This document provides an overview of the lymphatic system. It defines lymph as tissue fluid that has entered lymph capillaries. Lymph vessels carry lymph and drain into two main ducts: the thoracic duct and right lymphatic duct. The document describes key components like lymph nodes, spleen, thymus, and tonsils. It explains the functions of the lymphatic system in returning tissue fluid to circulation, transporting lymphocytes, filtering microorganisms, and producing antibodies for protection.

1. Prepared by
Ms. Nisha S. Mhaske
M.Pharm (Q.A.T)
Lecturer, PRES’s COPD, Chincholi.
Email : nisha.mhaske@pravara.in

2. Contents
 Lymph
 Lymphatic duct
 Components of lymphatic duct
 Lymphatic vessels
 Lymph node
 Spleen
 Thymus gland
 Tonsils
 Applied anatomy

3. What is lymph ???????
 Tissue fluid, when enters to the lymph capillaries,
from the tissue spaces is called as the lymph.
 Lymph is clear, colorless body fluid derived from &
closely resembling to the blood.
 The fluid within the lymph capillaries & vessels is
known as lymph.

5. lymphatic capillary
lymphatic trunks
lymphatic collecting vessels
lymphatic ducts
Lymphatic vessels start with
lymphatic capillaries

6. Lymphatic capillary

7.  Special lymph capillaries ---
Lacteals
 Lacteals-lymphatic vessels of
the small intestine which
absorb digested food.
 collect digested fats
( in chylomicrons)
Chylomicrons- are lipoprotein
particles that consist of
Triglycerides, phospholipids,
cholesterol & proteins.
They transport dietary lipid
from the intestine to other
locations of the body.

8. Lymphatic duct
 Tissue fluid, when enters the
lymph capillaries is known
as lymph. The lymph
capillaries unite to form
larger vessels which
eventually converted into
two large ducts
1. Thoracic duct
2. Right lymphatic duct.
 These ducts drain their
lymph or fluid into the left
& right innominate veins
respectively.

9. Components of lymphatic system
 Lymph vessels
 Lymph nodes & other lymphatic tissue
 Spleen
 Thymus gland
 Tonsils

10. Lymphatic vessels
 Larger ones composed of 3 layers
 tunica interna: endothelium and valves
 tunica media: elastic fibers, smooth
muscle
 tunica externa: thin outer layer
 Valves are present to prevent
backflow.

11. Lymph nodes
 The lymph nodes are the oval or bean or kidney shaped bodies.
 They are located in the passage of lymphatic vessels.
 They usually occurs in groups.
 The concave border of the gland is called as hilum.
 Efferent lymphatic vessels carries lymph from the lymph node.
 Afferent lymphatic vessels enters lymph into the gland.
 After entering the lymph gets filtered in lymph node by trapping of foreign
particles & micro-organism.
 Lymph reaches to blood only after passing through lymph node.
 There are many groups of lymph nodes in the body such as, neck, axilla, thorax,
abdomen & grain.
 FUNCTIONS
1. Production of lymphocytes and antibodies.
2. They acts as a filter & prevents spread of organism.

13. Spleen
 Largest lymphatic organ
 Located to the left of the stomach below the diaphragm under 9th,10th & 11th ribs.
 It is 12 cm long, 8 cm broad & 3 cm in thick, wighing 150 gm in adult.
 It is surrounded by kidney, colon, & pancreas.
 Histology
Red pulp contains all the components of circulating blood
White pulp is similar to lymphatic nodules
 Spleen is covered with persitonium. Below this,is the layer of connective tissue
capsules, fibroelastic capsules, that dips into organ,forming trabeculae.
 The cellular element, consisting of lymphocytes & macrophages, is called splenic
pulp. It lies between trabeculae.
 It consists of spleen artery, spleen vein, lymph vessels & nerves.
 Blood passing through the spleen passes through sinusoids, instead of capillaries,
allowing it to come in contact with splenic pulp.

14. Figure 20.6a,b
Arterioles and
capillaries
Capsule
Trabecula
Venous sinuses
Red pulp
Splenic cords
White pulp
Central artery
Splenic artery
Splenic vein
(b) Diagram of spleen histology
Splenic
artery
Splenic
vein Hilum
(a) Diagram of the
spleen, anterior view

15. Figure 20.6c
(c) Photograph of the spleen in its normal position
in the abdominal cavity, anterior view.
Diaphragm
Spleen
Adrenal
gland
Splenic
artery
Pancreas
Left
kidney

16. Functions of spleen
 Phagocytosis
Erythrocytes are destroyed in spleen, other cellular materials such as
leukocyte, platelets and microbes are also phagocytosed in the
spleen.
 Haemopoietic organ
Erythrocytes are formed by spleen in fetal as well as in adult.
 Red cell storage
During stress, it can liberate 150 ml of blood, since it acts as
reservoir of red blood cells.
 Antibodies formation
The spleen provides defense against infection by tubercle bacillus.

17. Thymus
 Location – behind the sternum in the mediastinum
 The capsule divides it into 2 lobes
 Development
Infant – conspicuous
Puberty – maximum size
Maturity – decreases in size
 At birth, gland is small increases in size till puberty and shrinks again the
thymus is concerned with antibodies production.
 Function
secretes hormones (thymopoietin, thymulin and thymosins)
It also controls the lymphocyte production by spleen & other spleen
glands.
 In elderly mostly fatty and fibrous tissue

20. Tonsils
 Multiple groups of
large lymphatic nodules
 Location – mucous
membrane of the oral
and pharyngeal cavities
 Palatine tonsils
Posterior-lateral
walls of the
oropharynx
 Pharyngeal tonsil
Posterior wall of
nasopharynx
 Lingual tonsils
Base of tongue

21. Functions of lymphatic system
 To return the tissue fluid to the general circulation
 Transportation of lymphocytes from lymph glands to the
circulation
 The lymph nodes filter & destroy the microorganisms
thereby preventing the spread of the infection.
 Antibody formation by the lymph glands for protection of
the body.

22. Derivation and Distribution of Lymphocytes

23. References
 Human Anatomy & Physiology, by
Rahul Phate, Career publications, First
edition-Jan 2004, Page no:67-71.
 Human Anatomy & Physiology, by
S.B.Bhise & A.V.Yadav, Nirali
Prakashan, 25th edition-July 2013, Page
no:6.1-6.3

24. Applied anatomy
 Lymphangitis---
Inflammation of the
lymph vessels
Lymphedema--- Occurs due
to accumulation of lymphatic
fluid in the interstitial tissue

25. Lymphadenopathy---
 Means a disease of the lymph
nodes
 Lymph nodes become
swollen/ enlarged and may be
painful to touch
Lymphomas--- Cancers
originating either from the
lymphocytes in the lymph
nodes or the lymphatic tissue
in organs
Risk factors -- HIV, Hepatitis.

26. Tonsillitis---
Infection of the pharyngeal
tonsils
Tonsils are swollen,
Fever and pain during
swallowing usually present
Treatment – surgical removal of
tonsils (Tonsillectomy)
 Splenomegaly---Enlarged
Spleen