Unit 2: Pharm: Chapter 56

Question 1

Gi Structures

Answer 1

Tube that openings at the mouth and ends at the anus.
Mouth contains salivary glands and enzymes for swallowing
Leads to esophagus, connect to stomach, empties into small intestine (absorption).
Pancreas deposits digestive enzymes and sodium bicarbonate into the small intestine.
Liver produces bile.
Small intestine leads to large intestine (excretion of waste).
Excretion occurs through rectum

Question 2

Gastrointestinal Activities

Answer 2

The GI system has four major activities:
•Secretion of enzymes, acid, bicarbonate, and mucus
•Digestion of food into usable and absorbable components
•Absorption of water and almost all of the essential nutrients needed by the body
•Motility (movement) of food and secretions through the system (what is not used is excreted in the form of feces)

Question 3

Nerve Plexus

Answer 3

Network of nerve endings running through the wall of the GI tract

Question 4

Segmentation

Answer 4

Process used by small intestine
Involves comm traction of one segment while the next is relaxed

Question 5

Local Gastrointestinal Reflexes

Answer 5

involve stimulation of the nerves in the GI tract and cause movement and secretion.

Question 6

Central Gastrointestinal Reflexes

Answer 6

which include swallowing and vomiting, are controlled by the medulla.

Question 7

Gastroenteric Reflex

Answer 7

Stimulation of the stomach by stretching, the presence of food, or cephalic stimulation (the body’s response to smelling, seeing, tasting, or thinking about food) causes an increase in activity in the small intestine. It is thought that this prepares the small intestine for the coming chyme.

Question 8

Gastrocolic Reflex

Answer 8

Stimulation of the stomach also causes increased activity in the colon, again preparing it to empty any contents to provide space for the new chyme.

Question 9

Duodenal-Colic Reflex

Answer 9

The presence of food or stretching in the duodenum stimulates colon activity and mass movement, again to empty the colon for the new chyme.

Question 10

Iieogastric Reflex

Answer 10

The introduction of chyme or stretch to the large intestine slows stomach activity, as does the introduction of chyme into the small and large intestine, allowing time for absorption.

Question 11

Intestinal-Intestinal Reflex

Answer 11

Excessive irritation to one section of the small intestine causes a cessation of activity above that section to prevent further irritation and an increase in activity below that section, which leads to a flushing of the irritant.
This reflex is active in traveler’s diarrhea.

Question 12

Perioneointestinal Reflex

Answer 12

Irritation of the peritoneum as a result of inflammation or injury leads to a cessation of GI activity, preventing continued movement of the GI tract and thus further irritation of the peritoneum.

Question 13

Renointestinal Reflex

Answer 13

Irritation or swelling of the renal capsule causes a cessation of movement in the GI tract, again preventing further irritation to the capsule.

Question 14

Vesciointestinal Reflex

Answer 14

Irritation or overstretching of the bladder can cause a reflex cessation of movement in the GI tract, again preventing further irritation to the bladder from GI movement.
Constipation can be due to this relfex

Question 15

Somatointesitnal Reflex

Answer 15

Taut stretching of the skin and muscles over the abdomen irritates the nerve plexus and causes a slowing or cessation of GI activity preventing further irritation.
This reflex was often seen in people who wore tight girdles when they were in fashion.
Constplation is common with tight fitting clothes

Question 16

Swallowing

Answer 16

reflex is stimulated whenever a food bolus stimulates pressure receptors in the back of the throat and pharynx.
These receptors send impulses to the medulla, which stimulates a series of nerves that cause actions of swallowing

Question 17

Vomiting

Answer 17

basic reflex that is centrally mediated and important in protecting the system from unwanted irritants.
The vomiting reflex is stimulated by two centers in the medulla.
The more primitive center is called the emetic zone. When stimulated, it initiates projectile vomiting.