WEEK 3: PROBLEMS IN NUTRITION AND GASTROINTESTINAL ● Emptying into the duodenum at the ampulla of Vater is the
FUNCTIONS common bile duct, which allows for the passage of both bile
I. ANATOMY & PHYSIOLOGY OF THE GASTROINTESTINAL and pancreatic secretions.
SYSTEM ● The large intestine consists of an ascending segment on the
right side of the abdomen, a transverse segment that extends
from right to left in the upper abdomen, and a descending
segment on the left side of the abdomen.
● The sigmoid colon, the rectum, and the anus complete the
terminal portion of the large intestine. A network of striated
muscle that forms both the internal and the external anal
sphincters regulates the anal outlet.
● The GI tract receives blood from arteries that originate along
the entire length of the thoracic and abdominal aorta and veins
that return blood from the digestive organs and the spleen. This
portal venous system is composed of five large veins: the
superior mesenteric, inferior mesenteric, gastric, splenic, and
cystic veins, which eventually form the vena portae that enters
the liver.
● Once in the liver, the blood is distributed throughout and
collected into the hepatic veins that then terminate in the
inferior vena cava. Of particular importance are the gastric
artery and the superior and inferior mesenteric arteries.
● Oxygen and nutrients are supplied to the stomach by the gastric
artery and to the intestine by the mesenteric arteries (see Fig.
43-2). Venous blood is returned from the small intestine,
cecum, and the ascending and transverse portions of the colon
(Fig 43-1) by the superior mesenteric vein, which corresponds with the
distribution of the branches 3253 of the superior mesenteric
● The GI tract is a pathway 7 to 7.9 meters (23 to 26 feet) in artery.
length that extends from the mouth to the esophagus, stomach,
small and large intestines, and rectum, to the terminal
structure, the anus (see Fig. 43-1). The esophagus is located in
the mediastinum, anterior to the spine and posterior to the
trachea and heart. This hollow muscular tube, which is
approximately 25 cm (10 inches) in length, passes through the
diaphragm at an opening called the diaphragmatic hiatus
● The remaining portion of the GI tract is located within the
peritoneal cavity. The stomach is situated in the left upper
portion of the abdomen under the left lobe of the liver and the
diaphragm, overlaying most of the pancreas (see Fig. 43-1). (Fig 43-2)
● A hollow muscular organ with a capacity of approximately 1500
mL, the stomach stores food during eating, secretes digestive ● Blood flow to the GI tract (GIT) is about 20% of the total
fluids, and propels the partially digested food, or chyme, into cardiac output and increases significantly after eating.
the small intestine. The gastroesophageal junction is the inlet to
● Autonomic nervous system
the stomach.
● The stomach has four anatomic regions: the cardia (entrance), o Both the sympathetic and parasympathetic portions of the
fundus, body, and pylorus (outlet). Circular smooth muscle in autonomic
the wall of the pylorus forms the pyloric sphincter and controls nervous system
the opening between the stomach and the small intestine. innervate the GI
tract.
● The small intestine is the longest segment of the GI tract,
accounting for about two thirds of the total length. It folds back
and forth on itself, providing approximately 70 m (230 ft) of
surface area for secretion and absorption, the process by which
nutrients enter the bloodstream through the intestinal walls. It
has three sections:
Sympathetic Parasympathetic
● The most proximal section is the duodenum, the middle section
Exert inhibitory effect on Causes peristalsis and
is the jejunum, and the distal section is the ileum. The ileum the GIT increases secretory activities
terminates at the ileocecal valve. In general, sympathetic The sphincters relax under the
● This valve, or sphincter, controls the flow of digested material nerves exert influence of
from the ileum into the cecal portion of the large intestine and an inhibitory effect on the parasympathetic stimulation, except
prevents reflux of bacteria into the small intestine. GI tract, decreasing for the sphincter of the upper
● Attached to the cecum is the vermiform appendix, an gastric secretion and
appendage that has little or no physiologic function.
1
, motility and causing the esophagus and the external anal Toxicity “SLUDGE” HOT as a HARE
sphincters and blood sphincter, which are under S – salivation DRY as a BONE
vessels to constrict. voluntary L – lacrimation BLIND as a BAT
control U – urination RED as a BEET
D – diaphoresis MAD as a HATTER
G – GI distress
Drugs That Act on The Sympathetic and Parasympathetic Nervous E – emesis
System Drugs Pilocarpine Atropine
Sympathetic Parasympathetic Rivastigmine Scopolamine
“on” “off” “on” “off” Galantamine Oxybutynin
Adrenergic Adrenergi Cholinergic Anticholinergics Donepezil Benztropine
agonist c agonist
antagonist Functions of the GIT: Digestion, Absorption, Elimination
Fight Rest Sludge Dry
Mimic the Inactivate Activate Inactivate Enzyme/Secretion Enzyme Digestive Action
functioning of the parasympathet parasympathetic Source
the sympathet ic nervous nervous system Enzymes that digest Carbohydrates
sympathetic ic nervous system Ptyalin (salivary Salivary Starch 🡪 dextrin, maltose,
nervous system system amylase) glands glucose
(activating it) Wide variety of Effects include Amylase Pancreas ● Starch 🡪 dextrin,
drugs that ● Reduced and maltose, glucose
Increase the ff: would work smooth intestinal ● Dextrin 🡪 maltose,
● HR through muscle mucosa glucose
● BP enhancing spasm
action of
● breathing, ● Reduced Maltase Intestinal Maltose 🡪 glucose
acetylcholine Sucrase mucosa Sucrose 🡪 glucose, fructose
● eye pupil GIT
size movement Lactase Lactose 🡪 glucose, galactose
Enzymes/Secretions that digest Protein
● Pupil
Pepsin Protein 🡪 polypeptides
dilation
Hydrochloric Acid Gastric Protein 🡪 polypeptides,
● Decreased mucosa amino acids
production Trypsin Pancreas Proteins and polypeptides 🡪
of polypeptides, dipeptides,
secretions amino acids
● Increased Aminopeptidase Intestinal Polypeptides 🡪 dipeptides,
HR mucosa amino acids
● Airway Dipeptidase Dipeptides 🡪 amino acids
relaxation Enzymes/Secretions that digest Fat (Triglyceride)
● Reduced Pharyngeal lipase Pharynx Triglycerides 🡪 fatty acids,
mucosa diglycerides, monoglycerides
urine
Steapsin Gastric
output mucosa
Sympathetic nervous system Acetylcholine is a neurotransmitter Pancreatic lipase Pancreas
causes the release of from the brain. Bile Liver and Fat emulsification
chemical messengers: Effects of increase from gallbladder
adrenaline from adrenal acetylcholine: UPPER GIT (mouth to duodenum):
glands ● Salivation ● Chewing 🡪 production of ptyalin/salivary amylase (an enzyme
● Digestion that begins the digestion of starches); production of water and
mucus to help lubricate food to facilitate swallowing
● Muscle relaxation
● 🡪 epiglottis moves to cover the tracheal opening and prevent
aspiration of food into the lungs
Cholinergic Anticholinergic ● 🡪 esophagus smooth muscle contraction (esophageal
HR Increased peristalsis)
RR NO change NO change ● Stomach 🡪 food is mixed with secretions/enzymes
Temperature Increased (hydrochloric acid, pepsin, intrinsic factor - secreted by gastric
Pupils Pinpoint Dilated mucosa to combine with dietary vitamin B12 so that this
Bowel Increased Decreased vitamin can be absorbed in the ileum) -> food is chemically and
Diaphoresis mechanically broken into small particles by the stomach ->
chyme (partially digested food mixed with gastric secretions)
LOWER GIT (duodenum to anus):
● Chyme is mixed with duodenal secretions from the accessory
digestive organs (pancreas, liver, gallbladder)
2
FUNCTIONS common bile duct, which allows for the passage of both bile
I. ANATOMY & PHYSIOLOGY OF THE GASTROINTESTINAL and pancreatic secretions.
SYSTEM ● The large intestine consists of an ascending segment on the
right side of the abdomen, a transverse segment that extends
from right to left in the upper abdomen, and a descending
segment on the left side of the abdomen.
● The sigmoid colon, the rectum, and the anus complete the
terminal portion of the large intestine. A network of striated
muscle that forms both the internal and the external anal
sphincters regulates the anal outlet.
● The GI tract receives blood from arteries that originate along
the entire length of the thoracic and abdominal aorta and veins
that return blood from the digestive organs and the spleen. This
portal venous system is composed of five large veins: the
superior mesenteric, inferior mesenteric, gastric, splenic, and
cystic veins, which eventually form the vena portae that enters
the liver.
● Once in the liver, the blood is distributed throughout and
collected into the hepatic veins that then terminate in the
inferior vena cava. Of particular importance are the gastric
artery and the superior and inferior mesenteric arteries.
● Oxygen and nutrients are supplied to the stomach by the gastric
artery and to the intestine by the mesenteric arteries (see Fig.
43-2). Venous blood is returned from the small intestine,
cecum, and the ascending and transverse portions of the colon
(Fig 43-1) by the superior mesenteric vein, which corresponds with the
distribution of the branches 3253 of the superior mesenteric
● The GI tract is a pathway 7 to 7.9 meters (23 to 26 feet) in artery.
length that extends from the mouth to the esophagus, stomach,
small and large intestines, and rectum, to the terminal
structure, the anus (see Fig. 43-1). The esophagus is located in
the mediastinum, anterior to the spine and posterior to the
trachea and heart. This hollow muscular tube, which is
approximately 25 cm (10 inches) in length, passes through the
diaphragm at an opening called the diaphragmatic hiatus
● The remaining portion of the GI tract is located within the
peritoneal cavity. The stomach is situated in the left upper
portion of the abdomen under the left lobe of the liver and the
diaphragm, overlaying most of the pancreas (see Fig. 43-1). (Fig 43-2)
● A hollow muscular organ with a capacity of approximately 1500
mL, the stomach stores food during eating, secretes digestive ● Blood flow to the GI tract (GIT) is about 20% of the total
fluids, and propels the partially digested food, or chyme, into cardiac output and increases significantly after eating.
the small intestine. The gastroesophageal junction is the inlet to
● Autonomic nervous system
the stomach.
● The stomach has four anatomic regions: the cardia (entrance), o Both the sympathetic and parasympathetic portions of the
fundus, body, and pylorus (outlet). Circular smooth muscle in autonomic
the wall of the pylorus forms the pyloric sphincter and controls nervous system
the opening between the stomach and the small intestine. innervate the GI
tract.
● The small intestine is the longest segment of the GI tract,
accounting for about two thirds of the total length. It folds back
and forth on itself, providing approximately 70 m (230 ft) of
surface area for secretion and absorption, the process by which
nutrients enter the bloodstream through the intestinal walls. It
has three sections:
Sympathetic Parasympathetic
● The most proximal section is the duodenum, the middle section
Exert inhibitory effect on Causes peristalsis and
is the jejunum, and the distal section is the ileum. The ileum the GIT increases secretory activities
terminates at the ileocecal valve. In general, sympathetic The sphincters relax under the
● This valve, or sphincter, controls the flow of digested material nerves exert influence of
from the ileum into the cecal portion of the large intestine and an inhibitory effect on the parasympathetic stimulation, except
prevents reflux of bacteria into the small intestine. GI tract, decreasing for the sphincter of the upper
● Attached to the cecum is the vermiform appendix, an gastric secretion and
appendage that has little or no physiologic function.
1
, motility and causing the esophagus and the external anal Toxicity “SLUDGE” HOT as a HARE
sphincters and blood sphincter, which are under S – salivation DRY as a BONE
vessels to constrict. voluntary L – lacrimation BLIND as a BAT
control U – urination RED as a BEET
D – diaphoresis MAD as a HATTER
G – GI distress
Drugs That Act on The Sympathetic and Parasympathetic Nervous E – emesis
System Drugs Pilocarpine Atropine
Sympathetic Parasympathetic Rivastigmine Scopolamine
“on” “off” “on” “off” Galantamine Oxybutynin
Adrenergic Adrenergi Cholinergic Anticholinergics Donepezil Benztropine
agonist c agonist
antagonist Functions of the GIT: Digestion, Absorption, Elimination
Fight Rest Sludge Dry
Mimic the Inactivate Activate Inactivate Enzyme/Secretion Enzyme Digestive Action
functioning of the parasympathet parasympathetic Source
the sympathet ic nervous nervous system Enzymes that digest Carbohydrates
sympathetic ic nervous system Ptyalin (salivary Salivary Starch 🡪 dextrin, maltose,
nervous system system amylase) glands glucose
(activating it) Wide variety of Effects include Amylase Pancreas ● Starch 🡪 dextrin,
drugs that ● Reduced and maltose, glucose
Increase the ff: would work smooth intestinal ● Dextrin 🡪 maltose,
● HR through muscle mucosa glucose
● BP enhancing spasm
action of
● breathing, ● Reduced Maltase Intestinal Maltose 🡪 glucose
acetylcholine Sucrase mucosa Sucrose 🡪 glucose, fructose
● eye pupil GIT
size movement Lactase Lactose 🡪 glucose, galactose
Enzymes/Secretions that digest Protein
● Pupil
Pepsin Protein 🡪 polypeptides
dilation
Hydrochloric Acid Gastric Protein 🡪 polypeptides,
● Decreased mucosa amino acids
production Trypsin Pancreas Proteins and polypeptides 🡪
of polypeptides, dipeptides,
secretions amino acids
● Increased Aminopeptidase Intestinal Polypeptides 🡪 dipeptides,
HR mucosa amino acids
● Airway Dipeptidase Dipeptides 🡪 amino acids
relaxation Enzymes/Secretions that digest Fat (Triglyceride)
● Reduced Pharyngeal lipase Pharynx Triglycerides 🡪 fatty acids,
mucosa diglycerides, monoglycerides
urine
Steapsin Gastric
output mucosa
Sympathetic nervous system Acetylcholine is a neurotransmitter Pancreatic lipase Pancreas
causes the release of from the brain. Bile Liver and Fat emulsification
chemical messengers: Effects of increase from gallbladder
adrenaline from adrenal acetylcholine: UPPER GIT (mouth to duodenum):
glands ● Salivation ● Chewing 🡪 production of ptyalin/salivary amylase (an enzyme
● Digestion that begins the digestion of starches); production of water and
mucus to help lubricate food to facilitate swallowing
● Muscle relaxation
● 🡪 epiglottis moves to cover the tracheal opening and prevent
aspiration of food into the lungs
Cholinergic Anticholinergic ● 🡪 esophagus smooth muscle contraction (esophageal
HR Increased peristalsis)
RR NO change NO change ● Stomach 🡪 food is mixed with secretions/enzymes
Temperature Increased (hydrochloric acid, pepsin, intrinsic factor - secreted by gastric
Pupils Pinpoint Dilated mucosa to combine with dietary vitamin B12 so that this
Bowel Increased Decreased vitamin can be absorbed in the ileum) -> food is chemically and
Diaphoresis mechanically broken into small particles by the stomach ->
chyme (partially digested food mixed with gastric secretions)
LOWER GIT (duodenum to anus):
● Chyme is mixed with duodenal secretions from the accessory
digestive organs (pancreas, liver, gallbladder)
2
