Immuno lec 4 lymphocytes pt2 Flashcards

1
Q

Why are lymphocytes mostly found densely packed in specific tissues?

A

To increase chance of APC presentation to other lymphocytes.
To increase

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2
Q

What is the difference between primary and secondary lymphoid organs?

A

Primary or central lymphoid organs is where lymphocytes first express antigen receptors and fully mature.
Secondary lymphoid organs are the places where lymphocytes respond to foreign antigens.

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3
Q

What is hematopoiesis?

A

generation of all types of blood cells.

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4
Q

Where does hematopoiesis take place?

A

In all the skeleton in birth but becomes limited to the marrow of flat bones.

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5
Q

Where do T cells recognize self-antigens?

A

Thymic medullary epithelial cells.
T cells start at the cortex of the thymus and migrate to the medulla.

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6
Q

What is DiGeorge syndrome?

A

A syndrome where T cell count is decreased due to a gene mutation required for the thymus to grow.

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7
Q

How do antigens, cells, and inflammatory mediators move from the tissue to lymph nodes?

A

They enter into the lymphatic system when tissue fluid is absorbed.

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8
Q

What are lymph nodes?

A

Secondary lymphoid organs that are encapsulated and vascularized. Contain follicles containing B cells around follicular dendritic cells. T cells are found near the cortex (parafollicular cortex)

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9
Q

How are B and T cells separated into different compartments in lymph nodes and what is its importance?

A

They respond to different chemokines present in each part of the lymph node, this ensures that each lymphocyte is near the appropriate APCs (T with DC) (B with FDC)

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10
Q

How are heavy and light antigens delivered differently to B cells in the lymph node?

A

Heavy antigens such as viruses are collected by sinus macrophages (around the lymph node) and delivered to cortical B cells.
Light and soluble antigens are transported to resident dendritic cells and then display the antigens to T cells INITIALLY, long-term response requires delivery via tissue dendritic cells

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11
Q

What is the function of the spleen?

A

Get rid of aging and damaged blood cells and particles and initiate the adaptive immune response to blood-borne antigens.

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12
Q

What are the divisions of the spleen?

A

Red pulp, made mainly of blood filled vascular sinusoids.
White pulp full of lymphocytes.

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13
Q

How is blood filtered in the spleen?

A

macrophages in the red pulp remove microbes and damaged cells.

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14
Q

Who are the people that are at risk of encapsulated bacteria infections?

A

people lacking a spleen.

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15
Q

What is the function of the white pulp in the spleen?

A

Promotes immunity against blood-borne antigens.

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16
Q

Where is the marginal zone located in the spleen?

A

Around marginal sinuses which are at the end of vascular branches entering the spleen. marginal zones contain B cells

17
Q

What are non encapsulated lymphoid structures?

A

lymph nodes in skin, GI and bronchial mucosa with immune responses specific for pathogens entering from there. (mucosa associated lymphoid tissue).