simply a "long tube" going through the body which has the sole purpose of extracting useful nutrients from ingested food and fluids. Tube called alimentary canal consisting of the oral cavity, pharynx, esophagus, stomach, small intesting and large intest
amylase
chemical in mouth that breaks down starch (carb) as the first part of digestion
daily secretion of saliva and pH
800 to 1500 ml; pH 6-7
large parotid
salivary gland
mumps
viral desease of the parotid salivary gland
parotitis
inflammation of parotid gland
ptyalocele
cystic tumor of a salivary gland
how many taste buds and taste cells per bud
4000 buds; 30-100 taste cells/bud
achalasia
lower esophageal sphincter (cardiac sphincter) fails to relax
symptoms of achalasia
dysphagia, substernal pain, food remain in esophagus for hours
careful diagnosis to rule out heart problems; surgery or use of a special dilating balloon
hiatal hernia
protrusion of the upper part of the stomach through the diaphragm and into the thorax; sympoms include gastroesophageal reflux, dysphagia, heartburn, and epigastic pain
chyme
blus of food, saliva, and gastric juices
zymogenic cells
also known as chief cells; secrete pepsinogen which becomes pepsin which digests proteins
parietal cells
secrete HCl and intrinsic factor; HCl kills bacteria and converts pepsinogen; intrinsic factor allos the ileum of the small intestine to absorb vitamin B12 which is required for erythopoiesis (pernicious anemia if lacking in intrinsic factor)
pyloric sphincter
permits passage of chyme and prevents backflow of chyme
pyloric stenosis
narrowing of the pyloric sphincter cuased by enlagement of circular muscle fibers. The major symptom is projectile vomiting (more common in males)
3 types of peptic ulcers
gastric, duodenal, and esophageal
peptic ulcer
HCl and pepsin eat away the lining of stomach, esophagus or duodenum
causes of ulcers
stress, poor eating habits, excess vagal stimulation, hypersecretion of HCl or pepsin, hypersecretion of adrenal corticoids, lack of mucus, presence of irritating chemicals in the GI tract (steroids, anti-inflammatoryagents,caffeine,alcohol,tobacco,aspiri
% of population with ulcers
10
treatement of peptic ulcers
surgery or diet or drugs
tagamet
treatment for peptic ulcers; blocks the H2 receptors in the stomach and decrease secretion of HCl
Helicobacter pylori
bacteria that may cause peptic ulcers
bacteria that may cause peptic ulcers
Helicobacter pylori
how to kill H. Pylori
three different antibiotics taken three times a day
vomiting
relaxation of cardiac sphincter and strong contraction of the diaphragm and abdominal muscles. cuased by toxic food, gagging, too much digestion, intense pain, dizziness, sight or smell of unpleasant things
pH of gastric juice
2
pH of urine
5.7
pH of sweat
4-6.8
pH of saliva
6.4
pH of breast milk
7
pH of blood
7.4
pH of pancreatic juice
7-9
length of small intestine
20 feet
secretion of intestinal juice
1-2 liters/day
pH of intestinal juice
7.6
what % of digestion takes place in small intestine
90
three divisions of small intestine
duodenum, jejunum, ileum
what breaks down proteins
peptidase
what breaks down carbs
arbohydrates
what breaks down fats or lipids
lipase
colon
large intestine
three divisions of large intestine
cecum, colon, anal canal
prevents backflow from large intestine into small intestine
absorption of water and electrolytes from food materials, ftorage and expulasion of feces from digestive
peristalsis
parasympathetic constriction and relaxation of the muscles of the intestine or any other canal to move contents along
major laxatives
bulk (bran and fiber), lubricants (mineral oil), mineral salts (Mg; they are not absorbed so they increase the osmotic pressure of the fecal material), irritants (speed up rate of preistalsis
peritonitis
infection from burst appendix that spreads from the gut to the lining of the abdominal cavity
irritable bowel syndrom
called spastic colitis; caused by emotional stress
colostomy
abdominal exit is made for the colon
dysentery
inflammation of intestinal mucosa with bleeding and mucus discarge with the stools
liver
largest gland of the body, weighs 3 pounds
liver has lobules containig cells called hepatocytes that produce
bile
8 functions of liver
1produce bile2store iron and copper3store glucose as glycogen4synthesis, storage, and release of vitamins5make fibrinogen and prothrombin for clotting6phagocytosis of foreign material in blood7detox of drugs and alcohol in blood8make plasma proteins
cirrhosis
liver epithelium is replaced by connective tissue causing blockage of sinusoids (caused by alcohol or malnutrition)
hepatitis
inflammation of liver from viruses, protozoa, and bacteria, or by toxic materials
jaundice
yellow color of skin and mucous membranes due to excessive free bilirubin
gallbladder
stores, concentrates, releases bile
amount of secretion daily by gallbladder
600-1000 ml/day
how much liquid can gallbladder store
30-70 ml
cystic duct
from gallbladder to common bile duct
hepatic ducts
from liver to common bile duct
sphincter of ampull
from pancreas, liver and gallbladder into the duodenum
regulation of bile release (4 things)
1presence of fat in si releases cholecystokinin from intestinal mucosa which passes via blood to gallbladder and stimulated gallbladder contraction2rhythmic contraction of gallbladder3peristaltic waves of duodenum relax sphincter of ampulla4vagal stimulat
gallstones
precipitation of cholesterol and bilirubin in bile; hyperconcentration is cuased by:1stasis of bile (too much absorption of water from bile)2high levels of cholesterol3inflammation of gallbladder
endocrine function of pancreas
secretion of insulin and glucagon into the blood
exocrine function of pancreas
secretion of digestive enzymes into the si in response to the presence of chyme in the upper si
amount of pancreatic fluid released each day and pH
1200-1500 ml; pH of 7.1-8.2
pancreatic juice enzymes
amylase, lipase, peptidases or proteolytic (trypsin, chymotrypsin, carboxypeptidase), bicarbonate
trypsinogen s activated to trypsin by
enterokinase enzyme
nervous control of gastric secretion
increased parasympathetic activity, secretion, contraction , release of gastrin (hormone)
hormonal control of gastric secretion
gastrin is a hormone released by G cells in the stomach
two hormones secreted by the si that regulate pancreatic secretion
secretin and cholecystokinin
secretin
secreted by S cells in SI because of drop in pH in duodenum b/c of too much acid; secretin travles in blood to pancreas which secretes bicarbonate
CCK cholocystokinin in pancreatic secretion regulation
released when proteins, fats, and fatty acids enter si. It stimulates the secretion of pancreatic juice rich in enzymes to aid digestion
CCK cholecystokinin in bile secretion
released from I cells in duodenum and upper jejunal mucosa when fats and proteins enter si. stimulates contraction of gallbladder and relaes of bile to digest lipids
anabolism
construiction of complex molecules from simple building blocks
catabolism
breaking down process
essential nutrients
cannot be formed in the body so they must be ingested. Ex: amino acids, vitamins, minerals
nervous tissue can only use what as energy source
glucose
breakdown of fats
fat-bile->fat globules-lipase->glycerol and fatty acids
breakdown of protein
protein->polypeptides->small polypeptides and aa->aa=amino acids
rate of transport of glucose into most cells in the body is greatly increased by
insulin
glycogen
form of storing glucose; many glucose molecules stuck together end to end
process of making glycogen from glucose is called
glycogenesis
glycogenolysis
breaking down glycogen to glucose molecules
glycolysis
splitting glucose into two molecules of pyruvic acid
cell respiration
when O2 is present, the two pyruvic acid molecules are converted to 2 acetyl coenzyme A's by a process called pyruvate decarboxylation
krebs cycle
citric acid cycle; acetyl portion of acetyl CoA is degraded to CO2 and H atoms; occur in matrix of mitochondria;
electron transport chain
oxidation of hydrogen atoms
summary of ATP production
glycolysis 2+krebs cycle 2+electron transport chain 32=36
% of caloried in our diet from fats
40-45; in addition, an average of 20-50% of the carbs ingested are converted into fatty acids
when large quantities of fatty acids are broken down into acetyl CoA, 2 molecules of Acteyl CoA condense to from one molecule of
Science Vocab 147928
