BIO 269 QUESTIONS AND ANSWERS LATEST UPDATE 100%
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What is the order of the digestive tract from start to finish?
mouth
salivary glands (sublingual/parotid/submandibular)
pharynx
esophagus
stomach
small intestine (duodenum, gallbladder, jejunum)
pancreas
large intestine (cecum, ascending colon, transverse colon, descending colon,
sigmoid colon)
rectum
anus
It takes ____ seconds for food to travel from the mouth to the stomach.
45
What organic molecules stay longer in the stomach?
fats and proteins, rather than carbs
What are the three types of salivary glands?
1. sublingual
2. submandibular
3. parotid
What are the three parts to the small intestine?
1. duodenum
2. jejunum
3. ileum
What are the five parts to the large intestine?
1. cecum
2. ascending colon
3. transverse colon
4. descending colon
5. sigmoid colon
What is another name for the large intestine?
colon
What is the most important part of the small intestine?
duodenum
Why is the duodenum the shortest, yet most important part of the small intestine?
it is where the liver and pancreas empty their contents into and also where most of food
breakdown + absorption happens
True or false?
The cecum and appendix are attached to each other.
true
What type of muscle are all the organs in the digestive system lined with?
,smooth muscle (no control over them)
What are the functions of the digestive system?
1. ingestion
2. motility
3. digestion
4. secretion
5. absorption
6. elimination of wastes
What is ingestion?
taking food into the mouth
Where does ingestion occur?
mouth
What is motility?
muscle contraction
What are the three types of motility (muscle movements)?
1. slow waves
2. propulsive movement
3. mixing movement
What is the importance of slow-wave motility?
maintains muscle tone
contracts very slow and very light, helps a muscle get smaller (return to normal) after it
expands
What is the importance of propulsive movement motility?
unidirectional; moving food forward from one point in the digestive system to another
point (never backwards)
Where does propulsive movement occur?
esophagus and intestines
What is the importance of mixing movement motility?
bidirectional; helps digestion and the breakdown of food
Where does mixing movement occur?
stomach and intestines
What is digestion?
breakdown of food
What are the two types of digestion?
1. mechanical
2. chemical
What does mechanical digestion mean?
the physical act of mixing and breaking down food in the body
What does mechanical digestion in the mouth refer to?
chewing
What does mechanical digestion in the stomach refer to?
churning
What does mechanical digestion in the small intestine refer to?
segmentation (mixing movement)
What does chemical digestion mean?
,breaking down of organic food groups; need to absorb those across a membrane to
bring into the blood (must be small)
What form do carbohydrates come into the body as?
tri and di saccharides
What must carbohydrates be turned into so they can travel across the plasma
membrane for absorption and digestion?
monosaccharides
What must proteins be turned into so they can travel across the plasma
membrane for absorption and digestion?
amino acids
What form do fats come into the body as?
triglycerides
What must fats be turned into so they can travel across the plasma membrane for
absorption and digestion?
monoglycerides and fatty acids
What parts of the digestive tract have the ability to secrete enzymes?
1. mouth
2. stomach
3. liver
4. pancreas
5. small intestine
What is secretion (digestive tract)?
enzymes that are secreted into the digestive tract to break down food
What is absorption (digestive tract)?
a substance moving through the cell walls into the bloodstream
Where does 80% of absorption happen in the digestive tract?
duodenum (majority of nutrients are absorbed through the duodenum wall)
Where does the rest of the 20% of absorption happen in the digestive tract?
small and large intestines
What are the layers of digestive tract wall?
1. mucosa
2. submucosa
3. muscularis externa
4. serosa
What is the lumen?
central blood-filled space of a vessel; where nutrients are
What is the mucosa?
inner lining of the digestive tract; most inner layer!
What are the three sublayers of the mucosa?
1. epithelium → one layer
2. lamina propria → connective tissue, made of capillary beds and lacteals
3. muscularis mucosae → muscle layer
What is the submucosa?
layer of connective tissue with big blood vessels and nerves
What is the muscularis externa?
responsible for segmentation and peristalsis
, What are the two sublayers of the muscularis externa?
1. INNER: circular layer (decreases size of lumen when contracted)
2. OUTER: longitudinal layer (contracts intestine along along axis)
What is the serosa?
holds all other layers together
Increased ____ ____ in the lumen will lead to more (and faster) ____ of nutrients.
surface area; absorption
What characteristic of the villi will affect how many nutrients are absorbed?
height
Where are villi the tallest and shortest in the digestive tract? How does this affect
physiology?
tallest: duodenum
shortest: ileum
Since villi are tallest in the duodenum, there is more surface area. The duodenum can
perform more nutrient absorption than the rest of the digestive tract.
What lines the outside of villi?
a single layer of epithelial cells
What is contained in the laminar propria?
blood vessels + lacteals
What type of hair-like projections are located on top of epithelial cells?
microvilli
epithelial cell surfaces are NOT flat, these projections increase surface area for nutrient
absorption
What are microvilli?
smaller hair-like projections that increase the surface area further
What are villi?
small fingerlike projections that greatly increase the surface area of the intestinal wall
Does nutrient absorption take place in the esophagus and mouth? Why or why
not?
there is NO absorption since there are no villi/microvilli to increase surface area and
nutrient absorption
Does nutrient absorption take place in the stomach? Why or why not?
very little occurs here because the surface is relatively flat, but does not contain
villi/microvilli
Does nutrient absorption take place in the small intestine? Why or why not!
yes! mainly in the duodenum, but there are many long villi/microvilli projections that
increase surface area and nutrient absorption
True or false?
Salt and H2O are only absorbed across the large intestine.
true
What organs in the digestive tract allow for enzyme secretions?
1. salivary glands (not an organ but glands secrete enzymes)
2. pancreas
CORRECT A+ GRADED. Buy Quality Materials!
What is the order of the digestive tract from start to finish?
mouth
salivary glands (sublingual/parotid/submandibular)
pharynx
esophagus
stomach
small intestine (duodenum, gallbladder, jejunum)
pancreas
large intestine (cecum, ascending colon, transverse colon, descending colon,
sigmoid colon)
rectum
anus
It takes ____ seconds for food to travel from the mouth to the stomach.
45
What organic molecules stay longer in the stomach?
fats and proteins, rather than carbs
What are the three types of salivary glands?
1. sublingual
2. submandibular
3. parotid
What are the three parts to the small intestine?
1. duodenum
2. jejunum
3. ileum
What are the five parts to the large intestine?
1. cecum
2. ascending colon
3. transverse colon
4. descending colon
5. sigmoid colon
What is another name for the large intestine?
colon
What is the most important part of the small intestine?
duodenum
Why is the duodenum the shortest, yet most important part of the small intestine?
it is where the liver and pancreas empty their contents into and also where most of food
breakdown + absorption happens
True or false?
The cecum and appendix are attached to each other.
true
What type of muscle are all the organs in the digestive system lined with?
,smooth muscle (no control over them)
What are the functions of the digestive system?
1. ingestion
2. motility
3. digestion
4. secretion
5. absorption
6. elimination of wastes
What is ingestion?
taking food into the mouth
Where does ingestion occur?
mouth
What is motility?
muscle contraction
What are the three types of motility (muscle movements)?
1. slow waves
2. propulsive movement
3. mixing movement
What is the importance of slow-wave motility?
maintains muscle tone
contracts very slow and very light, helps a muscle get smaller (return to normal) after it
expands
What is the importance of propulsive movement motility?
unidirectional; moving food forward from one point in the digestive system to another
point (never backwards)
Where does propulsive movement occur?
esophagus and intestines
What is the importance of mixing movement motility?
bidirectional; helps digestion and the breakdown of food
Where does mixing movement occur?
stomach and intestines
What is digestion?
breakdown of food
What are the two types of digestion?
1. mechanical
2. chemical
What does mechanical digestion mean?
the physical act of mixing and breaking down food in the body
What does mechanical digestion in the mouth refer to?
chewing
What does mechanical digestion in the stomach refer to?
churning
What does mechanical digestion in the small intestine refer to?
segmentation (mixing movement)
What does chemical digestion mean?
,breaking down of organic food groups; need to absorb those across a membrane to
bring into the blood (must be small)
What form do carbohydrates come into the body as?
tri and di saccharides
What must carbohydrates be turned into so they can travel across the plasma
membrane for absorption and digestion?
monosaccharides
What must proteins be turned into so they can travel across the plasma
membrane for absorption and digestion?
amino acids
What form do fats come into the body as?
triglycerides
What must fats be turned into so they can travel across the plasma membrane for
absorption and digestion?
monoglycerides and fatty acids
What parts of the digestive tract have the ability to secrete enzymes?
1. mouth
2. stomach
3. liver
4. pancreas
5. small intestine
What is secretion (digestive tract)?
enzymes that are secreted into the digestive tract to break down food
What is absorption (digestive tract)?
a substance moving through the cell walls into the bloodstream
Where does 80% of absorption happen in the digestive tract?
duodenum (majority of nutrients are absorbed through the duodenum wall)
Where does the rest of the 20% of absorption happen in the digestive tract?
small and large intestines
What are the layers of digestive tract wall?
1. mucosa
2. submucosa
3. muscularis externa
4. serosa
What is the lumen?
central blood-filled space of a vessel; where nutrients are
What is the mucosa?
inner lining of the digestive tract; most inner layer!
What are the three sublayers of the mucosa?
1. epithelium → one layer
2. lamina propria → connective tissue, made of capillary beds and lacteals
3. muscularis mucosae → muscle layer
What is the submucosa?
layer of connective tissue with big blood vessels and nerves
What is the muscularis externa?
responsible for segmentation and peristalsis
, What are the two sublayers of the muscularis externa?
1. INNER: circular layer (decreases size of lumen when contracted)
2. OUTER: longitudinal layer (contracts intestine along along axis)
What is the serosa?
holds all other layers together
Increased ____ ____ in the lumen will lead to more (and faster) ____ of nutrients.
surface area; absorption
What characteristic of the villi will affect how many nutrients are absorbed?
height
Where are villi the tallest and shortest in the digestive tract? How does this affect
physiology?
tallest: duodenum
shortest: ileum
Since villi are tallest in the duodenum, there is more surface area. The duodenum can
perform more nutrient absorption than the rest of the digestive tract.
What lines the outside of villi?
a single layer of epithelial cells
What is contained in the laminar propria?
blood vessels + lacteals
What type of hair-like projections are located on top of epithelial cells?
microvilli
epithelial cell surfaces are NOT flat, these projections increase surface area for nutrient
absorption
What are microvilli?
smaller hair-like projections that increase the surface area further
What are villi?
small fingerlike projections that greatly increase the surface area of the intestinal wall
Does nutrient absorption take place in the esophagus and mouth? Why or why
not?
there is NO absorption since there are no villi/microvilli to increase surface area and
nutrient absorption
Does nutrient absorption take place in the stomach? Why or why not?
very little occurs here because the surface is relatively flat, but does not contain
villi/microvilli
Does nutrient absorption take place in the small intestine? Why or why not!
yes! mainly in the duodenum, but there are many long villi/microvilli projections that
increase surface area and nutrient absorption
True or false?
Salt and H2O are only absorbed across the large intestine.
true
What organs in the digestive tract allow for enzyme secretions?
1. salivary glands (not an organ but glands secrete enzymes)
2. pancreas
