Download Lab 5 Digestion and Hormones of Digestion Summer 2015

Lab 5
Digestion and Hormones of
Digestion
7/16/2015
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Figure 23.1 Alimentary canal and related accessory digestive organs.
Mouth (oral cavity)
Tongue*
Parotid gland
Sublingual gland
Submandibular gland
Salivary
glands*
Pharynx
Esophagus
Stomach
Pancreas*
(Spleen)
Liver*
Gallbladder*
Transverse colon
Small
intestine
Duodenum
Jejunum
Ileum
Descending colon
Ascending colon
Cecum
Sigmoid colon
Rectum
Appendix
Anal canal
Anus
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Large
intestine
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Figure 23.2 Gastrointestinal tract activities.
Ingestion
Mechanical
breakdown
• Chewing (mouth)
• Churning (stomach)
• Segmentation
(small intestine)
Digestion
Food
Pharynx
Esophagus
Propulsion
• Swallowing
(oropharynx)
• Peristalsis
(esophagus,
stomach,
small intestine,
large intestine)
Stomach
Absorption
Lymph
vessel
Small
intestine
Large
intestine
Blood
vessel
Mainly H2O
Feces
Defecation
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Anus
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Figure 23.7a Anatomy of the oral cavity (mouth).
Soft
palate
Palatoglossal
arch
Uvula
Hard
palate
Oral cavity
Palatine
tonsil
Tongue
Oropharynx
Lingual tonsil
Epiglottis
Hyoid bone
Laryngopharynx
Esophagus
Trachea
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Sagittal section of the
oral cavity and pharynx
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Figure 23.13 Deglutition (swallowing).
Slide 1
Bolus of food
Tongue
Uvula
Pharynx
Bolus
Epiglottis
Epiglottis
Glottis
Upper
esophageal
sphincter
Trachea
Esophagus
1 During the buccal phase, the upper
esophageal sphincter is contracted.
The tongue presses against the hard
palate, forcing the food bolus into the
oropharynx.
2 The pharyngeal-esophageal phase
begins as the uvula and larynx rise to prevent
food from entering respiratory passageways.
The tongue blocks off the mouth. The upper
esophageal sphincter relaxes, allowing food
to enter the esophagus.
4 Peristalsis moves
food through the
esophagus to the
stomach.
Relaxed muscles
Circular muscles
contract
Bolus
3 The constrictor muscles of the
pharynx contract, forcing food into
the esophagus inferiorly. The upper
esophageal sphincter contracts
(closes) after food enters.
Relaxed
muscles
5 The gastroesophageal
sphincter surrounding the
cardial oriface opens, and
food enters the stomach.
Bolus of food
Longitudinal muscles
contract
Circular muscles contract
Gastroesophageal
sphincter closed
Gastroesophageal
sphincter opens
Stomach
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Figure 23.14a Anatomy of the stomach.
Cardia
Fundus
Esophagus
Muscularis
externa
• Longitudinal layer
• Circular layer
• Oblique layer
Serosa
Body
Lumen
Lesser
curvature
Rugae of
mucosa
Greater
curvature
Duodenum
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Pyloric sphincter
(valve) at pylorus
Pyloric
canal
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Pyloric
antrum
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Digestive Processes in the Stomach
• Physical digestion
• Denaturation of proteins by HCl
• Enzymatic digestion of proteins by pepsin (and
milk protein by rennin in infants)
• Lingual lipase digests some triglycerides
before digested as any other protein
• Delivers chyme to small intestine
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Figure 23.19 Deglutition (swallowing).
Pyloric
valve
closed
1 Propulsion: Peristaltic
waves move from the fundus
toward the pylorus.
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Slide 1
Pyloric
valve
slightly
opened
Pyloric
valve
closed
2 Grinding: The most
vigorous peristalsis and
mixing action occur close to
the pylorus.
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3 Retropulsion: The pyloric
end of the stomach acts as a
pump that delivers small amounts
of chyme into the duodenum,
simultaneously forcing most of its
contained material backward into
the stomach.
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Figure 23.1 Alimentary canal and related accessory digestive organs.
Mouth (oral cavity)
Tongue*
Parotid gland
Sublingual gland
Submandibular gland
Salivary
glands*
Pharynx
Esophagus
Stomach
Pancreas*
(Spleen)
Liver*
Gallbladder*
Transverse colon
Small
intestine
Duodenum
Jejunum
Ileum
Descending colon
Ascending colon
Cecum
Sigmoid colon
Rectum
Appendix
Anal canal
Anus
7/16/2015
MDufilho
Large
intestine
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Figure 23.29a Gross anatomy of the large intestine.
Left colic
(splenic) flexure
Right colic
(hepatic) flexure
Transverse
mesocolon
Transverse colon
Epiploic
appendages
Superior
mesenteric artery
Descending colon
Haustrum
Ascending colon
IIeum
Cut edge of
mesentery
IIeocecal valve
Tenia coli
Sigmoid colon
Cecum
Appendix
Rectum
Anal canal
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External anal sphincter
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Figure 23.21 The duodenum of the small intestine, and related organs.
Right and left
hepatic ducts
of liver
Cystic duct
Common hepatic duct
Bile duct and sphincter
Accessory pancreatic duct
Mucosa
with folds
Tail of pancreas
Pancreas
Jejunum
Gallbladder
Major duodenal
papilla
Hepatopancreatic
ampulla and sphincter
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Main pancreatic duct and sphincter
Duodenum
Head of pancreas
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Figure 23.28 Mechanisms promoting secretion and release of bile and pancreatic juice.
1 Chyme enter
-ing duodenum
causes duodenal
enteroendocrine
cells to release
cholecystokinin
(CCK) and
secretin.
4 Bile salts
and, to a lesser
extent, secretin
transported via
bloodstream
stimulate Liver to
produce bile
more rapidly.
5 CCK (via
blood stream)
causes gallbladder
to contract and
Hepatopancreatic
Sphincter to
relax. Bile Enters
duodenum.
6 During cephalic
and gastric phases,
vagal Nerve stimulates gallbladder to
contract weakly.
2 CCK (red
dots) and
secretin (yellow
dots) enter the
bloodstream.
3 CCK induces
secretion of
enzyme-rich
pancreatic juice.
Secretin causes
secretion of
HCO3− -rich
pancreatic juice.
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Slide 1
CCK secretion
Secretin secretion
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