PSL 310- Unit 5 Exam Test Questions
All Answered Correctly 2026.
The GI tract has its own - Answer local nervous system, therefore it doesn't need CNS
assistance
Why is the GI tract not part of the internal body - Answer because it has harsh conditions
that would damage the body, such as low ph or lots or beneficial (when located there) bacteria
What is the digestion of food? - Answer the mechanical break down of food into small
molecules (absorbable units)
In the lumen where is food molecules absorbed? - Answer in the lymph (fats) or blood
Pancreas - Answer exocrine, secretes hormones and bicarbonate solution into ducts which
lead to blood.
layers of GI tract - Answer Serosa, muscle layer (muscularis externa), submucosa, mucosa
Serosa - Answer outer layer of GI tract, secretes fluid (aka visceral peritoneum )
Parietal peritoneum - Answer layer that lines the abdominal wall
muscle layer (muscular externa) - Answer smooth muscle, longitudinal layer( contracts and
shortens tube) and inner layer (contract and constricts) this causes mixing and propelling
movements
submucosa layer - Answer connective tissue with nerve cells, blood and lymph vessels and
glands
mucosa - Answer the inner most layer of mucous membrane
What are the two nerve plexuses of the GI tract? - Answer sub mucous and myenteric plexus,
throughout enteric nervous system
GI local nervous system allows - Answer for reflexes to occur without CNS involvement, short
relexes .
, Short reflexes - Answer receptor to nerve plexus to effector cell (intratract) (stretch
receptors)
Long reflexes - Answer receptors ot CNS to nerve plexuses to effectors cells by ANS fibers
Function of saliva - Answer lubricates food (mucus), begins digestion of starches/carbs
(amylase), kills some bacteria (lysozyme) and keeps mouth clean.
pyloric sphincter - Answer between stomach and duodenum (small intestine)
What determines the rate of digestion and absorption - Answer duodenum
What are the 5 gastric secretions - Answer HCL (hydrochloric acid), pepsinogen, Mucus,
intrinsic factor, Gastrin
What secretes HCL? Function? - Answer parietal cells in the stomach
kills micro, decreases food size (acid breaks proteins) changes pepsinogen to pepsin, creates
acidic environment needed for pepsin (to work)
Pepsinogen is secreted by - Answer chief cells
What is the function of pepsinogen (inactive) - Answer breaks down into pepsin, which is a
protein digesting enzyme (starts, doesn't finish )
Why is it secreted as pepsinogen - Answer protects cells from self digestion, breaks proteins
to break them down into peptides
HCL changes pepsinogen to pepsin, then pepsin can - Answer autocatalytically, can act on
itself.
Mucus is secreted and functions to - Answer in the entire tract, functions as a protective
coating
Other function of Mucus - Answer is alkaline because of bicarbonate ion which helps
neutralize acid next to stomach lining. Not acidic therefore pepsin doesn't work here
All Answered Correctly 2026.
The GI tract has its own - Answer local nervous system, therefore it doesn't need CNS
assistance
Why is the GI tract not part of the internal body - Answer because it has harsh conditions
that would damage the body, such as low ph or lots or beneficial (when located there) bacteria
What is the digestion of food? - Answer the mechanical break down of food into small
molecules (absorbable units)
In the lumen where is food molecules absorbed? - Answer in the lymph (fats) or blood
Pancreas - Answer exocrine, secretes hormones and bicarbonate solution into ducts which
lead to blood.
layers of GI tract - Answer Serosa, muscle layer (muscularis externa), submucosa, mucosa
Serosa - Answer outer layer of GI tract, secretes fluid (aka visceral peritoneum )
Parietal peritoneum - Answer layer that lines the abdominal wall
muscle layer (muscular externa) - Answer smooth muscle, longitudinal layer( contracts and
shortens tube) and inner layer (contract and constricts) this causes mixing and propelling
movements
submucosa layer - Answer connective tissue with nerve cells, blood and lymph vessels and
glands
mucosa - Answer the inner most layer of mucous membrane
What are the two nerve plexuses of the GI tract? - Answer sub mucous and myenteric plexus,
throughout enteric nervous system
GI local nervous system allows - Answer for reflexes to occur without CNS involvement, short
relexes .
, Short reflexes - Answer receptor to nerve plexus to effector cell (intratract) (stretch
receptors)
Long reflexes - Answer receptors ot CNS to nerve plexuses to effectors cells by ANS fibers
Function of saliva - Answer lubricates food (mucus), begins digestion of starches/carbs
(amylase), kills some bacteria (lysozyme) and keeps mouth clean.
pyloric sphincter - Answer between stomach and duodenum (small intestine)
What determines the rate of digestion and absorption - Answer duodenum
What are the 5 gastric secretions - Answer HCL (hydrochloric acid), pepsinogen, Mucus,
intrinsic factor, Gastrin
What secretes HCL? Function? - Answer parietal cells in the stomach
kills micro, decreases food size (acid breaks proteins) changes pepsinogen to pepsin, creates
acidic environment needed for pepsin (to work)
Pepsinogen is secreted by - Answer chief cells
What is the function of pepsinogen (inactive) - Answer breaks down into pepsin, which is a
protein digesting enzyme (starts, doesn't finish )
Why is it secreted as pepsinogen - Answer protects cells from self digestion, breaks proteins
to break them down into peptides
HCL changes pepsinogen to pepsin, then pepsin can - Answer autocatalytically, can act on
itself.
Mucus is secreted and functions to - Answer in the entire tract, functions as a protective
coating
Other function of Mucus - Answer is alkaline because of bicarbonate ion which helps
neutralize acid next to stomach lining. Not acidic therefore pepsin doesn't work here
