Chapter 22: Digestive System

Match each of the following digestive tract structures with its general function: 1. Oral cavity 2. Duodenum 3. Colon 4. Esophagus 5. Stomach 6. Pharynx 7. Rectum

1. Contains salivary glands 2. Major site of digestion 3. Major site of water absorption 4. Connects pharynx to stomach 5. Beings enzymatic digestion of proteins 6. Connects mouth to esophagus 7. Terminal end of large intestine

Arrange the following in the order they would be encountered by an ingested food molecule:

1. Duodenal mucosa 2. Hepatic portal vein 3. Sinusoid 4. Hepatocytes 5. Central vein 6. Hepatic vein 7. Vena cava 8. Right atrium of heart 9. Systemic artery

Match each cell type with the molecule it release: 1. G cell 2. Parietal cell 3. Enterochomaffin (ECL) cell 4. D cell 5. Vagal Neuron

1. Gastrin 2. Hydrochloric acid 3. Histamine 4. Somatostatin 5. Acetylcholine

Arrange the teeth in the order they would be encountered, starting at the midsagittal plane and moving laterally:

1. Incisor 2. Canine 3. Pre-molar 4. Molar

Which is not a normal function of the large intestine?

Absorption of nutrients

Which cranial nerves stimulates saliva production

Glossopharyngeal

Why does the large intestine not contain villi and microvilli?

It is not specialized for absorption. Most nutrient absorption occurs in the small intestine.

Swallowing is controlled by which of the following:

- Trigeminal - Glossopharyngeal - Vagus

Match the following molecules with its function: 1. Trypsin 2. Chymotrypsinogen 3. Enterokinase 4. Carbonoxypeptidase

1. A peptidase that activates other peptidases 2. An inactive endopeptidase released from pancreatic vesicles 3. An enzyme of the intestinal mucosa 4. An exopeptidase

Match the following with their function: 1. Enterocolic reflex 2. Duodenocolic reflex 3. Segmentation contraction 4. Peristaltic contractions

1. Activates large intestine motility in response to stomach stretching 2. Activates large intestine motility in response to small intestine stretching 3. Occur infrequently in the large intestine 4. Carry chyme over large distances in the large intestine

Place the following events related to lipid digestion in order:

1. CCK stimulates gallbladder 2. Emulsification of fats 3. Pancreatic lipase begins to digest triglycerides 4. Micelles forms 5. Diffusion across luminal membrane 6. Free fatty acids enter endoplasmic reticulum 7. Chylomicron forms 8. Movement across basolateral membrane 9. Chylomicron

Place the following regions of the stomach in the order they would be encountered by a food molecule:

1. Cardiac 2. Fundus 3. Body 4. Pyloric

Rank the following structures in order from smallest to largest:

1. Microvilli 2. Villi 3. Plicae

Place the tissue layers of the digestive tract in the order you would encounter them moving from the lumen toward the abdominal cavity:

1. Mucosal epithelium 2. Lamina propria 3. Muscularis mucosa 4. Submucosa 5. Circular layer of smooth muscle 6. Myenteric plexus 7. Longitudinal layer of smooth muscle 8. Serosa

Place the following digestive tract structures in the order they would be encountered by an ingested food molecule:

1. Pharynx 2. Esophagus 3. Stomach 4. Duodenum 5. Jejunum 6. Ileum 7. Cecum 8. Ascending colon 9. Transverse colon 10. Descending colon

Match the following accessory organs with their general function: 1. Liver 2. Pancreas 3. Salivary gland 4. Gallbladder 5. Common bile duct

1. Produces bile 2. Digestive enzyme production 3. Begins digestion in the mouth 4. Bile storage 5. Carries bile into small intestine

Match each intestinal feature with its major function: 1. Peyer's patch 2. Villi 3. Goblet cell 4. Endocrine cell 5. Intestinal crypts

1. Supports the immune system 2. Increase surface area for digestion and absorption 3. Protects the small intestine from stomach acid and abrasion 4. Produce the hormone secretin 5. Contains stem cells

A 22-year-old girl presented to the emergency room for nausea, vomiting, fever, and abdominal pain. On physical examination, her abdominal pain was located to the right iliac region. The pain she was experiencing is classified as rebound tenderness, meaning when pressure is applied, there is no pain, but when pressure is released there is extreme pain. Given the location of the pain and the presentation, what would be the presumptive diagnosis?

Appendicitis * The appendix is located in the right iliac region. Nausea, vomiting, fever, and rebound tenderness in that region are all hallmark characteristics of appendicitis. It would be rare to find an ectopic pregnancy in the iliac region and would a constant pain, not rebound tenderness. Her symptoms were made worse after meals.

Which is most rapidly cleared form the stomach after eating?

Carbohydrates

What is the result of damage to the myenteric plexus within the wall of the GI tract?

Changes in gastric motility

How does excessive coffee consumption affect the stomach?

Coffee contains caffeine, which blocks the breakdown of cAMP. This acts to increase the production of stomach acid

During which phase of swallowing does food enter the stomach?

Esophageal phase

The innermost layer within the digestive tract is the:

Mucosa

Which are secreted into the large intestine?

Mucus

Which is produced in the gastric pit?

Mucus

A 43-year-old man presented to the emergency room one clear Tuesday morning complaining of severe pain in his epigastric and umbilical regions. He described the pain as a burning sensation that occurred as he was sitting in rush hour traffic. He was concerned that he may be having a heart attack, so he got to the hospital as fast as he could. Upon further investigation, his physician found that this was not the first time he had experienced this pain. He had frequent nausea and occasional vomiting, but noticed that the pain is worse between meals. He had a high-stress job and took antacids regularly for heartburn. He noted that during the last month, he had been very tired and had dark colored stools. What is a possible diagnosis?

Peptic Ulcer * All of the symptoms as well as location of the pain are indicators for a peptic ulcer. The patient had heartburn for months and was in a high stress job. The dark colored stool was caused by the break-down of red blood cells in the digestive tract. He had a bleeding ulcer.

What type of contraction pushes food through the digestive tract?

Peristalsis

Which does not occur during the cephalic phase?

Release of secretin from the small intestine

Which transporter allows glucose to move against a concentration gradient?

SGLT1

A 34-year-old woman called her family doctor late one evening asking for help because she was having severe pain on the right side of her face that started while she was having dinner. She described the pain as a muscle spasm followed by an excruciating, stabbing pain. Her doctor asked if she had any sour candy nearby and she did, so her doctor asked her to put a piece in her mouth while they were talking. In no time, she began to experience intense pain in the same area of her face as before. What structure(s) in her mouth are the cause of the intense pain?

Salivary glands * Having my friend put the sour candy in her mouth stimulated the salivary glands to release their enzymes to begin digestion. From my studies in anatomy, I know that the parotid gland lies just anterior to the ear on each side of the face and the ducts empty into the oral cavity. Placing a food item in the mouth stimulated the parotid gland to release its contents. In my friend's case, there was a stone blocking the parotid duct, leading to a backup of saliva. The backup causes the smooth muscle in the parotid duct to constrict more in an attempt to clear the blockage. This intense muscular contraction, along with the stone itself, were causing the pain on the side of her face.

Why are 3 muscles used to close the jaw but only one muscle used to open it?

Strength is needed to crush food to begin the digestive process, while opening the jaw is not usually under a load.

Why are dietary triglycerides digested to free fatty acids and glycerol, if they are then recombined to form triglycerides within the cell?

TGs cannot cross the cell membrane, while FFA can.

Why is the lumenal surface of the digestive tract lined with epithelium?

The epithelial layer and the immune presence inside the GI tract protect against microbes that would do us harm.

The intestinal phase is triggered by:

The presence of chyme in the small intestine

Why is the stomach one of the few places within the digestive tract that has 3 layers of smooth muscle within its wall?

The stomach needs to mix (segmentation) as well as push food through the pyloric sphincter (peristalsis). This requires the extra layer of muscle and suggests that less mixing occurs in other parts of the digestive system.

Where so the bacteria that colonize the large intestine come from in a newborn baby?

They come from breast or bottle-feeding, or when the baby puts their fingers in their mouths.

Villi formation is due to contraction of cells in the mucosal layer of the digestive tract.

True

What can you deduce from the fact that the large intestine wall is composed of simple columnar epithelia?

Water absorption by the large intestine does not require plicae

Bile is produced in the ___ and stored in the ___.

liver, gallbladder

Acid formation in the stomach is a result of:

secretion