Immune System pt 1 Flashcards
what are the functions of the immune system
- recognize and eliminate pathogenic agents
- disposing cells and debris (mutant cells to limit)
- wound healing
describe the 3 components of the immune system
- physical barriers
- leukocytes
- lymphoid tissues
briefly describe physical barriers
- skin (cells packed together tightly)
- mucous membranes (continuous barrier to skin)
describe the various layers of the skin and how they help with immunity
- epidermis has tightly packed epithelial cells
- dermis is thick connective tissue
- provide good physical protection unless pierced
where can we find mucous membranes and what is their purpose
- nose, mouth, anus, vagina make viscous mucous to block particles
- GI tract and stomach make acids to kill microorganisms
- next level of defense if skin not applicable
what are the types of leukocytes
- neutrophils
- eosinophil
- basophil
- monocyte
- lymphocyte
these are WBCs
what are the categories of leukocytes
- granulocytes (BENG)
- agranulocytes (LAM)
- based on presence of granules in cytoplasm
how do leukocytes derive
hemopoietic/hematopoietic stem cells in bone marrow
describe granulocytes
- have cytoplasmic granules
- contain secretory products
- release thru degranulation
describe phagocytes
- engulf foreign particles and microorganisms and remove them from blood or tissues
- neutrophils, eosinophils, monocytes (eat MEN) -> blood
- macrophages, dendritic cells (DM) -> tissues
what are the cells that mature in tissues
macrophages, mast cells, dendritic cells
describe macrophages
cells that derive from monocytes
describe mast cells; where are they found, what do they secrete
- cells forming in bone marrow from hematopoietic stem cells
- found in mucous membranes
- secrete histamine
describe dendritic cells
- cells forming in bone marrow from hematopoietic stem cells
- activate certain T-cells
- EX phagocytose pathogens
what are the roles of lymphocytes
to provide:
- diversity
- specificity
- memory
- ability to distinguish self from non-self in immune system
what are the main types of lymphocytes
- B cells
- T cells
- null cells (most natural killer = NK)
describe B cells, what is their speed
- flag antigens (targets) with antibodies
- intermediate speed
draw the pathway of B cell interacting with antigen
B cell contacts antigen so it differentiates into a plasma cell which then secrete antibodies (immunoglobins) that attach onto foreign invader
describe T cells
- direct attackers to foreign or abnormal cells (infected, mutant, transplanted)
- slowest speed
draw pathway of T cell interacting with infected cells
T cell contacts infected cells and after days it turns into a cytotoxic T cell which secretes molecules that make pores in the target cell’s membrane which causes the cell to fill with fluid which causes cell to rupture
describe NK cells
- small proportion of circulating lymphocytes
- crucial for fighting viral infections
- kill virus-infected cells which limits new virus production
- use similar mechanism to T cells but recognize infected cells differently
- fastest response
what are the 2 types of lymphoid tissues
central (primary) and peripheral (secondary)
describe central/primary tissues
- lymphocytes made and mature here
- bone marrow, thymus, fetal liver
describe cell development in bone marrow
- leukocytes and RBCs
- T cells migrate to thymus for maturation
- B and T cells migrate to peripheral tissues after maturity