Lymphatic System Flashcards
What are the functions of the Lymphatic System?
1) Production, Maintenance, and Distribution of Lymphocytes
2) Carry fluid and solutes from tissues to blood
3) Distribution of Hormones, Nutrients and Waste to General Circulation
What is the overall organisation of the Lymphatic System?
1) Lymphocytes
2) Lymphatic Vessels
3) Lymph
4) Lymphoid Organs
What are the Lymphocytes?
1) Lymph cells that perform specific immune functions
2) Defend against Envt. Hazards and protect against internal threats
3) Classified as a ‘Specific Defence’, or the Immune Response
What are Lymphatic Vessels?
Begins in Peripheral Tissues
Ends at a connection to the Venous System
What is Lymph?
Fluid that flows through Lymphatic Vessels
Similar to Plasma but fewer suspended proteins
What are Lymphoid Organs?
Connected to the Lymph Vessels
Lymph Nodes, Spleen, and Thymus
What are the different kinds of Lymphatic Vessels?
1) Lymphatic Capillaries - present almost everywhere, lacteals in Small Intestine transport lipids, act as one-way valve
2) Lymphatic Vessels - similar to veins including valves to prevent backflow
3) Thoracic Duct - Lymph from inferior to the diaphragm and left side superior to the diaphragm
4) Right Lymphatic Duct
What are Lymphocytes?
1) Constantly circulating through blood, lymph and tissues
2) Survive for long time periods
3) Stem cells produced in Red Bone Marrow
4) Differentiate into B, T, and NK Cells [B/T Respond to presence of antigen, NK recognise abnormal and kill]
5) T-Cells migrate to the Thymus for division and maturation
6) All end up in the blood stream and peripheral tissues
7) Retain their ability to divide
What are Lymphoid Nodules? What are some characteristics?
1) Loose connetive tissue and lymphocytes
2) Size can increase or decrease
3) Often have areas of actively dividing lymphocytes
4) Often found in areas open to the external environment
What are some examples of Lymphoid Nodules?
Tosils - Pharyngeal, Palatine, Lingual - Guard entrance to digestive and respiratory tract
Appendix
MALT [Mucosa-associated Lymphoid Tissue] - line digestive system; aggregated lymphoid tissue [Peyer’s patches] line the Intestines
What are the Lymphoid Organs?
1) Lymph Nodes - afferent deliver lymph to nodes; efferent away from node; filters lymph and detects and removes antigens; stimulates immune response
2) Thymus - Gland behind Sternum above heart; site of T-cell production and maturation
3) Spleen - Largest lymph organ; filters large amount of blood, removing antigens; stimulates immune response
What are Cytokines? What are the different categories of Cytokines?
Chemical Messengers:
1) Interleukins [IL]
2) Interferons
3) Tumour Necrosis Factors
4) Phagocyte-Activating Chemicals
5) Colony-Stimulating Factors
6) Miscellaneous Cytokines
What do Interleukins do?
Increase T-cell sensitivity
Stimulate B-Cell Activity
Enhance non-specific defences
Moderate Immune Reponse
What do Interferons do?
Make cells resistant to Infection
What do Tumour Necrosis Factors do?
Inhibit Tumour growth and kill sensitive cells
