Digestive System Part 1 Flashcards
The digestive system consists of what two parts?
The alimentary canal and associated organs or accessory digestive organs
What is the alimentary canal?
Also called the GI tract, which consists of the mouth, most of the pharyx, esophagus, stomach, small intestine, and large intestine
What does the associated or accessory digestive organs consists of?
Tongue (PB), teeth (PB), salivary glands (S), pancreas (S), liver (S), and gallbladder (S)
What are the 8 major processes of the digestive system?
Ingestion, secretion, mixing and propulsion, digestion, absorption, defecation, barrier, and immunologic function
How much fluid is secreted into the digestive system per day?
About seven liters
What are the two main types of digestion?
Mechanical and chemical
What is the mouth also referred to as?
The oral or buccal cavity
What is the oral cavity bound by?
Cheeks, hard and soft palate, tongue, and floor of the mouth
Define the lips.
Or labia, are fleshy folds that surround the opening of the mouth and contain the orbicularis oris muscle; the lips are the location of the mucocutanous junction
What does the oral cavity open to?
The oropharynx
What are the fauces?
This is the opening from the oral cavity to the oropharynx
What are the two main parts of the oral cavity?
The vestibule and the oral cavity proper
What is the vestibule?
This is the part of the oral cavity between the lips and teeth and between the cheeks and teeth
What is the oral cavity proper?
The superior border is the hard and soft palates; inferior border is the tongue and floor of the mouth; posterior border is the entrance to the oropharynx; all other borders are the teeth
What percent of saliva is solute and water?
Solute: 0.5%
Water: 99.5%
How much saliva is secreted per day?
1 - 1.5 liters
What are the five digestive and protective roles saliva plays?
Moisten oral mucosa, moisten dry foods, provide medium for food materials to dissolve so they can chemically stimulate taste buds, buffer contents of oral cavity, and contains amylase that partially breaks down starch
What are the two things in saliva that allow for buffering?
bicarbonate and phosphate ions
What does the pharynx connect?
Nasal and oral cavities to larynx and esophagus
What is the pharynx a passage way for?
Food and air
What tissue lines the pharynx?
Respiratory epithelium (ciliated pseudostratified columnar epithelium) and some stratified squamous epithelium
The pharynx is divided into what three things?
The nasopharynx, oropharynx, and the laryngopharynx
Where is the nasopharynx located?
found posterior to the nasal cavity, superior to the soft palate
Where is the oropharynx located?
Posterior to the oral cavity; between level of soft palate to the epiglottis
Where is the laryngopharynx located?
Begins at the superior border of the upright epiglottis and opens into the esophagus and larynx
What tissue lines the nasopharynx?
Ciliated pseudostratified columnar epithelium
What passes through the nasopharynx?
Air passageway only
What happens to close off the nasopharynx when someone swallows?
the soft palate and the uvula move superiorly to close off the nasopharynx
What tissue lines the oropharynx?
Nonkeratinized stratified squamous epithelium
What passes through the oropharynx?
Food and air
What tissue lines the laryngopharynx?
Nonkeratinized stratified squamous epithelium
What passes through the laryngopharynx?
Food and air
The laryngopharynx is continuous with what two structures?
The epiglottis to the larynx
The alimentary canal has what four layers from the lumen outward?
1.mucosa, 2.submucosa, 3.muscularis externa, and 4.serosa or adventitia
What are the three layers of the mucosa in the alimentary canal?
A.lining epithelium, B.lamina propria, C.muscularis mucosae
Lining epithelium of the alimentary canal is made up of what two kinds of tissue?
Nonkeratinized stratified squamous epithelium , and simple columnar epithelium
What two kinds of cells are in abundance in the lamina propria of the alimentary canal?
Macrophages and lymphocytes
The submucosa is what kinds of connective tissue?
Dense irregular connective tissue
What innervates the submucosa of the alimentary canal?
Meissner’s plexus (submucosal plexus)
The smooth muscle layer of the alimentary canal is made up of what two layers?
Inner circular layer and the outer longitudinal layer
If the inner circular layer of the muscularis externa is thickened a lot what structure is formed?
A sphincter
If the outer longitudinal layer of the muscualris externa is constricted what happens to the canal?
It will dilate and shorten the organ
If the inner circular layer of the muscularis externa is constricted what happens to the canal?
It will be constricted and lengthen the organ
What innervates the muscularis externa of the alimentary canal?
Myenteric nerve plexus (a.k.a. Auebach’s plexus)
Serosa of the alimentary canal is made up of what two layers?
Mesothelium and loose (areolar) connective tissue
What makes up the adventitia of the alimentary canal?
Loose (areolar) connective tissue
The esophagus can be both skeletal and smooth muscle tissue, where would each be located in the alimentary canal?
Skeletal is upper 1/3, smooth is distal 1/3 and middle 1/3 is mixed
The esophagus can be serous or adventitia, where would one find these tissues?
Adventitia in the thoracic cavity and serosa when we pass through the diaphragm
What are the two kinds of glands associated with the esophagus?
Esophageal glands (proper) and esophageal cardiac glands
Where are esophageal glands proper found and in what tissue?
Found along the entire tract (more numerous in the upper area) and are located in the submucosa
Where are the esophageal cardiac glands found and in what tissue?
Found in the terminal or distal portion of the esophagus and are located in the lamina propria
What does “I ate ten eggs at noon” refer to?
What level things pass through the diaphragm. I ate = IVC T8; Ten eggs = T10 Esophagus; At noon = Aorta T12
What are the 4 gross parts of the stomach?
Cardia, fundus, body, and pylorus
What are the folds (rugae) for in the stomach?
These are muscular and are intended to help with expansion and mechanical movement of food
What are the 3 histological divisions of the stomach?
Cardia, Fundus/body, and pylorus
What histologically comprises the cardia?
Cardiac glands; primarily mucous
What histologically comprises the fundus/body of the stomach?
Fundic glands that secrete HCL and Pepsin
What histologically comprises the pylorus of the stomach?
Pyloric glands; primaryly musous
What tissue is the mucosa of the stomach made up from?
Simple columnar epithelium
What lead to the glands in the wall of the stomach?
Gastric pits
What are the three layers of the muscularis externa of the stomach?
Outer longitudinal, middle circular, and inner oblique
What are the four layers of the wall of the stomach?
Mucosa, submucosa, muscularis externa, serosa
What cells produce the mucosa in the stomach?
Simple columnar epithelial cells, these are NOT goblet cells
What are the three glands of the stomach and where are they located?
Cardia has cardiac glands (primarily mucous), fundus/body has fundic glands (secrete HCL and pepsin), and pylorus (primarily mucous)
Chief cells are also called what?
Zymogenic cells
What do chief cells produce?
The inactive form of pepsin which is pepsinogen
What do parietal cells produce?
HCL
What do G cells secrete?
Gastrin
