Blood, Lymphatic and Immune 1 Flashcards
Definition:
Complex collection of cells and organs whose purpose is to destroy or neutralize pathogens that would otherwise cause disease or death
Immune system
Definition: Lymphatic system
System composed of vessels, cells, and organs which are responsible for carrying excess fluids to the bloodstream as well as fluids to the bloodstream as well as filtering pathogens from our blood
What are 2 examples that describe how closely connected our immune system and lymphatics systems are?
Swelling of the lymph nodes during an infection and the transport of lymphocytes via the lymphatic vessels
What are the 3 main functions of the lymphatic system?
- Drain interstitial fluid
- Help carry out immune responses
- Transport dietary fats
Why does the lymphatic system need to drain interstitial fluid?
Hydrostatic pressure causes leakage of the capillaries resulting in the accumulation of fluid in the interstitial space between the individual cells of tissues
What % of interstitial produced each day is reabsorbed? What happens to the rest?
85%, the remaining 15% of the interstitial fluid is absorbed by the lymphatic system as lymph
Where does the excess fluids go?
Drained back into the bloodstream via a series of vessels, trunks, and ducts
How do lymphatic vessels play a role in the immune system?
Transport immune cells throughout the body
Definition: Major staging area for the development of critical immune responses
Lymph nodes
Definition: Vessels where interstitial fluid enters the lymphatic system and becomes lymph
Lymphatic capillaries
Where are lymphatic capillaries located?
Interlaced among many of the arterials and venues of the circulatory
Definition: Lacteals
Located in the SI, critical for the transport of dietary lipids and lipid-soluble vitamins to the bloodstream
What is chyle?
Dietary triglycerides combine with other lipids and proteins and enter the lacteals to form a milky fluid which is chyle
Where does chyle go?
Travels through the lymphatic system, eventually entering the liver and then the bloodstream
What makes up lymphatic capillaries? Why is it designed this way?
Simple layer of endothelial cells. This allows interstitial fluid to flow into them as interstitial pressure increase
When interstitial pressure is low….
Endothelial flaps close to prevent backflow
What is the major difference between the lymphatic and the cardiovascular system?
Lymph is not actively pumped like blood is by the heart
How is lymph forced through lymphatic vessels?
- movements
- contraction of skeletal muscles during body movements
Movements associated with breathing
What do the lymphatic vessels merge to form?
Lymphatic trunks
Where does lymph from the upper right side of the body go?
Into the right lymphatic duct
Lymph from where enters the bloodstream through the thoracic duct on the left side via all remaining lymphatic trunks?
Everywhere except upper right side of the body
Explain the movement of lymph.
Flows from the lymphatic capillaries through lymphatic vessels, and then is dumped into the circulatory system via the lymphatic ducts located at the junction of the jugular and subclavian veins in the neck. A series of one-way semi-lunar valves keep the lymph moving toward the ducts and the heart
Review structure of the lymphatic system.
Interstitial fluid —> lymph capillaries —> lymph vessels/lymph nodes —> lymph trunks —> lymph ducts —> subclavian veins
What are the primary lymphoid organs?
- red bone marrow
- thymus gland
Where do lymphocytes development and mature?
Red bone marrow and thymus gland
Definition: Immunocompetent
The point at which lymphocytes become capable of mounting an immune response
Where does the B cell undergo nearly all of its maturation and development?
Red Bone marrow
Where does the T cell begin its development? Mature?
Begins its development in the red Bone marrow, matures in the thymus gland
What are the secondary lymphoid organs?
- lymph nodes
- spleen
- lymphatic nodules (tonsils)
Definition: naive lymphocytes
Fully functional lymphocytes that have not yet been activated by an antigen
Where are naive lymphocytes held before they mount an immune response?
Secondary lymphoid organs (lymph nodes, spleen, lymphatic nodules)
Definition: Bean shaped structure and help cleanse the lymph of pathogens and debris as the lymph travels through the compartments (sinuses)
Lymph nodes
What is the major route into the lymph node?
Afferent lymphatic vessels
How does the cells and lymph leave the lymph node?
Efferent lymphatic vessel
What is occurring inside the lymph nodes?
Germinal centres of rapidly dividing B, T plasma and accessory cells as they await activation via the adaptive immune response
Why do lymph nodes get swollen during infections?
More immune system cells arrive to fight the pathogen
Definition: Largest single mass of lymphatic tissue in the body located between the stomach and the diaphragm
Spleen
Definition: fragile organ surrounded by a relatively y weak capsule and is dark red to its extensive vascularization, sometimes referred to as the ‘filter of the blood’
Spleen
What are the two main components of the spleen?
Red pulp (mainly RBCs)
White pulp (mainly lymphatic tissue)
What does red pulp do in the spleen?
Functions as a filtration system of the blood (phagocytizes RBCs) and is a platelet storage centre
What is the function of the white pulp?
Functions to mount adaptive B and T cell responses in the body
Explain how blood flows through the spleen.
Upon entering the spleen, the splenic artery splits into several arteries surrounded by white pulp. Blood from the capillaries subsequently collects in the venous sinuses and leaves via the splenic vein
Definition: Dense cluster of lymphocytes without surrounding fibrous capsule
Lymphoid nodules
Where are lymphoid nodules located and why?
Located in the respiratory and digestive tracts, which are areas routinely exposed to environmental pathogens
Which lymphoid nodules are important for developing immunity to oral pathogens? Why?
Tonsils, help children’s bodies recognize, destroy, and develop immunity to come environmental pathogens in order to protect us from those pathogens later in life
