Lymphatic System (improved)

four functions of lymphatic network to maintain fluid balance in the human body

* collects H20 and solutes that drain from blood vessels
* return them to the blood via lymphatic vessels
* pick up absorbed fats and deliver to blood
* transprot foreign material to lymph nodes for disposal

difference between plasma, interstitial fluid, and lymph

* plasma - from capillaries and has gasses
* interstitial fluid - blood plasma that moves out of the capillaries and 90% moves back
* lymph - the remaining material that doesn’t return to capillaries

illustrate the pathway of lymph and identify the structures it passes through

1. thoracic duct collects lymph from below the diaphragm and the left side above the diaphragm
2. lymph empties into the bloodstream at the left subclavian vein
3. lymph originates in the lower abdomen and runs against the back wall to the neck
4. the right lymphatic duct collects lymph from the right side above the diaphragm, empties into right subclavian vein

describe how lymph forms

* plasma leaves blood capillaries and becomes interstitial fluid
* interstitial fluid increases in pressure by adding proteins
* increased pressure opens lymph capillaries, releasing interstitial fluid

what causes lymph to enter the lymphatic system

pressure pushes lymph from capillaries to vessels

what causes lymph to move through the lymphatic system

skeletal muscles push lymph in the direction that valves dictate

structure of lymph nodes

packed with white blood cells

function of lymph nodes

filter foreign material out of the lymph that is traveling through with lymphocytes and macrophages

define innate immunity

defenses that are already in humans (e.g. barrier defenses like the skin)

acquired immunity

defenses that are not already in humans (e.g. B and T lymphocytes)

example of barrier defense & how it works against infection

skin - prevents diseases and germs from going into our body

example of cellular innate defenses & how it works against infection

eosinophils - damage / kill multicellular invaders / parasites

example of natural killer cells & how it works against infection

NK cells - recognize and remove disease body cells or cancerous cells

steps involved in inflammatory response

1. histamines are release when tissue is damaged
2. this triggers dilation & permeability of nearby capillaries


1. clotting agents & phagocytic cells are delivered to the site, causing redness, swelling, and fever to occur

observable steps of inflammation

redness, soreness, swelling

define antigen

protein labels on molecules that identifies it. antibodies can bind to it to label it

define antibody

bind to antigens to identify foreign invaders for the other components of the immune system

describe how MHCs are used in the acquired immune response

they are a group of proteins designed to display proteins on a cell’s surface for a T cell to recognize

how do macrophages contribute to the immune system

engulfs foreign invaders

how do Helper-T cells contribute to the immune system

* contact B or T cells that also match the current protein antigen
* secretes cytokines which activate matching B or T cells

how do Cytotoxic T cells contribute to the immune system

produced by activated T cells and directly lyse body cells

how do Plasma B cells contribute to the immune system

produced by activated B cells & attach to specific antigens & incapacitates them & mark them for phagocytosis

how do memory cells contribute to the immune system

bear receptors for the same antigen & allow them to quickly mount an immune response if infected in the future

how do antigen-presenting cells contribute to the immune system

internalizes & digests foreign antigen & display it on its surface, allowing other cells to recognize the antigen & bind to it, instigating a series of events that allows the immune system to fight the foreign antigen

describe T cell maturation (process and location)

location: thymus

process: T cells bind to antigens, which activates the T cell, allowing it to directly attack cells or produce cytokines

describe B cell maturation (process and location)

location: bone marrow

process: B cells bind to an antigen & produces clones that become plasma cells, which produce large amounts of antibodies against the antigen, while others become memory B-cells

cell-mediated response

involves the use of cytotoxic cells in defending the body

humoral-mediated response

involves the use of antibodies for defending the body

naturally acquired active immunity

gained through natural exposure to antigens. body produces its own antigens

naturally acquired passive immunity

natural, passive acquisition of antibodies by the fetus from the mother. body does not produce its own antibodies

artificially acquired active immunity

the body produces its own antibodies from the vaccines

artificially acquired passive immunity

acquisition of antibodies through injection & the antibodies only last as long as the injected antibodies last

define allergic response

hypersensitive immune response to a substance that can result in inflammation, itching, or tissue damage, but is normally harmless

antigen-presenting cell (body cell)

travel around and make sure there are no foreign antigen; if there are, they digest and present it on its surface

antigen-presenting cell (macrophages)

engulf damaged cells and cell debris and present it on its surface