Histology Of Lymphatic System Flashcards
The lymphatic system is composed of?
Lymphoid organs and lymphatic vessels
The lymphatic vessels drain into the?
Systemic circulation
Large aggregation of lymphocytes forms?
Lymphoid organs
Lymphoid organs contain___&___
Lymphatic nodules
Diffuse lymphatic tissues
Lymphoid organs can be divided into two groups namely?
Primary lymphoid organs (central lymphoid organs)
Secondary lymphoid organs (peripheral lymphoid organs)
Centres of the immune system where lymphocyte development and maturation occur are called?
Primary lymphoid organs
The undifferentiated stem cells develop into?
B-lymphocytes
T-lymphocytes
Primary lymphoid organs include?
Bone marrow and thymus
T-lymphocyte maturation occurs in the?
Thymus
B-lymphocyte maturation occurs in the?
Bone marrow
Locations of immune system where lymphocytes are functionally specialized by coming in contact with different antigens are called?
Secondary lymphoid organs
Examples of secondary lymphoid organs are?
Mucosa associated lymphoid tissue (MALT)
Lymph nodes
Spleen
Tonsils etc
The three cells of the lymphoid system are?
B-lymphocyte
T-lymphocyte
Null cells
What activates naive B-cells and naive T-cells?
Antigens
Activated B-cells differentiate into?
Plasma cells and memory cells
Memory cells differentiate into plasma cells that produce____ to participate in the humoral immune response
Antibodies
Activated T-cells differentiate into?
Central Memory T cells and effector T cells
Central Memory T-cells secrete ____ that stimulates B-cells to proliferate
Interleukin-2
T-cells that express chemokine receptor surface molecules are called?
Central memory T cells
T-cells that don’t express chemokine receptor surface molecules are called?
Effector memory T-cells
Effector memory T-cells secrete___
Interleukin-4
The secretion of interleukin-4 stimulates
B cells and increase immunoglobulin G and immunoglobulin M
Effector memory T-cells differentiate into?
Effector T-cells
Cells that promote antibody production and stimulate proliferation of eosinophil and mast cells is called?
Helper T-cells
Effector T-Cells that promote antibody production and stimulate proliferation of eosinophil and mast cells is called?
Helper T-cells
Effector T-Cells that kill tumor cells, transplanted cells etc are called?
Cytotoxic T-cells
Effector T-Cells that are involved in immunological tolerance are called?
Regulatory or Suppressor T cells
Examples of effector T-Cells are?
Helper T-cells (secrete IL-2,IL-4 etc)
Cytotoxic T-cells
Regulatory or suppressor T-cells
Null cells include?
Pluripotential hemopoietic stem cells
Natural killer cells (NK cells)
The function of Pluripotential hemopoietic stem cells is to?
Function as stem cells and give rise to various types of blood cells
The function of natural killer cells is to?
Kill invading target cells such as tumour cells
Antigen presenting cells are?
macrophages
Dendritic cells etc
A soft, highly vascular and flexible connective tissue which serve as the primary site of hematopoiesis is called?
Bone marrow
Two types of bone marrow are?
Red bone marrow
Yellow bone marrow
The marrow that is responsible for the formation of blood cells as it contains blood and blood forming cells is called?
Red bone marrow
The inactive bone marrow that contains great number of adipose cells is called?
Yellow bone marrow
The 3 structures of the bone marrow are?
Stroma
Sinusoidal capillaries
Hematopoietic cords
Wide thin walled blood capillaries lined by fenestrated endothelial cells with discontinuous basement membrane are called?
Sinusoidal capillaries
____ are formed of hematopoietic cells which are population of developing blood cells
Hematopoietic cords
The stroma is formed from?
Cells(macrophages, reticular cells etc)
Fibres(collagen & reticular)
Intercellular substance(glycoprotein & proteoglycans)
The visible part of the red bone marrow under microscope are the?
Blood Sinusoids(thin white spaces) Adipocytes( large white circles) Megakaryoblast( large dark circles) Megakaryocyte Myelocytes Normoblasts Erythroblast
A bilobed gland located in the superior mediastinum is called?
Thymus
The thymus gradually atrophies to be replaced by ____ after puberty
Fat
Four microscopic features of thymus are?
Capsule of connective tissue covering both lobes
Numerous septa from the capsule divide it into lobules
Each lobule consists of peripheral cortex & central medulla
Septa contains blood vessels
The thymus is divided into two namely?
Cortex
Medulla
The peripheral dark zone mainly composed of densely packed T-lymphocytes is called?
Cortex
Other cells in the cortex are called?
Epithelial Reticular cells
Macrophages
The central lighter zone of each lobule with Hassal or thymic corpuscles & concentrically arranged epithiocytes is called?
Medulla
3 properties of epithelial reticular cells are?
They are interconnected with each other to hold T-lymphocytes together
They are classified into six types based on their functions and locations
Types I to III are located in the cortex, while types IV to VI are located in the medulla
The barrier that prevents antigen circulating in the blood from coming in contact with thymic lymphocytes is called?
Blood-thymus barrier
The blood-thymus barrier consists of?
Endothelium of capillaries
Thick basement membrane
Layer of epithelial reticular cells
Bean-shaped structures present in the course of the lymphatic vessels are called?
Lymph nodes
Lymph nodes consist of?
Capsule
Cortex
Medulla
Various sinuses
The lymph nodes capsule is made up of __1__ and gives rise to __2__
Reticular Connective tissue
Numerous trabeculae
The darkly stained peripheral part of the lymph node underneath the capsule is called?
The lymph node cortex
The lymph node cortex is divided into?
Outer cortex
Inner cortex
The lymph node cortex consists of?
Lymphocytes(packed)
Plasma cells
Macrophages
The outer cortex consists of ____, ____and a _____ for B-lymphocytes proliferation
B-lymphocytes
Germinal centre
Lymphoid nodule
The inner cortex is also known as the?
Paracortex(thymus dependent cortex)
The inner cortex consists of?
T-lymphocytes
The inner cortex surrounds the?
Medulla
Two properties of lymph medulla are?
Light stained central part of the lymph node
Consists of medullary cord and sinuses
Extensions of the inner cortex separated by medullary sinuses are called?
Medullary cords
The largest lymphoid organ is called the?
Spleen
The parenchyma of spleen consists of?
White pulp
Red pulp
Marginal zone
The connective tissue of the spleen is called?
Reticular dense connective tissue
The white pulp consists of?
Central artery
Lymphatic nodule
The dark ring region around the Germinal centre is called the?
Mantle zone
The region that surrounds the white pulp is called the?
Marginal zone
The red pulp is divided into two components namely?
Red pulp cords
Sinusoids
Red pulp cords are also called?
Cords of billroth
Irregular anastomosing cords surrounding the Sinusoids are called?
Red pulp cords
Two properties of red pulp Sinusoids are?
Wide lumen
Elongated and parallel endothelial cells
The lymphatic tissues found in the mucosa of the digestive, respiratory and genito-urinary tracts are called?
Mucosa-associated lymphatic tissues
Mucosa-associated lymphatic tissues is divided into?
Gut-associated lymphatic tissues(GALT)
Bronchus-associated lymphatic tissues(BALT)
The lymphatic tissues found in the respiratory tract is called?
Bronchus-associated lymphatic tissues(BALT)
The lymphatic tissues found in the digestive tract such as tonsils, large intestine etc are called?
Gut-associated lymphatic tissues(GALT)
Features of mucosa-associated lymphatic tissues are?
Presence of lymphatic nodules with germinal centres
Lymphoid tissues lie in the lamina propria
They are centres of lymphocyte production
Collections of lymphoid tissues near the junction of the oral cavity with the pharynx are called?
Tonsils
The largest tonsils are the?
Left and right palatine tonsils
The Left and right palatine tonsils are found?
On either side of the oropharyngeal isthmus
The pharyngeal tonsil is found on the?
Posterior wall of the pharynx
The lingual tonsils are found on the?
Dorsum of the posterior part of the tongue
The tubal tonsils are found around the?
Pharyngeal openings of the auditory tubes
The epithelium of palatine tonsils is?
Stratified squamous epithelium