Chapter 22 Flashcards
What are the three main functions of the lymphatic system
Fluid balance, lipid absorption and defense
How much fluid is collected by the lymphatic capillaries
3L
When interstitial fluid enters the lymphatic capillaries, what is it called
Lymph
Lymphatic vessels located in the lining of the digestive tract that absorb lipids and other substances
Lacteals
Lymph passing through the lacteals
Chyle
Filters lymph
Lymph nodes
Filters blood
Spleen
The lymphatic system includes
Lymph, lymphatic vessels, lymphatic tissue, lymphatic nodules, lymph nodes, the tonsils, the spleen, and the thymus
Lymphatic vessels that originate as small, dead-end tubes
Lymphatic capillaries
Areas of the body that lack lymphatic vessels
CNS, bone marrow, and tissues without blood vessels, such as cartilage, epidermis, and the cornea.
Inner layer of lymphatic vessels consists of
endothelium surrounded by an elastic membrane
The middle layer of lymphatic vessels consists of
Smooth muscle cells and elastic fibers
The outer layer of lymphatic vessels consists of
Thin layer of fibrous connective tissue
How does lymph move through lymphatic vessels
Contraction of lymph vessels, contraction of skeletal vessels and thoracic pressure changes
The largest lymphatic vessel is
Thoracic duct
Right lymphatic duct drains lymph from
Right side of the head, upper right limb and right thorax
The thoracic duct drains lymph from
The right side of the body inferior to the thorax, and the entire left side of the body
Lymphatic tissue consists of
Primarily lymphocytes, but also macrophages, dendritic cells, reticular cells, and other cells
Where do B cells and T cells originate
Red bone marrow
Encapsulated lymphatic tissue forms these organs of the lymphatic system
Lymph nodes, spleen and the thymus
Define Mucosa-associated lymphoid tissue (MALT)
Aggregates of nonencapsulated lymphatic tissue found in and beneath the mucosa membranes lining the digestive, respiratory, urinary and reproductive tracts
Examples of MALT
Diffuse lymphatic tissue, lymphatic modules and tonsils
Diffuse lymphatic tissue contains
Dispersed lymphocytes, macrophages and other cells
Where is diffuse lymphatic tissue located
Deep to the mucous membranes, around lymphatic modules and within lymph nodes and the spleen
Describe lymphatic nodules
Denser arrangements of lymphatic tissue organized into compact, somewhat spherical structures ranging in size from a few hundred microns to a few millimeters or more in diameter
Where are lymphatic modules found
Loose connective tissue of the digestive, respiratory, urinary and reproductive systems.
Define Peyer patches
Aggregations of lymphatic modules in the distal half of the small intestine and the appendix
Define lymphatic follicles
Lymphatic modules found within lymph nodes and the spleen
Define tonsils
Large groups of lymphatic modules and diffuse lymphatic tissue located deep to the mucous membranes within the pharynx
Define adenoid
Enlarged pharyngeal tonsil
Where are lymph nodes located
Along the course of lymphatic vessels
What is the function of lymph nodes
Filter lymph, removing bacteria and other materials. In addition, lymphocytes congregate , function and proliferate within lymph nodes
How many lymph nodes are in the body
Approx 450
Afferent lymphatic vessels
Carry lymph to the lymph nodes
Efferent lymphatic vessels
Carry lymph away from the lymph nodes
Germinal centers
Lymphatic modules of the cortex of the lymph node that is an area of rapid lymphocyte cell division
White pulp
Lymphatic tissue surrounding the arteries within the spleen
Red pulp
Associated with the veins within the spleen, consists of a fibrous network, filled with macrophages and red blood cells
White pulp/Red pulp ratios of the spleen
1/4 white pulp, 3/4 red pulp
Functions of the spleen
Destroying defective red blood cells, detecting and responding to foreign substances in the blood, and acting as a blood reservoir
Site for maturation of T cells
Thymus
Hormone that is important in T cell maturation
Thompson
Immunity
Is the ability to resist damage from foreign substances, such as microorganisms, harmful chemicals (toxins released by microorganisms), internal threats, such as cancer cells
How is immunity categorized
Innate and adaptive immunity
Describe immune response in innate immunity
The response to foreign substances is the same each time the body is exposed
Describe immune response in adaptive immunity
The body recognizes and destroys foreign substances, but the response to them is faster and stronger each tome the body is exposed
Specificity
Is the ability of adaptive immunity to recognize a particular substance
Memory
Ability of adaptive immunity to remember previous encounters with a particular substance
Body defenses that are present at birth and genetically predetermined
Innate immunity
Main components of innate immunity
- Physical barriers that prevent microbes from entering the body or that physically remove them from the body
- Chemical mediators that act directly against microorganisms or activate other mechanisms, leading to the destruction of the microorganisms
- Cells involved in phagocytosis and the production of chemicals that participate in the immune response
The physical barriers that make up innate immunity are
Skin and the mucous membranes
Define cytokines
Proteins or peptides secreted by cells that bind to receptors on cell surfaces, stimulating a response
Function of cytokines
Regulate the intensity and duration of immune responses and stimulate the proliferation and differentiation of cells
Examples of cytokines
Interferons, interleukins and lymphokines
Define complement
A group of about 20 proteins that protect the body by destroying abnormal cells or enhancing other components of immunity
Define complement cascade
A series of reactions in which each component of the series activates the next component
Alternative pathway
Part of innate immunity, initiated when the complement protein C3 becomes spontaneously active
Classical pathway
Part of adaptive immunity.
define Membrane attack complex (MAC)
Produces a channel through the cells plasma membrane that ultimately destroys the cell
Define opsonization
Complement proteins attach to the surface of the cells and stimulate macrophages to phagocytize the bacteria
Define interferons
Proteins that protect the body against viral infection and perhaps some forms of cancer
Define chemotaxis
Movement of the WBCs from areas of lower chemotactic factor concentration to areas of higher concentration
Define phagocytosis
The end oxytocin’s and destruction of particles by phagocytes
Describe Neutrophils
Small, phagocytic cells produced in large numbers. Often die after one phagocytic event
Describe macrophages
Large phagocytic cells, derived from monocytes. In addition to their phagocytic role, macrophages produce a variety of chemicals, such as interferons, prostaglandins, and complement, that enhance the immune response
Describe basophils
Motile WBC that can leave the blood and enter infected tissues.
Describe mast cells
Nonmotile cells in connective tissue, especially near capillaries. Located at points where microorganisms May enter the body, such as the skin, lungs, digestive tract and urogenital tract
Describe eosinophils
WBC, numbers increase in response to parasitic infections. Secrets enzymes to kill parasites. Number of eosinophils will also greatly increase in case of allergic reaction with much inflammation.
Describe Natural Killer Cells (NK cells)
Type of lymphocyte, not part of adaptive immunity. Recognize “classes” of cells, such as tumor cells or virus infected cells, rather than a specific target. Use a variety of methods to kill target cells, including releasing chemicals that damage the plasma membrane and cause the cell to lyse
Define local inflammation
An inflammatory response confined to a specific are of the body - symptoms include redness, swelling, heat due to increased blood flow and increased vascular permeability. Will also include pain cause by swelling and chemical mediators acting on pain receptors
Define systemic inflammation
Inflammatory response that occurs in many parts of the body.
Antigen
Substances that stimulate adaptive immunity
Foreign antigen
Not produced by the body, but are introduced from outside it
Examples of foreign antigens
Components of bacteria, viruses, and other microorganisms. Pollen, animal dander, feces of dust mites, foods and drugs
Define allergic reaction
An overreaction of the immune system
Self antigens
Molecules the body produces to stimulate an adaptive immune system response
Develop when self-antigens stimulate unwanted tissue destruction
Autoimmune disease
Antibody-mediated immunity
Involves proteins called antibodies, which are found in extracellular fluids, such as the plasma of the blood, interstitial fluid, and lymph. Involves B cells
Cell-mediated immunity
Involves T cells
Hormone that stimulate T cell maturation
Thymosin
Location of T cell formation
Red bone marrow
Location of B cell formation
Red bone marrow
Location of T cell maturation
Thymus
Location of B cell maturation
Red bone marrow
Results in survival of pre B cells and pre T cells capable of an immune response
Positive selection
Small group of identical lymphocytes
Clones
Process that eliminates or suppressed clones acting against self-antigens
Negative selection
Lymphocytes mature into functional cells in
Primary lymphatic organs, red bone marrow and thymus
General location that lymphocytes interact with each other, antigen-presenting cells, and antigens to produce an immune response
Secondary lymphatic organs and tissues
Antigenic determinants
Specific regions of an antigen
MHC I
Found on uncleared cells, display antigens produced inside the cell
MHC II
Found on antigen presenting calls, include B cells, macrophages, monocytes and dendritic cells. Presents cell fragments that are processed into antigens after endocytosis
Costimulation
Accomplished by cytokines released from cells as wells as molecules attached to the surfaces of cells
Antibody-mediated immunity
Exposure to an antigen leads to activation of B cells and the production of antibodies, effective against extracellular antigens
Memory response (secondary response)
Occurs when the immune system is exposed to an antigen against which isn’t has already produced a primary response
Cell-mediated immunity
Most effective against intracellular microorganisms through the action of cytotoxic T cells.
Effects of cytotoxic T cells
- Lyse cells
2. Produce cytokines
Perforin
Chemical released by Cytotoxic T cells, forms a channel in the plasma membrane of the target cell, water then enters, causing the cell to lyse
Active immunity
Results when an individual is exposed to an antigen
Passive immunity
Occurs when another person or an animal develops immunity and the immunity is transferred to a nonimmune individual
Natural exposure
Implies that contact with an antigen or antibody occurs as part of everyday living and is not deliberate
Artificial exposure
(Immunization) deliberate introduction of an antigen or antibody into the body
