A&P 2 Lymphatic System

what are the main functions of the lymphatic system

fluid balance. lipid absorption. defense

where do lympathic vessels originate

small dead end tubes. lymphatic capillaries

what areas of body lack lymphatic vessels

CNS. bone marrow. tissues without blood vessels (cartilage, cornea, epidermis)

how does lymphatic capillary differ from blood capillaries

lack a basement membrane. cells simple squamous epithelium slightly overlap, loosely attached to each other

structure of lymphatic capillary facilitating their function

more permeable. overlapping acts series one way vavles.

what do lymphatic capillaries join to form

larger lymphatic vessels. resemble small veins.

describe the layer of the lymphatic vessel

inner, endothelium surrounded by elastic membrane. middle, smooth muscle cells and elastic fibers. outer, thin layer fibrous connect tissue

the three mechanisms in which lymph moves through lymphatic vessels

contraction of lymphatic vessels. contraction of skeletal muscles. thoracic pressure changes

jugular trunk drains lymph from....

head and neck

subclavian trunk drains lymph from....

upper limbs. superficial thoracic wall. mammary glands

bronchomediastinal trunk drains lymph from....

thoracic orans. deep thoracic wall

intestinal trunk drains lymph from....

abdominal organs, intestines. stomach. pancreas. spleen. liver

lumbar trunk drains lymph from....

lower limbs, pelvic/abdominal walls. pelvic organs. ovaries or testes. kidneys. adrenal glands

right lymphatic duct

drains right upper arm and right side of head and thorax

largest lymphatic vessel

thoracic duct.drains lymph from right side body inferior to thorax and entire left side of body.

primary lymphatic organs

red bone marrow and thymus. where certain WBCs become immunocompetent

where do Pre-T cells become immunocompetent

move from red bone marrow through blood to thymus

secondary lymphatic organs

lymphatic nodules. tonsils. diffuse lymphatic tissue. lymph nodes. spleen.

what occurs at the secondary lymphatic organs

where lymphocytes interact with each other, other immune cells, and microorganisms/foreign materials produce an immune response

nonencapsulated lymphatic tissues

tonsils. associated with mucous membranes

mucosaassociated lymphatic tissue (MALT)

mucous membranes that line digestive, urinary, and reproductive tracts

diffuse lymphatic tissue

no clear boundaries. located deep to mucous membranes, around lymphatic nodules, and within the lymph nodes and spleen.

lymphatic nodules

denser arrangement, somewhat spherical structures.

what are the large collections of lymphatic nodules

Peyer patches. tonsil

tonsils

protect against bacteria and other stuff from entering pharynx from nasal/oral cavity

name the 3 types of tonsil

palatine. pharyngeal. lingual

pharyngeal tonsil

closely aggregated lymphatic nodules near junction between nasal cavity and pharynx

superficial lymph nodes

subcutaneous tissues beneath the skin

cervical and head lymph nodes filter lymph from.....

head and neck

axillary lymph nodes filter lymph from.....

upper limbs and superficial thorax

thoracic lymph nodes filter lymph from.....

thoracic wall and organs

abdominopelvic lymph nodes filter lymph from.....

abdomen and pelvis

inguinal and popliteal

lower limbs and superficial pelvis

what covers each lymph node and what are the extensions

dense connect tissue capsule covers each. extensions called trabeculae form delicate internal skeleton

reticular fibers......

extend from capsule and trabeculae to form a fibrous network throughout the lymph node

afferent vs efferent lymph vessels

afferent= carry lymph away. efferent= carry lymph toward

germinal centers

rapid lymphocyte division.

white pulp of spleen

lymphatic tissue surrounding arteries within spleen

red pulp of spleen

associated with veins within the spleen. fibrous network filled with macrophages/RBCs. and enlarged capillaries that connect to veins.

functions of the spleen

destroying defective RBCs. detecting/responding to foregin substances in blood. acting as blood reservoir

thymus

bilobed gland. framework consists of epithelial cells.

what is the site for maturation of T cells

thymus

Positive selection of T cells

ensures that T cells are functional and can respond to foreign
antigens

negative selection of T cells

eliminates developing T cells that bind strongly to self antigens.

innate immunity AKA....

nonspecific immunity. body recognizes and destroys certain foreign substances, but response is same each time

adaptive immunity AKA....

specific immunity. body recognizes and destroys foreign substances, but response is faster/stronger than first time was encountered

specificity

the ability of adaptive immunity to recognize a particular substance

memory

ability of adaptive immunity to "remember" previous encounters with particular substance

what are the main components of innate immunity

physical barriers. chemical mediators. cells involved in phagocytosis and production of chemicals that participate in immune response.

examples of physical barriers

skin and mucous membranes. prevent microorganisms/chemicals from entering the body

complement

group of about 20 proteins that protect body by destroying abnormal cells or enhancing other components of immunity.

how do complement proteins get activated

through complement cascade. series of reactions in which each component of series activates next component.

membrane attack complex

produces a channel through a cell's plasma membrane that ultimately destroys the cell

interferons

proteins that protect the body against viral infection and perhaps some forms of cancer. bind to surface neighboring cells and stimulate them to produce antiviral proteins

WBCs are attracted to chemical signals called.....

chemotactic factors

what are chemotactic factors

include parts of microbes and chemicals released by cells of body including complement. leukotrienes, kinins, and histamines

chemotaxis

movement by a cell or organism in reaction to a chemical stimulus

neutrophils

small phagocytic cells produced in large numbers in red bone marrow and released into blood

macrophages

large phagocytic cells. derived from monocytes. provide protection in these areas by trapping and destroying microorganisms entering the tissues

where are macrophages located?

beneath free surfaces of body. also around blood and lymphatic vessels.

basophils

derived from red bone marrow. motile cells that can leave blood and enter infected tissues.

mast cells

derived red bone marrow. nonmotile in connective tissue especially near capillaries.

eosinophils

produced in red bone marrow. increase in response to parasitic infections

natural killer cells

produced in red bone marrow. 15% of lymphocytes. not part of adaptive immunity.

local inflammation

confined to specific area of body

systemic inflammation

not limited

what is different between the feature of systemic and local inflammation

in systemic three aditional things can appear. red bone marrow produces/releases large numbers of neutrophils. fever is induced by release of pyrogens. increased vascular permeability causing large amounts of fluid being lost from blood to tissues.

cytotoxic T cells

responsible producing effects of cell mediated immunity

helper T cells and regulatory T cells

can promote or inhibit activities of both antibody mediated immunity and cell mediated immunity

self antigens

molecules the body produces to stimulate an adaptive immune system response

lymphocytes interact with....

specific regions of the antigen called antigenic determinants

antigen receptors

combine with specific antigenic determinant of given antigen.

T cell antigen receptors

consist of 2 polypeptide chains which are subdivided into variable regions and constant region

B cell antigen receptors

consist of 4 polypeptide chains with two identical variable regions

major histocompatibility complex molecules

glycoproteins found on plasma membranes of most of body's cells. display antigens produced in or processed by cell on cell's plasma membrane

MHC class I molecules

found on nucleated cells. display endogenous antigens on cell's plasma membrane.

MHC class II molecules

display antigens and are found on phagocytic cells called antigen presenting cells which engulf substances encountered in extracellular environment and process them within the cytoplasm.

clonal selection

occurs when lymphocyte proliferates and differentiates when exposed to a specific antigen.

thymosin

stimulate T cell maturation

positive selection

process results in survival of pre-B and pre T cells that are capable of an immune response.

negative selection

process eliminates or suppresses clones acting against self antigens thereby preventing destruction of a person own cells

what are the two general principles of lymphocyte activation

must be able to recognize the antigen. lymphocytes must increase in number to destroy the antigen.

costimulation

accomplished by cytokines released from cells as well as molecules attached to the surface of cells

the first lymphocytes to increase in number are the.....

helper T cells which is important since the increased number o helper T cells responding to the antigen can find and stimulate B cells and cytotoxic T cells

the three primary ways in which tolerance can be induced

deletion of self reactive lymphocytes. prevention of the activation of lymphocytes. activation of regulatory T cells.

antibody mediated immunity

involves proteins called antibodies which are found in extracellular fluids. involves production antibodies in response to extracellular antigens. exposure of body to an antigen can lead to activation of B cells and production of antibodies

the 5 general classes of antibodies are denoted....

IgG. IgM. IgA. IgE. IgD

variable region

antibody. formed by ends of combined heavy and light chains. part that combines with antigenic determinant of the antigen.

constant region

is the rest of the antibody that the variable region isn't

direct effects of antibodies include....

antibody can bind to antigenic determinant and interfere with antigen's ability to function. antibody can combine with an antigenic determinate on two different antigens rendering the antigens ineffective

when an antibody (IgG or IgM) combines with an antigen through the variable region....

the constant region can activate the complement cascade through the classical pathway

antibodies (IgE) can initiate....

inflammatory response. antibodies will attach to mast cells of basophils through constant region

opsonins

substances that make an antigen more susceptible to phagocytosis

first exposure of B cell to an antigen for which it's specific cause

primary response

secondary response or memory response

when immune system is exposed to an antigen against which it has already produced a primary response. provides better production than the primary response

what does the secondary resposne also includes

formation of new memory B cells which are the basis for adaptive immunity

cell mediated immunity

involves the actiosn of T cells. most effective agaisnt cytoplasmic microorganisms. involves hypersensitivity reactions and control of tumors

when do cytotoxic T ells become activated

when exposed to their specific antigen, leading to proliferation and subsequent destruction

what does increased number of helper T cells result in

greater stimulation of cytotoxic T cells

active immunity

results when an individual is exposed to an antigen and the response of the individual's immune response is the cause of the immunity