Download Stomach - Stephen Tavoni

Figure 22.2 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
Defecation
© 2014 Pearson Education,
Inc.
Blood
vessel
Mainly H2O
Feces
Anus
Figure 22.3a Peristalsis and segmentation.
From
mouth
Peristalsis: Adjacent segments of alimentary tract
organs alternately contract and relax, moving food
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along the tract distally.
Inc.
Figure 22.3b Peristalsis and segmentation.
Segmentation: Nonadjacent segments of
alimentary tract organs alternately contract and relax,
moving food forward then backward. Food mixing and
slow food propulsion occur.
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Inc.
Figure 22.5a The peritoneum and the peritoneal cavity.
Abdominopelvic
cavity
Vertebra
Dorsal
mesentery
Parietal
peritoneum
Ventral
mesentery
Visceral
peritoneum
Peritoneal
cavity
Alimentary
canal organ
Liver
Two schematic cross sections of abdominal cavity illustrate
the peritoneums and mesenteries.
© 2014 Pearson Education,
Inc.
Figure 22.30d Mesenteries of the abdominal digestive organs.
Liver
Lesser omentum
Pancreas
Stomach
Duodenum
Transverse mesocolon
Transverse colon
Mesentery
Greater omentum
Jejunum
Ileum
Visceral peritoneum
Parietal peritoneum
Urinary bladder
Rectum
© 2014 Pearson Education,
Inc.
Figure 22.6 Basic structure of the alimentary canal.
Intrinsic nerve plexuses
• Myenteric nerve plexus
• Submucosal nerve plexus
Glands in
submucosa
Mucosa
• Epithelium
• Lamina propria
• Muscularis
mucosae
Submucosa
Muscularis externa
• Longitudinal muscle
• Circular muscle
Mesentery
Nerve
Gland in mucosa
Artery
Vein
Duct of gland outside
Lymphatic vessel
alimentary canal
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Serosa
• Epithelium
(mesothelium)
• Connective tissue
Lumen
Mucosa-associated
lymphoid tissue
Figure 19.2a The lymphatic system.
Regional
lymph
nodes:
Internal
jugular vein
Entrance of
right lymphatic
duct into vein
Cervical
nodes
Entrance of
thoracic duct
into vein
Thoracic
duct
Axillary
nodes
Cisterna
chyli
Aorta
Collecting
lymphatic
vessels
Drained by the right lymphatic duct
Drained by the thoracic duct
Inguinal
nodes
General distribution of collecting lymphatic
and regional lymph nodes.
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vessels
Inc.
Figure 22.12a Microscopic structure of the esophagus.
Mucosa
(stratified
squamous
epithelium)
Submucosa
(areolar
connective
tissue)
Lumen
Muscularis
externa
• Circular layer
• Longitudinal
layer
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Inc.
Adventitia
(fibrous
connective
tissue)
Figure 18.24a Arteries of the abdomen.
Diaphragm
Abdominal
aorta
Inferior
phrenic
arteries
L. gastric artery
R. gastric
artery
Common
hepatic
artery
Hepatic
artery
proper
L
Splenic
artery
Gastroduodenal
artery
R
Celiac
trunk
R. gastroepiploic
artery
Middle
suprarenal
arteries
L. gastroepiploic artery
Intestinal arteries
Middle colic
artery
Superior
mesenteric
artery
R. colic
artery
Renal
arteries
Gonadal
arteries
Ileocolic artery
Sigmoidal
arteries
Inferior
mesenteric
artery
L. colic
artery
Lumbar
arteries
Superior rectal
artery
Median sacral artery
Common iliac arteries
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Schematic flowchart.
Figure 18.29a Veins of the abdomen.
Inferior vena cava
Cystic vein
Hepatic
portal
system
Inferior phrenic veins
Hepatic veins
Hepatic portal vein
Superior mesenteric vein
Splenic vein
Suprarenal veins
Renal veins
Inferior
mesenteric
vein
Gonadal veins
Lumbar veins
R. ascending
lumbar vein
L. ascending
lumbar vein
Common iliac veins
External iliac vein
Internal iliac veins
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Schematic flowchart.
Figure 14.3 The subdivisions of the ANS.
Parasympathetic
Sympathetic
Eye
Brain stem
Salivary
glands
Heart
Eye
Skin*
Cranial
Sympathetic
ganglia
Salivary
glands
Cervical
Lungs
Lungs
T1
Heart
Stomach
Thoracic
Stomach
Pancreas
Pancreas
Liver
and gallbladder
L1
Liver and
gallbladder
Adrenal
gland
Lumbar
Bladder
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Genitals
Inc.
Bladder
Sacral
Genitals
Figure 14.4 Parasympathetic division of the ANS.
Eye
Ciliary
ganglion
CN III
Lacrimal
gland
CN VII
Pterygopalatine
ganglion
CN IX
CN X
Submandibular
ganglion
Otic ganglion
Nasal
mucosa
Submandibular
and sublingual
glands
Parotid gland
Heart
Cardiac and
pulmonary
plexuses
Lung
Celiac
plexus
Liver and
gallbladder
Stomach
Pancreas
S2
Large
intestine
S4
Small
intestine
Pelvic
splanchnic
nerves
Inferior
hypogastric
plexus
Rectum
Urinary
bladder
and ureters
Genitalia (penis, clitoris, and vagina)
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CN
S
Preganglionic
Postganglionic
Cranial nerve
Sacral nerve
Figure 14.4 Parasympathetic division of the ANS. (2 of 2)
Celiac
plexus
Liver and
gallbladder
Stomach
Pancreas
S2
S4
Pelvic
splanchnic
nerves
Inferior
hypogastric
plexus
Large
intestine
Small
intestine
Rectum
Urinary
bladder
and ureters
Genitalia (penis, clitoris, and vagina)
Preganglionic
Postganglionic
CN Cranial nerve
S Sacral nerve
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Inc.
Figure 22.7b Anatomy of the oral cavity (mouth).
Upper lip
Gingivae
(gums)
Palatine
raphe
Hard
palate
Soft
palate
Uvula
Palatine
tonsil
Superior
labial
frenulum
Palatoglossal
arch
Palatopharyngeal
arch
Posterior wall
of oropharynx
Tongue
Sublingual
fold with
openings of
sublingual
ducts
Lingual frenulum
Opening of
Submandibular
duct
Gingivae (gums)
Oral vestibule
Lower lip
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Anterior view
Inc.
Inferior labial
frenulum
Figure 22.9 The salivary glands.
Tongue
Teeth
Ducts of
sublingual
gland
Frenulum
of tongue
Sublingual
gland
Parotid
gland
Parotid duct
Masseter muscle
Body of mandible
(cut)
Posterior belly of
digastric muscle
Mylohyoid
muscle (cut)
Submandibular
duct
Anterior belly of
digastric muscle
Submandibular
gland
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Mucous cells
Serous cells
forming demilunes
Figure 22.11 Longitudinal section of a canine tooth within its bony socket (alveolus).
Enamel
Dentin
Crown
Neck
Dentinal
tubules
Pulp cavity
(contains
blood vessels
and nerves)
Gingival
sulcus
Gingiva
(gum)
Cement
Root
Root canal
Periodontal
ligament
Apical
foramen
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Bone
Figure 22.7a 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
Inc.
Figure 22.13 Deglutition (swallowing).
Bolus of food
Tongue
Uvula
Pharynx
Bolus
Epiglottis
Epiglottis
Glottis
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
Upper
esophageal
sphincter
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 22.12a Microscopic structure of the esophagus.
Mucosa
(stratified
squamous
epithelium)
Submucosa
(areolar
connective
tissue)
Lumen
Muscularis
externa
• Circular layer
• Longitudinal
layer
© 2014 Pearson Education,
Inc.
Adventitia
(fibrous
connective
tissue)
Figure 22.13 Deglutition (swallowing). (4 of 5)
4 Peristalsis moves
Relaxed muscles
food through the
esophagus to the
stomach.
Circular muscles
contract
Bolus of food
Longitudinal muscles
contract
Gastroesophageal
sphincter closed
Stomach
© 2014 Pearson Education, Inc.
Figure 22.13 Deglutition (swallowing). (5 of 5)
Relaxed
muscles
5 The gastroesophageal
sphincter surrounding the
cardial oriface opens, and
food enters the stomach.
Circular muscles contract
Gastroesophageal
sphincter opens
© 2014 Pearson Education, Inc.
Figure 22.14a 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
Pyloric sphincter
(valve) at pylorus
Pyloric
canal
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Pyloric
antrum
Figure 22.15b Microscopic anatomy of the stomach.
Gastric pits
Surface epithelium
(mucous cells)
Gastric
pit
Mucous neck cells
Parietal cell
Gastric
gland
Chief cell
Enteroendocrine cell
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Inc.
Enlarged view of gastric pits and
gastric glands
Figure 22.15c Microscopic anatomy of the stomach.
Pepsinogen
HCI
Pepsin
Mitochondria
Parietal cell
Chief cell
Enteroendocrine
cell
Location of the HCl-producing parietal cells
and pepsin-secreting chief cells in a gastric
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Inc.
gland
Figure 22.18 Mechanism of HCl secretion by parietal cells.
Gastric gland
Blood
capillary
CO2
Chief cell
Stomach lumen
CO2 + H2O
H+-K+
ATPase
H2CO3
Carbonic
anhydrase
H+
K+
HCO3−
Alkaline
tide
Parietal cell
H+
K+
HCI
HCO3−
Cl−
Interstitial
fluid
© 2014 Pearson Education,
Inc.
HCO3−- Cl−
antiporter
Cl−
Cl−
Figure 22.15b Microscopic anatomy of the stomach.
Gastric pits
Surface epithelium
(mucous cells)
Gastric
pit
Mucous neck cells
Parietal cell
Gastric
gland
Chief cell
Enteroendocrine cell
© 2014 Pearson Education,
Inc.
Enlarged view of gastric pits and
gastric glands
Figure 22.15c Microscopic anatomy of the stomach.
Pepsinogen
HCI
Pepsin
Mitochondria
Parietal cell
Chief cell
Enteroendocrine
cell
Location of the HCl-producing parietal cells
and pepsin-secreting chief cells in a gastric
© 2014 Pearson Education,
Inc.
gland
Figure 22.17 Neural and hormonal mechanisms that regulate release of gastric juice.
Inhibitory events
Stimulatory events
Cephalic
phase
1 Sight and thought
of food
Cerebral cortex
Conditioned reflex
2 Stimulation of
taste and smell
receptors
Gastric
phase
1 Stomach
distension
activates
stretch
receptors
Hypothalamus
and medulla
oblongata
Vagovagal
reflexes
Intestinal
phase
Stimulate
Inhibit
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Inc.
Vagus
nerve
Vagus
nerve
Local
reflexes
2 Food chemicals
(especially peptides and
caffeine) and rising pH
activate chemoreceptors
1 Presence of
partially digested
foods in duodenum
or distension of the
duodenum when
stomach begins to
empty
Medulla
Lack of
stimulatory
impulses to
parasympathetic
center
G cells
Intestinal
(enteric)
gastrin
release
to blood
Gastrin
release
to blood
Gastrin
secretion
declines
G cells
Overrides
parasympathetic
controls
Sympathetic
nervous
system
activation
1 Loss of
appetite,
depression
1 Excessive
acidity
(pH < 2)
in stomach
2 Emotional
stress
Stomach
secretory
activity
Enterogastric
reflex
Brief
effect
Cerebral
cortex
Local
reflexes
Vagal
nuclei
in medulla
Pyloric
sphincter
Release of
enterogastrones
(secretin, cholecystokinin,
vasoactive intestinal
peptide)
1 Distension
of duodenum;
presence of
fatty, acidic, or
hypertonic
chyme; and/or
irritants in
the duodenum
2 Distension;
presence of
fatty, acidic,
partially
digested food
in the
duodenum
Figure 22.15c Microscopic anatomy of the stomach.
Pepsinogen
HCI
Pepsin
Mitochondria
Parietal cell
Chief cell
Enteroendocrine
cell
Location of the HCl-producing parietal cells
and pepsin-secreting chief cells in a gastric
© 2014 Pearson Education,
Inc.
gland
Figure 22.18 Mechanism of HCl secretion by parietal cells.
Gastric gland
Blood
capillary
CO2
Chief cell
Stomach lumen
CO2 + H2O
H+-K+
ATPase
H2CO3
Carbonic
anhydrase
H+
K+
HCO3−
Alkaline
tide
Parietal cell
H+
K+
HCI
HCO3−
Cl−
Interstitial
fluid
© 2014 Pearson Education,
Inc.
HCO3−- Cl−
antiporter
Cl−
Cl−
Figure 22.15c Microscopic anatomy of the stomach.
Pepsinogen
HCI
Pepsin
Mitochondria
Parietal cell
Chief cell
Enteroendocrine
cell
Location of the HCl-producing parietal cells
and pepsin-secreting chief cells in a gastric
© 2014 Pearson Education,
Inc.
gland
Figure 22.16 Photographs of a gastric ulcer and the H. pylori bacteria that most commonly cause it.
Bacteria
Mucosa
layer of
stomach
A gastric ulcer lesion
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Inc.
H. pylori bacteria
Figure 22.1 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
Anus
Duodenum
Jejunum
Ileum
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Inc.
Descending colon
Ascending colon
Cecum
Sigmoid colon
Rectum
Appendix
Anal canal
Large
intestine
Figure 22.21 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
Figure 22.25c Microscopic anatomy of the liver.
Interlobular veins
(to hepatic vein)
Central vein
Sinusoids
Bile canaliculi
Plates of
hepatocytes
Bile duct (receives
bile from bile
canaliculi)
Fenestrated
lining (endothelial
cells) of sinusoids
Stellate macrophages
in sinusoid walls
Portal vein
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Bile duct
Portal venule
Portal arteriole
Portal triad
Figure 22.21 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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Inc.
Main pancreatic duct and sphincter
Duodenum
Head of pancreas
Figure 22.21 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
© 2014 Pearson Education,
Inc.
Main pancreatic duct and sphincter
Duodenum
Head of pancreas
Figure 22.26a Structure of the enzyme-producing tissue of the pancreas.
Small
duct
Acinar cell
Basement
membrane
Zymogen
granules
Rough
endoplasmic
reticulum
Duct cell
One acinus
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Figure 22.22a Structural modifications of the small intestine that increase its surface area for digestion and absorption.
Vein carrying
blood to
hepatic portal
vessel
Muscle
layers
Circular
folds
Villi
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Inc.
Lumen
Figure 22.22b Structural modifications of the small intestine that increase its surface area for digestion and absorption.
Microvilli
(brush border)
Absorptive
cells
Lacteal
Villus
Goblet
cell
Blood
capillaries
Mucosaassociated
lymphoid
tissue
Intestinal
crypt
Muscularis
mucosae
Duodenal
gland
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Inc.
Enteroendocrine
cells
Venule
Lymphatic vessel
Submucosa
Figure 22.22c Structural modifications of the small intestine that increase its surface area for digestion and absorption.
Absorptive cells
Goblet
cells
Villi
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Inc.
Intestinal crypt
Figure 22.23 Microvilli of the small intestine.
Mucus
granules
Microvilli
forming the
brush border
Absorptive cell
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Inc.
Figure 22.28 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.
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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Inc.
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.
CCK secretion
Secretin secretion
Figure 22.30d Mesenteries of the abdominal digestive organs.
Liver
Lesser omentum
Pancreas
Stomach
Duodenum
Transverse mesocolon
Transverse colon
Mesentery
Greater omentum
Jejunum
Ileum
Visceral peritoneum
Parietal peritoneum
Urinary bladder
Rectum
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Inc.
Figure 22.30c Mesenteries of the abdominal digestive organs.
Greater omentum
Transverse colon
Transverse
mesocolon
Descending colon
Jejunum
Mesentery
Sigmoid
mesocolon
Sigmoid colon
Ileum
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Inc.
Figure 22.29a Gross anatomy of the large intestine.
Left colic
(splenic) flexure
Transverse
mesocolon
Right colic
(hepatic) flexure
Transverse colon
Epiploic
appendages
Superior
mesenteric artery
Haustrum
Descending colon
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
Figure 22.29a Gross anatomy of the large intestine.
Left colic
(splenic) flexure
Transverse
mesocolon
Right colic
(hepatic) flexure
Transverse colon
Epiploic
appendages
Superior
mesenteric artery
Haustrum
Descending colon
Ascending colon
IIeum
Cut edge of
mesentery
IIeocecal valve
Tenia coli
Sigmoid colon
Cecum
Appendix
Rectum
Anal canal
© 2014 Pearson Education,
Inc.
External anal sphincter
Figure 22.29b Gross anatomy of the large intestine.
Rectal valve
Rectum
Hemorrhoidal
veins
Levator ani muscle
Anal canal
External anal
sphincter
Internal anal
sphincter
Anal columns
Pectinate line
Anal sinuses
Anus
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Inc.
Figure 22.31 Defecation reflex.
Impulses from
cerebral cortex
(conscious
control)
Sensory
nerve fibers
Voluntary motor
nerve to external
anal sphincter
Sigmoid
colon
Rectum
External anal
sphincter
(skeletal muscle)
Stretch receptors in wall
2 A spinal reflex is initiated in which
parasympathetic motor (efferent) fibers
stimulate contraction of the rectum and
sigmoid colon, and relaxation of the
internal anal sphincter.
Involuntary motor nerve
(parasympathetic division)
Internal anal sphincter (smooth muscle)
3 If it is convenient to defecate,
voluntary motor neurons are inhibited,
allowing the external anal sphincter to
relax so feces may pass.
© 2014 Pearson Education,
Inc.
1 Feces move into and
distend the rectum,
stimulating stretch receptors
there. The receptors transmit
signals along afferent fibers
to spinal cord neurons.
• ALBUMIN
• GLOBULIN
• FIBRINOGEN
• CLOTTING FACTORS