Immunology Flashcards
(46 cards)
What are leukocytes and erythrocytes and where do they originate from? How long
do they live for?
In your blood, there are three types of cells. They’re commonly known as red blood cells, white blood cells and platelets - and formally named erythrocytes, leukocytes and thrombocytes. These cells move throughout your body in your blood to carry oxygen, fight infections and stop bleeding if a blood vessel is damaged
Describe the characteristic features and functions of:
a) Neutrophils
b) Eosinophils
d) Mast cells
Neutrophil (also known as neutrocytes) are the most abundant type of granulocytes and the most abundant (40% to 75%) type of white blood cells in most mammals. They form an essential part of the innate immune system.
a white blood cell containing granules that are readily stained by eosin. Basophils are Basophilic and easily staines
A mast cell (also known as a mastocyte or a labrocyte) is a type of white blood cell. Specifically, it is a type of granulocyte derived from the myeloid stem cell that is a part of the immune and neuroimmune systems and contains many granules rich in histamine and heparin.
Describe the characteristic features and functions of:
) Monocytes
f) Macrophages
g) B lymphocytes
h) T lymphocytes
i) Natural Killer cells
a large phagocytic white blood cell with a simple oval nucleus and clear, greyish cytoplasm.
a large phagocytic cell found in stationary form in the tissues or as a mobile white blood cell, especially at sites of infection.
a lymphocyte not processed by the thymus gland, and responsible for producing antibodies
a lymphocyte of a type produced or processed by the thymus gland and actively participating in the immune response.
a lymphocyte able to bind to certain tumour cells and virus-infected cells without the stimulation of antigens, and kill them by the insertion of granules containing perforin.
What is an ESR and CRP in terms of laboratory tests? What do they
measure?
The erythrocyte sedimentation rate (ESR or sed rate) and C-reactive protein (CRP)
They measure inflammation
Describe the process of phagocytosis. Which leukocytes can be described as
phagocytes?
the ingestion of bacteria or other material by phagocytes and amoeboid protozoans
two types of white blood cells, neutrophilic leukocytes (microphages) and monocytes (macrophages)
What are the functions of:
i. Lysozyme
ii. Interferons
iii. Complement
iv. Antibodies
an enzyme which catalyses the destruction of the cell walls of certain bacteria, and occurs notably in tears and egg white
Interferons (IFNs) are a group of signaling proteins made and released by host cells in response to the presence of several pathogens, such as viruses, bacteria, parasites, and also tumor cells and boost the immune system
The complement system is a part of the immune system that enhances (complements) the ability of antibodies and phagocytic cells to clear microbes and damaged cells from an organism, promotes inflammation, and attacks the pathogen’s plasma membrane.
An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein produced mainly by plasma cells that is used by the immune system to neutralize pathogens such as bacteria and viruses.
What is the complement cascade and what triggers it?
The complement system is a part of the immune system that enhances (complements) the ability of antibodies and phagocytic cells to clear microbes and damaged cells from an organism, promotes inflammation, and attacks the pathogen’s plasma membrane. can be activated directly by pathogens or indirectly by pathogen-bound antibody
. Describe the process of phagocytosis.
The membrane of a phagocyte surrounds a cell to be engulfed and then pinches off to create a phagosome inside of itself that contains the engulfed material. The cell then breaks it down using enzymes.
What mechanisms do the following cells have for killing bacteria:
a. macrophages
b. neutrophils
c. natural killer cells
Macrophage/Neutrophil - Phagocytosis
Typically, immune cells detect major histocompatibility complex (MHC) presented on infected cell surfaces, triggering cytokine release, causing lysis or apoptosis.
Explain the following:
Opsonisation
Chemotaxis
Pavementing
. The process of opsonization is a means of identifying the invading particle to the phagocyte.
movement of a motile cell or organism, or part of one, in a direction corresponding to a gradient of increasing or decreasing concentration of a particular substance.
the margination of leucocytes on the endothelium near a site of damage.
Describe the mechanism of inflammation. Why does it result in the characteristic
symptoms?
The inflammatory response (inflammation) occurs when tissues are injured by bacteria, trauma, toxins, heat, or any other cause. The damaged cells release chemicals including histamine, bradykinin, and prostaglandins. These chemicals cause blood vessels to leak fluid into the tissues, causing swelling
What factors cause vasodilatation and increase the permeability of blood vessels?
From where do they originate?
One of the best-known chemical mediators released from cells during inflammation is histamine, which triggers vasodilation and increases vascular permeability.
Stored in granules of circulating basophils and mast cells, histamine is released immediately when these cells are injured.
What is a granuloma? How does it differ to granulation tissue?
Granulation tissue contains new small blood vessels, fibroblasts, and mononuclear cells in an edematous extracellular matrix; formation of granulation tissue is part of the repair response.
A granuloma is a form of chronic inflammation it is a collection of immune cells known as histiocytes (macrophages)
Explain the following terms: Serous inflammation Haemorrhagic inflammation Suppurative inflammation Fistula Empyema Cellulitis
Serous inflammation: Is a type of acute inflammation which is characterised by the copious effusion of non-viscous serous fluid, commonly produced by mesothelial cells of serous membranes, but may be derived from blood plasma
form of exudative inflammation in which the enzymes produced by white blood cells cause liquefaction of the affected tissues, resulting in the formation of pus
inflammation of kidney and renal pelvis.
an abnormal or surgically made passage between a hollow or tubular organ and the body surface, or between two hollow or tubular organs.
the collection of pus in a cavity in the body, especially in the pleural cavity.
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inflammation of subcutaneous connective tissue.
Describe the process of healing in the following:
a) Damaged skin b) Fractured bone
While platelets play a crucial role in clot formation during hemostasis, inflammatory cells débride injured tissue during the inflammatory phase. Epithelialization, fibroplasia, and angiogenesis occur during the proliferative phase
1) the formation of hematoma at the break, 2) the formation of a fibrocartilaginous callus, 3) the formation of a bony callus, and 4) remodeling and addition of compact bone.
What is the difference between healing by First Intention and healing by Second
Intention?
First intention - surgery
Second - delayed
Explain the pathophysiology of fever. How may it be treated?
Fever results when something raises the hypothalamic set point, triggering vasoconstriction and shunting of blood from the periphery to decrease heat loss;
What is meant by the terms ‘antigen’ and ‘antibody’?
An antigen is any substance which can provoke an immune response in the body. This immune response results in the production of antibodies, which are immunoglobulin proteins, and which are usually made by immune cells known as plasma cells.
Describe the structure of an antibody. How is specificity achieved?
Each antibody consists of four polypeptides– two heavy chains and two light chains joined to form a “Y” shaped molecule.
What are the five types of antibody? Where are they found and what are their
respective functions?
Antibodies are divided into five major classes, IgM, IgG, IgA, IgD, and IgE,
AEDMG Immunoglobulin A (IgA), mucous membranes, particularly those lining the respiratory passages and gastrointestinal tract, as well as in saliva and tears.
mmunoglobulin G (IgG), the most abundant type of antibody, is found in all body fluids and protects against bacterial and viral infections.
Immunoglobulin M (IgM), which is found mainly in the blood and lymph fluid, is the first antibody to be made by the body to fight a new infection.
Immunoglobulin E (IgE), which is associated mainly with allergic reactions (when the immune system overreacts to environmental antigens such as pollen or pet dander). It is found in the lungs, skin, and mucous membranes.
How are antibodies formed in response to a specific antigen? How is this process
triggered and controlled?
When an antigen enters the body, it stimulates the immune system to produce antibodies
The antibodies attach, or bind, themselves to the antigen and inactivate it.
What is the difference in the primary response and secondary response to antigen
challenge?
. Following the first exposure to a foreign antigen, a lag phase occurs in which no antibody is produced, but activated B cells are differentiating into plasma cells. … The first antibody produced is manily IgM (although small amounts of IgG are usually also produced).
in a secondary response to the same antigen, memory cells are rapidly activated. This process is quicker and more effective than the primary response.
. What is MHC? Where are MHC Class I and II found, respectively and what is the
significance of this distribution?
MHC class I molecules are one of two primary classes of major histocompatibility complex (MHC) molecules (the other being MHC class II) and are found on the cell surface of all nucleated cells in the bodies of vertebrates.
class II molecules are a class of major histocompatibility complex (MHC) molecules normally found only on antigen-presenting cells such as dendritic cells, mononuclear phagocytes, some endothelial cells, thymic epithelial cells, and B cells.
How are T lymphocytes activated by antigen-presenting cells? What are the functions
of cytokines?
cells must be activated by interacting with a professional Anaphase promoting Complex presenting an antigen which their T cell receptor recognizes before they can divide and perform their function. The APC involved in activating T cells is usually a dendritic cell.
Cytokines are a category of signaling molecules that mediate and regulate immunity, inflammation and hematopoiesis.
