Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
76 Cards in this Set
- Front
- Back
|
digestion occurs within the alimentary canal
|
know
|
|
|
digestion is the process where food is broekn down into its organic molecules such as
|
lipids ---> fatty acids
starches --> monosaccharides proteins --> amino acids |
|
|
digestion involves two processes
|
mechanical
chemical |
|
|
mechanical digestion
|
physical breakdown of large food particles into smaller particles
-DOES NOT INVOLVE BREAKGE OF CHEMICAL BONDS |
|
|
chemical digestion
|
enzymatic clevage of chemical bonds
|
|
|
absorption involves the transport of products of digestion from the digestive tract into the circulatory system for distribution to the body's tissues and cells
|
know
|
|
|
flow of digestive tract...
|
mouth
pharynx larynx esophagus stomach small intestine large intestine |
|
|
accessory organs include...
|
pancreas, liver, gall bladder
|
|
|
epithelial cells are the 1st border/barrier of protection from outside world
|
know
|
|
|
mucous membranes
|
type of epithelial cell
|
|
|
epithelial layer helps prevent water loss and allowing selective absorption of materials
|
know
|
|
|
basement membrane attaches epithelium to body
|
know
replaced every few days |
|
|
types of layers of epithelium
|
simple = 1 layer
stratified = multiple layers pseudeostratified = looks like many layers but is only one |
|
|
shapes of epithelium cells
|
cuboidal
columnar squamous(scale-like) |
|
|
mouth can carry out both mechanical and chemical digestion
|
know
|
|
|
mechanical and mouth =
|
mastication(chewing)
|
|
|
chemical and mouth =
|
enzymatic activity
-saliva -moistens and lubricates the food |
|
|
saliva also contains
-amylase(ptyalin) -lipase |
amylase = breaks down starch into smaller sugars
lipase- hydrolyzes lipids |
|
|
tongue molds food into a ball called...
|
bolus
|
|
|
pharynx
|
mouth to esophagus
|
|
|
pharynx and airway/food
|
epiglottis covers respiratory aspect(trachea) when swallowing
|
|
|
esophagus
|
mouth to stomach
|
|
|
esophagus is a muscular tube with striated muscle and ends with smooth muscle
|
know
|
|
|
swallowing action is mostly involuntary
|
know
|
|
|
peristalysis =
|
wave-like contraction down esophagus
|
|
|
lower esophageal sphincter aka
cardiac sphincter = |
entrance to stomach from esophagus
|
|
|
stomach
|
site of digestion
|
|
|
stomach mucosa contain gastric glands and pyloric glands
|
know
|
|
|
these glands are composed of 3 types of cells
|
mucous cells
chief cells parietal cells |
|
|
mucous cells are protective layers on thie inside to prevent wear and tear from high acidic environment
|
know
|
|
|
stomach acid pH =
|
2
|
|
|
chief cells
|
secrete pepsinogen (form of pepsin)
|
|
|
pepsin is capable of protein digestion --> amino acids
|
know
|
|
|
parietal cells
|
secrete HCl
|
|
|
parietal HCl secretion activates pepsinogen release
|
know
|
|
|
pyloric glands
|
secrete gastrin (hormone)
|
|
|
gastrin induces stomach to secrete more HCl and to mix contents of stomach
|
know
|
|
|
chyme = acidic and mixed contents of stomach
|
know
|
|
|
chyme increases surface area for absorption
|
know
|
|
|
stomach is not involved in absorption
|
know
|
|
|
food leaves stomach through the pyloric sphincter
|
into the small intestines doudenum region
|
|
|
3 sections to small intestine
|
doudenum
jejunnum ileum |
|
|
small intestine has micro/villi to increase SA of intestines
|
know
|
|
|
bacteria found within the doudenum
|
know
|
|
|
most digestion occurs in the...
|
doudenum
|
|
|
accessory organs introduced here...
|
allow for more digestion to occur
|
|
|
pancreatic juices are acidic/basic
|
basic (pH = 8.5)
|
|
|
pancreatic juices can digest all the compounds
|
know
|
|
|
enzymes of pancreas
amylase peptidases |
amylase= poly --> monosaccharides
peptidases = protein digestion -trypsinogen chymotrypsinogen elastinogen carboxypeptides |
|
|
enterokinase =
|
responsible for trypsinogen --> trypsin; activates other things also
-main control switch |
|
|
pnacreatic juices include lipase also
|
fats --> fatty acids
|
|
|
bile =
|
produced by the liver and stored in the gall bladder
-includes bile salts, bile pigments and cholesterol |
|
|
gall bladder releases bile into the doudenum
|
this is caused by CCK
= cholecystokinin |
|
|
CCK is released by SI in response to movement of chyme out of stomach and into intestines
|
know
|
|
|
pH of bile =
|
7.5-8.8
-helps to neutralize acidity of stomach acids etc |
|
|
bile salts are made from cholesterol
|
know
|
|
|
bile salts are not enzymes meaning they do not directly impact chemical digestion
|
however, important part with mechanical digestion of fats
-bile salts allow fats to become emulsified |
|
|
emulsification =
|
mixture of two immiscible liquids
-allows fats to not separate and form another layers |
|
|
bile gets fat into the solution(chyme) and increases surface area
|
lipase hydrolyzes ester bonds
|
|
|
chyme in doudenum causes SI to release
-disaccharidases -peptidases -enterokinase -secretin -CCK |
know
|
|
|
secretin
|
horomone that causes pancreatic juice to be ecuded from pancreas
|
|
|
CCK
|
homrone that stimulates the release of pancreatic juice + BILE
|
|
|
bile release is closely related to level/amount of fat ingested
|
know
|
|
|
fatty meal = doudenum will release enterogastrone
|
slows the movement of the chyme through the SI to allow for increased digestion of fat
|
|
|
absorption of molecules occur in the...
|
jejunum and ileum
|
|
|
sugars(glucose) and amino acids are absorbed through active transport or facilitated diffusion into lining of gut
|
know
|
|
|
fats and absorption
1. form triglycerides 2. become chylomicrons 3. enter lymphatic circulation through lacteals 4. |
chylomicrons processed in blood stream as LDLs
-LDL taken up by liver an converted to HDL |
|
|
vitamin absorption
fat soluble |
A, D, K, E
all else are H2O soluble |
|
|
Large intestine main purpose
|
water reabsorption
|
|
|
three major sections of the large intestine
|
cecum
colon rectum |
|
|
cecum =
|
connects small and large intestine
-contains appendix |
|
|
appendix =
|
vestigial organ
|
|
|
colon =
|
responsible for H2O reabsorption and salts
|
|
|
rectum =
|
storage of feces
-indigestible materials -water -bacteria -enzymes -bile |
|
|
anus has 2 sphincters
|
1. internal
2. external |
|
|
internal sphincter is involuntary while external is voluntary
|
know
|
