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61 Cards in this Set
- Front
- Back
Digestive System
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Consists of the digestive tract/alimentary tract (mouth to anus) and its accessory organs
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Gastrointestinal Tract
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Refers to the stomach and intestines
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Regions of the digestive tract
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Oral Cavity, Pharynx, Esophagus, Stomach, Small Intestine, Large Intestine, Anus
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Functions of the Digestive System
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Ingestion, Mastication, Propulsion, Deglutition, Secretion, Digestion, Absorption, Excrement
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Ingestion
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The intake of solid or liquid food into the stomach.
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Mastication
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The process by which teeth chew food.
Digestive enzymes work effectively on particle surfaces, so foods must be broken down into smaller particles. |
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Propulsion
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The movement of food from one end of the digestive tract to the other.
Swallowing/deglutition - moves a bolus from the oral cavity into the esophagus Peristalsis - Propels material through the digestive tract. Mass Movements - Contractions that move material in some parts of the large intestine. |
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Paristaltic Waves
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Muscular contractions of the circular muscles in front of the bolus followed by a strong contraction of circular muscles behind the bolus force it along the digestive tube.
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Mixing
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Some contractions move food back and forth within the digestive tract to help break it into smaller pieces.
Process - A secretion in the digestive tract, segments of the digestive tract alternate between relaxation and contraction, material in the digestive tract is spread out in both directions and becomes more diffuse through time (segmental contractions) |
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Secretion
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Added to lubricate, liquify, buffer, and digest food.
Mucus is secreted along the entire digestive tract and protects the epithelial cells from mechanical abrasion, stomach acid, and digestive enzymes. Contain large amounts of water, which liquify the food and make it easier to digest and absorb. |
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Enzymes
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Secreted by the oral cavity, stomach, small intestine, and pancreas - break down large food molecules into smaller molecules that can be absorbed by the intestinal wall.
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Digestion
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The break down of large organic molecules into their component parts
Carbohydrates into monosaccharides Proteins into amino acids Triglycerides into fatty acids and glycerol |
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Mechanical Digestion
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Mastication and mixing of food.
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Chemical Digestion
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Digestive enzymes secreted along the digestive tract.
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Absorption
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The movement of molecules out of the digestive tract and into the circulation or lymphatic system.
Molecules pass out of the digestive tract by diffusion, facilitated diffusion, active transport, symport, or endocytosis. |
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Elimination
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The process by which the waste products of digestion are removed from the body.
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Mucosa
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The innermost tunic
Consists of the inner mucous epithelium, the lamina propria, and the muscularis mucosae. |
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Mucous epithelium
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Moist stratified squamous epithelium in the mouth, oropharynx, esophagus, and anal canal and simple columnar epithelium in the remainder of the digestive tract.
Extends deep into the lamina propria to form intestinal glands and crypts. |
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Lamina propria
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A loose connective tissue in the mucosa.
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Muscularis Mucosae
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A thin outer layer of smooth muscle.
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Submucosa
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Beneath the mucosa. Thick connective tissue layer with nerves, blood vessels, and small glands.
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Parasympathetic submucosal plexus
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A network of nerve cells in the submucosa. Consists of axons, scattered nerve bodies, and neuroglial cells.
Axons from the submucosal plexus extend to cells in the epithelial intestinal glands to stimulate secretion. The esophagus and the stomach lack a submucosal plexus. |
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Muscularis
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2 Layers of smooth muscle, which are circular and longitudinal (except the stomach and esophagus where muscles are striated)
Contains myenteric plexus between two muscle layers Important in control of movement and secretion |
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Myenteric Plexus
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Consists of axons, scattered neuron cell bodies, and neuroglial cells.
Controls the motility of the intestinal tract. |
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Enteric Nervous System
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Made up by the submucosal and myenteric pexuses and contains more neurons than the spinal cord.
Controls secretion and movement/ nervous control of the digestive tract. Functions through local reflexes Capable of controlling peristaltic and mixing movements, along with blood flow to DT without any outside influence. |
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Three major types of enteric nerurons
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Enteric sensory neurons - detect changes in the chemical composition digestive tract contents and mechanical changes like the stretch of intestinal walls.
Enteric Motor Neurons - simulate or inhibit smooth muscle contraction and glandular secretion. Enteric interneurons - connect the sensory and motor neurons. |
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CNS control of digestive system
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CNS works with the ENS.
Control of the DS by the CNS occurs when reflexes are activated by stimuli originating in the digestive tract or CNS. ex. sight or smell of food can stimulate hunger |
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Major neurotransmitters of the ENS
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Acetylcholine - Stimulates
norepinephrine - Inhibits motility and secretions Serotonin - Stimulates digestive motility (cancer treatments cause nausea because of increased serotonin release from endocrine cells) |
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Interstitial Cells
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In the Myenteric Plexus. Form a network of pacemakers that promote rythmic contractions of smooth muscle along the digestive tract.
Help transmit signals from neurons to muscles to regulate movement. |
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Serosa or Adventitia
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Connective tissue/serous membrane
Where serosa is present, called visceral peritoneum. Where adventitia is present, connective tissue blends with the tissue of surrounding structures - in esophagus and reproductive organs. |
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Serous Membranes
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Walls and organs of the abdominal cavity are lined with serous membranes.
Smooth and secrete a serous fluid that provides a lubricating film between the layers of membranes, which reduces friction as the organs move in the abdomen. |
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Peritoneum
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Visceral- Covers the organs
Parietal - Covers the interior surface of the body wall |
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Retroperitoneal
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Certain organs are covered by the peritoneum on one surface and are considered to be behind the the peritoneum
ex. kidneys, duodenum, adrenal glands, urinary bladder |
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Peritonitis
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A potentially life threatening inflammation of the peritoneal membranes as a result of chemical irritation by bile.
ex. appendix rupture |
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Mesenteries
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Two layers of peritoneum with a thin layer of loose connective tissue in between.
Hold organs in place. Routes by which vessels and nerves pass from body wall to organs. |
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Mesoappendix
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The mesentery of the appendix.
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Mesentery Proper
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The mesentery associated with the small intestine
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Transverse Mesocolon
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The mesenterys of part of the colon which extend from the transverse colon to the posterior body wall and the sigmoid mesocolon.
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Lesser Omentum
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The mesentery connecting the lesser curvature of the stomach and proximal end of the duodenum to the liver and diaphragm.
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Greater Omentum
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The mesentery extending as a fold from the greater curvature to the transverse colon.
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Ascites
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An accumulation of excess serous fluid in the peritoneal cavity. Can be caused by alcoholism, starvation, or liver cancer.
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Omental bursa (pocket)
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The cavity - the greater omentum forms a double fold of mesentery that extends inferiorly from the stomach over the surface of the small intestine.
"fatty apron" |
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Vestibule v. Oral Cavity Proper
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The vestibule is the space between the teeth, lips and cheeks.
The Oral cavity is lined with moist, stratified, squamous epithelium. Is located medial to the alveolar processes. |
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Two sets of teeth
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Primary, deciduous, milk
Secondary, permanent, adult - Incisors, canine, molars, and premolars |
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Parts of the teeth
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Anatomic Crown - Enamel covered part of the tooth
Clinical Crown - Section of tooth above the gum line Neck - Enameled part of the tooth below the gum line Enamel - Outer most layer of anatomical crown. Non-living. |
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Dentin
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Living, calcified tissue. In the root, dentin is covered by cellular, bone-like structures that help hold the tooth in place. Surrounds the pulp.
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Pulp Cavity
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Filled with nerves, blood vessels, and connective tissue.
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Lips
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Muscular structures formed by the orbicularis oris muscle and connective tissue.
Lips are not highly keratinized, so the epithelium of the skin is more transparent than the rest of the body. |
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Labial frenula
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Mucosal folds that extend from the alveolar process of the maxilla of the upper lip and from the alveolar process of the mandible to the lower lip.
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Cheeks
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Made up of buccinator muscle, which flattens the cheek against the teeth, and the buccal fat pad, which rounds out the profile on the side of the face.
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Palate
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Separates the oral and nasal cavities.
Consists of the hard palate and soft palate |
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Fauces
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The throat and posterior boundary of the oral cavity that is the opening to the pharynx.
The palatine tonsils are in the lateral wall of the fauces. |
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Lingual Frenulum
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Attaches the tongue to the floor of the mouth.
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Tongue Muscles
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Intrinsic Muscles - Within the tongue - responsible for changing the shape of the tongue.
Extrinsic Muscles - Attached to the outside of the tongue - protrude and retract the tongue and move it from side to side. |
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Terminal Sulcus
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A groove that divides the tongue in two.
The part anterior to the terminal sulcus is covered by papillae which contain taste buds. The posterior third of the tongue has no papillae and only a few taste buds. It has a few small glands that form the lingual tonsil. |
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Apical Foramen
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The nerves of the tooth enter and exit the pulp through a hole at the point of each root called the apical foramen.
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Muscles that move the mandible during mastication
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Temporalis - Retracts the jaw
Masseter, medial pterygoid, lateral pterygoid - Protraction, lateral, and medial excursion of the jaw |
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Mastication Reflex
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Integrated in the medulla oblongata and is stimulated by the presence of food in the mouth.
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Salivary glands/Compound acinar glands
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Parotid - Serous glands - produce watery saliva
Submandibular - Mixed glands with more serous than mucous acini Sublingual - Mixed glands with some serous acini, but mostly mucous acini |
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Salivary Amylase
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The serous part of saliva.
Breaks covalent bonds between glucose molecules in starch and other polysaccharides to produce the disaccharides maltose and isomaltose- which give starches a sweet taste. |
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Lysozyme
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An enzyme in saliva that has weak antibacterial action.
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