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A&P Chapter 20 & 21

Digestive System / Nutrition & Metabolism

QuestionAnswer
What are the organs of the digestive tract? Mouth, pharynx, esophagus, stomach, small intestine, large intestine, rectum, anus
What are the accessory organs of the digestive tract? Teeth, tongue, salivary glands, liver, pancreas, gallbladder
What is another name for the digestive tract? Alimentary canal
What are the three layers of the digestive tract? Mucosa, Submucosa, Muscularis
What is the mucosa layer? Contains three layers: inner layer of epithelium, layer of loose connective tissue & thin layer of smooth muscle
What is the Submucosa layer? Thicker layer of connective tissue; contains glands, vessels, lymphatic vessels & nerves
What is the Muscularis layer? Contains two layers of smooth muscle; this layer regularly contracts and relaxes to propel food through the digestive tract
Where does mechanical digestion occur? Mouth, stomach & small intestine
What are the mesenteries? Layers of visceral peritoneum that suspended the digestive organs within the abdominal cavity, while anchoring them loosely to the abdominal wall
What is the mesentery that extends over the stomach & hangs over the small intestine like an apron called? Greater omentum
What is the entryway to the digestive tract? Mouth
What consist of mostly skeletal muscles & forms an arch between the mouth and nasopharynx? Soft palate
What is the clear fluid that consist mostly of water, but also contains mucus? Saliva
What does saliva do? Moistens food, plays a role in taste, and has an enzyme that kills bacteria
Digestion begins when . . . . Food enters the mouth & is chewed
How many teeth does the adult mouth contain? 32
What is enamel? Hard tissue that covers the crown & can not regenerate
What is dentin? Firm, yellowish tissue, which is the bulk of the tooth
What is the first step of the pharynx? Food gets broken down, moistened by saliva, tongue manipulates the bolus to the back of the oral cavity
What is the second step of the pharynx? Soft palate lifts, while the larynx rises, food moves through the oropharynx and laryngopharynx on its way to the esophagus
What happens when a bolus enters the esophagus? Triggers a wavelike muscular contraction that propels the food towards the stomach
What is peristalsis? Wavelike muscular contraction that propels food towards the digestive tract
What is the stomach? Muscular sac whose primary function is to store food
What is chyme? Small particles of food mixed with gastric juice (semifluid)
What is rugae? Wrinkled folds of the mucosa & submucosa
What are the components of gastric juice that are secreted by the glands of the gastric pits? Mucus, hydrochloric acid, intrinsic factor, pepsin, ghrelin, gastrin
Why is the intrinsic factor so important? Necessary for B12 absorption
What secretes digestive enzymes such as pepsinogen? Chief cells
What is the first step once swallowing signals the stomach? Contractions move toward the pyloric region. Wavelike peristaltic contractions breakdown and mix it with gastric juices to form chyme
What is the second step once swallowing signals the stomach? Under the pressure of a contraction, about 30ml of chyme squirts into the duodenum
How long does it take for the stomach to empty after a typical meal? Four hours
What are the phases of gastric secretion? Cephalic, gastric, intestinal
The right & left lobes of the liver are separated by what? Falciform ligament
What is the purpose of the falciform ligament? Anchor the liver to the abdominal wall
What does the portal vein do? Carries oxygen poor but nutrient rich blood from the digestive organs & spleen to the liver
What are the functional units of the liver? Hepatic lobules
Where does the central vein pass through? Core of each lobule
What are hepatocytes? Sheets of hepatic cells that fan out from the center of the lobule
What are sinusoids? Passageways filed with blood in between the sheets of hepatic cells
What are the tiny canals that carry bile secreted by the hepatocytes called? Canaliculi
Blood filters thought the sinusoids allowing cells to remove what? Nutrients, hormones, toxins and drugs
What is the purpose of the gallbladder? Stores & concentrates bile
How does bile leave the liver? Right & left hepatic ducts
What is cholecystokinin (CCK)? Hormone secreted by the duodenum that causes the gallbladder to contract, forcing bile into the bile duct, an the release of pancreatic enzymes
Where does most chemical digestion & nutrient absorption occur? Small intestine
Most of the digestive process occurs in what part of the small intestines? Duodenum
What is the part of the small intestine that is an ideal location for nutrient absorption? Jejunum
What is the last 12 feet of the small intestine called? Ileum
What increases the surface area of the small intestine more than 500 times? Folds, villi, & microvilli
What does chemical digestion & absorption do? Uses digestive enzymes, transforms food molecules into particle that can be absorbed, occurs mostly in small intestine, & the process varies between nutrients
What does carbohydrate digestion do? Begins in mouth with amylase, continues in small intestine with pancreatic amylase, finished at villi with sucrase, lactase, and maltase
What do carbohydrates consist of? Saccharides
What are the three different types of saccharides? Polysaccharides, disaccharides, & monosaccharides
What saccharides do most foods contain? Polysaccharides
What does protein digestion do? Begins in stomach with pepsin, continues in duodenum with trypsin & chymotrypsin, and finishes in small intestine with peptidases
Before the body can absorb amino acids, what bond must be broken? Peptide
How does the peptide bond get broken? With enzymes called proteases that are NOT in saliva and only work in the stomach & small intestine
What is fat digestion? First requires emulsification, continues with pancreatic lipase, some fats are absorbed into bloodstream of villi, other fats changed into triglycerides and enter lymphatic system
Where is most of the fat digested? Duodenum
What does the large intestine absorb large amounts of? Water
What is metabolism? Nutrients that undergo a chemical reaction
What is calorie? Amount of heat (energy) needed to raise the temperature of 1 gram of water by 1 degree Celsius
What is energy expenditure? Measured by the output of heat from the body
What is BMR? Amount of energy the body needs at rest
What is the body's primary source of energy? Carbohydrates
How do you maintain your weight? Calorie intake must equal calorie output
What are the factors that can increase metabolic rate? Anxiety, fever, eating & thyroid hormones
What are the hormones that suppress the appetite? Leptin, insulin, & cholecystokinin (CCK)
What hormone produces hunger? Ghrelin
What hormone tells you that your satisfied and don't need to eat anymore? Peptide YY (PYY)
What types of nutrients are there? Macronutrients, micronutrients, essential nutrients, & nonessential nutrients
What are macronutrients? Carbohydrates, lipids, protein, & water
What are micronutrients? Vitamins and minerals
What are essential nutrients? Obtained through diet
What are nonessential nutrients? Synthesized by the body
What are the three types of carbohydrates? Monosaccharides, disaccharides, polysaccharides
What is a monosaccharide? Simple sugar; absorbed without being broken down (glucose, fructose, galactose)
What is a disaccharide? Simple sugar broken down to monosaccharide (table sugar, lactose, maltose)
What is a polysaccharide? Complex carbohydrate. (Starches found in vegetables, grains, potatoes, rice, & legumes) Most carbohydrates should be complex, contain other vital nutrients in addition to carbohydrates
What is cellulose? Major component of plant tissues that absorb water in the intestines and swell. This adds bulk to the stool and increases peristalsis, allowing stool to pass more quickly out of the body
What do lipids do? Act as reservoir of excess energy, enable absorption of certain vitamins (A, D, E, K), contribute to cellular structure, insulate & protect the body (organs)
What are saturated fats? Derived mainly from animals; tend to be solid at room temperature
What are unsaturated fats? Occurs in nuts, seeds, vegetable oils; tend to be liquid at room temperature
How must essential fatty acids be obtained? Diet
What are complete proteins? Supply all essential amino acids; mainly come from animal sources (meat, fish, eggs, & dairy)
What are incomplete proteins? Lack one or more essential amino acids; come from plant sources (nuts, grains, & legumes)
How are nonessential amino acids obtained? Body synthesizes them
How are essential amino acids obtained? Through food
What are the two different types of vitamins? Water-soluble & fat-soluble
How are water-soluble vitamins absorbed? With water in the small intestine, excreted by the kidney's
How are fat-soluble vitamins absorbed? With dietary fat; stored in the liver & fat tissues
What vitamin is needed for wound healing? C
What are the most abundant minerals in the body? Calcium (Ca) & Phosphorous (Ph)
What is catabolism? Break down of complex substances into simpler ones or into energy
What is anabolism? Forms complex substances out of simpler ones
Where are nutrients transformed through metabolism into energy that the body can use immediately or store for later use? Inside the cell
What are the three phases of carbohydrate metabolism? Glycolysis, anaerobic fermentation, & aerobic respiration
What is glycolysis? Occurs without oxygen; releases only a fraction of available energy
What is anaerobic fermentation? Oxygen in short supply
What is aerobic respiration? Oxygen available; produces large amounts of ATP (Adenosine Triphosphate)
What is the primary goal of glucose catabolism? Generate ATP
The breakdown of what produces more than twice as much energy as the breakdown of carbohydrates? Fat
What is protein metabolism? Builds tissue; During digestion, proteins are broken down & amino acids recombined to form new proteins; Protein catabolism converts proteins to glucose & fat or used directly as fuel.
What is a toxic by-product of protein metabolism called? Ammonia
How is body heat developed? Chemical reactions occurring in the body's cells
What are the three methods of heat loss & example? Radiation - standing in sunlight Conduction - sitting on a cold surface Evaporation - sweat
What is the body's thermostat? Hypothalamus
Created by: tandkhopkins