HUMAN ANATOMY AND PHYSIOLOGY

 Factors Affecting Lymph Circulation::

Lymph flows in a closed system of lymphatic vessels with one sided valves Lymph circulation is enhanced by the following factors (1) Gravitation (2) pressure ingredient (3) muscular movement (4) Respiratory movement and (5) Lymphagogues 

Lymph nodes or Lymph Glands::

Lymph nodes are important glandular structures which are spread at all strategic spots of the body to filter the germs their toxins and foreign bodies they also give birth to lymphocytes lymphatic glands are situated both superficially and deep they are named according to the region where they are situated as follows:
1. Cubital and axillary - Arm 
2. Popliteal and inguinal -Leg 
3. Submaxillary and cervical -neck 
4. Mediastinal - thorax 
5. Abdominal especially mesenteries -Abdomen 
6. Pelvic- pelvic organs 
Lymph node is an encapsulated collection of lymphatic tissue lying on the pathway of lymphatics at various sites histologically it has (a) cortex (b) medulla and (c) hilum
a. Cortex:The cortex is the outer part of the lymph gland containing peripherally the lymphatic nodules in the inner zone there are germinal centres which give birth to lymphocytes lymph sinuses separate the peripheral lymph nodules from the capsule 
b. Medulla: it is the inner part of the lymph gland devoid of lymphatic nodules it contains RES cells lymph cells and a few giant cells there are lymph cords and lymph sinuses as well in the medulla of the lymph node 
c. Hilum: it is the mouth of the gland which looks as a depression in the gland at one side here the cortex is thin and the medulla is thick hilum gives (1) entry to an artery (2) exit to a vein and (3) exit to an efferent lymphatic channel a efferent lymphatics pierce the gland from circumscribed periphery join and rejoin to drain the lymph centrally 
        in short afferent enter from all sides penetrate and pour the lymph node within the chief efferent vessel leaves the hilum carrying the filtered lymphocyte enriched lymph 
        the nerve supply to the lymph nodes is from autonomic nervous system 

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