Download Anterior Digestive Tract

Anterior part of the alimentary canal
1. Isthmus of the fauces
2. Tonsils
3. Salivary glands – minor and major
salivary glands
4. Pharynx
5. Esophagus
SPLANCHNOLOGY
Oropharyngeal isthmus
Isthmus of the fauces,
isthmus faucium (Lat. a vestibule
of an ancient Roman house):
palatine velum, velum palatinum
palatine uvula, uvula palatina
palatoglossal arch
palatopharyngeal arch
Prof. Dr. Nikolai Lazarov
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SPLANCHNOLOGY
Waldeyer’s ring
NALT – Nasal-Associated Lymphoid Tissue
Anulus lymphoides Waldeyeri:
von Waldeyer
(1836-1921)
lingual tonsil
pharyngeal tonsil
(tonsilla adenoidea)
tubal tonsils
palatine tonsils
Prof. Dr. Nikolai Lazarov
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SPLANCHNOLOGY
Lymphoid tissue – “lymphoepithelial organs”
MALT – Mucosa Associated Lymphatic Tissue
Prof. Dr. Nikolai Lazarov
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SPLANCHNOLOGY
Palatine tonsils, tonsillae palatinae
Macroscopic anatomy:
paired structures
egg-like shape – 25х15х20 mm
placed in triangular recess (tonsillar sinus)
supratonsillar fossa
plica semilunaris, plica triangularis
capsule, capsula tonsillae
Prof. Dr. Nikolai Lazarov
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SPLANCHNOLOGY
Palatine tonsils, tonsillae palatinae
Microscopic anatomy:
lamina epithelialis
stratified squamous epithelium
tonsillar crypts
lamina propria
desquamated epithelial cells
– loose connective tissue
lymphoid nodules
tela submucosa – capsule
trabeculae
lobules
Prof. Dr. Nikolai Lazarov
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SPLANCHNOLOGY
Blood vessels of palatine tonsils
Blood supply:
tonsillar branches of facial artery
ascending palatine artery
ascending pharyngeal artery
Venous drainage:
palatine vein, pharyngeal veins
facial vein
internal jugular vein
Lymphatic drainage:
submandibular nodes
lateral cervical nodes
Prof. Dr. Nikolai Lazarov
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SPLANCHNOLOGY
Salivary glands
Minor salivary glands, glandulae salivariae minores:
700-1000 minor glands
mixed (seromucous) glands
labial glands
buccal glands
molar glands
anterior linglual (Nuhn’s) glands
serous glands
gustatory (von Ebner’s) glands
mucous glands
palatine glands
posterior lingual (Weber’s) glands
produce only 5-8% of the total output
Prof. Dr. Nikolai Lazarov
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SPLANCHNOLOGY
Salivary glands
Major salivary glands, glandulae salivariae majores:
parotid gland,
glandula parotidea (parotis)
submanibular gland,
glandula submandibularis
sublingual gland,
glandula submandibularis
Prof. Dr. Nikolai Lazarov
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SPLANCHNOLOGY
Parotid gland, gl. parotidea
Macroscopic anatomy:
located subcutaneously
in the parotideomasseteric region
the largest salivary gland – 25-30 g
has own fascia, fascia parotidea
roughly wedge shaped and lobulated
superficial and deep lobes
internally:
Nicolas Steno
(Niels Stensen)
(1638-1686)
end branches of the external carotid artery
retromandibular vein
deep parotid lymphoid nodes
parotid plexus of facial nerve
auriculotemporal nerve (V3)
parotid duct (Stensen’s duct)
accessory parotid gland
Prof. Dr. Nikolai Lazarov
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SPLANCHNOLOGY
Parotid gland, gl. parotidea
Microscopic anatomy:
enclosed within a capsule
irregular, lobulated mass
a purely serous gland (watery secretion)
salivary ducts – mostly intercalated ducts
adipose tissue – fat cells
Prof. Dr. Nikolai Lazarov
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SPLANCHNOLOGY
Submandibular gland, gl. submandibularis
Macroscopic anatomy:
under the oral floor
in the submandibular trigone
weight – 15 g d=1.5-2 cm
(the size of a walnut);
U-shaped; smaller deep process
covered by fascia cervicalis superficialis
lobulated structure – 8-10 lobes
three surfaces
submandibular (Wharton’s) duct
– 5-6 cm
caruncula sublingualis
blood supply – facial and lingual arteries
lymphatic drainage – submandibular nodes
innervation – intermediate nerve, superior cervical ganglion
Prof. Dr. Nikolai Lazarov
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SPLANCHNOLOGY
Submandibular gland, gl. submandibularis
Microscopic anatomy:
enclosed within a capsule, lobulated
mixed (seromucous) gland
with predominant serous acini –
Giannuzzi’s demilunes or
Heidenhain crescents
duct system – mostly striated ducts
Prof. Dr. Nikolai Lazarov
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SPLANCHNOLOGY
Sublingual gland, gl. sublingualis
Macroscopic anatomy:
along the sublingual fold, plica sublingualis
the smallest one weight – 3-5 g
flattened, almond-shaped
covered by a thin capsule
lobulated mass – 4-16 lobules
a group of 30-50 single glands:
anterior 10-20 – major sublingual gland
major sublingual duct caruncula sublingualis
smaller sublingual ducts
sublingual fold
blood supply – sublingual artery
venous drainage – internal jugular vein
lymphatic drainage – submandibular nodes
innervation – intermediate nerve,
superior cervical ganglion
Prof. Dr. Nikolai Lazarov
14
SPLANCHNOLOGY
Sublingual gland, gl. sublingualis
Microscopic anatomy:
surrounded by a dense capsule, lobulated
predominantly tubulo-alveolar (acinar) gland
mixed (seromucous) gland consisting mostly
of mucous (60%) acini – minor sublingual glands;
serous caps, demilunes (30% of total gland volume)
excretory ducts – 8-20 in number
Prof. Dr. Nikolai Lazarov
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SPLANCHNOLOGY
Throat, pharynx
part of the digestive and
the respiratory systems
the common channel for
deglutition (swallowing)
and respiration
important also in vocalization
musculomembranous
cone-shaped tube:
height – 12-15 cm
diameter –
upper part: 3.5 cm
lower part: 1.5 cm
Prof. Dr. Nikolai Lazarov
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SPLANCHNOLOGY
Topography
base
of skull
6th cervical
vertebra
nasal cavity
oral cavity
larynx
cervical fascia (prevetrebral layer)
retropharyngeal space
posterior mediastinum
lateral:
cervical lymph nodes
neurovascular bundle
Prof. Dr. Nikolai Lazarov
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SPLANCHNOLOGY
Topography
base
of skull
6th cervical
vertebra
nasal cavity
oral cavity
larynx
cervical fascia (prevetrebral layer)
retropharyngeal space
posterior mediastinum
lateral:
cervical lymph nodes
neurovascular bundle
Prof. Dr. Nikolai Lazarov
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SPLANCHNOLOGY
Macroscopic anatomy
upper (nasal) part
middle (oral) part
lower (laryngeal) part
Prof. Dr. Nikolai Lazarov
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SPLANCHNOLOGY
Nasal part of the pharynx
synonyms: nasopharynx, epipharynx
anterior boundary:
nasal conchae
lateral wall:
pharyngeal opening
of the auditory tube
cranial boundary:
pharyngeal fornix – pharyngeal tonsil (adenoides)
Prof. Dr. Nikolai Lazarov
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SPLANCHNOLOGY
Oral part of the pharynx
synonyms: oropharynx,
mesopharynx
anterior boundary:
palatopharyngeal arch
palatoglossal arch
cranial boundary:
velum palatinum
caudal boundary:
upper part of the epiglottis –
epiglottic vallecula
Prof. Dr. Nikolai Lazarov
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SPLANCHNOLOGY
Laryngeal part of the pharynx
synonyms : laryngopharynx,
hypopharynx
cranial boundary:
ventral boundary:
epiglottis
aditus laryngis
dorsal boundary:
constrictio
pharyngoesophagealis
Prof. Dr. Nikolai Lazarov
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SPLANCHNOLOGY
Histological structure
Lamina epithelialis:
stratified squamous
non-keratinizing epithelium,
excl. the nasal part –
pseudostratified ciliated
columnar epithelium with
goblet cells
Lamina propria:
a high density of fibrillar elements
fibrous membrane
rich in elastic fibers
elastic membrane
contains glands:
nasal part – seromucous glands
oral and laryngeal parts –
mucous (pharyngeal) glands
Tela submucosa:
in the lateral walls of the nasal part
close to the esophagus
Prof. Dr. Nikolai Lazarov
23
SPLANCHNOLOGY
Pharyngeal musculature
striated muscles:
origin – pharyngeal arches
tunica muscularis pharyngis:
internal longitudinal layer
external circular layer
two functional groups:
three pharyngeal constrictors
two longitudinal elevators
Prof. Dr. Nikolai Lazarov
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SPLANCHNOLOGY
Vessels of the pharynx
Arterial blood supply:
a.
a.
a.
a.
a.
a.
thyroidea superior
palatina descendens
palatina ascendens
facialis – ramus tonsillaris
thyroidea inferior
pharyngea ascendens
Venous drainage:
plexus venosus pharyngeus
vv. pharyngeales
into the v. jugularis interna
Lymphatic drainage:
retropharyngeal lymph nodes
deep cervical lymph nodes
Prof. Dr. Nikolai Lazarov
25
SPLANCHNOLOGY
Innervation of the pharynx
Somatosensory innervation:
trigeminal nerve
Pharyngeal plexus:
motor, sensory and
parasympathetic innervation:
vagus nerve
glossopharyngeal nerve
sympathetic innervation:
superior cervical ganglion
of the trunk sympathetic
Prof. Dr. Nikolai Lazarov
26
SPLANCHNOLOGY
The gullet, oesophagus
Straight muscular tube
about 25-30 cm long –
to carry food, liquids,
and saliva from the
mouth to the stomach:
begins in the neck
at the level of C6
passes through the
thoracic cavity and
pierces the diaphragm
at the Th10 level
ends at the cardiac
orifice of the stomach
at the Th11 level
Prof. Dr. Nikolai Lazarov
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SPLANCHNOLOGY
Macroscopic anatomy
Three anatomical parts:
cervical part – 5-6 cm
thoracic part – 16-19 cm
abdominal part – 1-4 cm
Prof. Dr. Nikolai Lazarov
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SPLANCHNOLOGY
Anatomical constrictions
Three anatomical constrictions:
pharyngeal – 15 cm from the incisor teeth
bronchial – 24 cm from the incisors
diaphragmatic – 40 cm from the incisors
NB:The sites of these constrictions are clinically
important in connection with the passage of
instruments along the esophagus – gastroscopy!
Prof. Dr. Nikolai Lazarov
29
SPLANCHNOLOGY
Physiological constrictions
Two physiological constrictions –
formed by contraction of its musculature
1. Aortal constriction –
where esophagus is crossed by
the aortic arch
2. Cardiac sphincter – just before
entering the stomach cardia
Prof. Dr. Nikolai Lazarov
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SPLANCHNOLOGY
The closing mechanism between
the stomach and esophagus
2.
1.
submucosal venous plexus
contraction of the
spiral musculature
esophagitis
3.
elastic nature of the
phrenoesophageal ligament
esophagitis
4.
a pressure difference between
the abdominal and thoracic cavities
Clinical significance: insufficient closing mechanism –
gastroesophageal (acid) reflux disease → heartburn
Prof. Dr. Nikolai Lazarov
31
SPLANCHNOLOGY
Histological structure
Lamina epithelialis mucosae:
multilayered (20-24 cell layers)
nonkeratinizing squamous epithelium
no distinct border at the transition into
the stomach – intestinal metaplasia
(columnar epithelium)
Barrett oesophagus
Lamina propria mucosae:
collagen and elastic fibers
esophageal cardiac glands
venous plexus
lymphatic nodules
Lamina muscularis mucosae:
longitudinally organized smooth muscle
Prof. Dr. Nikolai Lazarov
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SPLANCHNOLOGY
Histological structure
Tela submucosa:
wide layer with longitudinal folds
contains esophageal glands proper
submucosal (Meissner’s) plexus
Tunica muscularis – transition zone:
inner circular layer (stratum circulare)
outer longitudinal layer (stratum longitudinale)
between them myenteric (Auerbach’s) plexus
Tunica adventitia:
loose, fibrous connective tissue
Clinical significance: muscular weakness
esophageal diverticula!
Prof. Dr. Nikolai Lazarov
33
SPLANCHNOLOGY
Vessels of the esophagus
Blood supply – esophageal branches:
cervical part: inferior thyroid artery
thoracic part: aorta, intercostal arteries
abdominal part: left gastric artery
Venous drainage:
brachiocephalic vein
azygos vein
hemiazygos vein
hepatic portal vein
drain into the:
superior vena cava
inferior vena cava
portal vein
Clinical significance: portal hypertension
esophageal varices!
Prof. Dr. Nikolai Lazarov
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SPLANCHNOLOGY
Innervation of the esophagus
motor, sensory and parasympathetic innervation:
vagus nerve
vagal trunks
sympathetic innervation:
sympathetic trunk
Prof. Dr. Nikolai Lazarov
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SPLANCHNOLOGY
Thank you ...
Prof. Dr. Nikolai Lazarov
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