Human Coelomic Divisions Coelomic Cavities Coelomic Cavities

Human Coelomic Divisions
Coelomic Cavities
• Coelom = body cavity within lateral
plate mesoderm, lined by mesothelium
and partitioned during development in
all amniotes
• Peritoneum = mesothelium & conn.
tiss. that lines the abdominal coelomic
cavity and the abdom. visceral organs
• Retroperitoneal = Description of
something that is “outside” the
peritoneum (bladder, rectum, kidneys)
Coelomic Cavities
• Transverse septum = separates
pericardial & pleuroperitoneal cavities
• Pericardial Cavity = coelomic cavity
around the heart
• Pleuroperitoneal cavity = coelomic
cavity around all visceral organs except
the heart
• Peritoneal cavity = abdominopelvic
cavity; lined by peritoneum
Coelomic Cavities
transverse septum
Coelomic Cavities
• Pleural / Pulmonary Cavity =
coelomic cavity around the lungs
evolved independently in reptiles and
mammals
• Pulmonary fold = (in reptiles) forms
along the dorsal midline of the
pleuroperitoneal cavity...
grows ventrolaterally around each lung.
Each lung in separate pleural cavity.
Avian Cross Section
pulmonary
fold
lu
ng
ng
lu
gut
pericardial
cavity
heart
pleural
cavity
peritoneal
cavity
Post Hepatic “Diaphragm”
• Unique to Crocodylians
Mammal Coelomic Cavities
• Coelomic (pleuroperitoneal) fold = in
mammals, forms transversely across
the dorsal pleuroperitoneal cavity,
behind the lungs and...
grows ventrally to meet the transverse
septum.
• Diaphragm = mucularized coelomic
fold separating pleural and peritoneal
cavities (anterior to the liver)
Mammal Longitudinal Section
coelomic fold
peritoneal
cavity
liver
pleural
cavity
lung
pericardial
cavity
Developing Human Coelom
Mammalian Diaphragm
• Coelomic fold component of
diaphragm becomes muscularized.
• Transverse septum component of
diaphragm become the central tendon.
Human Coelomic Divisions
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Amniota
*
prehepatic
diaphragm;
1 pleural cavity
2 pleural cavities
* posthepatic “diaphragm”
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Digestive System
Human Digestive System (and
assoc. digestive organ)
Development
General Digestive Terms
Human Digestive Tube Overview
(Oral Cavity to Anus)
Human Associated Digestive Organ
Development and Overview
Comparative Digestive Anatomy
Digestive System
• Digestive tract = continuous tube; for
extracting nutrients from food.
• Endoderm surrounded by splanchnic
mesoderm.
Digestive System Development
• Endoderm = epithelial lining of most of
digestive tract; usually simple epithelia.
• Splanchnic mesoderm = surrounds
endoderm, muscle and conn. tissues
• Stomodeum = ectoderm; forms most
of oral cavity & some salivary glands;
stratified squamous epithelium.
• Proctodeum = ectoderm; forms cloaca
(posterior rectum); strat. squamous
epithelium.
Human Endoderm Development
Human Endoderm Development
Endoderm Development
• Pharyngeal Pouches = paired anterior
pouches
(mammals – 4, but the last one = 2
pouches; in non-mammalian gnathostomes = 6).
2nd pouch of tetrapods forms Eustacian
tube between middle ear and pharynx
• Thyroid Bud - between 1st and 2nd pouches
• Other buds that form are respiratory
(Osteichthyans), hepatic, dorsal
pancreatic, ventral pancreatic, & allantoic
Human Endoderm Development
four pairs
pharyngeal
pouches
thyroid bud
respiratory bud
liver bud
ventral
pancreatic
bud
dorsal
pancreatic
bud
yolk sac
allantoic
bud
Human Liver
• Liver = Largest coelomic organ; regulates
chemical metabolism (detoxifies, glycogen
storage, secretes serum albumin) & produces bile
(emulsifies fats & contains RBC waste).
Develops from ventral hepatic bud from
duodenum in ventral mesentary. Mostly
endodermal; a little lateral plate mesoderm.
• Bile released into duodenum via hepatic duct
then common bile duct.
• Gallbladder = Stores bile; connected to bile
duct through cystic duct.
Vertebrate Embryo (section)
gut
coelom
Vertebrate Embryo (section)
dorsal
mesentery
gut
coelom
(splanchnic mesoderm)
hepatic bud
ventral mesentery
(splanchnic mesoderm)
Vertebrate Embryo (section)
dorsal
mesentery
(splanchnic mesoderm)
liver
falciform ligament
(ventral mesentery)
gut
coelom
Human Pancreas
• Pancreas = A distinct gland located
along the duodenum with endocrine
(sugar metabolism regulation) and exocrine
function (digestive enzyme secretion).
Endodermal.
Develops from dorsal and ventral
pancreatic buds off of duodenum.
• Human digestive enzymes enter
intestine through vent. pancreatic duct
connecting to common bile duct.
Pancreas Development
Human Digestive Development
Develop.
Adult Human
Epithelial Devel. Outpouchings
stomodeum
anterior oral &
nasal cavities
parotid salivary glands
pharynx
oropharynx &
nasopharynx
submandibular & sublingual
salivary glands
thyroid from thyroid bud
trachea & lungs from resp. bud
(with openings)
(only Eustacean tube)
esophagus
long
-
stomach
present
-
intestine
small intestine
liver + ducts from hepatic bud
pancreas from 2 pancreatic buds
(duodenum,
jejunoileum)
proctodeum
colon
cecum / appendix
ur. bladder in part from allantois
rectum
-
Digestive Tube Structure (Human)
Esophagus to Rectum
1. Epithelium – stratified squamous or endoderm
simple columnar epith. around lumen.
2. Lamina Propria – loose conn. tissue. mesoderm
3. Muscularis Mucosae – thin layer of
smooth muscle.
4. Submucosa – loose connect. tissue.
5. Muscularis – 2-3 layers of skeletal or
smooth muscle.
6. Serosa – thin layer of loose conn. tissue
covered by a simple squamous epith.
(coelomic mesothelium)
Esophagus Section
endoderm
mesoderm
muscularis mucosae
(thin lamina propria between
muscularis muc. & epithelium)
epithelium
(strat. squamous)
submucosa
muscularis
(2 layers, circular
& longitudinal))
serosa
Digestive Tube Structure (Human)
Esophagus to Rectum
• Sphincter – ring of muscle that can close
(or partially close) a point along the
digestive tube.
• Peristalsis – Rhythmic contraction of
smooth muscle that pushes something
along the digestive tract.
• Ridges/folds in digestive tube that are
perpendicular to the axis of the tube =
slow movement
• Ridges/folds parallel to the axis of the tube
= speed movement
Cleft Palate
• Cleft Palate = Secondary palate doesn’t fuse
along midline during development.
Human Salivary Glands
• Salivary Glands = Oral cavity glands
produce saliva; simple cuboidal epith.
Parotid Glands - ectoderm
Submandibular Glands - endoderm
Sublingual Glands - endoderm
Human Pharynx
Human Oropharynx
Human Esophagus Section
endoderm
mesoderm
muscularis mucosae
(thin lamina propria between
muscularis muc. & epithelium)
epithelium
(strat. squamous)
submucosa
muscularis
(2 layers, circular
& longitudinal))
serosa
Human Abdominal Viscera
Human Stomach
lesser
curvature
greater
curvature
Human Stomach Section
Muscularis has three layers, oblique, circular,
and longitudinal.
Human Small Intestine
Human Small Intestine
Human Small Intestine
• Plicae = folds of the intestinal epithelium.
• Villi = multicellular “finger-like” projections
of the intestinal epithelium.
• Columnar epith. cells have microvilli.
Human Large Intestine
Rectum
Liver Ducts
hepatic duct
cystic duct
common bile duct
pancreatic duct
Human Liver
Two big lobes, left & right separated by
falciform ligament. Right lobe has
subsidiary caudate and quadrate lobes.
ventral view
(anterior view)
Human Bile & Pancreatic Ducts
Human Digestive System
Comparative Digestive Anatomy
• Oral Cavity = mouth to pharynx, no
separate nasal cavity in vertebrates
without a secondary palate.
• Mammals, crocodylians, & many
turtles have a secondary palate, all
other verts. lack this.
• Salivary Glands = Present as
multicellular, large glands only in
Tetrapods, largest in amniotes.
Pharynx- Esophagus
• Pharynx in non-
amniotes also site or
respiration (gills).
• Esophagus is much
longer in tetrapods than
in non-tetrapods.
• Crop = Distended
region of the esophagus
in birds for food storage
Stomach
• Stomach is ancestrally absent in
vertebrates and its presence is a
synapomorphy of gnathostomes.
Secondarily lost in lungfishes and a few
groups of teleosts.
• Gizzard = Highly muscularized stomach
body of archosaurs, stratified squamous
(keratinized) epithelium. (Gastroliths =
“stomach stones”)
Bird Digestive Tract
Non-Tetrapod (Fish) Intestine
• No lg. & sm. distinction, just intestine.
• Pyloric ceca = out-pocketings of ant.
intestine for digestion & absorption in some
Actinopterygii.
• Spiral valve = Spiral flap in intestine,
increases surface area. In all craniates
except teleosts & tetrapods. Spiral valve
ntestines with spiral valves usually shorter
and wider.
• Rectal gland = out-pocketing of posterior
intestine; secretes excess salts in
Chondrichthys.
Shark Digestive Tract
Tetrapod Small & Large Intestine
• Tetrapods have small & large
intestines separated by the Ileocolic /
Ileocecal valve.
• Cecum = out-pocketing of anterior
large intestine for fermentation of
plant matter or other digestion.
Synapomorphy of amniotes
(ancestrally 1, birds have 2)
Cloaca
• Cloaca = (sewer in Latin) ectodermal;
intestine, reproductive system, & urinary
system all empty into the cloaca.
• Vent = external cloacal opening
• Cloaca lost in therian mammals and
Actinopterygiians.
Separate, external anal and urogenital
openings.
Associated Organs/Glands
• Liver usually large in chondrichthyans
because it stores fats for buoyancy.
• Gallbladder in gnathostomes but lost
in many groups.
• Pancreas distinct in gnathostomes
(may be incorporated into liver in some
teleosts & lungfishes as a hepatopancreas).
• Pancreas may be single (as in humans
and most verts.) or double when the
two buds do not fuse.
cloaca lost
rectal gland
stom.
lost
true teeth;
stomach
intestinal spiral valve; cloaca
cecum
salivary
glands; spiral
valve lost; lg.
& sm. intest.
(illeocecal
sphincter)
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Craniates
Intestinal
spiral
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cloaca lost (separate openings)
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Amniota
cloaca
lost
gizzard
crop;
2 large
intestinal
large intestinal cecum
ceca
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Subphylum Vertebrata
gallbladder; distinct pancreas
(from two developmental buds)
liver; pancreatic cells (diffuse in hagfishes & lampreys)
Vertebrate Digestive Tube
Myxini &
Chondrichthys
lampreys
Non-Teleost
Actinopterygii
oral cavity
oral cavity
oral cavity
oral cavity
pharynx
gill openings
gill openings
gill openings
esophagus
short
short
short
stomach
absent
present
present
intestine
simple with
spiral valve
present
simple with
spiral valve
present
simple with
spiral valve
absent
cloaca
Vertebrate Digestive Tube
Teleosts
Lungfishes
oral cavity
oral cavity
oral cavity
Amphibians
oral cavity
pharynx
gill openings
gill openings
gill openings
when larval
esophagus
short
short
long
stomach
present
absent
present
intestine
simple, NO
spiral valve
simple with
spiral valve
NO spiral valve,
small intestine
large intestine
cloaca
absent
present
present
Vertebrate Digestive Tube
oral cavity
pharynx
Montremes
Therians
Turtles
2ary palate oral & nasal
2ary palate oral & nasal
small 2ary palate
- oral & nasal
no openings
no openings
no openings
(only Eustacean tube)
(only Eustacean tube)
(only Eustacean tube)
esophagus
long
long
long
stomach
present
present
present
intestine
NO spiral valve,
small intestine
large intestine
(with 1 cecum)
NO spiral valve,
small intestine
large intestine
(with 1 cecum)
NO spiral valve,
small intestine
large intestine
(with 1 cecum)
cloaca
present
absent
present
Vertebrate Digestive Tube
oral cavity
pharynx
liz. & snakes
crocodilians
birds
oral cavity
large 2ary palate
- oral & nasal
oral cavity
no openings
no openings
no openings
(only Eustacean tube)
(only Eustacean tube)
(only Eustacean tube)
esophagus
long
long
long with crop
stomach
present
present with
gizzard
present with
gizzard
intestine
NO spiral valve,
small intestine
large intestine
(with 1 cecum)
NO spiral valve,
small intestine
large intestine
NO spiral valve,
small intestine
large intestine
(with 2 ceca)
cloaca
present
present
present
Cow Digestive System
Horse Digestive System
Human Digestive System