Lymphatic and Immunity Flashcards
Consists of two semi-independent parts and a network of lymphatic vessels
The Lymphatic System
- Interstitial fluid once it has entered lymphatic
vessels - “Clear water”
Lymph
Specialized lymph capillaries present in the intestinal mucosa
Lacteals
Functions of the Lymphatic System
- Fluid Balance
- Lipid Absorption
- Defense
- Originate as small, dead-end tubes called lymphatic capillaries
- Excess fluid passes through the tissue spaces and enters the lymphatic capillaries
Lymphatic Vessels
Round, oval, or bean-shaped bodies
distributed along the various vessels
and connected in a series
Lymph Nodes
Drains the right upper arm and the right side of the head and thorax
Right lymphatic duct
Lymph is delivered into one of two large
trunks
Lymphatic Vessels
Arises from the cisterna chyli and drains the rest of the body
Thoracic duct
- Consists of lymphocytes, macrophages, dendritic cells, reticular cells and others
- When the body is exposed to MOs, the
lymphocytes divide, increase in number and
become part of the immune system - Composed of very fine collagen fibers (reticular fibers) from reticular cells where lymphocytes attach and filter the passing fluid
Lymphatic Tissue
Loose arrangement of cells and reticular
fibers
Lymphoid Tissues
solid, spherical bodies
- B cells predominate
- Enlarges when B cells are dividing
Lymphoid follicles/nodules
- Isolated clusters of lymphoid tissue, similar to tonsils
- Found in the wall of the distal portion of the small intestine
- Similar structures are found in the appendix
Peyer’s Patches
- Simplest lymphoid organs
- Form a ring of lymphatic tissue around
the pharynx
Tonsils
Lie at the base of the tongue
Lingual tonsil
- Principal lymphoid organs of the body
- Embedded in connective tissue and clustered along lymphatic vessels
- Aggregations of these nodes occur near the body surface in inguinal,
axillary, and cervical regions of the body
Lymph nodes
Is in the left superior side of the abdomen. A limited reservoir for blood
Spleen
A bilobed organ that secretes hormones (thymosin and thymopoietin) that cause T lymphocytes to become immunocompetent
Thymus
The ability to resist the harmful effects of
microorganisms and other foreign substances
Immunity
Responds quickly and consists of:
* Mechanical mechanisms
- Skin and mucosae prevent entry of microorganisms
- Tears, saliva, and mucus remove them
* Chemical mediators
* Cells
* Inflammatory Response
Innate Immunity
Forms a mechanical barrier that prevent entry of pathogens
Intact mucous membranes
Provides resistance against acids, alkalis, and bacterial enzymes
Keratin
Is antigen-specific, systemic, and has memory
Adaptive Immunity
T cells recognize self major histocompatability proteins (self-MHC)
Positive selection
T cells must not recognize self-antigens
Negative Selection
display antigens on the surface of nucleated cells, resulting in the destruction of the cells
MHC class I molecules
Display antigens on the surface of antigen-presenting cells, resulting in the activation of immune cells
MHC class II molecules
is suppression of the immune system’s response to an antigen
Tolerance
Secreted into the saliva, tears, and onto mucous membranes to provide protection on body surfaces
lgA
An antibody that binds to an antigen and inactivates it.
Direct effects
- Cells infected with intracellular micro-organisms process antigens that combine
with MHC class I molecules - Cytotoxic T cells are stimulated to divide, producing more cytotoxic T cells and
memory T cells, when MHC class I/antigen complexes are presented to T-cell
receptors
Cell-Mediated Immunity
Enters tissues from the blood and releases chemicals that inhibit inflammation
Eosinophil
s is the ability of white blood
cells to move to tissues that release
certain chemicals
Chemotaxis
Can be activated by either the classical or the alternative pathway. Part of the adaptive immunity
Complement
- Prevent pathogens from penetrating mucous membrane
- Site for lymphocyte activation and proliferation
MALT
Normally acid pH inhibits bacterial growth, cleanses the lower urinary tract as it flushes from the body
Urine
An amine released from mast cells, basophils, and platelets; causes vasodilation, increases vascular permeability, stimulates gland secretions
Histamine
are proteins produced by most cells, that interfere with virus production and infection
Interferons
Are chemicals released by neutrophils, monocytes, and other cells, that stimulate fever production
Pyrogens
Promotes apoptosis (cell suicide) by directly attacking virus-infected or cancerous body cells; recognize general abnormalities rather than specific antigens.
Natural killer (NK) cells
