Flexures
The right colic or hepatic flexure separates the ascending and transverse colon, and the left colic or splenic flexure separates the transverse and descending colon.
110
large intestine
| How many parts?
has eight parts: cecum, appendix, ascending colon, transverse colon, descending colon, sigmoid colon, rectum, and anal canal
111
greater omentum
| peritoneum
hangs down almost like an apron. It attaches the greater curvature of the stomach to the posterior wall of the abdomen, covering the transverse colon and anterior surface of the small intestines.
112
circular folds
The surface area of the wall's mucous membrane is greatly increased by circular folds, which have small, finger-like projections called villi on which are many smaller projections called microvilli. These structures increase the surface area of the roughly 20-foot length of the small intestine to about 1800 square feet for greatly increased absorption of nutrients.
| Absorption of food by the small intestine is increased by three structur
113
ileocecal valve
| intestine
controls the entrance to the large intestine
114
Colon
The colon is also known as the large bowel or large intestine. It is an organ that is part of the digestive system (also called the digestive tract) in the human body.
115
Greater/Lesser curvatures
1. Greater curvature - **convex** greater curvature, which extends outward on the longer side of the stomach.
2. Lesser curvatures - Concave...which extends inward on the shorter side of the stomach
116
mucosa
| cross section view of the layers found in the alimentary canal
The first or innermost layer is the **mucosa**, which secretes mucus into the interior the gastrointestinal tract.
| muscular tube, containing four layers of tissue of the same types found
117
lesser curvature
| stomach
Concave...which extends inward on the shorter side of the stomach
118
greater curvature
| stomach
**convex** greater curvature, which extends outward on the longer side of the stomach.
119
tooth
| Dentin
is a bone-like substance composing most of each tooth.
120
aerobic respiration
Most organisms carry out aerobic respiration, which requires oxygen and a fuel (glucose, for example) and releases carbon dioxide, water, and ATP.
121
alimentary canal
is a continuous **muscular digestive tube** beginning in the oral cavity. It is open at both ends, winding its way through the body cavity. It is composed of the mouth (oral cavity), pharynx (throat), esophagus, stomach, small intestine, large intestine, and anus.
| also called the gastrointestinal tract, or GI tract
122
rectum
| large intestine parts
The rectum connects to the anal canal where feces are expelled through the anus, the end of the gastrointestinal tract.
| seventh
123
Jejunum
Small intestines- The jejunumis the second section,
124
tooth
is made of three main parts: the crown, neck, and root
125
Cellular respiration
Food contains stored energy. In order for cells to use this energy, the food must be broken down so that its energy can be released. This released energy is in the form of ATP. Cellular respiration is defined as the process by which cells generate ATP.
126
tooth
| Enamel
is located on the surface of the crown. is very hard connective tissue that protects the rest of the tooth
127
Lipids
Lipids can be divided into three categories: saturated fat, unsaturated fat, and cholesterol. Meat and dairy products, such as butter, contain **saturated fats, **
while nuts and vegetable oils, such as olive oil, contain **unsaturated fats**.
**Cholesterol** is made by our bodies but can also be ingested by eating animal products, such as meat (beef), cheese, and eggs (yolk).
| major biochemical categories of food that the body needs in large amount
128
bolus
food that has been chewed and mixed in the mouth with saliva.
| saliva adds digestive enzymes, water, and mucus that help chemically to
## Footnote
Muscles contract to move the bolus through the pharynx to the esophagus and into the stomach by peristalsis.
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glucose
Carbohydrates are the main source of energy for cells with the body digesting carbohydrates into glucose. Glucose metabolism is used by the body primarily during high energy demands. As glucose is one of the most abundant biomolecules, the catabolism of glucose is an important metabolic pathway used by microorganisms for ATP production. The complete catabolism of a single molecule of glucose (C6H12O6) yields up to 38 ATP and involves three distinct transitions. Energetically (ATP) speaking, glycolysis is the first step of this process and yields two molecules of ATP. Next, by either fermentation or respiration (see below) two additional molecules of ATP can be produced. Last, the electron transport chain produces 34 ATP via an oxidative phosphorylation event at the plasma membrane.
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Bile
| liver
before entering the small intestine, where it emulsifies fats. Bile is sent to the duodenum by way of the common bile duct (see Figure 3.26). Bile looks green because it contains pigments that are products of hemoglobin breakdown. Bile also contains bile salts, which are emulsifying agents that break up fat into fat droplets so that they mix with water. Emulsified fat is more easily acted on by enzymes.
| it produces bile. Bile is stored in the gallbladder
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lesser omentum
| peritoneum
attaches the lesser curvature of the stomach to the liver
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duodenum
| small intestine
The first section is the **duodenum**, which is the shortest section of the small intestine (see Figure 3.18). The small intestine produces enzymes itself, but more importantly the duodenum is where enzymes from the pancreas and bile from the liver enter the small intestine.
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ATP
| chemical use
By donating available phosphate groups, ATP transfers energy from catabolic (breaking down) reactions to be used for anabolism (building up). This process of donating and/or accepting energy is what fuels a cell to carry out the necessary biochemical reactions for survival.
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external sphincter
| anal canal
The anal canal has an involuntary smooth muscle internal sphincter and a **voluntary skeletal** **muscle external sphincter** (Figure 3.23). These sphincters open and close the anus during defecation to discharge solid waste material called feces.
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small intestine
is the longest part of the gastrointestinal tract. It has three sections.
| The human small intestine is a coiled tube approximately 20 feet long th
## Footnote
has cicular folds helps with large suface area.
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Bile
| Secretin causes the liver to secrete bile
Bile breaks down fat into smaller pieces and is needed for the absorption of fats.
| Bile contains bile salts that emulsify fats. It is producted in the live
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stomach
| Basic physiological responses
The stomach plays a major role in satiety and weight regulation. As the stomach expands from food intake and the nutrients consumed are absorbed, receptors within the stomach wall send signals to the brain and the desire to eat declines. This is an example of the nerve network and the GI tract communicating with the brain that the body no longer desires food.
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mastication
Mechanically, food is chewed by the teeth in the mouth, a process known as
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urea
| liver
the liver produces urea from amino groups that are removed from excess amino acids.
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Rugae
A fold or crease, esp. one of the folds of mucous membrane on the internal surface of the stomach. RUGAE Rugae of stomach as seen through an endoscope.
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glycogen
| liver
The liver breaks down glycogen to glucose between meals to maintain a constant glucose concentration (homeostasis) in the blood.
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Enamel
The hard, white, dense, inorganic substance covering the crown of the teeth. Enamel is composed of hydroxyapatite crystal, a salt that contains calcium
| hardest substance in the body.
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Hormones that increase hunger
Ghrelin, Endorphins, Neuropeptide-Y
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appendix
| large intestine parts
which hangs from the cecum and is usually twisted.
| second
## Footnote
Appendicitis occurs when bacteria accumulates and causes inflammation of the appendix.
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chemical digestion
| Digestion - two parts
is the chemical breakdown of food by enzymes into smaller nutrients.
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mouth is made up of
lips form the opening; the tongue forms the floor; the cheeks form the walls; the hard and soft palates form the roof; and the uvula forms the posterior border.
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Laryngopharynx
the lower part of the pharynx lying behind or adjacent to the larynx
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sigmoid colon
| large intestine parts
The sigmoid colon travels through the pelvis connecting with the rectum. The rectum connects to the anal canal where feces are expelled through the anus, the end of the gastrointestinal tract.
| sixth
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Vitamins
our bodies also need vitamins and minerals in a much smaller amount. Vitamins are organic compounds that are not consumed in metabolic reaction but help enzymes carry out the metabolic reactions, which convert nutrients to materials needed by the body. Vitamins can be classified as water soluble or fat soluble.
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lingual frenulum
is the vertical mucous membrane by which the body of the tongue is attached to the floor of the mouth.
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proteins
| Incomplete proteins
Incomplete proteins are food such as grains, legumes, seeds, and nuts.
| major biochemical categories of food that the body needs in large amount
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tooth
| center of each
is a pulp cavity, which contains nerves and blood vessels. Nervous innervation allows for sensations of heat, cold, and pain.
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Nasopharynx
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oblique layer
| stomach
The stomach has a unique third layer in the muscularis externa, an **oblique layer** . The extra muscular layer allows the stomach to mix food more efficiently with the gastric juices. Breaking food down into smaller pieces is necessary for digestion and later absorption of nutrients.
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Molar
The molars or molar teeth are large, flat teeth at the back of the mouth. They are more developed in mammals. They are used primarily to grind food during chewing.
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mouth
The beginning of the gastrointestinal tract
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Oropharynx
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Glycolysis
| ATP reaction
Glycolysis begins with the breakdown of a single molecule of glucose into two pyruvate molecules.
| Glycolysis is the process of breaking down a 6-carbon molecule of glucos
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Carbohydrates
| energy process
Carbohydrates are the main source of energy for cells with the body digesting carbohydrates into glucose. Glucose metabolism is used by the body primarily during high energy demands.
