the local support and defense system Flashcards
lesson 14
what makes up the Innate Immune System?
- non-specific defenses
- first line: physical and chemical surface barriers
- second line: internal cellular and chemical defense
what is the first line of defense made up of?
- tears
- skin/sweat and oil/pH
- large intestine
- saliva
- respiratory tract
- stomach
- bladder
what is the second line of defense made up of?
- defensive cells
- defensive proteins
- inflammation
- fever - slows the growth of bacteria
- identifies as foreign matter but isn’t specific and doesn’t develop a memory
what makes up the adaptive immune system?
- specific defenses
- the third line of defenses
- only kicks in if the pathogen survives the nonspecific internal defenses
what makes up cell-based defense?
- phagocytes
- non-phagocytes
- eosinophils
- natural killer cell
- destruction by phagocytosis
how do phagocytes work? what are the different types?
- neutrophils - first on the scene and consume bacteria
- macrophages - consume almost anything
how do non-phagocytes work?
target pathogens/invading organisms are too large for phagocytosis
how do eosinophils work?
discharge enzymes that digest the target
how do natural killer cells work?
- constantly circulate and ‘patrol’ for non-self.
- target cancer cells
- release perforin and proteases to destroy cells
why are protein-based defense mechanisms so important?
- lysis by the complement system
- enhances the ability of antibodies and phagocytic cells to clear microbes and damaged cells from the body, promotes inflammation, and attacks the pathogen’s cell membrane.
what are parenchymal cells?
- the critical ‘functional’ portion of the tissue (gland, organ)
- usually the most prominent cell type in terms of mass
name some examples of parenchymal cells
- liver
- skeletal muscle
- heart
- brain
- adipose tissue
- pancreas
what are stromal cells?
- also called non-parenchymal cells
- support the parenchymal cells, forming the LSDS
name some examples of stromal cells
- neurons
- astrocytes
- capillary endothelial cells
- fibroblasts
- stem cells
- gap junctions
what is the purpose of T-Cells?
- they kill by chemical means
- i.e., perforins, which punch holes in the target cell membrane
- memory t-cells are stored for continued surveillance in the bone marrow and thymus
what are the other names for a T suppressor cell?
- T regulatory cell
- Foxp3+
what is the purpose of T suppressor cells?
to suppress activation of the immune system, particularly the production of T helper cells
- important in allowing tolerance to self antigens
how does too little T suppressor response affect the body?
association with:
- autoimmune disease
- allergies
- graft rejection
- inflammatory bowel disease
how does too much T suppressor response affect the body?
possible connection to
- cancer
- increased incidence of infectious diseases
what does the LSDS do?
- local tissue damage by processes that are not due to infectious pathogens
- normal tissue turnover such as cell death and tissue repair or regeneration during wound healing
- looks out for the appearance of transformed cell populations such as cancerous cells
why is the LSDS said to be like the CCN?
because it’s always on!
what is required to trigger T and B cell responses to foreign antigens?
macrophages are required as the antigens or peptides will not be detected unless attached to an MHC
