DIGESTIVE and RESPIRATORY
ANATOMY
VERTEBRATE COELOM
I. Serous Membranes: composed of an epithelial covering and a supporting connective tissue; produces a serous fluid.
A. Peritoneum and Pleura: composed of
three parts:
1. Parietal Layer: lines inside of body
wall.
2. Visceral Layer: covers organs
within cavity
3. Mesentery: double layer of peritoneum that interconnects parietal
and visceral layers; acts to support digestive tube.
B. Pleuroperitoneal Cavity: found in
shark; lined by peritoneum; contains
digestive organs.
C. Peritoneal Cavity: found in abdominal
cavity of cat; lined by peritoneum;
contains digestive organs.
D. Pleural Cavities: two cavities found in
cat thoracic cavity; lined by pleura;
separated by pericardial cavity; contains lungs.
SHARK DIGESTIVE SYSTEM
I. Alimentary Canal: tube that food passes
through; also known as digestive tract or
gut.
A. Esophagus: short tube connecting
pharynx and stomach; contains numerous papillae, finger-like projections
B. Stomach: J-shaped organ; consists of
larger cardiac portion, continuous
with esophagus; smaller segment is
pyloric portion ending at pyloric
sphincter.
C. Small Intestine: distal to pylorus; made
of short, narrow duodenum, followed
by longer ileum; this encloses spiral
valve, that acts to increase intestinal
surface area.
D. Colon: extends from ileum to large,
finger-like rectal gland.
E. Rectum: last portion of tract which
empties into anus; anus projects into
cloaca.
II. Digestive Glands: organs associated with
the digestive process that do not come in
contact with food.
A. Liver: consists of long left and right
lobes with short median lobe; produces bile, which is stored in gall
bladder; found on right margin of
median lobe.
B. Pancreas: produces digestive enzymes
that empty into duodenum.
HEAD STRUCTURES of CAT
I. Mouth
A. Oral Cavity: area of mouth behind
teeth.
B. Tongue: mobile muscular organ
attached to floor of mouth.
C. Teeth: used to masticate food and for
defense; dental formula for adult cat
is:
3-1-3-1
3-1-2-1
(incisors, canine, premolar, molar).
D. Palate: partition separating oral and
nasal cavities; anterior portion, hard
palate, is supported by bone; posterior
portion, soft palate, is muscular.
E. Palatine Tonsils: masses of lymphoid
tissue on lateral wall of posterior oral
cavity.
II. Nose
A. External Nares: external openings that
lead into nasal cavity
B. Nasal Septum: bony structure that
divides nasal cavity
C. Internal Nares: internal openings that
lead from nasal cavity into pharynx
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D. Pharynx: common tube for food and
air; extends from internal nares to
entrances of larynx and esophagus;
divided into
1. Nasopharynx: just behind nasal
cavity.
2. Oropharynx: just behind oral
cavity.
3. Laryngopharynx: just behind
larynx.
E. Glottis: opening into larynx; guarded
by flap-like cartilaginous epiglottis.
CAT DIGESTIVE SYSTEM
I. General Anatomy: structure throughout
length of gut with modifications in specific
areas.
A. Mucosa: epithelial lining of gut; has
secretory and/or absorptive functions;
supported by lamina propria, where
blood and lymphatic capillaries are
found.
B. Submucosa: connective tissue
supporting mucosa; highly vascularized.
C. Muscularis: smooth muscle layers
1. Circular Smooth Muscle: inner
layer.
2. Longitudinal Muscle Layer: outer
layer.
D. Serosa: outer-most layer of gut; same
as visceral peritoneum.
II. Alimentary Canal
A. Esophagus: tube that food passes
through from pharynx to stomach,
passing through thoracic cavity.
B. Stomach: J-shaped enlargement of gut,
just inferior to diaphragm site of some
protein digestion
1. Cardia: proximal part joined to
esophagus.
2. Fundus: round portion on left side;
extends superiorly.
3. Body: large central portion inferior
to fundus.
4. Pylorus: distal, inferior portion of
stomach; ends at pyloric valve,
which regulates emptying of
stomach.
C. Small Intestine: site of most digestion
and absorption; mucosa of small intestine in highly folded into microvilli,
villi, and plicae circulares; these increase surface area for digestion and
absorption; divided into three
segments:
1. Duodenum: first segment of small
intestine on right; runs caudally
and forms a U-shaped bend; site
of final digestion of most food.
2. Jejunum: middle segment of small
intestine; most absorption of
nutrients occurs here.
3. Ileum: last segment of small intestine; empties into large intestine
through iliocecal valve.
D. Large Intestine
1. Cecum: blind pouch inferior to
iliocecal valve.
2. Colon: major part of large intestine; divided into ascending, on
right; transverse; descending; and
sigmoid segments.
3. Rectum: last segment of gut; empties to outside through anus.
III. Digestive Glands
A. Salivary Glands: three pair of glands;
secrete serous/mucus fluid into oral
cavity.
1. Parotid Glands: lies in front of ear;
duct passes over masseter.
2. Submandibular Glands: found just
under parotid gland.
3. Sublingual Glands: cone shaped
gland, anterior to submandibular
gland.
B. Pancreas: inferior to stomach, bending
sharply in middle at be-ginning of
duodenum; secretes ‘panc-reatic juice’
into duodenum; contains enzymes that
digest carbohydrates, proteins, lipids;
and buffers to counteract gastric acid.
C. Liver: large organ, just posterior to
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diaphragm partially covering stomach;
divided into larger left and right median lobes and smaller left and right
lateral lobes; produces bile (important
in digestion of lipids).
D. Gall Bladder: small pouch on posterior
right median liver lobe; stores bile
SHARK RESPIRATORY
SYSTEM
I. Buccal Cavity: chamber of the mouth;
oxygen-rich water enters here to bath gills;
characterized by transverse folds.
II. Pharynx: chamber posterior to mouth;
gill chambers open from this; characterized by longitudinal folds.
A. Spiracle: located on each side of
anterolateral wall of pharynx;
homologous to first gill slit.
B. Internal Gill Slit: five pairs of elongated apertures located on lateral
pharyngeal wall; each opens into a gill
chamber.
CAT RESPIRATORY
SYSTEM
I. Larynx
cartilaginous structure at anterior end of
trachea; surround and protects glottis
A. True Vocal Cords: folds of elastic
tissue; as air is forced over them, they
vibrate to create sound
IV. Trachea and Bronchial Tree: branching
tubular system which conducts air into
lungs.
A. Trachea: long tube extending from
larynx to bronchi, just anterior to esophagus; supported by C-shaped
cartilages.
B. Bronchi: tubes leading into and
through each lung.
V. Lungs: organs where gas exchange occurs
A. Lobes: portions of each lung, separated from each other by fissures; left
lung has three lobe; right lung has four
lobes.
III. Gill Chamber: cavity lying between an
internal and external gill slit.
A. Gill Arch: main skeletal framework
of each gill.
1. Gill Rays: relatively long cartilaginous spines that support gill
filaments; projects posteriorly.
2. Gill Rakers: relatively short
cartilaginous spines from gill arch
that project toward pharynx.
B. Gill Filaments: thin folds projecting
from gill rays; these are primary
lamellae; projecting perpendicular-ly
are secondary lamellae, small closely
packed folds.
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