--Carry lymph away from tissues
-Lymphatic capillaries
*More permeable than blood capillaries
*Epithelium functions as series of one-way valves
Functions of the Lymphatic System
Fluid balance
Excess interstitial fluid enters lymphatic capillaries + becomes lymph
Fat abs.
Abs, of fat + other substances frm digestive tract
Defense
Microorganisms + other foreign substances are filtered from lymph by lymph nod + frm blood by spl
Lymphatic Vessels
Carry lymph away from tissues
-Lymphatic capillaries=
*More permeable than blood capillaries
*Epithelium functions as series of one-way valves
Lymphatic capillaries join to form Lymphatic vessels
*Have valves that ensure one-way flow
Lymphatic Vessels II
Lymph nodes: Distributed along vessels and filter lymph
Lymphatic trunks: Jugular, subclavian, bronchomediastinal, intestinal, lumbar
Lymphatic ducts: Right and thoracic which connect to large veins
Lymphatic Tissue and Nodules
-Lymphatic tissue
*Consists mainly of lymphocytes
*Encapsulated or not
-Lymphatic nodules
*Numerous in loose connective tissue of digestive (Peyer’s patches), respiratory, urinary, reproductive systems
Tonsils
-Large groups of lymphatic nodules in nasopharynx and oral cavity
-Provide protection against bacteria and other harmful material
Groups
*Palatine
*Pharyngeal
*Lingual
Lymph Nodes
Organized in cortex and medulla
Substances removed by phagocytosis or stimulate lymphocytes or both
Only structures to filter lymph
**Afferent and efferent vessels
Spleen
-Can be ruptured in traumatic abdominal injuries resulting in bleeding, shock, death
-Blood flows through at 3 different rates
Fast (most), slow, intermediate
-Functions:
Destroys defective RBCs
Detects + responds 2 foreign subst
-reservoir for bld
Thymus
-Located in superior mediastinum
-Divisions: Cortex and medulla
-Site of maturation of T cells
