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Year 2 Semester 2 > Pathology > Flashcards

Flashcards in Pathology Deck (311)
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121

Give some examples of biotherapy (cancer treatment)

Glucocorticoids, NSAIDs, receptor tyrosine kinase inhibitors, immunotherapy

122

How does metronomic chemotherapy work?

Targets supporting cells of a tumour (not specific tumour cells)
Reduces new blood vessel formation, and numbers of regulatory T cells supporting the tumour
Most use a combination of an NSAID with cyclophosphamide (alkylator)

123

List 3 chemotherapy drugs which act in a cell cycle specific manner

Vinca-alkaloids eg Vinblastine, Vincristine
Anti-metabolites eg Methotrexate, Cytosine arabinoside

124

List 3 chemotherapy drugs which act in a cell cycle non-specific manner

Alkylators eg Melphalan, Cyclophosphamide, Lomustine
Anti-tumour antibiotics eg Doxorubicin, Epirubicin
Platinating agents eg Carboplatin

125

Which tumour type can L'asparaginase work against?
In which species is it more effective?
How does it work?

Lymphoma
Dogs
Converts L'asparaginase to to L'aspartic acid. Malignant lymphocytes are dependent on asparagine therefore it causes lymphocyte death

126

What is the definition of immunity?

The process which allows the recognition and removal of non-self material which enters the body

127

What is the difference between innate and adaptive immunity?

Innate: Non-specific. Body's first line of defence. Rapid onset. Phagocyte-mediated. No protective immunity.
Adaptive: Shows specificity and memory. Slower. Lymphocyte-mediated. Protective immunity possible. Activated.

128

What are defensins?

Small peptides secreted by cells, particularly in skin, which directly attack bacteria, viruses and fungi.
Part of innate immunity

129

What are lysozymes?

Enzymes found in many bodily secretions. They are capable of digesting cell wall proteoglycans and thereby destroying microorganisms.
Part of innate immunity

130

What is the function of the myeloperoxidase system?

Produces toxic oxygen and chlorine products which kill bacteria. Produced by phagocytes. Part of innate immunity.

131

What are acute phase proteins?

A group of proteins whose serum concentration rises rapidly shortly after infection. For example, C-reactive protein which is produced by liver in response to release of endogenous pyrogen (IL-1) from macrophages. It binds to bacterial cell walls and can activate the complement cascade, thereby promoting bacterial destruction.
Part of innate immunity

132

What are interferons?

A family of glycoproteins which are produced in response to viral infection. 3 types: IFNα, IFNβ and IFNγ. IFNα and IFNβ are produced by many cell types, whilst IFNγ is produced only by activated T cells.
Stimulate NK cell activity and promote differentiation of B lymphocytes.
Act as a link between innate and adaptive immune systems

133

Mast cells have receptors for which antibodies?

IgE

134

Macrophages and neutrophils have receptors for which antibodies?

IgG

135

Which cells do NK cells kill?

Tumour cells, virally-infected cells, antibody-coated cells
Part of innate immunity

136

What are antigens?

Molecules identified by the host as foreign, and to which the host reacts in an attempt to protect itself from infection and subsequent damage

137

What is immunogenicity?

The ability of an antigen to stimulate an immune response
Related to its molecular size

138

Where do B and T lymphocytes mature?

B lymphocytes: bone marrow (and Bursa of Fabricus in birds)
T lymphocytes: thymus

139

What do B cells differentiate into?

Plasma cells, which synthesise and secrete antibodies. Humoral immunity.

140

Give 3 examples of antigen-presenting cells

Macrophages
Dendritic cells
B cells

141

Where do antigen fragments come from and how do they result in antigen-presenting cells?

Antigen fragments are produced by degradation of the antigenic organism/material. The most obvious site for this is in lysosomes in macrophages where components of the large antigen, mainly the proteins, are only partially digested. Peptide fragments are then returned to the macrophage cell surface where they are presented to lymphocytes.

142

What are the primary lymphoid organs?
What are the secondary lymphoid organs?
What happens at each?

Primary=(Bursa of fabricus in birds), bone marrow and thymus. Here, T and B cells mature into Ag-recognising cells. Lymphocytes acquire Ag-specific receptors.
Secondary=spleen and lymph nodes. Here, Ag-driven lymphocyte proliferation and differentiation takes place.

143

Describe the structure of the thymus

Connective tissue capsule. Internal framework of long thin processes of epithelial cells in which macrophages and dividing immature and mature T cells are scattered. The thymus is divided into an outer cortex where lymphocytes are densely packed, and an inner medulla where the epithelial-like cells predominate. The medulla also contains Hassall's corpuscles. Invaginations of the connective tissue capsule divide the cortex, but not medulla, into lobes. The thymus is seeded with immature T cells from BM which mature and leave via postcapillary venules in the medulla.

144

Why does the thymus degenerate with age?

The thymus loses its role once all secondary lymphoid tissues have been richly seeded with mature T cells, which are then capable of dividing

145

Describe the flow of lymph through a lymph node

Lymph enters via many afferent lymphatic vessels, which penetrate the convex surface of the capsule. It then filters through the tissue of the node and is drained by a few efferent lymphatic vessels leaving from the concave surface

146

What are trabeculae (in lymph nodes)?

Extensions of the capsule into the cortex to give mechanical support

147

In which part of the lymph node do B and T cells congregate?

B cells: cortex
T cells: paracortical zone (junction of cortex and medulla)

148

What are germinal centres in lymph nodes?

Pale-staining areas consisting of blast-like cells which are activated B cells.

149

Describe the structure of the spleen

Capsule of connective tissue (or in some species such as cat, smooth muscle). Internal framework of reticular fibres containing macrophages and antigen-presenting cells. Trabeculae extend in from capsule to give internal support. Internal structure is divided into red and white pulp. Blood enters via trabecular arteries. Branches leave the trabeculae and enter the tissue of the spleen where they are immediately surrounded by a periarterial sheath (PALS). These arteries are called central arteries.Venous drainage is via trabecular veins.

150

What is contained in the red pulp of the spleen?

Open sinusoids containing RBCs