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.
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.
12.
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.
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
18.
19.
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.
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