Chapter 17: Digestive System Flashcards
What is the Alimentary canal?
Consists of organs that extend form the mouth to the anus; the food passageway
What are accessory organs?
Consists of organs that empty secretions into the alimentary canal; food does not pass through them
Alimentary canal is how long?
8 m
Innermost to outermost layers of alimentary canal?
Mucosa
Submucosa
Muscularis
Serosa
What is the mucosa
innermost layer, mucous membrane
What is the submucosa?
nourishes cells, transports absobred food molecules
What is the muscularis?
muscle tissue, moves tube and food materials
What is the serosa?
outermost layer; serous fluid eliminates friction
What are mixing movements?
Muscle in small sections contracts rhythmically
moving movements does not move
materials in one direction
example of mixing movements?
segmentation
Examples of propelling movements?
moves materials in one direction such as peristalsis
What is the submucosal plexus?
controls secretions
what is the myenteric plexus?
controls GI motility
What are parasympathetic impulses?
increases activites of digestive system
What are sympathetic impulses?
inhibit digestive action
The lingual frenulum connects
tongue to floor of mouth
Papillae are
projections that move food, contain taste buds
Lingual Tonsils are
lymphatic tissue masses on root of tongue
Palate forms
the roof of the oral cavity
Palate consists of a
hard anterior part and a soft posterior part
The uvula extends from the
soft palate
What are palatine tonsils?
Lymphatic masses on sides of tongue
What are pharyngeal tonsils
MAsses of lymphatic tissue in posterior wall of pharynx
How many primary teeth are there?
20
How many secondary tetth are there
32
What are dental caries?
Cavities within enamel of tooth
Dental caries formed when
sticky food lodge between teeth
DEntal Caries: Bacteria on teeteh metabolize
sugars
DEntal Caries: acidic-by-products desroy
enamel and dentin
Salviary glands secrete
salvia
Saliva moistens
food particles and binds them together
Saliva contains
enzymes (begin chemical digestion of carbohydrates) and bicarbonate (keep pH favorable)
What are the 3 pairs of salivary glands?
Paortid glands
Submandibular glands
Sublingual glands
Different pairs of salivary glands have how many varying proportions of types of secretory cells?
2: Serous and Mucous Cells
What are serous cells?
Produce a watery fluid, containing a digestive enzyme called salivary amylast which splits starch and glycogen into disaccharides
What are mucous cells
Secrete mcus, which binds food particles and lubricates food while swallowing
What are parotid glands?
LArgest glands.
Anterior / inferior to ear
Serous glands
Saliva contains amylase
What are submandibular glands?
Serous and mucous glands
Floor of mouth
What are sublingual glands?
Under tongue
Mainly mucous glands
Pharynx location?
Cavity posteiror to the mouth
Pharynx extends from
nasal cavity to esophagus
Esophagus extends rom
pharyxn to the stomach
Pharynx divided into what parts?
Nasopharynx
Oropharynx
Laryngopharynx
Swallowing Mechanism: First stage
Voluntary stage. Saliva is mixed with chewing food
Swallowing Mechanism: SEcond Stage
Begins as food reaches oropharynx, stimulates sensory receptors.
Swallowing Mechanism: Third stage
Peristalsis transports food in the esophagus to the stomach
What protections food from going into lungs?
Epiglottis
Esophagus penetrates the diaphargm through the
esophageal hiatus
Esophagus: Lower esophageal sphincter rgulates
food passage into stomach
Stomach location
inferior to the diaphargm, in the upper left portion of the abdominal cavity
Three parts of the stomach?
Fundus, body, pylorus
Gastric Secretions: Pepsinogen
inactive form of pepsin; secreted by chief cells
Gastric Secretions: Pepsin
Active enzyme that breaks down proteins into polypeptides; forms from pepsinogen in presence of hydrochloric acid
Gastric Secretions: gastric lipase
Fat-splitting enzyme, found in small quantities, action inhibited by low pH
Gastric Secretions: HCl
Produced by parietal cells; converts pepsinogen into pepesin
Gastric Secretions: Mucus
Secreted by mucuous cells; provides lubrication and protects stomach lining
Gastric Secretions: Intrinsic Factor
Produced by parietal cells; required for absorption of vitamin B12
Gastric Secretions: Sympathetic impulses decrease
gastric activity
Gastric Secretions: Parasympathetic impulses increase
gastric activty; promote release of histamine which stimualtes gastric secretion
Gastric Secretions: Somatostatin
inhibits Hcl acid secretion
Gastric Secretions: Gastrin
Increases gastric juice secretion
Gastric Secretions: Cholecystokinin
Released by small intestine cells when proteins and fat enter the small intestine
What is the Cephalic phase?
The sight, taste, smell, or thought of food triggers parasympathetic reflexes. Gastric juice is secreted in response
What is the Gastric Phase
Food ins tomach chemically and mechanically stimualtes release of gastrin
What is the Intestinal Phase?
AS food enters small intestine, it stimulates intestinal cells to release intestinal gastrin
Mixing of food in stomach with juice produces paste called
chyme
When chyme starts to fill the duodenum, stretch receptors initiate the
enterogastric reglex. This slows stomch emptying and iintestinal filling
Heartburn: results from
eating a lot of food too quickly
Heartburn: takes hypothalamus how long to sense full stomach
20 minntutes
Heartburn: excess fullness leads to
abdominal pain and gastric reflux, as stomach contents enter esophagus
Heartburn: stomach contents in esophagus cause
inflammation called esophagitis. feel like its from heart
What does the Pancreas gland do?
Secretes insulin and glucagon to regulate blood glucose
Pancreas is what type of gland of digestive system
Exocrine
In the exocrine function, pancreas secretes digestive fluid called
pancreatic juice
What makes up most of pancreas?
Pancreatic acinar cells, which reelase pancreatic juice into tiny ducts which lead to the pancreatic duct
What is the pancreatic duct?
empties into teh duodenum
Pancreatic duct and common bile duct joint at dilated tube called
hepatompancreatic ampulla
Heptopancreatic sphincter surrounds
ampulla; controls movement of bile and pancreatic juice
Pancreatic jucie contains
enzymesthat digest carbohydrates, fats, proteins, and nucleic acids
What is pancreatic amylase
splits starch and glycogen into disaccharides
What is pancreatic lipase
breaks down triglycerides
what is trypsin
digest proteins; released as inactive trypsinogen which is actived by enterokinase in small intestine
what is chymotrypsin
digest proteins; released as inactive ; and actived by trypsin
What is carboxypeptidase
digests proteins; released as inactive, activated by trypsin
What are nucleases
digest nucleic acids
what are bicarbonate ions
make pancreatic juice alkaline
What is secretin
stimualtes pancreas to release pancreatic juice high in bicarb ions
what is CCK
stimulates pancrease to release pancreatic juice ihigh in enzymes
location of liver
upper-riught abdominal quadrants
how many lobes in liver?
four
What are teh lobes in the liver
right: largest
left: smaller than right
quadrate lobe: monor lobe, near gallgladder
caudate: minor, near inferior vena cava
Liver lobes divided into hepatic lobules, there are
functional units of the liver
Oxygen por blood form teh digestive tract is transported to the liver through the
hepatic portal vein
Major functions of the liver: carbohydrate metabolism
polymerizes glucose to glycogen; breaks down glycogen to lgucose
Major functions of the liver: lipid metabolism
oxidizes fatty acids, synthesizes lipoproteins , phospholipids, and cholesterol
Major functions of the liver: Protein metabolism
deaminates amino acids, forms urea
Major functions of the liver: storage
stores glycogen, vitamins a, d, and b12, iron, and blood
Major functions of the liver: blood filtering
removes damaged red blood cells and foreign substances
Major functions of the liver: detoxification
removes toxins from the blood
Major functions of the liver: secretion
produces and secretes bile
Liver is capable of regeneration if
25-30% of it is healthy
What can a extracorporeal liver assist device do?
can temporarily perform blood cleansing functions of the live runtil donor liver becomes available
Components of bile?
Water Bile Salts Bile Pigments Cholesterol Electrolytes
Hepatitis is an
inflamamtion of the liver
what is not effective against viral hepatitis?
Antibiotics
Job of gallbladder?
stores and concentrates bile
Dystic duct from gallbladder joints with the
common hepatic duct to form common bile duct
Gallbladder normally concentrates
bile salts, bile pigments, cholesterol
someties cholesterol precipitates to form
solid crystals
causs of gallstones?
excess bile concentration, too much cholesterol secretion by liver or inflammation of the gallbladdder
CKK causes the gallbladdder to
contract, in response to fats entering the dupdenum.
bile salts aid digestive enzymes through
emulsification
Bile salts help absorb fat soluble vitamins such as
a, d, e, k
Symptoms of gallbladdedr disease
pain in right upper abdominal quadrant, back and right shoulder, perhaps nausea and sweating
tests to observe the gallbladeeer
Ultrasonography
Cholecystogram
Treatment for gallstones?
Cholecystectomy (surgical removal of the gallbladder)
Endoscopy to find stomes and remove them
Three parts of small intestine?
Duodenum
Jejunum
Ileum
Enzymes in the membranes of the microvilli: Peptidases
break down peptides into amino acids
Enzymes in the membranes of the microvilli: Sucrase, maltase, lactase
break down disaccharides into monosaccharides
Enzymes in the membranes of the microvilli: lipase
break down fats into fatty acids and glycerol
What joints ileum of small intestine to cecum of large intestine?
Ileocecal sphincter
Parts of Large Intestiine?
Cecum
Colons
Rectum
Anal Canal
What is Divertiiculosis?
Weaking of intstinal wall leads to protrusion of mucous membrane
What is IBD: Ulcerative Colitis?
Affects mucosa, and submucods of large intestine causing bloody diarrhea
What is IBD: Chrohns Disease?
More serous, affects all layers. Causes diarrhea and pain
