The Digestive System and Nutrition Flashcards
the basic body plan of bilateral animals is…
a tube within a tube
What is another word for the outer tube of the gut?
body wall
What is another word for the inner tube of the gut?
gut
what are the four layers of the idealized gut from inside to out?
1) Mucosa
2) Submucosa
3) Serosa
4) Musculares
the inner most epithelial layer where absorption and secretion take place
mucosa
the very thin outer layer of the gut of connective tissue and serous membrane
serosa
layer of gut that serves as route for nerves
serosa
layer of gut containing lymph and blood vessels that carry off absorbed nutrients
submucosa
the two sublayers of smooth muscle in the gut
muscularis
what is motility?
moving food along, breaking it down mechanically
what part of gut allows motility of food
muscularis
what is a good visual example of peristalsis?
snake swallowing food whole
what process moves food back and forth to mix food with digestive juices during peristalsis?
segmentation
the release of various enzymes into lumen of gut for digestion and lubrication
secretion
2 types of digestion
mechanical and chemical
type of digestion that is the physical breakup of large food particles into smaller pieces
mechanical
type of digestion involved in breaking chemical bonds with nutrient molecules
chemical digestion
what part of saliva binds the mucus to be thick
mucins
what is secreted from salivary glands?
Saliva, mucins, and bicarbonate ions
what do bicarbonate ions in the mouth do?
buffer mouth ph so amylase can function
what is in saliva that helps chemical digestion?
salivary amylase
what does teeth help with?
mechanical digestion
deglutition is another word for…
swallowing
swalling is a for of…
motility
What is the name for chewed food that the tongue forms
bolus
The forcing of the bolus into the pharynx triggers…
swallowing reflec
what closes during swalling?
epiglottis
what process takes the bolus down the esophagus into the stomach?
peristalsis
what comes first for the bolus? pharynx or esophagus?
pharynx
the muscular tube extending from pharynx to stomach is called
esophagus
4 functions of the stomach:
1) Stores chewed and swallowed food
2) mixes food with gastric juice to form chyme
3) continues and elaborates chemical digestion
4) regulates passage of chyme into small intestine
4 regions of the stomach (moving down)
1) Cardia
2) Fundus
3) Body
4) Pylorus
folds in stomach that allow stomach to stretch considerably
rugae
3 layers of stomach
1) Circular
2) Longitudinal
3) Oblique
what do the lower esophageal sphincter and the pyloric sphincter do?
create peristaltic contractions to force chyme to mix and move toward pyloric sphincter
time it takes to empty and force contractions of a meal
2-6 hours
how much gastic juices do perople secrete per day?
2L
secretion of gastic juices are stimulated by…
direct food signals
components of gastric juices (4)
- Water
- Mucus
- HCl
- Pepsinogens
What does the HCl in gastric juice do?
increase acidity, helps break down food into semiliquid chyme
what do pepsinogens do?
digest proteins
secretion of bicarbonate and mucus from mucosa form what layer ?
gastric mucousal barrier
what does the gastric mucousal barrier do?
prevents absorption across gastic mucosa
the organ in which the greatest diversity of chemical digestion and absorption
small intestine
How many regions are in the small intestine?
3
mucosa and submucosa are folded into…
plicae
in the small intestine, the mucosa develops into…
villi
each cell in the mucosa of the small intestine are topped with…
microvilli
what do microvilli and plicae and villi all do in the small intestine?
increase the internal surface area
each villus in the small intestine encloses a small capillary plexus and lacteal for what?
transport of absorbed nutrients
What does the intestinal mucosa divide the lumen of the gut from ?
extracellular fluid pool
3 accessory glands
pancreas, liver and gallbladder
most of the fluids secretes in the small intestine come from….
accessory organs
what does pancreatic juice break down?
proteins, sugars, nucleic acids
what stimulates the production of pancreatic juice?
chyme in the duodenum
function of bicarbonate in pancreatic juice
neutralize gastic HCl
what types of transport are used across the epithelial cells of mucosa with pancreatic juice?
active and fascilitated transport
once nutrients are transported through the mucosa?
they go into capillaries for transport away from digestive system
digestion of proteins, sugars and nucleic acids by pacreatic juice is what type of digestion?
chemical
fat digestion is partly by pancreatic enzymes and partly…
bile from the liver
where is bile stored when food is not in intestine?
gall bladder
What do bile salts do to fat?
emulsify fat globules as a form of mechanical digestion
emulsified, digested fatty acids and monoglycerides form what in fat digestion
micelles
what does water based pancreatic lipases do?
effectively digest fats in smaller globules
another word for the large intestine
colon
whatever is not absorbed in the small intestine moves into the…
colon
what is reabsorbed in the large intestine?
water and salts
how many bacteria are in your large intestine?
15 trillion
what role does the central nervous system have in digestive system?
local blood flow (maintaining conditions for proper operation)
the role of the autonomic of nervous system play in the digestive system?
stimulates gut in response to sensory cue (sight or smell of food)
what is the enteric nervous system
cluster of nerves in the gut
