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Med-Surg Exam 5
Chapter 39: Gastrointestinal System
➢ Functions of The GI System
• Composed of four common layers, (1) mucosa, (2) submucosa, (3) muscles, & (4) serosa. The muscular layers consist of two layers
the circular (inner), & longitudinal (outer) layers.
• The GI tract is innervated by the parasympathetic & sympathetic branches of the autonomic nervous system. The
parasympathetic (cholinergic) system is mainly excitatory, & the sympathetic (adrenergic) system is
mainly inhibitory.
• The GI tract has its own nervous system, the enteric (or intrinsic) nervous system. The enteric nervous system is
composed of two layers that lie between the mucosa & the muscle layers, these neurons have receptors for pressure &
movement.
• The main functions of the GI system are to supply the nutrients to body cells, this is accomplished through the process
of (1) ingestion (taking in food), (2) digestion (breaking down food), (3) absorption (transferring food products into
circulation), & (4) elimination (process of excreting waste products of digestion)
• Mouth: the oral cavity contains the teeth, used in mastication (chewing), & the tongue that assist in chewing &
moving food to the back of the throat for swallowing (the mouth starts digestion, & teeth are used to bite, crush, &
grind food).
• Salivary Gland: Parotid, submaxillary, & sublingual glands reside in the oral cavity, & they produce saliva, which
contains water, protein, mucin, inorganic salt, & salivary amylase (main function is to secrete saliva).
• Esophagus: with swallowing the upper esophageal sphincter relaxes & a peristaltic wave moves the bolus into the esophagus.
Between swallows, the esophagus is collapsed, there are four layers (1) inner mucosa, (2) submucosa, (3) muscularis propria, & (4)
outermost adventitia.
• There are two sphincters in the esophagus: the upper esophageal sphincter (UES) & the lower esophageal sphincter
(LES), the LES remains contracted except during swallowing, belching, or vomiting. The LES is an important barrier that
normally prevents reflex of acidic gastric contents into the esophagus.
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• The main function of the esophagus is muscular layer’s contract (peristalsis) & propel the food into the stomach
• Stomach: the functions of the stomach is to store food, mix food with gastric secretions, & empty contents in small boluses into the
small intestine (the stomach only absorbs small amounts of water, electrolytes, & alcohol). The fundus of the stomach is where the
chief cells secrete pepsinogen & partial cells, which secrete hydrochloric acid (HCl), water, & intrinsic factor, the secretion of HCl acid
is what makes gastric juices acidic.
• Small Intestine: the two primary functions of the small intestine are digestion (most digestion occurs here) &
absorption (uptake of nutrients from the gut lumen to the bloodstream).
• The intestine extends from the pylorus to the ileocecal valve, this prevents reflex of large intestine contents into the small
intestine.
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• Large Intestine: Absorption of water & electrolytes, also form feces & serves as a reservoir for fecal mass until defecation
occurs.
• Rectum: expels the feces.
➢ Liver
• The liver is essential for life! It functions in the manufacturing, storage, transformation, & excretion of a number substances
involved in metabolism.
• Metabolic Functions: carbohydrate metabolism, protein metabolism, fat metabolism, detoxification, & steroid
metabolism.
• Bile Synthesis: bile production & bile excretion.
• Storage: fatty acids, amino acids, glucose in the form of glycogen, vitamins (fat & water soluble), & minerals.
• Mononuclear Phagocyte System: Kupffer cells (carry out phagocytic activity, removal of bacteria & toxins from the blood), the
breakdown of old RBCs, WBCs, bacteria, & other particles. The breakdown of hemoglobin from old RBCs to bilirubin & biliverdin.
➢ Biliary Tract
• Consists of the gallbladder & the duct system. The function of the gallbladder is to concentrate & store bile (holds approximately
45 mL of bile). Bile consists of water, cholesterol, bile salts, electrolytes, & phospholipid. Bile salts are needed for fat emulsification
& digestion.
➢ Pancreas
• Has both exocrine & endocrine functions, the exocrine contributes to digestion through production & release of enzymes. The
endocrine function occurs in the islet of Langerhans, whose β-cells secrete insulin & amylase, & ά-cells secrete glucagon.
Gerontologic Assessment Table 39-5
Mouth Gingival retraction (loss of teeth, dental implants, & difficulty swallowing), decreased taste
buds, sense of smell, & volume of saliva, & atrophy of gingival tissue (poor fitting dentures)
Esophagus Lower esophageal sphincter pressure & motility is decreased (potential for hiatal hernia &
aspiration)
Abdominal Wall Thinner & less taut(visible peristalsis & easier palpation of organs) & decreased number &
sensitivity of sensory receptors (less sensitivity to surface pain)
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Stomach Atrophy of gastric mucosa & decreased blood flow (food intolerances, sign of anemia as a
result of cobalamin malabsorption, & slower gastric emptying)
Small Intestine Slightly decreased motility & secretion of most digestive enzymes (complaints of
indigestion, slowed intestinal transit, delayed absorption of fat-soluble vitamins)
Liver Decreased size & lowered position (easier palpation) & decreased protein synthesis
(decreased drug & hormone metabolism)
Pancreas Pancreatic duct distended, lipase production is decreased, & pancreatic reserve is impaired
(impaired fat absorption & decreased glucose tolerance)
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Med-Surg Exam 5
Chapter 39: Gastrointestinal System
➢ Functions of The GI System
• Composed of four common layers, (1) mucosa, (2) submucosa, (3) muscles, & (4) serosa. The muscular layers consist of two layers
the circular (inner), & longitudinal (outer) layers.
• The GI tract is innervated by the parasympathetic & sympathetic branches of the autonomic nervous system. The
parasympathetic (cholinergic) system is mainly excitatory, & the sympathetic (adrenergic) system is
mainly inhibitory.
• The GI tract has its own nervous system, the enteric (or intrinsic) nervous system. The enteric nervous system is
composed of two layers that lie between the mucosa & the muscle layers, these neurons have receptors for pressure &
movement.
• The main functions of the GI system are to supply the nutrients to body cells, this is accomplished through the process
of (1) ingestion (taking in food), (2) digestion (breaking down food), (3) absorption (transferring food products into
circulation), & (4) elimination (process of excreting waste products of digestion)
• Mouth: the oral cavity contains the teeth, used in mastication (chewing), & the tongue that assist in chewing &
moving food to the back of the throat for swallowing (the mouth starts digestion, & teeth are used to bite, crush, &
grind food).
• Salivary Gland: Parotid, submaxillary, & sublingual glands reside in the oral cavity, & they produce saliva, which
contains water, protein, mucin, inorganic salt, & salivary amylase (main function is to secrete saliva).
• Esophagus: with swallowing the upper esophageal sphincter relaxes & a peristaltic wave moves the bolus into the esophagus.
Between swallows, the esophagus is collapsed, there are four layers (1) inner mucosa, (2) submucosa, (3) muscularis propria, & (4)
outermost adventitia.
• There are two sphincters in the esophagus: the upper esophageal sphincter (UES) & the lower esophageal sphincter
(LES), the LES remains contracted except during swallowing, belching, or vomiting. The LES is an important barrier that
normally prevents reflex of acidic gastric contents into the esophagus.
Page 1 of 47
, 1
• The main function of the esophagus is muscular layer’s contract (peristalsis) & propel the food into the stomach
• Stomach: the functions of the stomach is to store food, mix food with gastric secretions, & empty contents in small boluses into the
small intestine (the stomach only absorbs small amounts of water, electrolytes, & alcohol). The fundus of the stomach is where the
chief cells secrete pepsinogen & partial cells, which secrete hydrochloric acid (HCl), water, & intrinsic factor, the secretion of HCl acid
is what makes gastric juices acidic.
• Small Intestine: the two primary functions of the small intestine are digestion (most digestion occurs here) &
absorption (uptake of nutrients from the gut lumen to the bloodstream).
• The intestine extends from the pylorus to the ileocecal valve, this prevents reflex of large intestine contents into the small
intestine.
Page 2 of 47
, 1
• Large Intestine: Absorption of water & electrolytes, also form feces & serves as a reservoir for fecal mass until defecation
occurs.
• Rectum: expels the feces.
➢ Liver
• The liver is essential for life! It functions in the manufacturing, storage, transformation, & excretion of a number substances
involved in metabolism.
• Metabolic Functions: carbohydrate metabolism, protein metabolism, fat metabolism, detoxification, & steroid
metabolism.
• Bile Synthesis: bile production & bile excretion.
• Storage: fatty acids, amino acids, glucose in the form of glycogen, vitamins (fat & water soluble), & minerals.
• Mononuclear Phagocyte System: Kupffer cells (carry out phagocytic activity, removal of bacteria & toxins from the blood), the
breakdown of old RBCs, WBCs, bacteria, & other particles. The breakdown of hemoglobin from old RBCs to bilirubin & biliverdin.
➢ Biliary Tract
• Consists of the gallbladder & the duct system. The function of the gallbladder is to concentrate & store bile (holds approximately
45 mL of bile). Bile consists of water, cholesterol, bile salts, electrolytes, & phospholipid. Bile salts are needed for fat emulsification
& digestion.
➢ Pancreas
• Has both exocrine & endocrine functions, the exocrine contributes to digestion through production & release of enzymes. The
endocrine function occurs in the islet of Langerhans, whose β-cells secrete insulin & amylase, & ά-cells secrete glucagon.
Gerontologic Assessment Table 39-5
Mouth Gingival retraction (loss of teeth, dental implants, & difficulty swallowing), decreased taste
buds, sense of smell, & volume of saliva, & atrophy of gingival tissue (poor fitting dentures)
Esophagus Lower esophageal sphincter pressure & motility is decreased (potential for hiatal hernia &
aspiration)
Abdominal Wall Thinner & less taut(visible peristalsis & easier palpation of organs) & decreased number &
sensitivity of sensory receptors (less sensitivity to surface pain)
Page 3 of 47
, 1
Stomach Atrophy of gastric mucosa & decreased blood flow (food intolerances, sign of anemia as a
result of cobalamin malabsorption, & slower gastric emptying)
Small Intestine Slightly decreased motility & secretion of most digestive enzymes (complaints of
indigestion, slowed intestinal transit, delayed absorption of fat-soluble vitamins)
Liver Decreased size & lowered position (easier palpation) & decreased protein synthesis
(decreased drug & hormone metabolism)
Pancreas Pancreatic duct distended, lipase production is decreased, & pancreatic reserve is impaired
(impaired fat absorption & decreased glucose tolerance)
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