Term
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Definition
| taking food into the mouth |
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Term
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Definition
| the passage of food along the gastrointestinal (GI) tract |
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Term
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Definition
| the breakdown of food by chemical and mechanical means |
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Definition
| the passage of digested food from GI tract into bloodstream (and lymph) for distribution to cells |
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Definition
| the elimination of undigested material |
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Term
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Definition
| Ingestion Movement of Food Digestion Absorption Defecation |
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Term
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Definition
Alimentary canal (GI Tract)
◦ mouth
◦ pharynx
◦ esophagus
◦ stomach
◦ small intestine
◦ large intestine |
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Term
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Definition
◦ salivary glands
◦ liver
◦ gallbladder
◦ pancreas |
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Term
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Definition
MUCOSA
SUBMUCOSA
MUSCULARIS
SEROSA |
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Term
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Definition
= innermost
} composed of epithelium + CT (areolar); and small amounts of smooth muscle
} contains many glands that secrete mucus
} functions:
◦ protection
◦ secretion
◦ absorption (of nutrients) |
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Term
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Definition
= beneath mucosa
} composed of areolar CT, blood vessels, lymph vessels, and nerves;
} functions:
◦ nourishment of mucosa
◦ carrying absorbed nutrients away |
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Term
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Definition
2 layers of muscle
} circular muscle layer around submucosa
} longitudinal layer around circular layer
} function: movements of food through canal (mixing & peristalsis) |
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Term
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Definition
outermost layer
} visceral peritoneum
} functions:
◦ lubrication
◦ free movement of canal in abdominal cavity |
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Term
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Definition
Smooth muscle is arranged in 2 layers at right
angles to each other:
} When circular muscles contract the lumen constricts and the organ lengthens
} When longitudinal muscles contract it shortens and dilates
} This results in a rhythmic motion called?
} This is also how earthworms crawl |
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Term
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Definition
Oral cavity
} Intake of food
◦ Mechanical digestion = physical breakdown of food by tongue and teeth
Taste
} Forms bolus for swallowing
} Initiates swallowing process
◦ Chemical digestion = breakdown of molecules by enzymes |
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Term
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Definition
First teeth (20)
} = Deciduous, baby or milk teeth
} Second teeth (32)
} = permanent, adult teeth
} Every tooth has a specific job |
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Term
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Definition
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Term
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Definition
= cuspids
used for tearing food. |
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Term
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Definition
= bicuspids
used for crushing and tearing |
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Term
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Definition
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Term
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Definition
◦ Only part normally seen
◦ Covered in enamel |
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Term
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Definition
| Where the tooth and the gums meet |
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Term
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Definition
part of the tooth embedded in bone.
◦ The root makes up about two-thirds of the tooth and holds the tooth in place |
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Term
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Definition
| Hardest tissue in the body |
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Term
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Definition
| Layer of the tooth under the enamel |
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Term
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Definition
| Soft tissue found in the center of all teeth, where the nerve tissue and blood vessels are. |
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Term
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Definition
| Basic secretory units of salivary glands = acini (clusters of cells) |
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Term
| 2 major types of cells in acini |
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Definition
◦ Serous
Secrete watery fluid, rich in amylase (enzyme)
◦ Mucous
Secrete thick mucous |
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Term
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Definition
Parotid
Submandibular
Sublingual |
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Term
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Definition
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Term
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Definition
Equal in serous and mucous cells
– More viscous secretion |
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Term
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Definition
– Smallest
– Mostly mucous cells |
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Term
SALIVARY GLANDS/SALIVA
FUNCTIONS |
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Definition
Start chemical digestion of starches, amylose
} Moisten and lubricate food for swallowing
} Put food into solution for tasting
} Moisten mouth |
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Term
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Definition
| Basic secretory units of salivary glands = acini (clusters of cells) |
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Term
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Definition
99.4% water
} 0.6% includes:
◦ mucus
◦ antibodies
◦ Enzymes/amylase
◦ other |
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Term
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Definition
Voluntary muscle
} Functions
◦ Mechanical digestion
◦ Sense of taste
◦ Aides in swallowing
◦ Aides in speech |
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Term
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Definition
Initiated voluntarily then
proceeds automatically
} Divided in 3 phases:
◦ Buccal
Compression of bolus against hard palate
Tongue forces bolus into oropharynx
Nasopharynx sealed off by uvula
◦ Pharyngeal
Bolus moves by peristalsis
◦ Esophogeal
Contraction of pharyngeal muscles forces bolus into esophagus
ESOPHAGUS |
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Term
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Definition
Functions mainly in storing food and mixing it with gastric juice to form chyme
} Other functions include:
◦ Chemical digestion of proteins
◦ Secretion of intrinsic factor – a chemical that is necessary for vitamin B12 absorption. ( B12 is necessary for RBC synthesis)
◦ Destruction of bacteria by hydrochloric acid
◦ Absorption of water, aspirin, and alcohol |
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Term
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Definition
The gastric pits lead into gastric glands, which secrete the gastric juice (2-3 L/ day). The basic cell types are:
◦ Mucous neck cells –
upper portion of gland
Secrete acidic mucus
◦ Chief cells –secrete pepsinogen, an inactive form of pepsin (Pepsinogen is activated by HCl and by pepsin itself)
◦ Parietal cells –
mid-portion of glands
Secrete hydrochloric acid and intrinsic factor.
◦ Enteroendocrine cells – secrete multiple hormones into the plasma. An example is gastrin, a hormone that regulates the stomach’s motility and secretory activity. |
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Term
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Definition
Site of most digestion and almost all nutrient absorption
} Longest part of the alimentary tube
} 3 sections:
◦ duodenum
◦ jejunum
◦ ileum
VILLUS/LACTEAL
} MICROVILLI |
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Term
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Definition
| Gastrin Secretin Cholecystokinin/ CCK |
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Term
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Definition
| causes the pancreas to send out a digestive juice that is rich in bicarbonate. It stimulates the stomach to produce pepsin, an enzyme that digests protein, and it also stimulates the liver to produce bile. |
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Term
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Definition
| causes the stomach to produce an acid for dissolving and digesting some foods. It is also necessary for the normal growth of the lining of the stomach, small intestine, and colon. |
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Term
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Definition
| causes the pancreas to grow and to produce the enzymes of pancreatic juice, and it causes the gallbladder to empty. |
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Term
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Definition
} The “double gland”
} Two major functions:
◦ Endocrine - Secrete insulin and glucagon to control blood sugar levels
Alpha cells secrete glucagon (increase blood sugar)
Beta cells secrete insulin (decrease blood sugar)
◦ Exocrine – Secrete pancreatic juice (1.5 L/day) to aide in digestion
Acinar cells contribute digestive enzymes to the pancreatic juice including:
Protein-digesting enzymes (a.k.a. proteases).
Fat-digesting enzymes such as pancreatic lipase.
Carbohydrate-digesting enzymes such as pancreatic amylase.
Duct cells secrete a bicarbonate-rich solution to neutralize the acidity of the chyme |
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Term
PANCREAS
} Largest internal organ/gland in the body
} Multiple functions |
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Definition
◦ Carbohydrate metabolism – storage and release of glucose
◦ Removal of drugs, toxins, and foreign chemicals from the plasma
◦ Storage of vitamins (A, D, E, and K) and minerals (iron and copper)
◦ Protein metabolism
◦ Lipid metabolism
◦ Synthesis of plasma proteins (e.g., albumin, fibrin, etc.)
◦ Phagocytosis of old RBCs and of pathogens.
◦ Production of bile (0.5-1 L/day). |
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Term
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Definition
GALL BLADDER/BILE
} Bile = bile salts, pigments (e.g., bilirubin) and other chemicals
} made by liver
} secreted into duodenum
} Fatty chyme in SI, triggers intestinal glands to secrete cholecystokinin
} CCK causes the contraction of the gallbladder and bile to be released into the duodenum
Bile salts from liver
emulsify the fats
In a larger fat globule
only the surface lipids are exposed
to the enzymes
Lipase from the
pancreatic juice
cleave off fatty acids |
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Term
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Definition
Reabsorbtion
◦ Water
◦ Vitamins – K, biotin, and B5
◦ Organic wastes
◦ Bile salts
◦ Toxins
} Defecation
◦ Mass movements of material through colon and rectum
◦ Defecation reflex triggered by distention of rectal walls |
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