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Chapter 22 part 1
Digestive System part 1
Question | Answer |
---|---|
What two groups are organs divided into? | 1. The alimentary canal (GI tract) 2. Accessory digestive organs |
What are the organs of the alimentary canal? | 1. Mouth, pharynx, and esophagus 2. Stomach, small intestine, and large intestine (Colon) |
What are the Accessory Digestive Organs? | 1. Teeth and tongue 2. Gallbladder, salivary glands, liver, and pancreas |
Accessory digestive organs lie what to the alimentary canal? | lie external |
How are the Accessory digestive organs and the alimentary canal connected? | by ducts |
What do the accessory digestive organs secrete? | bile, saliva, and digestive enzymes |
Sate the Digestive Process. | 1. Ingestion 2. Propulsion 3. Mechanical digestion. 4 Chemical digestion 5. Absorption 6. Defecation |
What group of organs does Peristalsis take place in? | Alimentary Canal |
What is Peristalsis? | a means of propulsion by action of smooth muscle in walls of alimentary canal |
How does Peristalsis work? | adjacent segments of the alimentary canal relax and contract in alternate waves |
What does Peristalsis function to do? | functions to mix and propel food |
Where does segmentation take place? | in the intestines |
What is segmentation? | Rhythmic coordinated constrictions of non adjacent areas of the intestines |
What does segmentation function to do? | mixes food with digestive juices |
What does segmentation increase and how? | it increases the efficiency of nutrient absorption by repeatedly moving different parts of food over intestine wall |
What is the Peritoneum | a continuous serous membrane with two layers 1. Parietal Peritoneum 2. Visceral Peritoneum |
What does the Parietal Peritoneum do? | lines the internal surface of the body wall (abdominopelvic wall) |
What does the Visceral Peritoneum do? | surrounds the digestive organs |
Visceral and Parietal Peritoneum are what with each other? | they are CONTINUOUS with each other |
What is the Peritoneal cavity? | a slit like potential space between Parietal Peritoneum and Visceral Peritoneum |
There is no what in Peritoneal Cavity? | there is no viscera |
The Peritoneal cavity contains what that allows? | cavity contains serous fluid that allows organs to glide easily over one another |
What does it mean when an organ is in the Retro-peritoneal? | 1. Behind the peritoneum 2. Do NOT have a mesentary 3. only partially covered with peritoneum |
What happens to Retro-Peritoneal organs during development? | they become part of the posterior abdominal wall |
State examples of Mesentery organs. | Liver, stomach, most small intestine, and transverse and sigmoid colon |
What are the functions of Mesenteries? | 1. provides a route for blood vessels and nerves to reach the organ 2. holds organs in place 3. sites of fat storage |
What are Mesenteries? | a double layer of peritoneum pointing away from the abdominal wall to cover all or part of one organ |
What are Interaperitoneal Organs? | Orangs that are almost completely covered with visceral peritoneum |
What do Interperitoneal organs have that Retro-Peritoneal organs don't have? | mesentery |
What are four basic layers of the wall of the alimentary canal from the esophagus to the anus? (starting with innermost layer) | 1. mucosa 2. submucosa 3. muscularis externa 4. seros |
What is the inner most layer of the wall of the alimentary canal? and what are its sublayers? | mucosa 1. Epithelium, Lamina propria, Muscularis mucosae |
Which layer of the wall of alimentary canal is responsible for peristalsis and segmentation? | muscularis externa |
The INNERVATION of motility and secretion in the alimentary canal (GI tract) depends on what things? | 1. Extrinsic parasympathetic and sympathetic innervation 2. Intrinsic innervation by Enteric Nervous System (ENS) |
What contains all neurons of ENS, parasympathetic, sympathetic and visceral sensory fibers of ANS? | Nerve Plexuses in GI wall |
What are two types of Nerve Plexuses? | 1. Myenteric Nerve Plexus 2. Submucosal Nerve Plexus |
Where is the Myenteric nerve plexus located and what does it do? | 1. in the muscularis extrema 2. controls peristalsis and segmentation |
What controls peristalsis and segmentation? | Myenteric nerve plexus |
Where is submucosal nerve plexus located and what does it do? | 1. in the submucosa 2. signals glands in the mucosa to secrete and muscularis mucosae to contract |
What happens in the mouth? | food is chewed, manipulated and by tongue and moistened with saliva |
What lines the mouth? | mucosa with stratified squamous epithelium |
What is the function of the lips and cheek? | to help keep food inside mouth during chewing |
What are the lips and cheeks formed from? | the lips are formed from orbicularis oris and the cheeks are formed by the buccinator muscles |
What forms the roof of the mouth? | the palate |
What is the tongue? | a mass of skeletal muscles covered by mucous membrane |
What are the functions of the tongue? | 1. Grips food and repositions it 2. Helps form some consonants 3. Houses taste buds |
Where are intrinsic tongue muscles and what do they do? | 1. within the tongue; not attached to the bone 2. alter the shape of the tongue |
Where are extrinsic tongue muscles and what do they do? | 1. external to the tongue 2. alter the position of the tongue |
What are the three types of tongue papillae and which ones contain taste buds? | 1. Filiform papillae- do not contain taste buds 2. Fungiform papillae- do contain taste buds 3. Circumvallate Papillae- do contain taste buds |
Three Salivary Glands. | Parotid gland, Sublingual gland, and submandibular gland |
What is the PHARYNX lined with? | stratified squamous epithelium |
What pharyngeal constrictors and what do they do? | 1.voluntary skeletal muscles 2. contract in sequence, from superior to inferior, to squeeze the bolus into the esophagus |
What innervated the Pharyngeal Constrictors? | Vagus Nerve (CN X) |
What does the esophagus pass through in the diaphragm? | esophageal hiatus |
The esophagus joins to the stomach at the what? | cardiac orifice |
What closes off the lumen of the esophagus and what does this do? | 1. cardiac sphincter 2. prevents regurgitation of acidic juices from stomach |
The Esophagus has all 4 layers of the alimentary canal except what? and what is it replaced with? | 1. serosa 2. replaced with adventitia |
Why does adventitia replace serosa in esophagus wall? | because peritoneum is not present about diaphragm |