There are three pairs of salivary glands, which pour their
secretions into the mouth. They are
two parotid, two submandibular and
two sublingual.
Pharynx
It is divisible into three parts:
(i) Nasopharynx,
(ii) Oropharynx and
(iii) Laryngopharynx.
Only oropharynx and laryngopharynx are associated with
the alimentary tract.
Oesophagus
The oesophagus is the first part of the alimentary tract. It
is about 25 cm long and about 2 cm in diameter. It lies in
the median plane in the thorax in front of the vertebral
column behind the trachea and the heart.
Stomach
The stomach is continuous with the oesophagus at the
cardiac orifice and the duodenum at the pyloric
sphincter.
Small Intestine
The small intestine is continuous with the stomach at the
pyloric sphincter and leads into the large intestine at the
ileocaecal valve.
Cardiac orifice
Fundus
Oesophagus
Le
sser
curvat
ure Body
Rugae
Gre
ater
curvatu
re
Duodenum
Pyloric
sphincter
Pyloric antrum
Longitudinal section of the stomach
Oesophagus
Trachea
Aorta
L. bronchus
Diaphragm
End of
oesophagus
and beginning
of stomach
Aorta
R. bronchus
Inferior
vena
cava
T8
T10
T12
Oesophagus and some associated structures
Parotid gland and its duct
Muscles of
the cheek
Tongue
Opening of
submandibular duct
Sublingual gland
Ductules
Sternocleidomastoid muscle
B
A
A. The position of the salivary glands,
B. Enlargment of part of a gland
L. adrenal gland
Spleen
Splenic artery
Tail of pancreas
Body of
pancreas
L. kidney
Inferior
mesenteric artery
Descending colon
L. ureter
Aorta
Sup. mesenteric
artery and vein
Inf. vena
cava
R. ureter
Ascending
colon
Duodenum
Head of
pancreas
R. kidney
Common
bile duct
R. adrenal gland
Portal vein
Inferior
vena
cava
Common
hepatic
artery
The duodenum and its associated structures
Greenland sharks (Somniosus microcephalus) The
Greenland shark, an iconic species of the Arctic
Seas, can found from surface waters in shallow
estuaries and bays to depths of at least 4,000 feet
(1,200 m) in continental shelf and slope waters. The
species is one of the larger sharks and by far the
largest of Atlantic-Arctic and Antarctic fishes. The
life period of this shark is at least as long as
400 years.