(3) Chapter 24 - the digestive system Flashcards Preview

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Flashcards in (3) Chapter 24 - the digestive system Deck (35):
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gastroenterology

the study of the structure, function, diagnosis, and treatment of diseases found in the stomach and intestines

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proctology

diagnosis and treatment of diseases found in the rectum and anus

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GI tract organs (6)

mouth, pharnyx, esophagus, stomach, and small and large intestines

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accessory digestive organs (6)

teeth, tongue, salivary glands, liver, gallbladder, and pancreas

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6 functions of digestive system + brief definition

ingestion (eating/drinking), secretion (saliva, bile, stomach acid, enzymes), mixing/propulsion (in mouth, along tract, in stomach), digestion (physical breakdown beginning in mouth w/majority in stomach/s. intest), defecation (releasing waste products)

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mucosa + components

a mucous membrane: epithelium (superficial), lamina propria (deep), muscularis mucosae (only in stomach and small inst.)

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epithelial mucosa - types and location of cells

non-keratinized stratified squamous epithelium (moist and withstands abrasion) in mouth, pharynx, esophagus, and anal canal; simple columnar in stomach and small intestines (increases surface area/rate of absorption)

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lamina propria

deep layer of mucosa; areolar connective tissue containing blood and lymphatic vessels to GI tract and surrounding tissue. includes MALT (musoca associated lymphoid tissue) which is nodules containing a personalized lymphatic system for thr mucosa

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muscularis mucosa

smooth muscles unique to the mucosa of the stomach and small inst. which fold to increase surface area for digestion and absorption

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submucosa

thin meshwork of collagenous fibers, nerves (submucosal plexus), secretory cells (mostly digestive enzymes and mucus) and blood vessels (highly vascular) surrounding the mucosa and bound by areolar CT.

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submucosal plexus

AKA plexus of Meissner - portion of ENS (enteric nervous system of digestive tract that functions despite paralysis) consisting of sensory and motor neurons that innervate the mucosa and submucosa to regulate movement and vasoconstriction (deals w/infection and slowing digestion)

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muscularis

smooth muscle with circular inner sheet and longitudinal outer sheet to progress food along the GI tract; contains the myenteric plexus (also part of ENS) which controls movement of the muscularis

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serosa

superficial layer of stomach and intestines whose epithelial portion composes the visceral peritoneum, so this is a serous membrane made of areolar CT and simple squamous epithelium (aka mesothelium) which secretes serous fluid (electrolytes and solutes)

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peritoneum

largest serous membrane - parietal peritoneum (lines wall of abdominopelvic cavity) and visceral peritoneum (aka serosa) which covers some organs

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retroperitoneal organs (4)

organs laying behind the peritoneum closest to the spine (ascending and descending colons, duodenum, and pancreas)

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greater omentum

fatty apron covering intestines as a protective layer

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lesser omentum

steadies and divides stomach and duodenum from the liver

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falciform ligament

remnant of umbilical cord that suspends liver to anterior abdominal wall and diaphragm

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mesentary

fan shaped membrane arising from the peritoneum to bind jejunum to ileum to posterior abdominal wall

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mesocolon

CT holding transverse and sigmoid colons to posterior abdominal wall

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mouth

buccal cavity - covered ext. by skin and int. by mucous membranes enclosing CT and buccinator muscles (move food w/in mouth). includes labia (lips) connected to gumline by labial frenulum (superior and inferior), lingual frenulum (holds bottom of tongue to mouth), hard (anterior) and soft (posterior) palates, fauces (opening b/w oral cavity and oropharynx), and uvula (guides food down throat)

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salivary glands

stimulated by sympathetic and parasympathetic systems; produces saliva (begins breakdown of starch in mouth) and lingual glands also produce lingual lipase (starts break down of fat) and mucus; major pairs - parotid (anterior to ears), submandibular (under mandible), and sublingual (under tongue)

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tongue

accessory digestive organ consisting of skeletal muscle (extrinsic and intrinsic) covered with mucous membrane and connected to mouth by lingual frenulum

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types of teeth

decidual (baby, 20) vs. permanent (grown up, 32). 4 pairs of central/lateral incisors, 2 pairs of cuspids/canines, 1st and 2nd premolars (bicuspids), 3 molars (3rd = wisdom teeth)

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dental caries

cavities AKA THE MOST COMMON DISEASE

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pharynx + 3 regions

composed of skeletal muscle lined by mucous membrane extending from internal nares to esophagus posteriorly and larynx anteriorly (back of throat); nasopharynx (posterior to nasal cavity), oropharynx (posterior to oral cavity), and laryngopharynx (below larynx)

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4 functions of esophagus

relax upper esophageal sphincter (UES) to let bolus pass, peristalsis (push bolus along tract), relax lower esophageal sphincter (LES) to pass bolus into stomach, and secrete mucus to lubricate bolus and reduce friction

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function of stomach

mixing area and holding reservoir; digestion of starch continues, digestion of proteins and triglycerides begins, and bolus becomes the liquid chyme

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anatomy of stomach - 4 main regions + some other things

main regions: cardiac (entry point), fundus (top), body, and pylorus (where pyloric sphincter is - antrum and canal); 2 curvatures: lesser (top, contacts liver), greater (bottom, contacts omentum); muscle layers also oblique layer (innermost, pushes down)

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gastric glands

3 types of exocrine gland cells (mucous, chief, parietal) that begin production of gastric juice (turns bolus to chyme) when you eat or sense food or think about it

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mucous neck cells

(type of gastric cells) assist with absorption (water, ions, short fatty acid chains, and some drugs) and secreting mucus, forming a protective barrier inside stomach to prevent digestion by HCl (aka ulcers)

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chief cells

(type of gastric cell) secretes pepsinogen (needs to be activated to break down proteins), gastric lipase (breaks triglycerides into monoglycerides), and intrinsic factor (helps absorb B12)

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parietal cells

(type of gastric cells) secretes HCl (kills microbes, denatures proteins, activates pepsinogen to its active form pepsin, denatures proteins) and intrinsic factor (helps absorb B12, which is needed for RBC formation)

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G cells

(type of gastric cell) found primarily in the pyloric antrum to secrete gastrin (stimulates secretion of HCl and pepsinogen, growth of gastric glands, secretion of lots of gastric juice, and increases stomach motility by contracting LES and relaxing the pyloric sphincter)

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serosa of stomach

simple squamous epithelium (mesothelium), visceral peritoneum, areolar connective tissue