immunology lecture 2

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Questions and Answers

What is the primary function of the red pulp in the spleen?

It produces antibodies.

It generates new immune cells.

It stores excess blood for emergencies.

It filters blood by removing old or damaged red blood cells. (correct)

Which of the following structures is primarily associated with T lymphocytes?

Periarteriolar Lymphoid Sheath (PALS) (correct)

Germinal Center

Marginal Zone

B Cell Corona

What characterizes the marginal zone in the spleen?

It contains specialized macrophages and B cells. (correct)

It is the main region for red blood cell filtration.

It is primarily a site for antibody production.

It is only involved in T cell activation.

What is the role of Peyer's patches in the immune system?

They monitor intestinal bacteria and initiate immune responses. Signup and view all the answers

In the flow of lymph through lymph nodes, what is the sequence of spaces that the lymph fluid passes through?

Afferent lymphatic vessel → sub-capsular space → cortical sinus → efferent lymphatic vessel Signup and view all the answers

What defines the structure of the germinal center?

It is a site where B cells proliferate and differentiate. Signup and view all the answers

Which area is involved in coordinating immune responses surrounding lymphoid follicles?

Perifollicular Zone Signup and view all the answers

What role do efferent blood vessels serve in lymphoid organs?

They transport immune cells and waste products away from the organ. Signup and view all the answers

What is the composition of the B Cell Corona in the germinal center?

It is primarily made up of B cells. Signup and view all the answers

Which lymphoid tissue structure is mostly found in the ileum and focuses on intestinal immunity?

Peyer's Patches Signup and view all the answers

Where does B cell maturation specifically occur?

Red bone marrow Signup and view all the answers

What is the main role of secondary lymphoid organs?

To initiate immune responses Signup and view all the answers

Which structure serves as the site of positive selection for thymocytes?

Cortex of the thymus Signup and view all the answers

What type of lymphoid tissue provides protection at mucosal surfaces?

MALT Signup and view all the answers

What defines the endosteal niche in the bone marrow?

It supports hematopoietic stem cells. Signup and view all the answers

What happens to the thymus as a person ages?

It undergoes involution. Signup and view all the answers

What is the primary function of reticular cells in lymphoid tissues?

Providing structural support Signup and view all the answers

Which area contains developing thymocytes within the thymus?

Cortex Signup and view all the answers

What is contained in the medullary cavity of long bones?

Bone marrow responsible for blood cell production Signup and view all the answers

How do afferent blood vessels contribute to lymphoid organs?

They supply blood for oxygen and nutrient delivery. Signup and view all the answers

Study Notes

Primary and Secondary Lymphoid Organs

Primary lymphoid organs are crucial for lymphocyte maturation; include bone marrow (B cells) and thymus (T cells).
Secondary lymphoid organs, such as lymph nodes, spleen, and MALT, are where immune responses are activated.

Tertiary Lymphoid Organs

Tertiary lymphoid organs develop in areas of chronic inflammation or infection, facilitating localized immune responses.

Types of Bone Marrow

Yellow bone marrow is fatty tissue that stores fat and can transform into red marrow when there is an increased need for blood cell production.
Red bone marrow is active in hematopoiesis, primarily located in flat bones and the ends of long bones.

Bone Marrow Structure

Medullary cavity is the central area within long bones containing bone marrow, essential for blood cell creation.
Endosteal niche is a specialized microenvironment near the bone surface that supports hematopoietic stem cells.
Bone marrow vascular niche is where stromal cells and blood vessels interact with hematopoietic cells, regulating blood cell production.

Thymus Structure and Function

The thymus is encased in a connective tissue capsule that offers support and protection.
Subcapsular space beneath the thymic capsule houses developing thymocytes.
Cortex of the thymus is where thymocytes undergo positive selection, while the medulla is where they face negative selection and mature T cells enter circulation.
Thymic involution refers to the age-related decline in thymus size and function, reducing new T cell production.

Mucosa-Associated Lymphoid Tissue (MALT)

MALT includes lymphoid tissues at mucosal surfaces like GALT, BALT, and NALT, essential for protecting mucosal areas and initiating immune responses.

Spleen Structure and Function

Red pulp filters blood, removing damaged red blood cells and pathogens.
White pulp contains lymphocytes that are integral to immune responses and antibody production.
Periarteriolar lymphoid sheath (PALS) surrounds central arterioles in white pulp, containing T lymphocytes that aid immune responses.

Lymphoid Follicles and Germinal Centers

Follicles in secondary lymphoid organs are clusters of B cells vital for activation and proliferation.
Germinal centers are specialized environments in lymphoid follicles where B cells proliferate and differentiate.
B cell corona forms the outer layer of a germinal center, primarily composed of B cells supporting the internal structure.

Marginal Zone and Perifollicular Zone

The marginal zone at the interface of red and white pulp in the spleen has specialized macrophages and B cells.
Perifollicular zone surrounds lymphoid follicles containing T cells, supporting coordinated immune responses.

Peyer’s Patches

Peyer’s patches are clusters of lymphoid tissue in the ileum that monitor intestinal bacteria and play a role in initiating immune responses.

Lymph Flow Through Lymph Nodes

Lymph fluid enters lymph nodes via afferent lymphatic vessels into the sub-capsular space (marginal sinus).
The fluid moves through cortical (trabecular) sinuses and drains into the medullary sinus.
Lymph exits the medullary sinus via efferent lymphatic vessels.
The lymph is transported through lymphatic vessels to other lymph nodes before re-entering the bloodstream.

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Description

Explore the vital roles of primary, secondary, and tertiary lymphoid organs in the immune system. This quiz will help you understand where lymphocytes mature and where immune responses are initiated. Test your knowledge on the anatomy and functionalities of these crucial components of immunity.