Book: chp 23 digestive system
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Book: chp 23 digestive system
digestive system bio120
book notes only
What 2 main grous divide the various organs in the digestive system?
1. the alimentary canal
2. the aaccessory digestive organs
This is also called the gastrointestinal tract, and is the muscular digestive tube that winds through the body (mouth to anus)
What are the organs of the alimentary canal? (7) (MESS LAP)
What are the accessory digestive organs? (TTGSLP)
What are the abdominal regions?
What are the 6 digestive processes?
3. mechanical breakdown
This digestive process is the movement of food through the alimentary canal.
This is the major means of propulsion throughout the alimentary canal, involves alternate waves of contraction and relaxation of musculature in the organ walls.
This part of mechanical breakdown means to repeatedly move parts of the food over the intestinal wall to increase efficiency of nutrient absorption.
What are the four main layers of the alimentary canal?
3. muscularis externa
What is the innermost layer of the alimentary canal and its 3 sublayers?
1. a lining epithelium
2. a lamina propria
3. a muscularis mucosae
In the mucosa, this layer contains most of the MALT which defends against invasion by bacteria and other microorganisms.
This layer of the mucosa can dislodge sharp food particles embedded in the mucosa
In the muscularis externa, the circular layer (squeeze/shortens) and the longitudinal layer (squeeze/shortens) it.
What layer is responsible for peristalsis and segmentation? How?
The muscularis externa: by using both the inner circular layer and longitudinal layer
What is the outermost layer of the interperitoneal organs in the alimentary canal?
When parts of the alimentary canal does not have a serosa, what does it have instead? Name an example.
: ordinary fibrous CT
The esophagus in the thorax
What are the six major locations of smooth muscle?
1. the iris of the eyes
2. walls of circulatory vessels
3. respiratory tubes
4. digestive tubes
5. urinary organs
6. reproductive organs
T or F: mitochondria are abundant in smooth muscle fibers
Only a few smooth muscle fibers are innervated. The whole sheet contracts as a single unit. This arrangement is called...?
Where can multiunit innervation in smooth muscle be found? 2 places
iris of the eye and the arrector pili muscles of the skin.
This nerve plexus innervates the muscularis externa to control peristalsis and segmentation
myenteric nerve plexus
This nerve plexus signal the glands in the mucosa to secrete and the muscularis mucosae to contract
submucosal nerve plexus
What controls the smooth muscle and glands of the alimentary canal?
the enteric nervous system
What is the sphincter called in the esophagus that acts t close off the lumen and revent regurgitation of acidic stomach juices?
As bolus passes through the esophagus, what glands are being compressed and secretes a lubricating mucus?
T or F: the most external esohageal layer is an adventitia.
True: it is not a serosa because the thoracic segment is not suspended in the peritoneal cavity
What is the rotein-digesting enzyme in the stomach that can function ONLY under acidic conditions, to destroy harmful bacteria in food.
T or F: some substances can be absorbed in the stomach, including water, electrolytes, and some drugs (aspirin, alcohol)
What is the sphincter called between the stomach and the stomach and duodenum?
g) greater curvature
h) pyloric antrum
i) pyloric canal
j) pyloric sphincter
k) lesser curvature
What is the maximum amount of food in liters can the stomachh hold?
Within the folds of the stomach are gastric pits which lead to gastric glands. What are the 3 types of secretory cells in these glands?
1. mucous neck cells
2. parietal cells
3. chief cells
This gastric gland is in the middle regions of the gland and roduces the stomach's HCl.
This gastric gland make and secrete enzymatic protein PEPSINOGEN, which is to activate pepsin when it encoounters acid.
This cell in the gastric gland releases a hormone to signal parietal cells to secrete HCl when food enters the stomach.
This cell is located throughout the stomach, and they divide continuously relacing the entire lining of mucus secreteing cells every week.
undifferentiated stem cells
The villi of the small intestine are covered by a simple columnar epithelium made up of absorptive cells, called this...
T or F: In the small intestine, lymph is squeezed through the lacteals.
What is the liver's digestive function?
What does bile do?
break up fats
what is another name for a liver cell?
In the liver, where do most of the major vessels and nerves enter and leave it?
In the liver sinusoids, what are the names of the marophages that destroy bacteria and other foreign particles in the blood flowing through them?
stellate macrophages (hepatic macrophages)
The liver contains over a million classical liver lobules. Each lobule consists of plates of liver cells called this.
What are the channels called in hepatocytes that bile enters?
What are the two major hormones the pancreas secretes?
insulin an glucagon
In the pancreas, what is the name of the cell that makes, stores, and secretes at least 22 kinds of pancreatic enzyme.
In the acinar cell, enzymes are stored in inactive form in intracellular secretory granules called what?