Immune system and lymphoid organs Flashcards
What are the general functions of the lymphoid system
- Can distinguish self (own body) from non self (foreign substances)
- Neutralizes or inactivates foreign substances
- Destroys foreign substances
What does “self” imply
It means that the immune system is able to distinguish the bodies own cells from foreign substances
What does “nonself” imply
It means that the immune system is able to recognize foreign substances
Innate immunity
Immunity you are born with.
Adaptive immunity
Acquired immunity over time and through exposure to foreign substances (IE vaccines).
Which cells are part of the adaptive immunity
B and T lymphocytes
Which cells are part of the innate immunity
Neutrophils, basophils, eosinophils, macrophages, natural killer cells
Which type of immunity makes antibodies as its response to a foreign subject
The adaptive immunity (Bcells)
How does the innate immunity get rid of foreign substances
Usually through phagocytosis. The cells of the innate system are directly involved in killing pathogens
How does the adaptive response work
T and B cells must recognize the antigens and have a corresponding antibody that will deactivate the foreign substance (antigen)
What is an epitope
The specific portion of an antigen that is recognized by a B or T cell.
Which immune response works faster
The innate immunity response
Immunocompetent cell
Means that a B or T cell is mature and can recognize antigens allowing for immune responses to occur
Immune response
How body recognizes and defends itself against bacteria, viruses and foreign substances
Humoral immunity
(Fluid based) Involves the B cells. Begins with antigen recognition by naive B cells. They then undergo clonal expansion and differentiation. B cell matures into an antibody secreting plasma cells which secretes antibodies. These antibodies will then recognize future exposure
Cellular immunity
Does not involve antibodies, instead it involves the activation of phagocytes, antigen- specific cytotoxic T cells, and the release of cytokines in response to the antigen
Memory cells
The pool of B cells that will recognize an antigen next time it enters the body (i.e. vaccinations)
antigen presenting cell (APC)
Cells that present (or display) the foreign antigen on their surface in order for T cell to interact with
What is the predominant APC for naive T cells
Dendritic cells
Other cells include macrophages, B cells, and basophils
Lymphoid tissue
Tissue that possess lymphocytes (B/T)
Central (primary) lymphoid organs
- Bone marrow
- Thymus
(sites of antigen independent lymphocyte generation)
Peripheral (secondary) lymphoid organs
Tissues in which adaptive immune responses are initiated. Includes:
lymph nodes, spleen, tonsils
(MALT, GALT,BALT, CALT, NALT)
Waldeyer’s ring
3 tonsils make up ring of NALT
Palatine, nasophargyngeal, and lingual tonsil (circle at entrance of gut/airway)
Peyers Patch
Small masses of lymphatic tissue (and nodes) all grouped together found in the ileum region of SI
Immunoglobulin
Antibody, glycoprotein made by plasma cells (WBC). Binds with specific antigens on bacteria and viruses. All mature B cells bear these.
antigen
Any substance that causes your body to make antibodies against it
immunodeficiency
Immune system is having difficulty fighting off infection or disease
Where are B cells made
Bone marrow
Where do B cells mature
In the bursa of the mucosa or basically in the peripheral (secondary) lymph organs
Where are T cells made
Bone marrow
Where do they mature
In the thymus and tonsils
What is a plasma cell
also called a plasma B cells. WBC that secrete large volumes of antibodies.
How are plasma cells transported
By the blood plasma and lymphatic system
Function of lymphatic vessels
- Move fluid from interstitial space
- Carries humoral and antigen bearing cells from tissue to lymph nodes
- Connects lymph nodes
- Dumps lymph fluid back into venous system
What are the two subcategories of adaptive immunity
- Humoral
2. Cellular
3 sets of tonsils
- Palantine
- nasopharyngeal
- Lingual
Function of palatine tonsils
Protect body against respiratory and GI infections
Function of pharyngeal tonsils
Aid in sweeping out or removing foreign substances from the throat to prevent GI or respiratory
Function of Lingual tonsils
Remove invading organisms before it enters throat
Afferent lymphatic vessel
Carries lymph fluid to a lymph node
Efferent lymphatic vessel
Carries lymph fluid away from a lymph node
Follicular Cortex
Outer portion of the lymph node (underneath the capsule) B cell rich!!!
Parafollicular cortex
Deep cortex (or cortex just below the follicular cortex) T cell rich!!!!
Medulla
Inner portion of lymph node, contains medullary cords that are made up of macrophages and plasma cells
Cortical sinuses
The sinuses (or tracts) located in the cortex that drain lymph fluid into the medullary sinuses
Medullary sinuses
The sinuses (or tracts) that separate the medullary cords. Lymph flows from medullary sinuses to efferent lymphatic vessel
Medullary cords
Cords of lymphatic tissue found in the medulla and are made up of plasma cells and macrophages
Which area of the lymph node are rich in B cells
Follicular cortex
Which area of the lymph node are rich in T cells
Parafollicular (deep) cortex
Function of the spleen
- Largest 2ndary lymphoid tissue
- Assesses immune and vascular systems
- Filters blood to remove damaged and worn out RBC
- Activates immune responses
What is the spleen made up of
red and white pulp
Red pulp
Filters blood (flow of blood is from trabecular arteries, to central arteries to red pulp)
White pulp
Lymphoid tissue, made up of PALS (t cells around central artery) and scattered B rich follicles
What are PALS
T cells around a central artery
Splenic sinusoids
Wide blood vessels that drain into the trabecular artery (filters blood)
Splenic cords
Cords in the red pulp that separate the sinusoids. Eat old RBC’s. Macrophage rich!!!!!
Two functions of the thymus
- Site of T cell maturation/production
2. Produces hormones
Blood thymus barrier
Barrier between circulatory system and thymus. Allows T-cells to mature
Thymus cortex
Outer region composed of Immature T cells
Thymus medulla
Inner portion of thymus, composed of MATURE T cells
Hassal’s corpuscle
In thymus, made of flat reticular cells, usually circular. May secrete cytokine, function relatively unknown
