Cardiac lymphatic capillaries form complicated networks with ramifications and anastomosis13 and can be found in subepicardium, myocardium, and subendocardium. The direction of lymphatic drainage is from subendocardial lymphatics toward the subepicardial lymphatics, eventually leading to the mediastinal lymph nodes. Fluid that is forced out of the bloodstream during normal circulation is filtered through lymph nodes to remove bacteria, abnormal cells and other matter. This fluid is then transported back into the bloodstream via the lymph vessels. Lymph only moves in one direction, toward the heart. The lymphatic plexus in the epicardium is characterized by the presence of thinner initial lymphatics or capillaries consisting of a single layer of lymphatic endothelial cells (LECs). These highly permeable vessels are critical to drain macromolecules, extracellular fluid, and cells (lymph). The biochemical make up of lymph — the fluid found in the lymphatic vessels — varies with the site of origin. For example, lymph from bone marrow, spleen, and thymus have high concentrations of white blood cells for fighting infection, while lymph from intestines is high in fat that has been absorbed during digestion. Damage to the lymphatic and circulatory systems leaves the body more susceptible to sickness and infection, as well as to serious conditions such as cancer. As most of the cells in the human body are not in direct contact with the external environment, the circulatory system acts as a transport system for these cells. Two distinct fluids move through the circulatory system: blood and lymph. Blood carries oxygen and nutrients to the body's cells, and carries waste materials away. Blood also carries hormones, which control body processes, and antibodies, to fight invading germs. The heart is the pump that keeps this transport system moving. Together, the blood, heart, and blood vessels form the circulatory system.
The lymphatic system (lymph, lymph nodes and lymph vessels) supports the circulatory system by draining excess fluids and proteins from tissues back into the bloodstream, thereby preventing tissue swelling. It also serves as a defense system for the body, filtering out organisms that cause disease, producing white blood cells, and generating antibodies. The mammalian circulatory system comprises both the cardiovascular system and the lymphatic system. In contrast to the blood vascular circulation, the lymphatic system forms a unidirectional transit pathway from the extracellular space to the venous system. It actively regulates tissue fluid homeostasis, absorption of gastrointestinal lipids, and trafficking of antigen-presenting cells and lymphocytes to lymphoid organs and on to the systemic circulation. The cardinal manifestation of lymphatic malfunction is lymphedema. Recent research has implicated the lymphatic system in the pathogenesis of cardiovascular diseases including obesity and metabolic disease, dyslipidemia, inflammation.
4. Essentially a
drainage system
accessory to venous
system
larger particles that escape
into tissue fluid can only be
removed via lymphatic
system
LYMPHATIC SYSTE
5. Functions of the Lymphatic
System
24-
5
Reabsorbs excess interstitial fluid:
returns it to the venous circulation
maintain blood volume levels
prevent interstitial fluid levels from rising out of
control.
Transport dietary lipids:
transported through lacteals
drain into larger lymphatic vessels
eventually into the bloodstream.
lymphocyte development, and the immune
8. Lymphatic Capillaries
24-
8
Features of structure:
Blind end
Single layer of overlapping
endothelial cells
More permeable than that of
blood capillary
Absent from avascular
structures, brain, spinal cord
splenic pulp and bone
marrow
9. Lymphatic Capillaries – Lacteals
The small intestine contains special
types of lymphatic capillaries called
lacteals.
Lacteals pick up not only interstitial
fluid, but also dietary lipids and lipid-
soluble vitamins.
The lymph of this area has a milky
color due to the lipid and is also called
10. Lymphatic Vessels
Features of
structure
Three layered wall
but thinner than vein,
More numerous
valves than in vein
Interposed by lymph
nodes at intervals
Arranged in
superficial and deep
11. LYMPH TRUNKS
right and left jugular trunks
right and left subclavian
trunks
right and left
bronchomediastinal trunks
right and left lumbar trunks
12. LYMPHATIC DUCTS
24-
12
Right lymphatic duct
Formed by union of
right jugular,
subclavian, and
bronchomediastinal
trunks
Ends by entering the
right venous angle
13. Thoracic duct
Begins in front of L1 as a
dilated sac, the cisterna
chyli,
formed by left and right
lumbar trunks and
intestinal trunk
Enter thoracic cavity &
ascends
Travels upward, veering
LYMPHATIC
DUCTS
14. 14
THORACIC DUCT…..
At the root of the neck,
it turns laterally
arches forwards and
descends to enter the
left venous angle
before termination, it
receives the left
jugular, Subclavian
and broncho-
mediastinal trunk
15. DRAINAGE PATTERN
THORACIC DUCT -
Drains lymph from lower
limbs, pelvic cavity,
abdominal cavity, left
side of thorax, and left
side of the head, neck
RIGHT LYMPHATIC DUCT
-Receives lymph from
right half of head, neck,
thorax and right upper
limb, right lung, right side
of heart, right surface of
liver
16. Lymphatic Cells
24-
16
Also called lymphoid cells.
Located in both the lymphatic system
and the cardiovascular system.
Work together to elicit an immune
response.
Types of lymphatic cells are:
macrophages
epithelial cells
dendritic cells
lymphocytes
18. Lymph
Nodes
24-
18 Small, round or oval
located along the
pathways of lymph
vessels.
length from 1 - 25
millimeters
Typically found in
clusters
receive lymph from
many body regions.
Lymph nodes are also
19. LYMPHEDEMA
Occurs due to
accumulation of
lymphatic fluid in
the interstitial tissue
Sometimes can be
appreciated after
wearing tight
clothing or jewellary
on affected limb
20. LYMPHADENOPATHY
Means a disease
of the lymph
nodes
Lymph nodes
become swollen/
enlarged and may
be painful to touch
22. TONSILLITIS
Infection of the
pharyngeal tonsils
Tonsils are swollen,
Fever and pain
during swallowing
usually present
Treatment –
surgical removal of
tonsils
(TONSILLECTOMY)
25. Myocardial contractions help to propel cardiac
lymphatic flow
During diastole, when the heart muscle relaxes,
the ventricles fill with blood, and the resultant
increase in chamber pressure drives the flow of
lymph from the subendocardial to the
myocardial lymphatics
Subsequently, during systole, ventricular
contraction supplies the necessary force to
propel lymph from the myocardial to the
subepicardial lymphatics 4/14/2024
26. If flow rate becomes reduced-> increased
myocardial interstitial edema.
Cardiac surgery often produces damage to the
lymphatic vasculature that can lead to acute or
occasionally chronic edema.
Acute cardiac lymphatic obstruction causes
interstitial myocardial edema, which in turn
degrades ventricle performance, characterized
by decreased contractility and increased
diastolic stiffness
4/14/2024
28. I am a part of lymphatic system and protect
the body by clearing worn out red cells and
foreign bodies from the blood stream. Who
am I?
A. Thymus
B. Palatine
Tonsil
C. Spleen
QUESTION. 1
29. Which is the correct statement about the
Lymphatic system?
A. It Reabsorbs excess interstitial fluid and
returns it to the venous circulation.
B. Transports dietary lipids through lacteals.
C. Helps in lymphocyte development, and the
immune response.
D. All of the above
QUESTION. 2
30. Which disease caused by
mosquito bite blocks the
lymphatic drainage causing
huge swelling of body parts
(commonly lower limb)
A. Malaria
B. Filaria
C. Dengue
D. Yellow fever
QUESTION. 3
