Module 2 lymphatic system Flashcards
3 Functions of lymphatic system
1 - part of immune system (fights pathogens)
2 - Returns excess fluids to the blood
3 - Absorbs lipids in the digestive tract
Lymph
- fluid in the lymphatic vessels
- interstitial fluid collected through lymph capillaries
Lymph vessels
- these begin as lymph capillaries
- resemble veins
Lymph capillaries
- act as filters to trap foreign substances
- in the small intestine the are called lacteals
Lymph nodes
- act as filters to trap foreign substances
- encapsulated masses of B and T cells
- many in head, neck & abdomen
Lymph nodules
- non capsulated masses of lymph tissue
- contain B and T cells
- found in mucous membranes
Lymphocytes
2 types:
- B cells
- T cells
B cells
- Origination & maturation
- Immune response responsible for
- What does it do
- Created in Red bone marrow
- Stays in Red bone marrow & matures there
- Antibody-mediated response
- secretes antibodies
- when activated - becomes plasma cells
- attacks antigens found outside body cells
- produces memory cells
T cells
- Origination & maturation
- Immune response responsible for
- 2 types
- What does it do
- Created in Red bone marrow
- Matures in thymus
- Cell-mediated response
- Helper T (CD4) & Cytotoxic T (CD8)
- Attack invaders directly
- attack antigen found INSIDE body cells
Thymus gets ______ with age.
SMALLER
Most important in infancy when no immunity has developed - shrinks considerably by teens.
Specific Immune response
- Antigen-antibody response
- destruction of a foreign object by a cytotoxic T lymphocyte
- adaptive response
- activated by non-specific response
Non-specific immune response
- Innate defenses; present at birth
- physical barriers: skin etc
- Inflammation
- Phagocytosis
- Interferon - produced by lymphocytes infected with a virus
- Fever
- Chemicals; lysozyme, sweat, sebum
- NK cells; releases perforin to destroy cell
Inflammation
- Vasodilation & increased permeability of capillaries allows more blood flow, antibodies & clotting factors to injured area.
- Emigration of phagocytes: w/in 1 hour phagocytes arrive - neutrophils begin to stick to endothelium of blood vessel - squeeze thru wall to damaged area
- tissue repari = hemostasis
Specific Immunity Types
Intracellular/extracellular
- Cell-mediated: Tcells
- Antibody-mediated: B cells
Antigen
- a foreign substance
- provokes an immune response
Antibodies
- a protein produced by plasma cells in response to specific antigens (immunoglobins).
- combines with antigens to destroy it.
MHC Antigens
- Major Histocompatibility Complex
- self-antigens (marks it as yours)
- used in tissue typing
Cell-mediated response
general response
- Adaptive Immunity
- Intracellular (inside cells)
- Main lymphocyte = Cytotoxic T cells
- directly attacks invading antigens
- faster response
Antibody-mediated response
general response
- humoral immunity
- Extracellular
- B cells transform into plasma cells which then secrete anti-bodies
- Antibodies bind to specific antigens & destroy them
3 major types of Lymphocytes
- B cells
- T cells
- NK cells (natural killer)
Cell mediated immune response STEPS 1 - recognition 2 - activation & proliferation 3 - Attack
1- Naive T cell meets threat (detection)
2- Co-stimulation - Activation of Helper T
- Differentiation - Active & Memory T’s
-Secretion of Cytotoxic T’s
3- Active effector T cells attack target cells
Antibody mediated immune response STEPS 1 - recognition 2 - activation & proliferation 3 - Attack
1-Hangs out in lymphatic tissues until activated
2- Antigen bind to Bcell receptors
-Helper T co-stimulates B cells which then differentia into Plasma cells & Memory cells
3- Plasma cells secrete antibodies
-go to invasion
-antibodies bind to antigen & destroy it.
Memory cell
- remember the antigen
- formed by activation of B-cell
- involved in Antibody mediated immunity
- involved in cell mediated immunity
Helper T-cell
- CD4 cells
- stimulates proliferation of both B & cytotoxic T cells
- mediator of Secondary immune response
