Circulatory System: Lymphatic and Immunity Flashcards
Functions of the lymphatic system
- Drainage of interstitial fluid
- Transport of lipids (from digestive system)
- Protection and immune responses
Structures of the Lymphatic System
- Lymph (fluid of the system)
- Lymphatic Vessels (transport fluid)
- Structure and organs that contain lymph tissue
- Red bone marrow (BCs develop)
What is lymph?
It is the excess filtered fluid of plasma and solutes
Where does lymph come from?
From blood from the capillaries, into the interstitial space–> then drains into lymphatic system
How do proteins that leak out of the blood return to circulation?
Via the lymphatics
What are the steps of lymphatic flow?
Capillaries–> Lymphatic Vessels–> Trunks –> Ducts
Structure of Lymphatic Capillaries
- Begin in the spaces between cells
- Closed at one end
- High permeability
How is fluid allowed into the capillaries and not out?
Endothelium overlap, pressure drives interstitial fluid in
Lymphatic capillaries merge into ____
Larger vessels called lymphatic vessels
What do lymphatic vessels to help move lymph along?
One way valves (little smooth muscle component)
At regular intervals, lymph passes through ___
Lymph nodes
Structure of Lymph Nodes
- Clusters of lymphocytes (B cells/T cells), surrounded by a dense CT capsule
- Bean shaped
Function of Lymph Nodes
Lymph Filtration
Lymph flows in, foreign substances trapped and destroyed
Larger Lymphatic Vessels merge into ___
Trunks
What are the two lymphatic ducts?
- Thoracic Duct
2. Right Lymphatic Duct
What does the thoracic duct drain and where?
-Left side of the head/neck
-Left side of the body
-Entire body below ribs
Drains into Left Subclavian Vein
What doest the right lymphatic duct drain and where?
-Right side of head/neck
-Right side of chest
Drains into Right Subclavian Vein
Lymphatic Flow:
- Blood Capillaries (Blood)
- Interstitial Space (Interstitial Fluid)
- Lymphatic Capillaries (Lymph)
- Lymphatic Vessels (Lymph)
- Lymphatic Ducts (Lymph)
- Subclavian Veins (Blood)
What is Lymphatic Flow maintained by?
- Skeletal Muscle Pump
- Diaphragmatic Breathing/Respiratory Pump
- Smooth Muscle Contraction (minimal)
Lymphatic Organs
- Red Marrow
- Thymus
- Spleen
Produces B cells and immature T cells
Red Marrow
Produce mature T cells from pre-T cells
Thymus
Where is the thymus located?
Mediastinum
How is the thymus at birth, what happens to it as we age?
Large, atrophies with maturity
Filters blood, removes ruptured, worn out, defective RBCs and stores platelets and monocytes
Spleen
Spleen’s structure and location.
Large mass of lymphatic tissue between stomach and diaphragm
What are the two divisions of the Immune System?
- Non-specific defences
2. Specific Defences
Rapid response. No memory component. Reacts to all invaders the same.
Non-specific Defences
Three examples of Non-Specific Defences
- Skin
- Mucous Membrane
- Body Fluid
Fives examples of Specific Defences
- Antimicrobial Proteins
- Natural Killer Cells
- Phagocytes (fixed and wandering)
- Inflammation
- Fever
Specific Defences A.k.a
Immunity!
Substances that are recognized as foreign and elicit an immune response
Antigen
In specific responses, antigens/invaders are..
- Identified
- Killed
- Remembered
2 Types of Specific Responses
- Cell Mediated (T-Cells)
2. Antibody Mediated (B-Cells)
Effective against fungi, parasites, viruses, some cancer cells, foreign tissue
Cell-Mediated Immune Response
What do T-Cells do when an invader is recognized?
- Activate
- Enlarge
- Proliferate (make more of themselves)
- Differentiate
What do T-Cells differentiate into?
- Helper T-Cells
- Cytotoxic T-Cells
- Memory T-Cells
Help facilitate immune response (trigger proliferation, other immune responses)
Helper T-Cells
Migrate to site and destroy invader
Cytotoxic T-Cells
(T-Cell) Remain after response, don’t attack, record who attacked for future
Memory T-Cells
Effective against antigens in body fluids, extracellular pathogens (bacteria)
Antibody-Mediated Immune Response
What do B-Cells do when an invader is recognized?
- Activate
- Enlarge
- Differentiate
What do B-Cells differentiate into?
- Plasma Cells
2. Memory B-Cells
B-Cell that secretes antibodies
Plasma Cells
(B-Cell) Remain after response, don’t attack, remember invader
Memory B-Cells
Antibody’s A.k.a
Immunoglobulins
Proteins produced by plasma cells in response to an antigen
Antibodys
What do antibodies do?
Neutralize, inhibit, or destroy the antigen
What are the 5 classes of antibodies
IgG, IgA, IgM, IgE, IgD
Most common antibody class
IgG
Found in blood, lymph, intestines
IgG
Found in sweat, tears, saliva, mucous, breast milk, GI
IgA
Found in blood, lymph
IgM
Found in blood
IgE, IgD
Protect against bacteria, viruses. Cross the placenta to confer immunity to the newborn
IgG
Levels decrease during stress
IgA
Part of blood transfusion reactions
IgM
Involved in allergic, hypersensitivity reactions, protect against parasitic worms
IgE
Help activate B-cells
IgD
Following exposure to a microbe, antigen recognition (Bs/Ts) lead to formation of antibody-secreting plasma cells, cytotoxic Tcells, and B/T memory cells
Naturally Acquired Active Immunity
IgG antibodies are transferred from mother to fetus across placenta, or IgA antibodies are transferred from mother to baby in milk during breastfeeding
Naturally Acquired Passive Immunity
Antigens introduced during vaccination stimulate cell-mediated and antibody-mediated immune responses, leading to production of memory cells.
Artificially Acquired Active Immunity
Intravenous injections of immunoglobulins (antibodies)
Artificially Required Passive Immunity
Aging and the Immune System (5)
- Increase susceptibility to infections and malignancies
- Responses to vaccines is decreased
- More autoantibodies are produced
- Lower level of immune function
- Ts and Bs are less responsive
