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120 terms

Digestive System

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Name 6 types of nutrients.
carbohydrates
proteins
lipids
water
vitamins
minerals
What are the functions of the digestive system?
Provide energy
Provide building materials
Eliminate wastes
What does mechanical digestion do?
physically prepares food for chemical digestion
How does mechanical digestion prepare food for chemical digestion?
chewing by teeth; churning of stomach
What happens in chemical digestion?
complex food molecules are broken down to monomers that can be absorbed
What is absorption?
movement of nutrients from digestive tract into blood or lymph
What is ingestion?
intake of food
What is defection?
elimination of undigested or unabsorbed materials
What does an enzyme do?
Speed up chemical reactions
Name the parts of the digestive tract from mouth to anus.
mouth, pharynx, esophagus, stomach, small intestine, large intestine, anus
Name 4 accessory structures to the digestive tract.
salivary glands, liver, gallbladder, and pancreas
Why do the lips appear red?
poorly keratinized; allowing blood to show through
Where are the taste buds located?
on the tongue
What do taste buds do?
detect sweet, sour, salty, and bitter tastes
What is the tongue composed of?
skeletal muscle covered with mucous membrane
What bones make up the hard palate?
maxilla, palatine
What makes up the soft palate?
made up mostly of muscle
What is the uvula?
A finger like projection at the end of the soft plate
Where are tonsils located?
back of mouth on either side of tongue;
also in the nasopharynx (adenoids)
What do the tonsils do?
help protect body against disease
Name the three types of salivary glands.
parotid, sublingual, submandibular
Are salivary glands endocrine or exocrine?
exocrine glands
What do they produce?
1000-1500 ml of saliva
What is the chemical composition of saliva?
99.5 % is water; other 0.5 % are ions
What digestive enzyme is in saliva?
salivary amylase
Give the chemical reaction for the activity of amylase.
Salivary amylase
Starch or glycogen + H20 -> maltoses
What is the part of the tooth above the gumline called?
the crown
What are the parts of the crown?
layer of enamel, dentin, pulp
What is the part of the tooth below the gumline?
the root
What are the parts of the root?
dentin, pulp
Name the different types of teeth.
incisors, canine, premolars, molars
How many sets of teeth do we have?
two
Name each.
Primary or Deciduous
Secondary or Permanent
How many teeth in each set?
Primary 20 teeth
Secondary 32 teeth
What are dental caries?
tooth decay; cavities
What is the bolus?
chewed food mixed with saliva
What is the pharynx?
Region that receives air from nasal cavities and food from the mouth
Where does swallowing occur?
the pharynx
When the bolus leaves the pharynx, where should it go?
esophagus
Is swallowing a reflex action?
yes
What is the role of the soft palate in swallowing?
moves back to close off the nasopharynx
What is the epiglottis' role in swallowing?
covers the glottis during swallowing
What is the glottis?
opening to the larynx (voicebox)
What is the glottis' role in swallowing?
close glottis
After swallowing, where does the food go?
esophagus
Do we breathe when we are swallowing?
no
What is the esophagus?
Tube from pharynx to the stomach
What does the esophagus do?
move bolus from the mouth to the stomach
What is peristalsis?
rhythmic contraction that move nutrients or wastes along tube
What is the esophageal sphincter?
muscle that closes or opens the esophagus by contracting and relaxing
What does the esophageal sphincter do?
allows the bolus to move into the esophagus and keeps stomach acid out of the esophagus
Where is the stomach located?
Left side of body below diaphragm
What are its rugae?
Folds of mucosa (wall of the stomach)
What do gastric glands secrete?
gastric juice
What is the chemical composition of gastric juice?
pepsinogen, HCl, and muscus
What digestive enzyme is in gastric juice?
pepsin
Give the chemical reaction for pepsin.
Pepsin
Protein + Water ------> Polypeptides
What is the pH of the stomach?
2
What does this do?
Kills most bacteria
What is the role of the stomach with regard to storage?
stores food
What is chyme?
mixture of stomach fluids and food produced in the stomach
Where is the small intestine?
between stomach and large intestine
What are the small intestines regions?
Duodenum
Jejunum
Ileum
What two glands send digestive juices into the duodenum?
Pancreas and Liver
What are villi and microvilli?
They are small fingerlike projections in the small intestine
What are lacteals?
Lymph containing capillaries found at the center of villi
What enzymes are produced by the small intestine?
amylase, trypsin, and lipase
Give the chemical reaction for maltase.
Maltase
Maltose + Water ---> glucose + glucose
Give the chemical reaction for sucrase.
Sucrase
Sucrose + Water ---> glucose + fructose
Give the chemical reaction for lactase.
Lactase
Lactose + Water ---> glucose + galactose
Give the chemical reaction for peptidase.
Polypeptidases or Peptidases
Polypeptides or Peptides + Water ---> amino acids or dipeptides
Where does practically all chemical digestion take place?
small intestines
Where does practically all absorption take place?
small intestines
Is absorption an active or passive process?
both
How is absorption accomplished?
active transport
diffusion
facilitated transport
Into what are monosaccharides absorbed?
blood
Into what are amino acids and dipeptides absorbed?
blood
Into what are glycerol and fatty acids absorbed?
lacteals (lymph capillaries)
Where is the pancreas?
in abdominal cavity, resting on posterior abdominal wall
What are functions of the pancreas?
endocrine and exocrine secretion
What is pancreatic juice?
sodium bicarbonate (NaHCO3)
What enzymes are contained in pancreatic juice?
amylase, trypsin, lipase
What is the role of sodium bicarbonate in pancreatic juice?
neutralizes chyme
Where is the liver?
upper right section of abdominal cavity; under diaphragm
What are eight functions of the liver?
1. Makes bile
2. Detoxifies poisons and destroys old erythrocytes
3. Makes plasma proteins
4. Stores glucose as glycogen and breaks down glycogen to glucose
5. Makes glucose from non-carbohydrates
6. Stores iron and fat-soluble Vitamins A, D, E, K
7. Produces urea from amino acids
8. Helps regulate blood cholesterol level
Where is the gall bladder?
attached to the surface of the liver
What is the function of the gall bladder?
stores bile
What is bile?
A substance produced by the liver that breaks up fat particles.
What secretes bile?
the liver
What stores bile?
gallbladder
In what part of the small intestines does the bile work?
duodenum
What is biles function?
emulsifies lipids which increases surface area
What is the site of production of CCK?
small intestines
Where does CCK work?
pancreas or gall bladder
What does CCK do?
stimulate gall bladder to release more bile
What is the site of production of gastrin
lower stomach
What does gastrin do?
stimulates gastric glands
Where does gastrin work?
Upper stomach
What is the site of production of secretin?
small intestines
Where does secretin work?
pancreas or liver
What does secretin do?
stimulates the liver to make more bile
What is the site of production of insulin?
pancreas
Where does insulin work?
liver
What does insulin do?
lowers blood sugar
breaks glucose into glycogen
What is the site of production of glucagon?
pancreas
Where does glucagon work
liver
What does glucagon do?
raises blood sugar
breaks down glucose
Where is the large intestine?
Between the Ileum and the anus
What are its regions?
Cecum with attached appendix;
Ascending colon
Transverse colon
Descending Colon
Sigmoid Colon
Rectum
Anus
What are the functions of the large intestine?
Forms and eliminates wastes
Absorbs water, ions, and vitamins
Does chemical digestion occur in the large intestines?
no
What are the layers of the wall of the digestive tract and the tissue makeup of each?
mucosa
submucosa
muscularis
serosa
What two tissues makes up mucosa?
epithelium and connective
What tissue makes up submucosa?
connective
What tissue makes up muscularis?
smooth
What two tissues makes up serosa?
loose connective and squamous epithelium
What does the liver make?
bile, plasma proteins, non-carbohydrates, urea
What does the liver regulate?
blood cholesterol levels
What does the liver store?
glycogen, glucose, ions, vitamins
How does the liver get rid of poisons and old erythrocytes?
it detoxifies them