Lymphoid & Immune System Flashcards
All organisms belonging to same species have a ______ molecular organization.
Unique
They have developed an _______ or _______ that protects them from macromolecules other than their own
- Immune system
- Lymphoid system
The system consists of lymphoid tissues and organs whose main constituents are ______________ connected through lymphatic and cardiovascular system.
Lymphocytes and their aggregations
These cells are enmeshed in a supportive framework (______) of reticular cells and fibers
Stroma
Lymphoid organs
- Thymus
- Lymph nodes
- Spleen
- Tonsils
Thymus, bursa of Fabricius (in birds) and fetal liver (in mammals) are _________ for developing lymphocytes.
Training centers
Peripheral lymphoid tissues are _________.
Battle fields
The lymphoid tissues ________ invaders by directly attacking them or by producing _______ against them.
- Dispose of
- Antibodies
Immune response involves ______ and _______.
- Antigens
- Antibodies (immunoglobulins)
Immune system components
- Lymphocytes
- Lymphoid tissues
- Lymphoid organs
Lymphocytes arise in _______ and are main warriors of immune system.
Bone marrow
Lymphocytes mature into 2 kinds of cells (____ and _____) and protect against antigens.
T & B lymphocytes
B cells produce _____.
Plasma cells
______ (macrophages) phagocytize foreign substances.
T cells
________ dominate and form connective tissue for support.
Reticular cells
Lymphoid tissues _____ and _______ a proliferation site for lymphocytes
House and provide
Lymphoid Tissue furnishes ideal surveillance point for ______ and ______.
- Lymphocytes
- Macrophages
Lymphoid tissue comes in various packages such as ________ and ________.
- Diffuse lymphoid tissue
- Lymphatic follicles (nodules)
Diffuse lymphoid tissue is a scattered reticular tissue element found in every organ and lacks ______.
-Capsule
Lymphatic follicles (nodules) also…
- Lack ______ but are solid spherical bodies
- Often have _______ (light staining)
- Isolated aggregations of lymphoid follicles are called _______.
- Capsule
- Germinal centers
- Peyer’s patches
Lymph nodes are small organs that occur in series along _______.
Lymphatic vessels
Lymph nodes recognize ________ and are rich in _______.
- Antigenic material
- Macrophages
Lymph nodes are flattened, ovoid, or reniform in shape and have a slight indentation called ______.
Hilus
________ enter lymph nodes at many places through the capsule and have one way valves.
Afferent lymphatic vessels
________ exit lymph node through hilus.
Efferent lymphatic vessels
Blood vessels (arteries and veins) and nerves enter and exit through the _____ along with the efferent lymphatic vessels.
Hilus
The cortex of the lymph node has ____ areas of parenchymal cells.
Three - primary, secondary, diffuse
Primary lymph nodules are in the ______ and consist of tightly packed _____-.
- Outer cortex
- B cells
Secondary lymph nodules are in the _______ and are formed after _______.
- Outer cortex
- Antigentic stimulation
Diffused lymph nodules are in the _______.
Inner cortex
The medulla has aggregations of lymphoid tissue forming _______ and ______.
- Medullary cords
- Sinuses
Histophysiology: lymph nodes are very effective ______.
Lymph filters
Histophysiology: antigens --> lymph nodes --> activated T or B cells (produce antibodies) --> release through \_\_\_\_\_\_\_\_.
Efferent lymphatic vessels or blood vessels
Lymph nodes are masses of ______________.
Parenchymal lymphoid tissue
Lymph nodes are traversed by specialized lymphatic vessels called _______.
Sinuses
Lymph nodes are covered with a _________ which extends into the organ as _________.
- Collagenous capsule
- Trabeculae
Lymph nodes have two sinuses in the cortex - _________ under the capsule and one sinus in the medulla, the ________ sinus
- Marginal or subcapsular and intermediary
- Medullary
The cells in lymph nodes include…
- Reticular cells
- Plasma cells
- Lymphocytes
- Macrophages
Lymphocytes undergo intense mitotic activity and ________ mutations are common
Neoplastic
________ are solid tumors affecting lymph nodes and spreading from node to node
Lymphomas
Hodgkin’s Disease is a major type of _________ characterized by presence of _____________.
- Lymphoma
- Reed-Sternberg cells
Origin of Reed-Sternberg cells is not known but they have unique morphology: ______ nuclei, ______ nucleoli resembling _________.
- Bilobed
- Prominent
- Owl’s eyes
The thymus is located in the superior ________ anterior to the great blood vessels.
Mediastenum
The thymus attains greatest relative weight at the end of ______ and then grows up to 30-40 grams.
Fetal life
The thymus in adults is mostly replaced by ________.
Adipose tissue
The thymus is the only ________ identified in mammals.
Primary lymphoid organ
The thymus is the _____ organ to become lymphoid during embryonic life.
First
The thymus is seeded by _________ which differentiate into lymphocytes.
Blood borne stem cells
The thymus has ___ lobes enclosed in a _____, each divided into several thymic lobules - ______ below capsule
- Two
- Capsule
- No sinuses
Each lobe of the thymus has a _____ and ______.
- Cortex
- Medulla
Lobules are separated by septa and communicate by ___________.
Parenchymal bridges
Has _____ populations of cells – lymphocytes, reticular (epithelial) cells (6 types) and macrophages
Three
The main function of thymus is the maturation of ________- also called ________.
- T lymphocytes
- Thymocytes
_______ are concentric rings of _____ squamous epithelial cells – a unique feature of thymus. The function is not understood.
- Hassall’s or thymic corpuscles
- Type 6
The thymic cortex is
dark staining, has abundant ________, fewer reticular acidophilic cells with large nuclei.
Epithelial reticular cells, called ______, form part of ________ in the cortex.
- Lymphocytes
- Nurse cells
- Blood-thymus barrier
The thymic medulla is light staining, has fewer lymphocytes, abundant _______, Hassall’s corpuscles present.
-Reticular cells
Thymus _______ with age, involves decrease in lymphocyte production; cortex becomes thinner.
Involutes
The thymus is replaced by ________.
Adipose tissue
Age related involution coincides with_____; it ______ disappear completely.
- Puberty
- Does not
______ involution may be due to diseases, stress, diet, radiation, infection etc.
Accidental
______ involution may be due to diseases, stress, diet, radiation, infection etc.
Accidental
The thymus is essential for development of _________.
T lymphocytes
The thymus is generally _______ for immune response to various foreign bodies like microorganisms, fungi, viruses, grafting, hypersensitivity etc
Required
_______ from thymus include: thymosin, thymopoietin, thymic humoral factor and thymic serum factor
Secretions
The spleen is an _______ organ located beneath the diaphragm.
Abdominal
The spleen is _______ to the stomach by peritoneal membrane, diaphragm and the left kidney
Connected
The spleen is enclosed in a ______ forming _______ inside the organ
- Capsule
- Trabeculae
Spleen tissue is differentiated into a _______ (lymphocytes) and a ______ (venous sinuses).
- White pulp
- Red pulp
Tissue between venous sinuses is called _____________.
Splenic cords of Billroth
The White Pulp is similar to lymph nodules and forms _________ (PALS) around arteries.
Peri-arterial lymphoid sheath
The _______ is a network of venous sinuses and has collagen fibers, macrophages and blood vessels
Red Pulp
Blood supply – branching of arteries Splenic --> Trabecular --> Central (in white pulp) --> Penicillar (in red pulp) --> Sheathed capillaries (\_\_\_\_\_\_\_\_\_\_\_) [2-3 capillaries in a sheath]
Schweiger-Siedel sheaths
The spleen is a ________.
Blood reservoir
The spleen _____ and filters blood but ______ filter lymph because there are no afferent lymphatic vessels.
- Cleans
- Does not
The spleen _______ hemoglobin and _______ lymphocytes.
- Degrades
- Produces
Tonsils are the ______ lymphoid organs.
Simplest
The tonsils form a ________ of lymphatic tissue around entrance to the pharynx.
Waldeyer’s ring
The paired ______ tonsils, the largest and most often infected at the back of the mouth.
Palatine
The paired _______ tonsils at the base of the tongue.
Lingual
The single _______ tonsil (adenoids if enlarged).
Pharyngeal
The _____ tonsils surround openings of auditory tubes into the pharynx.
Tubal
The lymphoid tissue of tonsils contain follicles with obvious _________.
Germinal centers
Tonsils are _________ and have _____ that trap bacteria.
- Not fully encapsulated
- Crypts
_______, an inflammation of tonsils, is common in children and often accompanies _______.
- Tonsillitis
- Pharyngitis
Tonsillitis results from infection with bacteria such as _______ or viruses such as __________.
- Streptococcus
- Epstein-Barr virus
_________, surgical removal of tonsils, was standard treatment 20 years ago, but no longer advised unless necessary.
Tonsillectomy
