TOPIC 10 - LYMPHOID SYSTEM Flashcards
What is the main purpose of lymphoid system?
Detect and inactivate foreign substances
Lymph also brings nutrients from blood vessels to cells and picks up waste products. True or False?
True
It is formed when interstitial fluid seeps into lymphatic vessels.
Lymph/Lymphatic fluid
Lymphatic fluid contains?
Lymphocytes, proteins, sometimes bacteria or metastatic tumor cells
Usually, lymph is clear. What about the consistence and composition of lymph draining the gut?
Milky and contains a lot of triglycerides
Lymph draining the gut is also called as?
Chyle
Lymphatic vessels eventually merge together and empty into the blood circulation via the ____ ____ and ____ ____ ____.
thoracic duct, right lymphatic duct
The stroma of all lymphoid organs except the ____ is composed of reticulin fibers.
Thymus
The stroma of thymus is composed of cell processes of ____ ____ ____.
Epithelial reticular cells
Reticular fibers are stainable with silver stains. With that, they are called ?
Argyrophilic
What are the cells of the lymphoid system?
- B-lymphocytes
- T-lymphocytes
- Natural killer cells
Some of the lymphocytes have surface receptors that recognize infected cells. True or False?
False, all of the lymphocytes.
All types of cells of the lymphoid system are distinguishable under a microscope. True or False?
False
This technique is used to looked for markers on the surface of the cells.
Flow cytometry
Sometimes, T cells and NK cells are smaller and have larger granules in their cytoplasm. True or False?
False, they are smaller and have little granules.
What are the antigen-presenting cells of the lymphoid system?
- Macrophages
- Dendritic cells - accessory cells
What are the blood cells associated with the lymphoid system?
- Mast cells
- Neutrophils
- Monocytes
- Eosinophils
This type of immunity involves B cells turning into plasma cells, which make antibodies.
Humoral immunity
This type of immunity involves T cells turning into cytotoxic T cells and helper T cells.
Cellular immunity
What are the two primary (central) lymphoid orrgans?
- Bone marrow
- Thymus
All lymphocytes arise in the bone marrow. True or False?
True
T-cells mature in?
Thymus
When B-lymphocytes and natural killer cells leave the bone marrow, they populate in ____ ____ ____ and recirculate through ____, ____, and ____ ____.
secondary lymphoid organs, blood, epithelia, connective tissue
When T-cells finish maturing in the thymus and leave, they are now called as?
CD4+ and CD8+ cells
What are the T-lymphocytes precursor cells?
CD4 - and CD8 - T lymphocyte precursor
Thymus is located in the ?
Mediastinum
What are the three parts of thymus?
- Lobes
- Capsule
- Septa
What are the 2 regions of lobules of thymus?
- Cortex
- Medulla
CORTEX:LIGHTER::MEDULLA:DARKER
True or False?
False
T cells in the cortex are matured whereas in the medulla, they undergo various stages of differentiation. True or False?
False, other way around.
What are the cells of the thymus?
- T-lymphocytes
- Thymic epithelial reticular cells
Thymic epithelial reticular cells are only present in the cortex. True or False?
False, cortex and medulla
Thymic epithelial reticular cells have scarce cytoplasm. True or False?
False, abundant cytoplasm.
Thymic epithelial reticular cells are have large lightly-staining nuclei and long cytoplasmic processes attached to processes of adjacent cells by ____.
Desmosomes
T-cell precursors from the bone marrow enter the thymus in what region?
Subscapular region
Between inner/deeper and outer cortex of the thymus, where do T-cells undergo active proliferation?
Outer cortex
Between inner/deeper and outer cortex of the thymus, where do T-cells undergo selection?
Inner/deeper outer cortex
Many T cells are produced 97% die. True or False?
True
Hassll’s corpuscles are located at cortex or medulla of the thymus?
Medulla
What is the function of Hassll’s corpuscles?
Unknown
Hassll’s corpuscles are made up of?
Degenerating epithelial reticular cells and keratin filaments
Arterioles and capillaries in thymic cortex are surrounded by ____ ____ ____ with tight junctions, forming a ____-____ ____ which excludes most circulating antigens.
epithelial reticular cells, blood-thymus barrier
Thymus has afferent lymphatics. True or False?
False
Thymus does not filter lymph like a lymph node does. True or False?
True
The thymus is well-developed after birth. True or False?
False, before birth.
The thymus is heaviest at what stage of development?
Puberty