(M) Lec 3: Lymphatic System Flashcards
Also called immune system
Lymphatic System
These are aggregates of lymphocytes in different regions of the body
Lymphoid Tissue
Parenchyma of the system
Lymphocytes
Stroma of the system
Reticular tissue / Reticular cells and fibers
Other cells found in the system
Plasma cells, macrophages, neutrophils, eosinophils
Location of parts of the Lymphatic system
lamina propria of respiratory and digestive system thymus, spleen, lymph node, tonsils
Types of lymphocytes according to size
Small, medium, large
This system protects the internal environment from invasion and damage by foreign substances, cells or microorganisms
Lymphatic system
These refer to which cell:
- Small, spherical or oval
- Large rounded nucleus or slightly indented on one side
- Narrow non-granular cytoplasm
Lymphocytes
Type of lymphocyte according to size
- Majority of cells
- 6-9 um
- Dark staining
Small lymphocytes
Type of lymphocyte according to size
- 9-15 um
- Pale
- Lymphoblasts
Large lymphocytes
What sensitizes small lymphocytes?
Antigenic stimulation
small lymphocytes recognize foreign proteins and they store this info
Referred to as memory cells
T and B lymphocytes
A memory cell that directly attack the foreign organism
t-lymphocyte
The lymphocytes in the thymus contains:
A. T Lymphocytes
B. B Lymphocytes
C. AOTA
D. NOTA
A (100%)
The lymphocytes in the bone marrow contains:
A. T Lymphocytes
B. B Lymphocytes
C. AOTA
D. NOTA
C (10% of the T Lymph and 90% of the B Lymph)
The lymphocytes in the blood contains:
A. T Lymphocytes
B. B Lymphocytes
C. AOTA
D. NOTA
C (70/30)
The lymphocytes in the spleen contains:
A. T Lymphocytes
B. B Lymphocytes
C. AOTA
D. NOTA
C (45/55)
The lymphocytes in the Lymph nodes contains:
A. T Lymphocytes
B. B Lymphocytes
C. AOTA
D. NOTA
C (60/40)
These are programmed to recognize and react with specific types of antigen
Lymphocytes
What are the classifications of lymphoid tissue?
- Loose lymphoid tissue
- Dense lymphoid tissue
- Nodular lymphoid tissue
Trachea, Esophagus, Internodular deep cortical and medullary sheaths of the spleen, Internodular regions of the tonsils and Peyer patches
These are example of which lymphatic issue?
Loose lymphatic tissue
Type of lymphatic tissue
- Few lymphocytes
- Irregularly and loosely scattered
- Stroma: reticular cells and reticular fibers
Loose lymphatic tissue
Type of lymphatic tissue
- Lymphocytes are abundant and closely packed
- Examples: Ileum, Colon, Vermiform appendix
Dense LT
Also known as lymphoid follicles
Nodular LT
Type of lymphatic tissue
- Compact, circumscribed aggregations of lymphocytes
- Aka lymphoid follicles
- Not permanent structures
- Solitary lymphoid nodules
Nodular LT
Found in:
Lamina propria of the digestive, respiratory, and urinary tract
- Aggregates are found in Walls of the ileum called Peyer patches, Veriform appendix
Nodular LT
Type of lymphatic tissue
characterized as compact, circumscribed aggregations of B-cells forming lymphatic follicles or lymphatic nodules
Nodular LT
Refers to:
Aggregates of uniform cell density and staining; Has not encountered any antigen yet; No stimulation of any antigen
Primary lymphoid nodule
Refers to:
Aggregates with larger, more euchromatic cells centrally; Has already encountered an antigenic stimulation
Secondary lymphoid nodule
Its germinal center is a central, pale staining portion of a secondary nodule. This is composed of large activated B
lymphoblasts (centroblasts)
Tonsils
The peripheral, dark staining portion of lymphatic nodules is called the __________.
mantle/corona
Part of tonsil
➢ Smaller, naive lymphocytes pushed to the sides
➢ This is due to the rapid proliferation of activated B lymphoblasts
➢ Crowded together peripherally
➢ This is made up of small lymphocytes with dark staining nucleus and closely packed cells
Mantle/corona of the tonsils
Two classifications of lymphoid organs
Primary and Secondary
Example of primary lymphoid organ
Bone marrow and Thymus
Example of secondary lymphoid organs
➢ Spleen
➢ MALT (Mucosa-associated lymphoid tissue)
o Tonsils
o Peyer patch
Cells of the major lymphoid lineages mature and become functional in two different central or ______________
primary lymphoid organs
After activation in the primary, B and T cells circulate to which type of lymphoid organs?
Secondary
➢ Site of T-lymphocyte differentiation
➢ Selective removal of T-cells reactive against self antigens
Thymus
- Bilobed structure in mediastinum
- Remains large & active in T cell production until puberty
- Undergoes involution
Thymus
Two parts of thymus
Cortex and medulla bitch
Part of thymus
- Darkly basophilic
- Plenty of lymphoblasts aka thymocytes
- A peripheral zone of dense lymphatic tissue consisting of T-lymphocytes
- Do not form lymphatic nodules
Thymic cortex