Lymph
Lymph
Lymph
Lymph : a transparent, usually slightly yellow, liquid found within the lymphatic
vessels, collected from the tissue and has the same constituents as blood plasma.
Lymphatic System
Lymphatic vessels.
Lymph nodes.
Lymphatic organs.
Functions
1.To return excessive tissue fluid from the
interstitial fluid to the blood.
2.return leaked proteins to the blood
3.To transport fat absorbed from the GIT to the
blood.
4. defend the body
5. Hemopoiesis, production of cells like
lymphocytes and monocytes.
• The lymphatic vessels collect tissue fluid and transport it to the
bloodstream.
• Tissue fluid arises from blood filtered through the capillary walls
and consists of the small molecules of blood plasma, including
water, various ions, nutrient molecules, and respiratory gases
• The lymphatic vessels function to collect excess tissue fluid from
the loose connective tissue around blood capillaries and return it to
the bloodstream.
• Once inside the lymphatic vessels, this fluid is called lymph.
Because lymph flows only toward the heart, the lymphatic vessels
form a one-way system.
orders of lymphatic vessels;
lymphatic capillaries- lymphatic collecting vessels, along which are
scattered lymph nodes - lymph trunks- lymph ducts - veins.
1. Lymphatic capillaries,
• highly permeable vessels that collect the excess tissue fluid,
• located near blood capillaries in the loose connective tissue
• Once this fluid enters the lymphatic capillaries, it is called lymph.
• Lymph cannot leak out of the lymphatic capillary because
backflow forces the minivalve flaps together.
Lacteals= lymphatic capillaries located in small intestine
absorb digested fats from the intestine, which causes the
lymph draining from the digestive viscera to become milky white
(chyle)
2. Lymphatic collecting vessels
superficial lymphatic collecting vessels in the skin travel with
superficial veins,
deep lymphatic collecting vessels of the trunk and digestive viscera
travel with the deep arteries
They have the same tunics as blood vessels but their walls are always
much thinner.
To direct the flow of lymph, lymphatic collecting vessels contain more
valves than do veins
contracting skeletal muscles and the pulsations of nearby arteries push
on the lymphatic vessels, squeezing lymph through them
the muscular tunica media of the lymphatic vessels contracts to help
propel the lymph.
3. Lymph nodes
• cleanse the lymph of pathogens
• are bean-shaped organs situated along lymphatic collecting vessels
• The node is surrounded by a fibrous capsule of dense connective
tissue, from which fibrous strands called trabeculae extend inward
to divide the node into compartments.
• Lymph enters the convex aspect of the node through several
afferent lymphatic vessels
• and exits from the indented region on the other side, the hilum
through efferent lymphatic vessels.
4. Lymph trunks
•After leaving the lymph nodes, the largest lymphatic collecting vessels
converge to form lymph trunks.
•The five major lymph trunks, from inferior to superior
1. Lumbar trunks.
paired trunks,
lie along the sides of the aorta in the inferior abdomen
receive all lymph draining from the lower limbs, the pelvic organs, and
from some of the anterior abdominal wall.
2. Intestinal trunk.
unpaired trunk,
lies near the posterior abdominal wall in the midline,
receives fatty lymph (chyle) from the stomach, intestines.
3. Bronchomediastinal trunks.
Ascending near the sides of the trachea,
paired trunks
collect lymph from the thoracic viscera and thoracic wall.
4. Subclavian trunks.
Located near the base of the neck,
paired trunks
receive lymph from the upper limbs; inferior neck and the
superior thoracic wall.
5. Jugular trunks.
Located at the base of each internal jugular vein,
paired trunks drain lymph from the head and neck.
5. Lymph duct
The lymph trunks drain into the largest lymphatic vessels, the lymph ducts.
have two lymph ducts
1.Thoracic duct
its most inferior part, located at the union of the lumbar and intestinal trunks,
is the cisterna chyli (lies on the bodies of vertebrae L1 and L2)
From there, the thoracic duct ascends along the vertebral bodies.
In the superior thorax, it turns left and empties into the venous circulation at
the junction of the left internal jugular and left subclavian veins.
the thoracic duct is often joined by the left jugular, subclavian, and/or
bronchomediastinal trunks just before it joins with the venous circulation.
• When it is joined by the three trunks, the thoracic duct drains three-quarters
of the body:
the left side of the head, neck, and thorax; the left upper limb; and the
body’s entire lower half
2. Right lymphatic duct.
The upper right quadrant of the body is drained by the right jugular,
subclavian, and bronchomediastinal trunks.
In about 20% of people, these ducts join to form a short right lymphatic duct.
When present, this duct empties into the neck veins at or near the junction of
the right internal jugular and subclavian veins
Lymph organ