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101 Cards in this Set
- Front
- Back
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Long narrow pathway called... |
Alimentary canal |
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Where does digestive system begin and end |
Mouth and anus |
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Consists of ____ and ____ organs |
Primary and periphery |
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Food passes through which type of organ? |
Primary |
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Which type of organ plays a role in digestion, but food does not pass through it? |
Periphery |
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What are the four stages of digestion? |
Ingestion, Digestion, Absorption, Egestion |
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What is digestion and what are the two types of digestion? |
Breaking down food. Mechanical and chemical. |
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What is mechanical digestion? |
Physical change only, breaks food into smaller pieces and makes surface area larger |
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What is chemical digestion? |
Enzymatic breakdown to small organic molecules |
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What is an enzyme? |
A protein that breaks down food, produced by glands and organs. Results in simple molecules that can easily pass through the blood. |
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Which occurs first, mechanical or chemical digestion? |
Mechanical, then chemical |
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What is absorption? |
Transportation of molecules into the blood |
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What is egestion? |
Removal of solid, undigested materials from the body. |
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How does the mouth aid in mechanical digestion? |
Chewing food, mixing with saliva, bolus formation. |
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How does the mouth aid in chemical digestion? |
Begins digestion of starches to disaccharides |
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How does the tongue aid in digestion? |
Taste buds - chemical sensation of taste Rough surface - aids in mechanical digestion |
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What is the tongue composed of? |
Skeletal muscle |
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What is the hard palate composed of? |
Bone |
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What is the soft palate composed of? |
Muscle |
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How does the hard palate assist with mechanical digestion? |
Ridges break food apart |
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How does the soft palate aid in digestion? |
Uvula, and it closes off nares before swallowing |
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What are the tonsils composed of? |
Lymphoid tissue |
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What is the function of the tonsils? |
They protect against infection |
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What are the three types of tonsils? |
Palatine, pharyngeal, and lingual |
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Where are the palatine tonsils located? |
Both sides of the pharynx |
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Where are the pharyngeal tonsils located? |
In the nanopharynx |
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Where are the lingual tonsils located? |
At the base of the tongue |
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How many pairs of salivary glands are there? |
Three |
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How does saliva aid in digestion? |
Lubricates food so it can pass through canal, dissolves food particles, allows us to taste food, and contains amylase enzyme for starch digestion |
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How many deciduous (baby) teeth do we have, and how long do we have them? |
20, 2 years |
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How many adult teeth do we have? |
32 |
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What are the two parts of the tooth? |
Crown and root |
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What are the parts of the crown (tooth)? |
Outer enamel covering, dentin, pulp |
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What are the parts of the root (tooth)? |
Dentin and pulp |
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What are the four types of teeth? |
Incisors, canines, premolars, and molars |
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What are incisors, and what are their purpose? |
Chisel shaped teeth, for cutting and slicing |
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What are canines, and what are their purpose? |
They form a single point, and they are used to hold and tear food |
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What are molars and premolars, and what are their purpose? |
They are broad and flat teeth, and they are for crushing and grinding |
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What are dental carries? |
They are cavities in teeth. |
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How can cavities be prevented? |
The use of fluoride, brushing, and flossing |
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What does the pharynx do? |
It connects the nasal and oral cavities, is part of the respiratory and digestive system, and it actively pushes food down. Triggers the swallowing reflex |
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What are the steps of swallowing? |
Uvula closes off nares, trachea moves upward under epiglottis, epiglottis closes airway off, and bolus of food moves down into esophagus |
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What is the esophagus? |
An organ that passes from the pharynx to the stomach. |
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What is peristalsis? |
A rhythmic wave of contraction throughout the esophageal tract, propels bolus down into the stomach |
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What are sphincters? |
At the entrance to the stomach, not well developed, relaxes with the peristaltic wave, and pushes the bolus into the stomach |
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What is heartburn? |
Gastroesphageal reflux, acidic contents enter esophagus, causes irritation |
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What is vomiting? |
Abdominal muscle contracts, diaphragm contracts, positive pressure pushes stomach contents up through the esophagus |
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What are the four parts of the walls of the digestive tract? |
Mucosa, submucosa, muscularis, and serosa |
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What is the mucosa? |
It is the epithelium supported by connective tissues, lines the lumen. Glandular epithelial cells produce enzymes, and goblet cells produce mucous. |
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What is the submucosa? |
Loose connective tissue, contains blood vessels and lymph nodes. |
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What is another term for lymph nodes? |
Peyer's patches |
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What is muscularis? |
2 layers of smooth muscle. Longitude (outer, runs along length of gut) and circular (inner, encircles tube) |
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What is the serosa? |
Squamous epithelium, supported by connective tissue, and secretes serous fluid |
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What is the stomach? |
It is a thick walled J shaped organ that lies on the left side of the stomach |
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How does the stomach aid in mechanical digestion? |
Mixes food with gastric juice, forms a semi liquid called chyme |
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How does the stomach aid in chemical digestion? |
Initiates of protein digestion, and stores food |
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What are rugae? |
They are folds in the stomach wall that aid in mechanical digestion and allow expansion |
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What do the gastric glands produce? |
Gastric juice, which are chief cells. Contains pepsinogen, and HCl |
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What is pepsinogen? |
An inactive form of proteolytic enzyme |
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What are parietal cells? |
HCl, which activates pepsinogen to become pepsin, and decreases bacterial growth |
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What is the function of mucous cells? |
They produce thick protective mucus layers |
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What are ulcers? |
An open sore in the stomach wall, can be caused by stress or an infection that decreases mucous production. Also called helicobacter pyloris |
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What is the duodenum? |
First 25 cm of the small intestine. Principal site of digestion. Receives bile from the liver and pancreatic juice from the pancreas. |
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What are the jejunum and the ileum? |
Principal site of absorbing nutrients. |
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What are villi? |
Line the outer layer of the columnar epithelium, cells have microvilli. Villi contain blood capillaries which absorb sugars and amino acids |
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What are the hormones produced by the duodenum? |
Secretin and cholecystokinin |
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What stimulates secretin release? |
Acid |
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What stimulates cholecystokinin? |
Digested protein and fat |
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What are the effects of the hormones cholecystokinin and secretin? |
Increased pancreatic secretion and increased bile secretion |
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What is the cecum? |
Blind end of the large intestine, at juncture of the small intestine |
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What is the appendix? |
Projection of the cecum. May play a role in fighting infection |
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What can the rupture of the appendix cause? |
Peritonitis |
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What are the three parts of the colon? |
Ascending, transverse, and descending |
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What are the functions of the colon? |
Absorbs water and salts. |
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Where does the colon terminate? |
The rectum |
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What are the steps of the defecation reflex? |
Feces is forced into the rectum by peristalsis, stretching of the walls imitates reflex, anal sphincters relax, and defecation occurs |
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What is feces made of? |
75% water, undigested material and intestinal flora |
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What is intestinal flora? |
99% facultative anaerobes, which produce vitamin K |
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Why is feces the color that it is? |
Breakdown of bilirubin and and oxidized iron |
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What does the pancreas produce? |
Insulin and glucagon |
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What does insulin do? |
Regulates blood glucose (sugar) |
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What is the function of the exocrine? |
Produces soda bicarbonate, pancreatic amylase, trypsin, and lipase |
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What is the function of soda bicarbonate? |
Neutralizes chyme |
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What is the function of pancreatic amylase? |
Chemical starch digestion |
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What is the function of trypsin? |
Chemical protein digestion |
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What is the function of lipase? |
Chemical fat digestion |
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What is the liver? |
Largest gland in the body. |
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What are lobules? |
Structural and function units |
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What are the trains between lobules? |
Bile duct, branch of hepatic artery, and branch of hepatic portal vein |
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What are the functions of the liver? |
Removes and stores iron, vitamins A, D, E, K and B12. Makes plasma proteins, regulates cholesterol, and absorbs or chemically modifies toxins |
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What does the liver modify into less harmful compounds? |
Alcohol and drugs, toxins, pesticides, and carcinogens |
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What are less harmful compounds filtered through, as opposed to the liver |
Kidneys |
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What is cirrhosis? |
When the liver is chronically exposed to toxins, and the cells become damaged and die |
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Where is bile stored? |
The gallbladder |
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What is bile composed of? |
Bilrubin and bile salts |
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What is bilirubin? |
Breakdown of hemoglobin, is a greenish colour |
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What are bile salts? |
Derived from cholesterol, emulsifies fats in the duodenum |
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Where is the gallbladder located? |
It is a separate organ on the lower surface of the liver |
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How does bile reach the duodenum? |
It is secreted through the common bile duct to the duodenum |
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What are gallstones and how do they occur? |
Cholesterol in bile salts precipitates and forms crystals, which can become gallstones |
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What medical condition can gallstones cause? |
If large enough, they can block the common bile duct and cause obstructive jaundice, a yellowing of the skin, which is a symptom of liver failure |
