Major lymphoid organs and their composition

What are the two primary lymphoid organs

Bone marrow and thymus gland

What is bone marrow responsible for?

Bone marrow is responsible for development of the B cells and production of Thrombocytes.

Where does thrombocytes mature to after leaving the bone marrow?

Thymus

What organ is bilobed found in the space between the sternum and aorta of the heart? What hold the lobes together?

Thymus. Connective tissue holds them together but separates them into a capsule.

Describe the structure of the thymus.

The thymus is a bilobed organ that contains an outer cortex and inner medulla. The outer cortex is packed with lymphocytes and macrophages. The medulla contains thymocytes, epithelial cells, and dendritic cells.

What are the two main functions of the thymus?

T lymphocyte maturation, but does not directly fight antigens. Secretes hormones that stimulate lymphocytes to become immunocompetent.

What are the lymphoid organs of the body?

Thymus, bone marrow, lymph nodes, spleen, lymph nodules (tonsils, MALT,)

Where are lymph nodes found?

Embedded and clustered along lymphatic vessels, that occur on the body surface in inguinal, axillary, and cervical regions of the body.

Describe the structure of a lymph node

Bean shaped with a surrounding capsule, trabeculae that extend inward from the capsule and divided into two regions: a cortex and a medulla.

What region of a lymph node contains follicles with germinal centers, heavy with B cell, and houses T cells in transit?

Cortex

What region of a lymph node extend from the other region and contains B cells, T cells, and plasma cells?

The medulla

What are the two functions of lymph nodes?

Filtration of macrophages that destroy microorganisms and debris. Immune system activation-monitor antigens and mount an attack against them.

What is the location, structure, and 4 functions of the spleen?

The spleen is located on the left side of abdominal cavity below the diaphragm. it is the largest lymphoid organ that is fragile without a strong capsule and has extensive vascularization. The spleen is divided into nodules, each containing red pulp and white pulp.

The spleen is the site for lymphocyte formations, the immune response and cleansing of blood, fetal erythrocyte production, and storing of blood platelets.

What is the purpose of a tonsil?

To trap and destroy bacteria and particulate matter

What are the 4 types of tonsils and their locations?

Palatine tonsils. Located in the posterior oral cavity.

Lingual tonsils. Located at the base of the tongue.

Pharyngeal tonsils. Located in the posterior wall of the nasopharynx.

Tubal tonsils. Found around the auditory tubes into the pharynx.

What lymphoid organ consists of an aggregate of lymphoid follicles directly associated with the mucous membrane epithelia, located in the mucosa of the GI tract, breast tissue, lungs, and eyes?

Mucosa-associated lymphoid tissue (MALT)