Lecture 10 - Lymphatic System Flashcards
Lymphatic System
Network of tissues , vessels & organs that work together to move lymph back into circulatory system
Transport excess fluid back to blood circulation
Lymphatic System - Characteristics
- Thin walled vessels that transport fluid throughout the body resembling veins ( but thinner walls and more valves)
- From lymphatic capillaries which unite to form larger lymphatic vessels
- Lympathic vessels drain into the THORACIC DUCT or the RIGHT LYMPATHIC DUCT ( schema )
Lymphatic System - Functions
- Tissue drainage Return proteins , lipids & water from interstitial fluid to blood
- Immunity against harmful organism
- Absorption
Lymphatic System Constitution
- Lymph fluid
- Lymph vessels : fluid moves through
- Lymph nodes : filtering station
- Lymph organs : spleen & thymus
- Lymphoid tissue ( tonsils ) : MALT / GALT
- Bone Marrow : WBC production
Lymph Fluid
Watery fluid similar to blood plasma but less plasma proteins & same composition as interstitial fluid
Contains :
- Water
-Leukocytes
-Plasma proteins ( sepped out of capillaries )
-Fats( absorbed from small intestines )
- Bacteria & cell debris from damage tissue
Lymphatic vessels - Capillaries
- Located in spaces between cells
- One -way structure - blind-end tubes
Lymphatic vessels - Larger lymph vessels
- 3 layers like veins
- Numerous valves
- Vessels unite to form lymph trunk
Lymphatic vs Cardiovascular system
Cardiovascular : Circular & closed system
Lymphatic : Linear
Lymphatic fluid transports it back to vascular system
Lymphatic Nodes - Overview
- Filter Lymph & remove foreign matter such as microbes , cell debris & tumor cells
- Lymph passes through many lymph nodes before returning to blood ( 600 beans structures )
- Same route as vein
- Filled with immune cells (lymphocytes & phagocytes)
Lymphatic Nodes - How does it works
1.Lymph enters via afferent vessels
2. Foreign substances trapped by reticular fibres
3.Macrophages destroy foreign substances by phagocytosis
4. If needed Lymphocytes will destroy remainder
5. Filtered Lymph leaves via efferent vessels
Many afferent vessels few efferent => Allows immune cells time to remove foreign matter
Lymph Nodes - Location
5 locations contain many :
- Cervical
- Axillary
- Inguinal
- vertebral column
- Mesenteric ( intestinal )
Lymph Nodes - Growth
Develops during childhood & atrophy begins in adolescence
Lymph Nodes - Infection
Early stage of infection -> Incomplete phagocytosis of microbes => Lymphadenopathy ( swelling )
Spleen - Overview
- Largest Lymph organ ( like heart )
- Between stomach & diaphragm on the left
- Similar in shape & structure to lymph node
- Contains White & Red pulp :
- White pulp :lymphocyte + Macrophages
- red pulp : components of circulating blood
Spleen - Functions
- Hematopoiesis in foetus
- Blood reservoir (adult ) -> RBC graveyard ( where they are broken down )
- Phagocytosis of worn out / defectives erythrocytes
- Immunity : T&B-lymphocytes.