Digestion Flashcards
What organs are included in the alimentary canal? What is the function of this continuous structure?
Mouth, pharynx, esophagus, stomach, small intestine, large intestine. The function of these organs is to pull nutrients out of our food to nourish the body.
What are the accessory digestive organs?
The liver, gall bladder and pancreas.
Ingestion
which just means eating.
Propulsion
means moving food through the system. This includes swallowing and peristalsis, which is the contraction of the involuntary smooth muscle surrounding the organs of this system.
Mechanical breakdown of food
increases the surface area of the food for enzymes to work on it. This includes chewing, mixing the food with saliva and segmentation.
Segmentation
is the contraction of the circular layer of smooth muscle. This swishes the food back and forth within one section of the intestine, making sure that all nutrients have a chance to come into contact with the cells lining the intestine, so that they can be absorbed.
Digestion of food
refers to the enzymes working on the food, breaking it into its monomers (monosaccharides for carbs, amino acids for proteins, fatty acids and glycerol for lipids and nucleotides for nucleic acids.
Absorption
refers to how these monomers move from the intestine into the body (blood and lymph). They are absorbed into the cells that line the intestine.
Defecation
refers to eliminating any waste that is left over from this process.
What membrane lines the wall of the abdominopelvic cavity? Lines the organs of the cavity?
Parietal peritoneum lines the wall of the abdominal cavity. The visceral peritoneum lines the organs in this cavity.
What is a mesentery and what are their functions?
A mesentery is a double layer of peritoneum fused together. These anchor organs to the wall of the body cavity.
What is the retroperitoneal cavity? What organs are found there?
Retroperitoneal organs lie behind the peritoneum. They don’t have a mesentery, but adhere to the dorsal wall of the cavity.
What are the four layers of the digestive tract?
Mucosa, sub-mucosa, muscularis and serosa.
What are the functions of the mucosa?
To secrete mucous, enzymes and hormones, to absorb nutrients from the products of digestion and to protect against disease (there are MALT tissues here).
What are the three layers of the mucosa?
Simple columnar epithelium, lamina propria and the muscularis mucosae.
What type of epithelium lines the digestive tract?
Simple columnar epithelium.
What type of tissue is the lamina propria made out of?
Areolar C.T. This brings blood supply to the epithelial cells and contains the MALT tissues to protect against bacteria that can enter with your food.
Describe the submucosa.
The submucosa is made out of areolar connective tissue. It has blood and lymph supply, MALT tissues, nerve fibers and many elastic fibers.
Describe the muscularis externa.
There are two layers of smooth muscle here. The inner layer is longitudinal and when it contracts it propels food forward. We call this peristalsis. The second layer is circular. When it contracts it swishes food back and forth within a compartment. We call this segmentation.
Describe the serosa.
This is also the visceral peritoneum. It is a very thin layer of areolar C.T. with one layer of simple squamous epithelium.
What is the splanchnic circulation?
Circulation of the digestive tract (GI tract). These vessels branch off of the aorta and serve the spleen, liver, stomach, pancreas, small and large intestines.
What’s the enteric nervous system?
Nerve supply to the GI tract.
Where is the submucosal nerve plexus? Myenteric?
This is part of the enteric system that is in the submucosa. The myenteric nerve plexus is found between the circular and longitudinal muscle layers in the muscularis.
Describe the anatomy of the mouth. What main function occurs here?
The cavity is called the oral cavity. The palate is the roof of the mouth. The hard palate is anterior and is made up of the palatine processes of the maxilla anteriorly and the two palatine bones posteriorly. The rigid surface is used by the tongue to mash food into smaller pieces and the corrugated texture provides friction to break food apart. The soft palate is posterior and is made up of mostly skeletal muscle.
Describe the anatomy of the palate and how it contributes to mastication of food in the mouth.
helps masks foods and turn then into a bolus.
What are the main functions of the tongue?
To break food into smaller pieces, mix it with saliva, which contains enzymes, and form a bolus to swallow..
What are the three different types of papilla found on the tongue? Function of each?
Filiform papillae roughen the tongue to increase friction for food. Fungiform papillae are scattered over the tongue and have taste buds on them. Vallate papillae are in the back of the tongue and foliate papillae are on the lateral sides of the tongue.
What’s a bolus?
A ball of food that is swallowed.
What are the functions of saliva?
Cleanse the mouth, dissolve food chemicals so that they can be tasted, moisten food to help create a bolus out of it, and contains 2 enzymes that begin to break down food: linguinal lipase (breaks down lipids) and salivary amylase (breaks down carbs).
What are the three main salivary glands and where are they?
They are outside the oral cavity and empty saliva into the mouth. THey include the parotid gland, submandibular gland and sublingual gland.