23 Digestive Flashcards
Study of the digestive system
Gastroenterology
Digestive tract,
alimentary canal; GI tract, gut
Accessory organs
aid in digestion, salivary glands, liver, gallbladder, pancreas
Digestion
breaking of large particles of food to smaller ones; mechanical & chemical
Mechanical digestion
chewing, churning of stomach
Chemical digestion
digestive enzymes- break chemical bonds; alter chemical structure (HCl)
Absorption
blood, lymph(fats)
4 layers
mucosa, submucosa(connective tissue), muscle layer, serosa
Muscle layer
churns/mixes food/ propels down; innervated by autonomic parasymp=vagus nerve 10;
circular layer and longitudinal layer=peristalsis
Serosa layer
serous membrane-serous fluid-lubricates; omentum- extension of serosa-“apron” prevents infection from spreading to blood vessels and nerves
Polysaccharide
starch, broken down by amylase to disaccharide
Disaccharides
broken down by disaccharidase to monosaccharides; maltose (g+glucose), lactose (g+galactose), sucrose (g+fructose)
Monosaccharides
glucose, fructose, galactose
Proteins
broken down by protease to peptides or amino acids
Peptides
broken down by peptidase to amino acids
Lipids
broken down by lipase to glycerol and fatty acids, ADEK vitamins
Bile
mechanically breaks down fat by emulsification (chemical)
Oral cavity
Buccal cavity(between cheek and gum); process of chewing-mastication; stomatitis- mouth inflammation
Teeth
4 sets of teeth that match top and bottom(incisors, cuspid/canine, (pre)molars); veins, arteries, nerve that innervate the teeth-pulp
Tongue
Facilitates mastication/deglutination
Frenulum
anchors tongue to bottom of mouth
Salivary ducts
Sublingual, parotid, submandibular
Saliva
softens and moistens food (amylase)
Pharynx
naso and oro separated by hard and soft palate and uvula; cleft palate occurs when palates dont close in fetal development
Esophagus
passes through diaphragm to stomach- gastroesophageal sphincter prevent acid reflux GERD
Top outer curve of stomach
fundus
Bottom outward curve of stomach
great curvature
Top inward curve of stomach
lesser curvature
Small top outward curve
Pylorus
Region close to pyloric sphincter
Pyloric region
Connects pylorus to duodenum
Pyloric sphincter
Allows stomach to expand/contract
pleats called rugae
Layer of stomach that churns fewd
3rd layer- oblique muscles
Chyme
mixture of food, gastric juices, saliva in stomach; ejected through pyloric sphincter
Secretory cells in stomach
-mucous (thin)
-chief pepsin=protease
-parietal-HCl=break protein down to digest/absorb
make up gastric juice^^
-mucous(thick) protect stomach from HCl-ulcers
Hiatal hernia
If opening in diaphragm the espophagus enters thru is weakened/enlarged, stomach protrudes/ herniates from abdominal -> thoracic cavity
Nasogastric tube
empties stomach to prevent vomiting; abdominal wall->stomach food tube- gastrostomy
Gastric Resection (gastrectomy)
cant regulate rate the chyme is delivered to the duodenum. chyme is dumped into duodenum, since there is no stomach= dumping syndrome
Pyloric stenosis
during infancy, the pylorus is too narrow, food cant move out of stomach;characterized by projectile vomiting immediately after feeding
Duodenum
10” where most of digestion/absorption takes place
Villi/ microvilli
increase surface area for nutrient absorption; blood capillary and lacteal for lymph
Carbohydrates and protein end products ->
nutrients absorbed thru duodenal wall->vein of villi->portal vein->liver for processing
End products for fat digestion
absorbed by lacteal in villi->white lymph->chyle->lymphatic system
Small intestine secretes
lipase, protease, amylase, disaccharidoses
other 2 sections of small intestine
jejunum-> ileum (ileocecal valve) -> cecum (large instestine)
Large intestine
Ileocecal valve-> anus;ascending (hepatic flexure) transverse (splenic flexure) descending , sigmoid colon; absorbs water; contains e coli; 30% of feces is bacteria
Twisted intestine
Volvulus
Colostomy
incision to colon/re-routing colon to surface of abdomen
Veins that drain anal region become stretched and distorted
varicosities
Liver (hepatic) accessory organ
Largest organ; partially protected by ribs; produces bile; hepatic portal circulation-process nutrients
Hepatic portal curculation
blood collected from hepatic artery and portal vein taken through central vein; bile produced by liver cells->bile ducts-> stored in gall bladder
Bile salts and pigments
bile salts- emulsify fats; pigments formed from breakdown of hemoglobin that couldnt be reused
Gallstone=
blocks bile from getting to duodenum= grey/clay colored stools; jaundice= backup of bile pigments in blood stream
Where the pancreatic duct and the common bile duct meet
Ampulla of Vater
Gallbladder
stores bile that liver produces
CCK
Cholecystokinin causes the release of bile from the cystic duct->common bile duct-> duodenum
Stones in gallbladder
Cholecystitis
Pancreas
(exocrine) ->pancreatic duct->pancreatic juice-has enzymes and alkaline secretions
Digestive enzymes are secreted by
Acinar cells in pancreas
carbs
proteins
fat
carbs-amylase
proteins-proteases- trypsin and chymotrypsin
fat-lipase
secreted inactive form; activated in duodenum, work best in alkaline ph
Response to acidic chyme
secretin released from duodenal walls -> Alkaline secretions to neutralize
Chyme results in a
secretion of cholecystokinin from duodenal walls to break down fat/protein
