BPK 105 FINAL QUESTIONS WITH VERIFIED
ACCURATE ANSWERS
Briefly describe the functions of the digestive system - Answers - Ingestion -
Consumption through the mouth in solid or liquid form
Digestion -
Breakdown of large organic molecules into smaller absorbable molecules
Absorption -
Movement of molecules out of the digestive tract and into the blood or lymphatic system
Elimination -
Removal of undigested material through feces
Describe the structure and general functional roles of the four tunics (layers) of the
digestive tract and briefly highlight the differences between the different organs related
to their specialized functions - Answers - The four tunics include:
- Muscosa
Consists of the muscosa epithelium, lamina propria, muscularis mucosae
- Submucosa
Thick layer of connective tissue that contains nerves, vessels and glands
- Muscularis
Inner layer of smooth muscle and outer layer of longitudinal smooth muscle
- Serosa (Adventitia)
Smooth epethelial layer with connective tissue
Name and describe the three phases of deglutition (swallowing). Include the relevant
anatomy involved in each phase - Answers - Divided into:
- Voluntary phase
Bolus or mass is formed in the mouth with the tongue pushing it towards the hard palate
and into the oropharynx
- Pharyngeal phase
Soft palate elevates to block the nasopharynx keeping the larynx and pharynx elevated.
Epiglottis is pushed down over the larynx. Bolus is pushed into the esophagus.
- Esophageal phase
Peristaltic contractions move the bolus down the esophagus towards the stomach
,Describe the cephalic phase of stomach secretion. Include the function, stimulation for
release and gland of origin of each secretion. - Answers - Smells of food and relevant
thoughts trigger the medulla oblongata to influence gastric secretions.
The enteric plexus becomes stimulated by preganglionic neurons which stimulates
secretory cells in the stomach to release:
Hydrochloric acid
Mucus
Intrinsic factor
Gastrin
Histamine
All released by parietal and chief cells
Describe the intestinal phase of stomach secretion. Describe the hormones and
pathways involved in modifying gastric activity - Answers - Inhibits gastric secretions
and is controlled by the entrance of acidic chyme into the duodenum
When pH of chyme drops below 2.0 the inhibitory effect of the intestinal phase is
greatest
With low pH the hormone secretin is released to stop gastric secretions. Fatty acids and
peptides release cholecystokinin also inhibiting gastric secretions.
Negative feedback loop that raises pH
Compare and contrast the structure of the mucosal layers of the stomach and small
intestine. What does this tell you about the roles of the stomach and small intestine
within the digestive system? Provide a brief description of two specialized structures
from each organ's mucosal layer to support your discussion of its role. - Answers -
Surface mucosal cells of the stomach:
Inner surface of the stomach and lining of the gastric pits
Produce mucous
Chief cells of the stomach:
secrete pepsinogen which is a precursor for pepsin
Mucosa cells of the small intestine: Absorptive cells that produce digestive enzymes
and absorb digested food.
Epithelial cells of the Small intestine: Secretes peptidases and disaccharidases
, The Small intestine and stomach play a key role in digesting foods to their most basic
components and preparing them for more extensive absorption
Describe the control of release and function of each of the secretions from the exocrine
pancreas. - Answers - Bicarbonate Ions:
- Neutralize chyme from the stomach and allows pancreatic enzymes to function
- Released by the presence of chyme in the duodenum
Proteolytic Enzymes:
- Includes trypsin, chymotrypsin and carboxypeptidase and all continue protein digestion
started in the stomach
- Release triggered by cholecystokinin
Pancreatic Amylase:
- Continues polysaccharide digestion
- Release triggered by cholecystokinin
Lipase:
- Digests lipids
- Release triggered by cholecystokinin
Nuclease:
- Degrades DNA and RNA to
nucleotides
- Release triggered by cholecystokinin
Parasympathetic stimulation causes further stimulation through the vagus nerve leading
to more pancreatic enzyme release
Distinguish between the processes of digestion and absorption through definition and
description. Where in the gastrointestinal system do they generally take place? -
Answers - Absorption:
The taking in or movement of molecules in the digestive tract through the intestinal wall
and into the bloodstream. Most absorption occurs in the duodenum and jejunum;
potentially the ileum
Digestion:
Breakdown of carbs, lipids and proteins into their basic component to prepare for
absorption. Occurs in the oral cavity, stomach, small intestine, large intestine; implicates
the salivary glands, liver and pancreas.
Describe the digestion and absorption of carbohydrates through the entire digestive
system. Include the site, stimulation and function of important secretions and describe
the details of absorption across the cell membrane. - Answers - Mouth: Salivary
ACCURATE ANSWERS
Briefly describe the functions of the digestive system - Answers - Ingestion -
Consumption through the mouth in solid or liquid form
Digestion -
Breakdown of large organic molecules into smaller absorbable molecules
Absorption -
Movement of molecules out of the digestive tract and into the blood or lymphatic system
Elimination -
Removal of undigested material through feces
Describe the structure and general functional roles of the four tunics (layers) of the
digestive tract and briefly highlight the differences between the different organs related
to their specialized functions - Answers - The four tunics include:
- Muscosa
Consists of the muscosa epithelium, lamina propria, muscularis mucosae
- Submucosa
Thick layer of connective tissue that contains nerves, vessels and glands
- Muscularis
Inner layer of smooth muscle and outer layer of longitudinal smooth muscle
- Serosa (Adventitia)
Smooth epethelial layer with connective tissue
Name and describe the three phases of deglutition (swallowing). Include the relevant
anatomy involved in each phase - Answers - Divided into:
- Voluntary phase
Bolus or mass is formed in the mouth with the tongue pushing it towards the hard palate
and into the oropharynx
- Pharyngeal phase
Soft palate elevates to block the nasopharynx keeping the larynx and pharynx elevated.
Epiglottis is pushed down over the larynx. Bolus is pushed into the esophagus.
- Esophageal phase
Peristaltic contractions move the bolus down the esophagus towards the stomach
,Describe the cephalic phase of stomach secretion. Include the function, stimulation for
release and gland of origin of each secretion. - Answers - Smells of food and relevant
thoughts trigger the medulla oblongata to influence gastric secretions.
The enteric plexus becomes stimulated by preganglionic neurons which stimulates
secretory cells in the stomach to release:
Hydrochloric acid
Mucus
Intrinsic factor
Gastrin
Histamine
All released by parietal and chief cells
Describe the intestinal phase of stomach secretion. Describe the hormones and
pathways involved in modifying gastric activity - Answers - Inhibits gastric secretions
and is controlled by the entrance of acidic chyme into the duodenum
When pH of chyme drops below 2.0 the inhibitory effect of the intestinal phase is
greatest
With low pH the hormone secretin is released to stop gastric secretions. Fatty acids and
peptides release cholecystokinin also inhibiting gastric secretions.
Negative feedback loop that raises pH
Compare and contrast the structure of the mucosal layers of the stomach and small
intestine. What does this tell you about the roles of the stomach and small intestine
within the digestive system? Provide a brief description of two specialized structures
from each organ's mucosal layer to support your discussion of its role. - Answers -
Surface mucosal cells of the stomach:
Inner surface of the stomach and lining of the gastric pits
Produce mucous
Chief cells of the stomach:
secrete pepsinogen which is a precursor for pepsin
Mucosa cells of the small intestine: Absorptive cells that produce digestive enzymes
and absorb digested food.
Epithelial cells of the Small intestine: Secretes peptidases and disaccharidases
, The Small intestine and stomach play a key role in digesting foods to their most basic
components and preparing them for more extensive absorption
Describe the control of release and function of each of the secretions from the exocrine
pancreas. - Answers - Bicarbonate Ions:
- Neutralize chyme from the stomach and allows pancreatic enzymes to function
- Released by the presence of chyme in the duodenum
Proteolytic Enzymes:
- Includes trypsin, chymotrypsin and carboxypeptidase and all continue protein digestion
started in the stomach
- Release triggered by cholecystokinin
Pancreatic Amylase:
- Continues polysaccharide digestion
- Release triggered by cholecystokinin
Lipase:
- Digests lipids
- Release triggered by cholecystokinin
Nuclease:
- Degrades DNA and RNA to
nucleotides
- Release triggered by cholecystokinin
Parasympathetic stimulation causes further stimulation through the vagus nerve leading
to more pancreatic enzyme release
Distinguish between the processes of digestion and absorption through definition and
description. Where in the gastrointestinal system do they generally take place? -
Answers - Absorption:
The taking in or movement of molecules in the digestive tract through the intestinal wall
and into the bloodstream. Most absorption occurs in the duodenum and jejunum;
potentially the ileum
Digestion:
Breakdown of carbs, lipids and proteins into their basic component to prepare for
absorption. Occurs in the oral cavity, stomach, small intestine, large intestine; implicates
the salivary glands, liver and pancreas.
Describe the digestion and absorption of carbohydrates through the entire digestive
system. Include the site, stimulation and function of important secretions and describe
the details of absorption across the cell membrane. - Answers - Mouth: Salivary
