Module 15: The Lymphatic and Immune Systems Flashcards
3 functions of lymphatic system
drainage
absorption
protection
Lymph
interstitial fluid that has entered the lymphatic vessels
3L of lymph formed a day
eventually mixes with venous blood in right atrium
lymphatic vessels
capillaries, vessels, trunks, ducts
lymphatic organs and tissues
lymph nodes spleen thymus tonsils peyers patches appendix
Transportation of lymph
only flows towards the heart (away from tissue)
Contraction of skeletal muscles
Movement of lungs/thoracic cage during breathing
Contraction of smooth muscles in walls of lymphatic vessels
valves in vessels
Contractions of nearby arteries
Lymph capillaries
woven between tissue cells and blood capillaries
everywhere except bone marrow, teeth, bones, CNS and tissues lacking blood vessels
Drain excess interstitial fluid
Lymphatic vessels
more valves than veins
Lymphatic trunks
collect lymph from large regions of body into 2 specific lymphatic ducts
Lymphatic ducts
Right - lymph from right upper body; drains into superior vena cava
Thoracic - lymph from the rest of the body; drains into superior vena cava
Cisterna chyli
forms the beginning of the thoracic duct
Lymph nodes
600 nodes in the body
3 main clusters of nodes
axillary (armpit)
inguinal (groin)
cervical (neck)
Structure of nodes
bean shaped, 1inch
Capsule around node
Cortex (outer) contains T and B cells
Meduall (inner) contains B and plasma cells
Trabeculae divide nodes into compartments
Sinuses are channels where lymph flows
Germinal enters of the follicles contains areas of diving lymphocytes
Afferent vessels
transport lymph INTO the node
Efferent vessels
transport lymph OUT of the node
Functions of nodes
filter and clean lymph
Spleen
storage tank for blood Upper left abdominal region White pulp (mostly lymphocytes) Red pulp (old RBC destroyed)
Forms blood during fetal development
Filters and stores blood
Destroy old RBC
Stores Lymphocytes
Thymus
Larger in children
Located within mediastinum (behind sternum)
Pink/gray color in children, yellow with age (fat)
2 lobes
Provides source of lymphocytes before birth
Secrets thymosin that stimulate T cells to attach pathogens
Tonsils and adenoids
palatine - each side of throat
pharyngeal (adenoids) - near opening of nasal cavity
lingual - base of tongue
clusters of lymphatic tissue with crypts that trap foreign substances
Prevent bacteria from entering opening around nasal/oral cavities
Mucosa-associated lymphatic tissue (MALT)
collectively peyers patches in small intestine, appendix, other lymphoid tissue in respiratory tract
First line of defence: nonspecific resistance general defence
skin mucous membrane tears saliva urine vaginal secretions defecation vomiting
second line of defence: additional
antimicrobial substances (protective chemicals) interferon, complement
Natural killer cells
phagocytosis
inflammation
fever
third line of defence: specific resistance
immunity
T cells (cell mediated) B cells (antibody mediated)
antigens
foreign bodies capable of generating a specific response by immune system
Found the surface of pathogens
B cells
develop in bone marrow
mature in bone marrow
t cells
develop in bone marrow
mature in thymus
Humoral (antibody-mediated) immunity
involves production of antibodies
Invading antigen recognized by macrophage and t cell
Helper t cell presents antigen to b cells
B cells divide into plasma cells (produce antibodies) and memory b cells (recognize antigen if it invades again)
Cell-mediated immunity
Antigen presenting cells (APC) aka macrophages present antigen to t cell for destruction
T cell divides into cytotoxic, helper, regulatory, memory
Buboes
infected lymph nodes
Autoimmune diseases
body treats its own tissue as being foreign
Lymphocytes attack
Systemic lupus erythematosus (SLE) rheumatoid arthritis (RA) Multiple sclerosis (MS)
AIDS
acquired immunodeficiency syndrome
caused by HIV
virus destroys helper T cells
Immune system slowly collapse
Aging and the lymphatic system
incidence of infection and cancer is higher because t and b cells are deficient
decreased macrophage activity
Elderly take lots of drugs which may interfere with immune system
