Exam (elaborations)
Immunology HMX (Exam Elaborations) – Q’s And A’s
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Immunology HMX (Exam Elaborations) – Q’s And A’s
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Immunology HMX (Exam Elaborations) – Q’s And A’sImmune cells differentiate from progenitor cells in the primary lymphoid
organs. What are the two primary lymphoid organs? Right Ans - Bone
marrow and thymus
Most types of mature immune cells can circulate through blood vessels, where
they are known as __________________ ________________. Right Ans - circulating
leukocytes
Within ______________, particularly epithelial barriers, tissue-resident sentinel
cells function to sense microbes and respond to infections. Right Ans -
tissues
Immune cells called ___________________ are particularly abundant in the
lymphatic system. Right Ans - lymphocytes
Lymph is a clear fluid that drains from tissues to the heart through
__________________ ______________. Right Ans - lymphatic vessels
Crucially, lymphocytes and other immune cells concentrate in the secondary
lymphoid organs (notably _____________ ________), which are connected to the
lymphatic system. Right Ans - lymph nodes
__________________ (primary or secondary) lymphoid organs play a critical role in
generating a robust pathogen-specific immune response. Right Ans -
secondary
What consists of mechanisms that exist prior to infection and are capable of
rapid responses to microbes? These mechanisms react in essentially the same
way to each repeat infection. (2 words) Right Ans - innate immunity
Part of the innate immune response is ________________, and it is essential for
survival and is a common, symptom-producing feature of many infections.
Right Ans - inflammation
,What is a more complex defense system against infection that requires some
time to develop after initial exposure to the microbe? (2 words) Right Ans -
adaptive immunity
The defining characteristics of adaptive immune responses are exquisite
______________ for millions of different distinct molecules, _________________ of the
immune response to different types of microbes, and the ability to
"remember" and respond more vigorously to repeated exposures to the same
microbe, called ____________. Right Ans - specificity, specialization, memory
Adaptive immunity is mediated by ________________ _____ ___________ _________
_________ __________________. Right Ans - lymphocytes with highly diverse
antigen receptors
There are two main types of adaptive immunity: responses mediated by
antibodies secreted by __ cells and responses mediated by __ cells. (answer has
2 letters, in order of this question, and with a comma between them) Right
Ans - B, T
The innate immune system is capable of _____ ________ responses to an infection.
Crucially, an innate immune response is required to activate the slower-acting
adaptive immune system, which is capable of mounting a more targeted
response to a microbe. Right Ans - very rapid
Identify the main types of leukocytes that contribute to acute inflammation.
Right Ans - Neutrophils, Macrophages, Mast Cells, Dendritic Cells
Cytokines Right Ans - Molecules are released by tissue sentinel cells when
a microbe is digested. Pro-inflammatory
Circulating leukocytes Right Ans - Cells that are circulating the
bloodstream. Neutrophils and monocytes
Dendritic cells Right Ans - Tissue-resident blood cells that have innate
immune receptors that will bind microbes and secrete pro-inflammatory
cytokines upon microbe digestion
Endothelial cells Right Ans - The cells that line the blood vessel or venule
,Innate immune receptors Right Ans - Receptors that detect microbes.
These receptors are on neutrophils, macrophages, dendritic cells, and mast
cells.
Innate immunity Right Ans - Describes all the immune defenses that exist
before any exposure to a pathogen
Macrophages Right Ans - Tissue-resident blood cell is phagocytic of
microbes and dead neutrophils. Releases pro-inflammatory cytokines upon
microbe digestions. Monocytes will become macrophages when they enter the
tissue
Mast cells Right Ans - Tissue-resident blood cells that secrete pro-
inflammatory cytokines upon microbe digestion. The mast cell has granules
that regulate inflammation which also include histamines.
Microbes Right Ans - Foreign substances (e.g. bacteria) that can cause
infection.
Monocytes Right Ans - A circulating leukocyte in the blood. When it enters
the tissue, it becomes a macrophage
Neutrophils Right Ans - A circulating leukocyte in the blood that will bind
microbes and digest them. Undergoes apoptosis upon microbe digestion.
Phagocytosis Right Ans - The process of a cell consuming and destroying
foreign materials (e.g. microbes)
Tissue-resident sentinel cells Right Ans - Dendritic cells, mast cells, and
macrophages. These cells secrete pro-inflammatory cytokines when ingesting
microbes.
Cells Important for Inflammation Right Ans - Blood cells - neutrophils and
monocytes. Monocytes become macrophages. They are phagocytes.
Tissue-resident blood cells (tissue sentinel cells)- dendritic cells,
macrophages, and mast cells. These all release pro-inflammatory cytokines.
Macrophages are also phagocytes. Mast cells have granules that release
histamine and cytokines.
, Response of Sentinel Cells Right Ans - Tissue-resident sentinel cells
respond to microbes that enter the tissue and secrete cytokines and other
mediators. The cytokines and mediators activate endothelial cells which
allows the migration of blood cells into the tissue
Response of Blood Cells Right Ans - Microbes enter tissues, sentinel cells
secrete cytokines, and cytokines act on blood vessels. Cytokines bind to the
endothelial cell receptors which causes increased expression of adhesion
molecules that allow circulating leukocytes to stick to the endothelial cells.
The low-affinity binding between E-selectin (endothelial) and e-selectin ligan
(leukocyte) allows the leukocytes to roll along the walls of the venule. High-
affinity binding between ICAM-1 (endothelial) and integrin LFA-1 (leukocyte)
allows the leukocyte to flatten and enter the tissue between endothelial cells.
Then these phagocytic leukocytes kill microbes. Eventually, tissue
homeostasis is restored.
Formation of Pus Right Ans - When you have microbes collecting in the
tissue, many macrophages and neutrophils collect trying to digest microbes,
and as this occurs neutrophils are dying and releasing their contents. This
buildup of contents and fluid is called pus.
Adhesion molecules Right Ans - When cytokines bind to the endothelial cell
receptors, they cause increased expression of these molecules on the lumenal
side (blood side) of the endothelium. Leukocytes have ligands that will bind to
them. E.g. adhesion molecules: e-selectin, ICAM-1
Contrast the functions of the two main types of phagocytic immune cells -
neutrophils and macrophages. Right Ans - Neutrophils only consume
microbes and undergo apoptosis when they digest the microbe. Macrophages
can consume microbes as well as dead neutrophils. They do not undergo
apoptosis as frequently as neutrophils do.
Explain the role of tissue-resident sentinel cells in innate immunity. Right
Ans - The tissue-resident sentinel cells are always present in the tissue and
ready to detect microbes. This is the main point of innate immunity because
they are ready to defend before infection occurs and before the body
encounters pathogens.
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