20 & 21) Lymphatic & Immune System Flashcards
1-18 quiz, 19- lecture notes
the lymphatic trunk that drains the head and neck is called the ___ trunk
jugular
the lymphatic trunk that drains the abdominal viscera is called the ___ trunk
intestinal
lymph enters a node through a (an) ___ lymphatic vessel
afferent
the lymph nodes associated with the lymphatic vessels that drain the lower limbs are located in the ___ region
inguinal
lymphatic vessels contain ___ that help prevent the backflow of lymph
valves
peyer’s patches, tonsils, and the appendix constitute this group
MALTs
lymphatic vessels usually lead to ___ that filter the fluid being transported
lymph nodes
large lymphatic organ that filters both blood and lymph
spleen
lymph nodes contain large numbers of white blood cells called ___ and macrophages that fight invading microorganisms
lymphocytes
antibody producing cells
B cells
type of humoral immunity that you get by being exposed to a disease or vaccine
active
nonspecific immunity that you are born with
innate
specific, acquired immunity
adaptive
type of humoral immunity that you can receive from your mother or an antiserum
passive
substance released from a cell infected with a virus
interferons
the process of a cell engulfing a foreign substance
phagocytosis
an important phagocyte of the lymph system
macrophage
cytotoxic and helper cells
T cells
lymphatic system
*network of vessels that assist in circulating fluids
*closely associated with the circulatory system
functions of lymphatic system
*transporting excess fluid away from interstitial space to the bloodstream
*absorption of dietary fats and transporting fats to the bloodstream
*helps defend the body against disease
lymphatic pathways
lymphatic capillaries=> lymphatic vessels=> lymph nodes=> lymphatic trunks=> lymphatic collecting ducts=> subclavian veins
lymphatic capillaries
*microscopic, closed end tubes, extend into interstitial spaces, parallel blood capillaries
*single layer simple squamous epithelium
*fluid filters out of capillaries that is reabsorbed, promotes movement of interstitial fluid into lymphatic capillaries
lymph
fluid in the lymphatic system
lacteals
special lymphatic capillaries that transport absorbed fats to venous circulation
lymphatic vessels
*walls similar to veins but thinner
*composed of three layers- endothelial lining, smooth muscle, connective tissue
*large vessels lead to lymph nodes=> larger lymphatic trunk
lymphatic trunk (collecting ducts)
*drain lymph from vessels
*collecting ducts drain lymph trunk
*thoracic duct (larger)- drain into left subclavian vein
*right lymphatic duct (smaller)- drains into right subclavian vein
lymph flow
*filtration from plasma exceeds reabsorption, leading to excess tissue fluid (edema)
*increased tissue fluid = increased hydrostatic pressure forcing fluid into lymphatic capillaries
*skeletal muscle action, respiratory movement, smooth muscle in large lymphatic vessles, and vales help move fluid in lymphatic system
lymphatic cells
*immune system cells- found in lymphoid tissue (lymphocytes)
*supporting cells- form lymphoid tissue structures
lymphocytes
*adaptive immune system (two types)
*T cells (T lymphocytes)
*B cells (B lymphocytes)
*both protect against antigens (e.g. bacteria, toxins, viruses, cancer cells)
*other immune cells: macrophages, dendritic cells, reticular cells
T cells (T lymphocytes)
manage immune response and destroy infected cells
B cells (B lymphocytes)
produce plasma cells- type of WBC that excrete antibodies
antibodies
mark antigens for destruction by phagocytosis
macrophages
phagocytize foreign substances and help activate T cells
dendritic cells
capture antigens and deliver them to lymph nodes and help activate T cells
reticular cells
produce reticular fibers (stroma)- support and act as scaffolding for immune cells
lymphatic tissue functions
*house and provide proliferation sites for lymphocytes
*“surveillance vantage points” for lymphocytes and macrophages as they filter through lymphatic system
lymphatic organs
*primary lymphoid organs- areas where T and B cells mature (red bone marrow and thymus)
*secondary lymphoid organs- areas where mature lymphocytes first encounter their antigens and become active (nodes, spleen, MALT, diffuse lymphoid tissue)
lymph nodes function
*filter potentially harmful particles from lymph
*immune surveillance by macrophages and lymphocytes
lymph nodes
*bean shaped mass of lymphatic tissue
*collect lymph fluid through afferent vessels into sinuses of lymph nodes, exit through efferent vessels
* afferent vessel=> subcapsular sinus=> smaller sinuses (in cortex and medulla)=> medullary sinuses=> efferent lymphatic vessel=> hilum
cervical lymph nodes
drain skin of the scalp, face, tissues of nasal cavity and pharynx
axillary lymph nodes
drain the upper limbs, wall of thorax, breasts, upper wall of abdomen
supratrochlear lymph nodes
located in the elbow region
inguinal lymph nodes
drain lower limbs, genitalia, and lower abdominal wall
pelvic lymph nodes
drain pelvic viscera
abdominal lymph nodes
drain abdominal viscera
thoracic lymph nodes
drain thoracic viscera and internal wall of thorax
thymus
*organ of the lymphatic system, similar to lymph nodes
*located within the mediastinum, posterior to the upper part of sternum
*divided into two lobes
*site of T lymphocyte production
*secretes thymosin- stimulates maturation of T cells
spleen
*organ of the lymphatic system, similar to lymph nodes, filters blood
*located in upper left abdominal quadrant
*consists of:
white pulp- contains many lymphocytes
red pulp- capillaries in red pulp are porous, cellular debris and other foreign particles are engulfed and destroyed by macrophages.
mucosa-associated lymphoid tissue (MALT)
*lymphoid tissue in mucous membranes found throughout the body, protects from pathogens entering the body
*found in respiratory tract, genitourinary organs, digestive tract, tonsils, appendix, peyers patch (in small intestine)
innate (non-specific) defenses
*general defenses
*protects against many types of pathogens
adaptive (specific) defenses
*known as immunity
*more specific and precise, targets specific antigens
*carried out by lymphocytes that recognize foreign molecules
species resistance
*certain species are resistant to certain diseases
*certain species lack receptors for certain pathogens
*or not appropriate temp, chemical environment for a particular pathogen to proliferate
first line defense
mechanical barriers: skin and mucous membranes, prevent pathogen entrance
second line defense
inflammation: triggered when body tissue injured
chemical barriers: enzymes, interferons, defensins, collectins, complements
natural killer (NK) cells
Phacocytosis
fever
inflammation
*triggered by tissue injury
*benefits:
prevent spread of damage, disposes of cell debris and pathogens, alerts adaptive immune system, sets stage for repair
chemical barriers
*enzymes- provide chemical barrier to pathogens
*interferons- block viral replication, acts against growth of tumors, stimulate phagocytosis
*defensins- peptides produced by neutrophils, cripple microbes
*collectins- proteins that protect against bacteria, yeast and some viruses
*complements- group of proteins stimulate inflammation, attract phagocytes, and enhances phagocytosis
natural killer (NK) cells
*small population of lymphocytes
*provide adaptive defenses against viruses, cancer cells (produce Perforins-lyse cell membranes)
*enhance inflammation
third line of defense
*adaptive defenses- carried out by lymphocytes and macrophages that recognize specific antigens
*cellular immune response- performed by immune cells
*humoral immune response- performed by antibodies
lymphocyte development
*origin- originate in red bone marrow
*maturation- B cells in bone marrow, T cells in thymus, lymphocytes in lymph organs
*seeding secondary lymphoid organs and circulation
*antigen encounter and activation
*proliferation and differetiation
effector cells
clone cells that fight infections
memory cells
respond to same antigen more quickly second time it is encountered
cellular immune response
T cell activation by antigenic fragments attached to macrophages, or B cells=> then recognize the antigen=> T cells secrete Cytokines- enhance cellular response to antigen
humoral immune response
*B cells activated when antigen fits shape of receptors, bind to them
*cytokine released, T&B cells proliferate