Download Lymphatic System

The Lymphatic System
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The lymphatic system – an overview
Structure of the lymphatic vessels
The major lymphatic vessels
Structure of lymph nodes
Regional lymph nodes
Hematopoietic and lymphopoietic organs
The lymphatic system
The lymphatic system, systema lymphaticum:
integral part
of the circulatory system
synonym: immune system –
provides the immune response
composed of:
lymph vessels – lymph
lymph organs
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The lymphatic system
lymph vessels and nodes
hemopoietic and lymphatic organs
central lymphoid tissue
peripheral lymphoid tissue
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Structural plan of lymph vessels
Lymphatic capillaries:
single layer of endothelium
incomplete basal lamina, no pericytes
Small lymphatic vessels:
presence of internal valves
elastic and collagen fibers
around the endothelium
single muscle cells
Large lymphatic vessels >0.2 mm
tunica intima
endothelium
longitudinal elastic fibers
tunica media
1-3 layers of muscle cells
tunica adventitia
collagen and elastic fibers
longitudinal muscle cells
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Lymphatic vessels, vasa lymphatica
The major lymphatic vessels:
lymph ducts, ducti lymphatici
lymph trunks, trunci lymphatici
The lymphatic capillaries
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The lymph trunks
Unpaired lymph trunks:
intestinal trunk,
truncus intestinalis
Paired lymph trunks:
lumbar trunk, truncus lumbalis
bronchomediastinal trunk,
truncus bronchomediastinalis
subclavian trunk,
truncus subclavius
jugular trunk, truncus jugularis
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The cisterna chyli
angulus venosus sinister
ductus thoracicus
cisterna chyli – Th11-L2
truncus intestinalis
trunci lumbales
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The main lymphatic vessels
The thoracic duct, ductus thoracicus
angulus venosus sinister:
length 38-45 cm;
diameter 5 mm
passes through hiatus aorticus
before opening it joints:
truncus subclavius sinister
truncus jugularis sinister
truncus bronchomediastinalis sinister
collects the lymph from the:
left side of the head and neck
left upper limb
left half of the thoracic cavity
organs in abdominal cavity and its wall
pelvis
lower limbs
rich in valves
well-developed smooth musculature
own blood vessels
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The main lymphatic vessels
The right lymphatic duct,
ductus lymphaticus dexter
angulus venosus dexter
(v. subclavia dextra) – variable:
length 10-12 mm;
diameter 2 mm
has two valves at its orifice
before opening it joints:
truncus subclavius dexter
truncus jugularis dexter
truncus bronchomediastinalis dexter
collects the lymph from the:
right side of the head and neck
right upper limb
right half of the thoracic cavity
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Structure of lymph nodes
The lymph nodes, nodi lymphatici (lymphonodi):
in groups or rows along the lymphatic vessels
regional lymph nodes
Major functions:
mechanical filters of the lymph
phagocytosis
production of antibodies
house Т-lymphocytes
lymphopoiesis
Morphological characteristics:
size –2-20 mm
shape – highly variable,
usually ovoid or bean-shaped
Macroscopic anatomy:
the capsule, capsula
trabeculae
hilum
vasa lymphatica afferentia
vasa lymphatica efferentia
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Microscopic anatomy
Histological structure:
reticular supporting elements
reticular (collagen type ІІІ) fibers
reticulum cells – fibroblasts
macrophages
dendritic cells – antigen-presenting cells
follicular dendritic cells
The parenchyma of the lymph node
– three zones:
the cortex, cortex
paracortical region, paracortex
inner medulla, medulla
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Microscopic structure
The cortex, cortex –
B-cell zone:
lymphatic follicles with or
without germinal centers
arranged in layers
The paracortical zone,
paracortex, deep cortex
– thymus-dependent zone:
Langerhans cells
dendritic cells
high endothelial venules
Medullary region, medulla:
anastomosing cords
of lymphoid tissue
B-lymphocytes
plasma cells
T-lymphocytes
macrophages
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Microscopic structure
Lymphatic sinuses:
marginal (subcapsular) sinuses,
sinus subcapsulares
afferent lymph vessels
intermediary (cortical) sinuses,
sinus corticales perinodulares
medullary sinuses, sinus medullares
hilar sinuses
afferent lymph vessels
Sinus wall:
mantle (littoral)
cells – role of
endothelial macrophages
Sinus spaces:
free macrophages
lymphocytes
monocytes
plasma cells
The angioarchitectonics
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The lymphatic drainage
of the head and neck
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The lymph nodes of the head
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Lymphatic drainage of the neck
The lymph nodes of the neck:
nodi supraclaviculares
nodi cervicales
anteriores:
superificial
deep
• pharynx,
larynx,
thyroid gland
nodi cervicales
laterales:
superficial
deep:
• nodus
jugulodigastricus
• nodus juguloomohyoideus
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The lymphatic drainage
of the upper limbs
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The lymph nodes
of the upper limb
Nodi lymphoidei cubitales:
1-3 isolated nodes:
around the large blood vessels
subcutaneously above
the medial epicondyle
Nodi lymphoidei axillares:
five groups (15-40):
apical group: 6-10
central group: 4-6
lateral group: 3-8
pectoral group: 3-8
subscapular group: 3-6
subcutaneously, subfascially
around the blood vessels
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The lymphatic drainage
of the upper limb
Superficial vessels:
internal group:
along the basilic vein
nodi lymphoidei cubitales
external group:
run parallel
with the cephalic vein
nodi lymphoidei axillares
Deep vessels – along the course
of the large arterial vessels:
radial artery
ulnar artery
cubital lymph nodes
brachial artery
axillary lymph nodes
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The lymphatic drainage
of the thorax
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The lymph nodes
of the thoracic wall
and deeper tissues
The parietal lymph nodes:
nodi parasternales
nodi intercostales
The visceral lymph nodes:
nodi
nodi
nodi
nodi
nodi
nodi
intrapulmonales
bronchopulmonares
tracheobronchiales
paratracheales
juxtaesophageales
prepericardiaci
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The lymphatic drainage
of the abdomen
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The parietal lymph nodes
The lumbar (pre-aortic, lateral aortic – right and left, and retro-aortic)
lymph nodes (nodi lumbales):
30-50 lymph nodes
around the abdominal aorta
and the inferior vena cava
The common iliac lymph nodes
(nodi iliaci communes)
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The visceral lymph nodes
the coeliac lymph nodes, nodi coeliaci
the gastric lymph nodes:
nodi gastrici dextri
nodi gastrici sinistri
nodi pylorici
the hepatic and cystic lymph nodes
the pancreaticosplenic lymph nodes
– 15-20 small nodes
the lymph nodes
of the colon:
four groups
along the vessels
the lymph nodes
of the mesentery:
150-200 (300) nodes
hilar nodes –
in the mesentery
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The lymphatic drainage
of the pelvis
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The lymph nodes of the pelvis
the
the
the
the
external iliac lymph nodes
internal iliac nodes: 9-12
sacral lymph nodes
anorectal lymph nodes
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The lymphatic drainage
of the lower limbs
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The lymphatic vessels
of the lower limb
The superficial lymph vessels:
the vessels of
the medial group:
along the great saphenous vein
the superficial inguinal
lymph nodes – 12-16 nodes
the vessels of
the postero-lateral group
run parallel to
the small saphenous vein
end in the popliteal lymph nodes
The deep lymph vessels –
accompany the main blood
vessels of the limb:
anterior tibial artery
posterior tibial artery
popliteal lymph nodes
femoral artery and vein
deep inguinal lymph nodes
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The lymph nodes
of the lower limb
Nodi inguinales superficiales:
12-16: around hiatus saphenus
parallel to the inguinal fold
Nodi inguinales profundi:
3-5 nodes: in fossa ileopectinea
over the femoral vein
Nodi poplitei:
4-6 nodes: in fossa politea
around the popliteal artery
and vein
Nodus tibialis anterior:
over membrana interossea cruris
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Lymph node
inflammation sites
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The cardinal signs of inflammation
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Clinical manifestations
lymphadenitis
lymphangitis
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The lymphoid organs
The lymphopoietic organs, organa lymphopoetica:
primary lymphatic organs:
bone marrow
thymus
secondary lymphatic organs:
lymph nodes
spleen
diffuse lymphoid tissue, tonsils,
MALT, GALT and BALT
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Hematopoietic organs
The bone marrow, medulla ossium:
red bone marrow,
medulla ossium rubra –
epiphyses of the long bones,
spongy bone of the short
and flat bones, ~ 1500 g
haematopoiesis
biological defense
yellow (fatty) bone marrow,
medulla ossium flava –
medullary canal of long bones
a reserve haematopoietic organ
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The red bone marrow
Microscopic structure:
connective tissue stroma
reticular fibers
adventitial (reticular) cells
macrophages
lipocytes (adipocytes)
osteoblasts
marrow parenchyme – stem cells
erythroblasts
myeloblasts and
myelocytes
megakaryocytes
venous sinusoids
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The thymus, thymus
The thymus, thymus
(Gr. θύμος, θυμάρι, the herb thyme):
differentiation of T-lymphocytes
a true endocrine gland
Embryonic origin:
endodermal derivative
3rd & 4th pharyngeal pouches
Postnatal growth:
maximum relative weight – 2 years
slow age involution after puberty
residual thymus in the elderly
adipose thymus organ
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Thymus location
Location and somatotopy:
in anterior mediastinum –
trigonum thymicum
behind sternum,
anterior to the heart and
great vessels
External appearance:
right and left lobes
shape – variable, an irregular cone
weight ~15 g (at birth); 20-40 g (at puberty)
size at birth:
length 5 mm
width 4 mm
thickness 6 mm
color:
in children – pinkish grey
in adults – yellowish
soft and finely lobulated
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Structure of the thymus
Macroscopic anatomy:
thin connective tissue capsule
trabeculae (septa), septa interlobularia
pseudolobular structure, lobuli thymi
The structure of a thymus lobule:
peripheral cortex, cortex thymi
central medulla, medulla thymi
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Microscopic anatomy
Histological structure:
cortex – darkly stained,
densely cellular:
does not possess
lymphoid nodules
rich in compact
lymphoid tissue
• small lymphocytes,
thymocytes (Т-lymphocyte
precursors)
• epithelial reticular
cells
• thymic nurse cells
• macrophages
reticular fibers not present
medulla – lightly stained
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Microscopic anatomy
Histological structure:
thymic medulla:
epithelial reticular cells
antigen-presenting
large dendritic cells
differentiated Т-lymphocytes
• immunocompetent Т-lymphocytes
• Т-helpers – humoral immunity
• Т-killers – cell-mediated immunity
• suppressor Т
amplifier Т cells
thymic (Hassall) corpuscles
• epithelial reticular cells
in degeneration
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The spleen, splen
The spleen, splen (Lat. lien):
the largest lymphoid organ
in the human body
an unpaired organ of the
immune and circulatory systems
Location in abdomen:
in left upper part of abdominal cavity
between the 9th and 11th ribs
longitudinal axis follows the 10th rib
Main functions:
immunological protection – role
in the production of antibodies
production of
activated lymphocytes
destruction of erythrocytes
and platelets (thrombocytes)
mechanical blood filtration
reservoir of blood
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Macroscopic anatomy
External features:
typically coffee bean shaped
weight 150-200 g
the size of a clenched fist
length ~11 cm
width 6-8 cm
thickness up to 4 cm
color – reddish purple; soft tissue
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Macroscopic anatomy
General structure:
anterior extremity
posterior extremity
superior border
inferior border
diaphragmatic surface
– convex and smooth
visceral surface
splenic (lienal) hilum
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splenic artery and vein
efferent lymphatic vessels
postgangionic sympathetic fibers
gastric impression
colic impression
pancreatic impression
renal impression
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Microscopic anatomy
Histological structure:
serous coat, tunica serosa
gastrosplenic ligament
phrenicosplenic ligament
fibro-elastic coat (capsule),
tunica fibrosa
splenic trabeculae
collagenous fibrous tissue,
abundant elastic fibers and
a few myofibroblasts
the trabecular blood vessels
The parenchyme, pulpa splenica:
white pulp, pulpa alba
red pulp, pulpa rubra
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Histological structure
The white pulp, pulpa alba:
compact lymphoid tissue
folliculi lymphatici splenici,
splenic lymph follicles
(Malpighian corpuscles)
– rich in В-lymphocytes
Periarterial Lymphatic Sheath
(PALS) – Т-cell region
marginal zone – sinusoids
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Histological structure
The red pulp, pulpa rubra:
splenic or venous sinuses (sinusoids)
endotheliocyti fusiformes – 2-3 µm gaps
fibrae reticulares annulares
afferent and efferent sphincters
splenic cords (of Billroth),
chordae splenicae
loose meshwork of reticular fibers
reticular cells, Т- and В-lymphocytes,
macrophages, plasma cells and
numerous blood cells (Er, Leu and Thr)
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Histological structure
The red pulp, pulpa rubra:
splenic or venous sinuses (sinusoids)
endotheliocyti fusiformes – 2-3 µm gaps
fibrae reticulares annulares
afferent and efferent sphincters
splenic cords (of Billroth),
chordae splenicae
loose meshwork of reticular fibers
reticular cells, Т- and В-lymphocytes,
macrophages, plasma cells and
numerous blood cells (Er, Leu and Thr)
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