Lymphatic system

1. Lymphatic System
ISRAR HUSSAIN YOUSAFZAI
BS (ANESTHESIA) PGRT MSPH
SR. RT, HMC PESHAWAR

2. Introduction
 A closed system of lymph channels
or lymph vessels, through which
lymph flows
 It is a one-way system and allows
the lymph flow from tissue spaces
toward the blood
 Arises from tissue spaces as a
meshwork of delicate vessels called
lymph capillaries

3. Lymph Capillaries
 Starts from tissue spaces as enlarged terminals called capillary
bulbs
 These bulbs contain valves, which allow flow of lymph in only one
direction
 There are some muscle fibers around these bulbs which pushed
the lymph by contraction
 Lymph capillaries are more porous to allows the fluid to move
back and forth
 Capillaries unite to form large lymphatic vessels

4. Drainage
 Lymphatic vessels become larger and
larger along their course and form the
right lymphatic and thoracic duct
 Right lymphatic duct opens into right
subclavian vein
 Thoracic duct opens into left subclavian
vein
 Thoracic duct drains the lymph from more
than 2/3 of the tissue spaces in the body

5. Locations
Present
1. Deeper layers of skin
2. Subcutaneous tissues
3. Diaphragm
4. Wall of abdominal cavity
5. All tracts
6. Liver
7. Heart
Absent
1. Superficial layers of skin
2. Central nervous system
3. Cornea
4. Bones
5. Alveoli

6. Functions of the Lymphatic System
1. The removal of excess fluids from body tissues
2. Absorption of fatty acids and subsequent transport of fat, chyle,
to the circulatory system
3. Production of immune cells such as lymphocytes, monocytes
and plasma cells

7. Lymph Nodes
 Small glandular structures located in the course of lymph vessels
 Also called lymph glands
 Each node is covered by a dense connective tissue capsule
 The structures are arranged in three layers
 Cortex
 Para cortex
 Medulla

8. Cont’d….
1. Cortex
 Consists of primary and secondary lymphoid follicles
 When some antigens enter the body and reach the lymph nodes, the
cells of primary follicle proliferate
 After proliferation, primary follicles become the secondary follicle
 Cortex also contains some B lymphocytes and macrophage
2. Para cortex
 Present in between the cortex and medulla, and contains T
lymphocytes
3. Medulla
 Medulla contains B and T lymphocytes, and macrophages

9. Cont’d….
 Lymph node receives lymph by
one or two lymphatic vessels
called afferent vessels
 It divide into small channels
 Lymph passes through these
vessels and reaches the cortex
 It circulates through out the lymph
node and leaves the node via one
or two efferent vessels

10. Locations
 Lymph nodes are present along the
course of lymphatic vessels in:
 Elbow
 Axilla
 knee
 Breast
 Groin
 Neck

11. Functions of Lymph Nodes
 When lymph passes through the lymph nodes, it remove water
and electrolytes
 But, the proteins and lipids are retained in the lymph
 Bacteria and other toxic substances are destroyed by
macrophages
 Because of this, lymph nodes are called defense barriers

12. Lymph
 When blood passes via blood capillaries in the tissues, 9/10th of
fluid passes into venous end
 1/10th of the fluid passes into lymph capillaries, which have more
permeability than blood capillaries
 Proteins present in the interstitial fluid cannot enter the blood
capillaries, so enter the lymph vessels
 When the lymph passes through the lymph nodes, it is
concentrated due to absorption of water and electrolytes
 About 120mL/hr of lymph flow into blood (100 thoracic and 20
right lymphatic duct)

14. Functions of Lymph
 Return the proteins from tissue spaces into blood
 Redistribution of fluid in the body
 Bacteria, toxins and other foreign bodies are removed from
tissues
 Intestinal fat absorption. This is why lymph appears milky after a
fatty meal
 Immunity by transport of lymphocytes

15. Lymphatic Organs
Assignment+Presentation
1. Spleen (Dental 1+Radiology 1+ Surgical 1)
2. Thymus (MLT+ Cardiology+ Anesthesia)
3. Tonsils (Dental 2+ Radiology 2+ Surgical 2)