Structural and Functional Organization of the Digestive System

Question 1

What are the two groups of organs that make up the digestive system?

Answer 1

Gastrointestinal tract/Alimentary canal- A continuous tube that extends from the mouth to the anus. Mouth, pharynx, esophagus, stomach, small instestine, and large intestine.
Accessory digestive organs.-Organs that aid in digestion. Teeth, tongue, salivary glands, liver, gallbladder, and pancreas.

Question 2

What are the three divisions of the abdomen?

Answer 2

Intrathoracic (enclosed by lower ribs and immediately distal to the diaphragm)- Liver, gallbladder, spleen, stomach, and transverse colon.
True abdomen- Small intestines, large intestines, liver, lower portions, bladder, Female(Uterus, fallopian tubes, and ovaries.)
Retroperitoneal abdomen lies behind the thoracic and true portions.-Kidneys, Urters, Pancreas, Posterior Duodenum, Ascending and Descending colon, inferior vena cava.

Question 3

What are the six basic functions on digestion?

Answer 3

Ingestion-Taking in food and liquid through the mouth.
Secretion- Cells lining GI tract produces water, acid, buffers and enzymes to aid digestion.
Mixing and propulsion- Continuous contraction and relaxation moving food along the GI tract.
Digestion- Mechanical and chemical process that breaks down the food we ingest.
Absorption- Small molecules produced in digestion moved into spaces to be used by cells.
Defecation- Elimination of materials not absorbed by our body indigestion.
ISMDAD

Question 4

What is the Mucosa?

Answer 4

Innermost lining of the GI tract in direct contact witht he substances passing through.

Question 5

What is the submucosa?

Answer 5

Made up of areolar connective tissues that bind the mucosa to the muscularis. Contains blood and lymphatic vssels which absorb food molecules as they are broken down.

Question 6

What is the Muscularis?

Answer 6

Contains skeletal (voluntary) muscles and smooth (involuntary) muscles.

Question 7

What is serosa?

Answer 7

Made up of two sub layers.
-Visceral peritoneum. Outermost layer around the organs of the GI tract.
-Parietal peritoneum. Lines the walls of the abdominal activity.
-Greater omentum- Fatty apron that drapes over the transverse colon and small intestine
-Mesentery- binds the small intestine to the posterior abdominal wall.

Question 8

What are the three pairs of salivary glands and their functions?

Answer 8

Parotid- Located inferior and anterior to the ears between the skin and the masseter muscle.
Submandibular- Located medial and partly inferior to the mandible in the floor of the mouth.
Sublingual- Beneath the tongue and superior to the submandibular glands.

Functions- Helps dissolve foods and begins digestion, 99.5 water and .5 percent solutes, contain lysozomes that kill bacteria protecting the mouth from infection and tooth decay, salivary amylase begins the digestion of starches in the mouth, mucous produced by the salivary glands lubricated food to assist with the swallowing of the food.

Question 9

What is the function of the toungue?

Answer 9

accessory digestive organ made up of skeletal muscle.

Question 10

What is the function of the teeth?

Answer 10

Accessory organs of the gi tract, located in the bony sockets of the mandible and maxilla. They perform mechanical digestion by chewing and breaking down food into small pieces.

Question 11

What is the function of the pharynx?

Answer 11

A funnel shaped tube, located at the posterior end of the oral cavity, lined with mucous membranes and is comprised of skeletal muscle.
-Nasopharynx. That is involved in respiration.
-Oropharynx. Located at the back of the mouth between the naso-and laryngopharynx
-Laryngopharynx: which helps to propel food into the esophagus via muscular contractions

Question 12

What is the esophagus?

Answer 12

a muscular tube lined with stratified squamous epithelium that lies posterior to the trachea.
Upper esophageal sphincter- composed of skeletal muscle
Lower esophogeal sphincter- composed of smooth muscle
The esophagus funcitons to transport food along its path while micing it with mucous

Question 13

What are the phases of swallowing?

Answer 13

Voluntary- bolus forced into the oropharynx by the movement of the tongue upward and backward against the palate.

Pharyngeal- Begins when the bolus is in the oropharynx. Breathing is temporarily interrupted. The soft palate and uvula move upward to close off the nasopharynx. The epiglottis seals off the larynx. The upper esophageal sphincter relaxes and the bolus moves into the esophagus.

Esophageal- Begins w the bolus moves into the esophagus. Food is pushed through the esophagus via peristalsis. When the bolus reaches the bottom of the esophagus the lower esophageal sphincter relaxes and the bolus moves into the stomach.

Question 14

What is the stomach?

Answer 14

A J shaped organ of the GI Tract, serves as a reservoir and mixing chamber for food, and aids in digestion. The environment of the stomach is acidic with a PH of 2.
-Extends from the end of the esophagus to the tip duodenum
Is the most elastic part of the GI tract
It can be stretched to accommodate up to 6.4 liters of food.

Question 15

What are the four main regions of the stomach?

Answer 15

Cardia, Fundus, Body and pylorus.

Question 16

What are the functions of the stomach?

Answer 16

Secretes 3 types of contents to create gastric juice.
Exocrine cells.
-mucous neck cells
-Chief cells
-Parietal cells which produce hydrochloric acid which convert pepsinogen into pepsin. Secretes intrinsic factors.

Question 17

What do gastric cells produce?

Answer 17

Gastric which is the major hormonal regulator of HCL secretion and regulates gastric emptying at pyloric sphincter.

Question 18

What makes up chyme?

Answer 18

Gastric juice and macerated food particles.

Question 19

What are the functions of the pancreas?

Answer 19

Endocrine: specialized areas within the pancreas called islets of Langerhans which are made of different hormone making cells.
Exocrine functions.

Question 20

What are the most common pancreas cells?

Answer 20

Beta cells which produce insulin.

Question 21

What is a hormone that is produced by alpha cells found in the islet of langerhans?

Answer 21

Glucagon, responsible for preventing blood glucose from dropping too low.

Question 22

What is one of the most important accessory organs within the GI system, lies behind the stomach, passes secretions into the duodenum, and plays a vital role in chemical digestion?

Answer 22

Pancreas

Question 23

How do secretions pass through the pancreas?

Answer 23

Pancreatic duct>joins to common bile duct to form hepatopancreatic duct>pass through sphincter of Oddi into the duodenum.

Question 24

What is pancreatic juice made from?

Answer 24

Clear, colorless liquid. Made up of mostly water, some salts, sodium bicarbonate, and several enzymes.

Question 25

What are the enzymes of the pancreas?

Answer 25

Trypsin and chemotrypsin-protein digesting. Proteins are broken down by enzymes into amino acids, dipeptides, and tripeptides.

Pancreatic amylase-carbohydrate digesting. Broken down by enzymes and absorbed as monosaccharides.

Pancreatic lipase: triglyceride digesting. Triglycerides broken down by enzymes and absorbed as monoglycerides and fatty acids.

Ribonuclease-nucleic acid digesting

Question 26

Where is the liver?

Answer 26

2nd largest organ in the body located below the diaphragm mostly in the URQ

Question 27

What are the functions of the liver?

Answer 27

Carb/lipid/protein metabolism
Processing of drugs and hormones
Excretion of bilirubin
Storage of vitamins and minerals
Activation of vitamin D

Question 28

What are hepatocytes?

Answer 28

Major functional cells of the liver
Perform metabolic, secretory and endocrine functions

Question 29

What is the functions of the gallbladder?

Answer 29

Pear shaped sac that hangs from the front margin of the liver.

Stores bike to be excreted into the small intestines.

Aids in chemical digestion, especially in the digestion of fat

Question 30

What is the path of the liver and gallbladder secretions?

Answer 30

Left and right hepatic duct: bile and waste created in the liver are passed into the hepatic ducts>cystic duct:bile produced in the gallbladder is secreted through the cystic duct>left and right hepatic combine with cystic duct to create common bile duct>hepatopancreatic duct: common bile duct forms with the pancreatic duct to form the hepatopancreatic duct>sphincter of oddi:muscular valve that controls the passage of contents from the hepatopancreatic duct into the duodenum.

Question 31

What is the function of the small intestine?

Answer 31

Comes into the stomach, approximately 10ft in a living person, but stretches out to 21 ft in a cadaver.

Question 32

What are the three types of endocrine cells that secrete hormones into the bloodstream?

Answer 32

S cells-secrete the hormone secretion, which stimulates the secretion of pancreatic juice

CCK cells-secrete cholecystokinin which regulates gastric emptying, stimulates bile and pancreatic juice secretion, causes relaxation of the sphincter of Oddi, and the feeling of satiety

K cells-Secrete glucose-dependent insulinotropic peptide which stimulates the release of insulin

Question 33

What are the three divisions of the small intestine?

Answer 33

Duodenum
Jejunum
Ileum

Question 34

What are the two manners of digestion?

Answer 34

Mechanical via segmentation and peristalsis.
Chemical via pancreatic enzymes, bile and intestinal juice.

Question 35

How does absorption work?

Answer 35

Carbs are broken down and absorbed as monosaccharides.
Proteins broken down to amino acids, dipeptides and tripeptides.
Triglycerides broken down to and absorbed as monoglycerides and fatty acids.
Ions and water: 90% of water is absorbed by the GI tract in the jejunum.
KADE is fat(fat soluble vitamins)

Question 36

What is the ileum function in concern to absorption?

Answer 36

Final segment of the small intestine that attaches to the large intestine at the ileocecal sphincter valve.
The ileum absorbs nutrients, B12, and bile salts. Bile salts are recycled to the liver and gallbladder for reuse.
The small intestine is important in the absorption of Iron, folate and vitamin B12.

Question 37

Iron Fist Bro

Answer 37

Iron-Duodenum
Folate-Jejunum
B12-Ilium
Bile-Ilium

Question 38

What is the location/composition of the large intestine?

Answer 38

Last prt of the GI tract, and divided into four regions.
Cecum-appendix attaches here
Colon-Ascending,transverse,descending, and sigmoid.
Anal canal

Question 39

What does the large intestine do?

Answer 39

Completes absorption
Absorbs water and electrolytes
Helps to absorb certain b vitamins and vitamin k produced by healthy gut bacteria in large intestine.
Forms feces to be expelled by the body.

Question 40

What are the three phases of digestion?

Answer 40

Cephalic- smell, sight, sound and thought of food activates neural centers in the brain stimulating salivary glands to secrete saliva and the gastric bands to secrete gastric juice.

Gastric- starts when food enters the stomach. Gastric is released promoting the release of gastric juice which increases the mobility of the stomach, relaxes the pyloric sphincter and promotes gastric emptying.

Intestinal-starts when food enters the small intestine. Inhibitory effects slow gastric emptying and stimulates the secretion of pancreatic juices to aid in absorption and digestion.