Innate & Adaptive Immunity Flashcards
These cells are unique, because they arise from a hematopoietic stem cell and then are further differentiated in the primary lymphoid organs.
Lymphocytes
Lymphocytes
They can be separated into two main classes, depending on where this differentiation takes place.
The primary lymphoid organs in humans are the (2)
bone marrow and the thymus.
Once lymphocytes mature in the primary organs, they are released and make their way to secondary organs, which include the…
spleen, lymph nodes, appendix, tonsils, and other mucosal-associated lymphoid tissue.
PRIMARY LYMPHOID ORGANS
Bone marrow
Thymus
SECONDARY LYMPHOID ORGANS
spleen
lymph nodes
mucosal-associated lymphoid tissues (MALT)
cutaneous-associated lymphoid tissue (CALT)
It is in the ______ that the main contact with foreign antigens takes place.
The____ serves as a filtering mechanism for antigens in the bloodstream, and_____ filter fluid from the tissues.
secondary organs
spleen
lymph nodes
Lymphocyte circulation is complex and is regulated by different cell surface adhesion molecules and by chemical messengers called______.
cytokines
Lymphocytes are segregated within the secondary organs according to their particular functions.
_______are effector cells that serve a regulatory role, and ______produce antibody.
Both types of cells recirculate continuously from the bloodstream to the secondary lymphoid organs and back, in an attempt to increase contact with foreign antigens.
T lymphocytes
B lymphocytes
. A third type of lymphocyte, the______, is large, granular, and plays a role in both the innate and adaptive immune response.
NK cell
All lymphocytes arise from ____________ that appear initially in the yolk sac of the developing embryo and are later found in the fetal liver.
pluripotential hematopoietic stem cells
It can be considered the largest tissue of the body
Bone marrow
Bone marrow fills the core of all ______and is the main source of_____, which develop into…
long FLAT bones
hematopoietic stem cells
erythrocytes, granulocytes, monocytes, platelets, and lymphocytes.
Bone Marrow
Main Functions
Source of hematopoietic stem cells
Development into erythrocytes, granulocytes, monocytes, platelets, and lymphocytes
Most authorities agree that T, B, and NK cells arise from a common precursor known as the…
common lymphoid precursor (CLP)
The_____ functions as the center for antigenindependent lymphopoiesis
bone marrow
Lymphocyte stem cells are released from the marrow and travel to additional ________ where further maturation takes place.
One subset goes to the thymus and develops into_____.
In humans, _____maturation takes place within the bone marrow itself.
primary lymphoid organs
T cells
B-cell
BONE MARROW
• Lymphocyte subsets
B cells
T cells
B Cells
Named after the…
Maturation occurs in…
bursa of Fabricius in birds
bone marrow
T Cells
Precursors go to the____ for
maturation
Immature T cells appear as early as _____in gestation
thymus
8 weeks
T cells develop their identifying characteristics in the______, which is a small, flat, bilobed organ found in the thorax, or chest cavity, right below the thyroid gland and overlying the heart
thymus
Thymus
Function
Site of T-cell maturation and differentiation
Once differentiation occurs, mature T and B lymphocytes are released from the bone marrow and the thymus. They migrate to_______ and become part of a______
secondary lymphoid organs
recirculating pool.
Each lymphocyte spends most of its life span in______, entering the_____ only periodically to go from one secondary organ to another.
solid tissue
circulation
The secondary lymphoid organs include the…
spleen
lymph nodes
tonsils
appendix
Peyer’s patches in the intestines
other mucosal-associated lymphoid tissue (MALT)
Lymphopoiesis, or reproduction of lymphocytes, occurs in the secondary tissue, but this is strictly dependent on______, while formation of lymphocytes in the bone marrow is______.
antigenic stimulation
antigen-independent
The______ is the largest secondary lymphoid organ, having a length of approximately_____ and weighing____ in the adult.
It is located in the _________and surrounded by a thin connective tissue capsule.
spleen
12 cm
150 g
upper-left quadrant of the abdomen, just below the diaphragm
The organ can be characterized as a large discriminating filter, as it removes old and damaged cells and foreign antigens from the blood.
Spleen
Splenic tissue can be divided into two main types:
red pulp
white pulp
The red pulp makes up more than onehalf of the total volume, and its function is to…
destroy old red blood cells.
Blood flows from the arterioles into the_____ and then exits by way of the splenic vein.
red pulp
The _____comprises approximately 20 percent of the total weight of the spleen and contains the lymphoid tissue, which is arranged around arterioles in a______
white pulp
periarteriolar lymphoid sheath
Periarteriolar lymphoid sheath. This sheath contains mainly_____
Attached to the sheath are primary follicles, which contain_____ that are not yet stimulated by antigen.
T cells
B cells
Surrounding the PALS is a______ containing _____that trap antigen.
Lymphocytes enter and leave this area by means of the many capillary branches that connect to the arterioles.
marginal zone ; dendritic cells
Each day, an adult’s blood volume passes through the spleen approximately____ times, where_____ and ____ can constantly survey for infectious agents or other foreign matter.
four
lymphocytes and macrophages
LYMPH NODES
• Function
Central collecting points for lymph fluid from adjacent tissues
Filtration of interstitial fluid allows contact between lymphocytes and foreign antigens
Lymph node
Filtrate of blood from water and low-molecular-weight solutes
Lymph fluid
Lymph node
Location
Along lymphatic ducts, numerous near joints and where arms and legs join the body
Lymph nodes
________is a main function of these organs. The lymph fluid flows slowly through spaces called sinuses, which are lined with _____, creating an ideal location for phagocytosis to take place.
Filtration
macrophages
If contact with antigen takes place, lymphocyte traffic shuts down due to the proliferation of activated cells.
Accumulation of lymphocytes and other cells causes the lymph nodes to become enlarged, a condition known as______. Recirculation of expanded numbers of lymphocytes then occurs.
lymphadenopathy
Secondary lymphoid organs
OTHERS
• Mucosal-Associated Lymphoid Tissue (MALT)
• Cutaneous-Associated Lymphoid Tissue (CALT)
Mucosal-Associated Lymphoid Tissue (MALT)
Tonsils
Appendix
Peyer’s patches
is found in the gastrointestinal, respiratory, and urogenital tracts
MALT, the mucosal associated lymphoid tissue
represent a specialized type of MALT and are located at the lower ileum of the intestinal tract.
Peyer’s patches
The______ are another area of lymphoid tissue found in the mucous membrane lining of the oral and pharyngeal cavities.
Their function is to respond to pathogens entering the respiratory and alimentary tracts.
tonsils
near the junction of the small intestine and the large intestine and has abundant infection-fighting lymphoid cells
Appendix
small masses of macrophage lining oral and pharyngeal cavities
Tonsils
The epidermis contains a number of intraepidermal lymphocytes. Most of these are_____, which are uniquely positioned to combat any antigens that enter through the skin.
This association of lymphocytes is known as the______
T cells
cutaneous-associated lymphoid tissue
differentiate into memory cells and plasma cells and are responsible for humoral immunity or antibody formation
B cells
play a role in cell-mediated immunity, and as such, they produce sensitized lymphocytes that secrete cytokines
T cells
are small polypeptides that regulate the functions of lymphocytes and other cells involved in the immune response.
The characteristics and markers for each type of lymphocyte are considered separately.
Cytokines
certain humoral, or circulating, factors called_______ acted to coat bacteria so that they became more susceptible to ingestion by phagocytic cells.
opsonins
BRANCHES OF IMMUNITY
INNATE (NATURAL) IMMUNITY
ADAPTIVE IMMUNITY
Natural, or innate, immunity
is the ability of the individual to resist infection by means of normally present body functions.
These are considered nonadaptive or nonspecific and are the same for all pathogens or foreign substances to which one is exposed.
No prior exposure is required, and the response does not change with subsequent exposures.
Many of these mechanisms are subject to influence by such factors as nutrition, age, fatigue, stress, and genetic determinants.