21.1 Anatomy of the Lymphatic and Immune Systems

define immune system

complex collection of cells and organs that destroys or neutralizes pathogens that would otherwise cause disease or death.

define lymphatic system

the system of vessels, cells, and organs that carries excess fluids to the bloodstream and filters pathogens from the blood.

what is an example of the lymphatic and immune system working together

The swelling of lymph nodes during an infection and the transport of lymphocytes via the lymphatic vessels are but two examples of the many connections between these critical organ systems.

main function of lymphatic system

to drain body fluids and return them to the bloodstream.

what happens to the fluid that leaks out of caps

the accumulation of fluid in the interstitial space—that is, spaces between individual cells in the tissues.

what is interstital space

space between individual cells in the tissue

how much plasma is released into the interstitial space daily

20 liters of plasma is released into the interstitial space of the tissues each day

wen does the filtrate of blood in the cap. filtration become interistial fluid

Once this filtrate is out of the bloodstream and in the tissue spaces, it is referred to as interstitial fluid.

what happens to most of the interstitial fluid

17 liters is reabsorbed directly by the blood vessels, while 3 L enters the lymphatic system

when do lymphatic system come to play after ciricualtory filtration

It drains the excess fluid and empties it back into the bloodstream via a series of vessels, trunks, and ducts.

define lymph

term used to describe interstitial fluid once it has entered the lymphatic system.

what happens when lymphatic system is damages

protein-rich interstitial fluid accumulates (sometimes “backs up” from the lymph vessels) in the tissue spaces.

how can lympatic system b damaged

such as by being blocked by cancer cells or destroyed by injury

what is lymphedema

This inappropriate accumulation of fluid referred to as lymphedema may lead to serious medical consequences.

define lymph nodes

small, bean-shaped organs located throughout the lymphatic system that serve as staginh areas for immune responses

what else is transported through lymphatic syste,

dietary lipids and fat-soluble vitamins absorbed in the gut uses this system.

how do lymphatic vessels begin

begin as a blind ending, or closed at one end, capillaries, which are closed at 1 end

what happens to lmyph as it travels through the lymphatic vessels

travel through larger and larger lymphatic vessels, and eventually empty into the bloodstream by a series of ducts.

where r lymph nodes found

groin, armpits, neck, chest, and abdomen.

how many lymph nodes do humans have

about 500–600 lymph nodes throughout the body

how is lymph moved through lymphatic vessels

that lymph is not actively pumped by the heart, but is forced through the vessels by the movements of the body, the contraction of skeletal muscles during body movements, and breathing.

what keeps lymph moving in one direction through lymphatic vessels

One-way valves (semi-lunar valves) in lymphatic vessels keep the lymph moving toward the heart.

where do lymphatic vessels empty into

dumped into the circulatory system via the lymphatic ducts located at the junction of the jugular and subclavian veins in the neck.

define lympathic caps

vessels where interstitial fluid enters the lymphatic system to become lymph fluid.

lymphatic caps also called

terminal lympahtics

where are lympathic caps located

Located in almost every tissue in the body, these vessels are interlaced among the arterioles and venules of the circulatory system in the soft connective tissues of the body

are lympathic caps foind in all tisssues

no, not in the CNS, bone marrow, teeth, and cornea of eye

how do lypmatic caps collect intersitial fluid

slips through spaces between overlapping endothelial cells that compose the lymphatic capillary

what controls the entry of fluid into lyphatic caps

entry is controlled by intersittial pressure, which opens or closes the spaces between endothelial cells, and collagen filaments that anchor the caps t surrunding structures

what is special abt lympahtic caps in small intestin

lymphatic caps called lacteals transport dietary lipids and lipid soluble viatmins to bloodstreasm

what is lacteal

lymphatic caps in small intestine that trnapost dietary lipids and lipid soluble vitmains to bloodsteam

what is chyle

milk fluid formed in small intest when dietary triglycerides combine with other lipids and porteins, which enters the lacteals and travels through lyphatic system

what do lymp caps empty into

larger lympatic vess

wat is the strucute of larger lympathic ves similar to

veins in terms of their three runic structure and presense of valves

what are lymphatic trunks

larger lympahtic ves formed by merging of superficiial and deep lympahtics

what is cisterna chyli

sac like chamber that receives lymph from the lower abdomne, pelveis, and lower limbs and marks the beginning of the thoracic duct

which side of the body drain into right subclavian vein via right lymphatic duct

On the right side of the body, the right sides of the head, thorax, and right upper limb drain lymph fluid

which side of the body drain into thoracic duct and event. left subclavian vein

On the left side of the body, the remaining portions of the body drain into the larger thoracic duct, which drains into the left subclavian vein.

where does throacic duct begin

beneat diaphragm in cisterna chyli

what is the difference in drainage area between the throacic duct and right lymphatic duct

throacic duct drains a much larger poriton of body than right lympathci duct

which parts of body drain into right lympahtic duct

receives lymph from only upper right side of body

how do suerpicial and depp lymphatic vessels generally follow blod vessels

superficials lympahtic follow same route as veins, while deep lympahtic vessels follow the paths of arteries

what is throacic fuct

major lymphatic fuct that drains lymph from most of the body (ecept upper right side) and empties into subclavian vein

what is right lymphatic fuct

what are barrier defenses in the immune system

such as the skin and mucous membranes, are bodys first liine of defense against pathogens, which act instantaneously to prevent pathogenic invasion into the body tissues

the immune system is a collefect of

barreirs, cellsm and soluble proteins that interact and comm with each other in extraordinary complex ways

what are the three phases of immune sysstem based on timing of their effects

the 3 temporal phases

what r 3 temporal phases

barrier defense, innate immune response, and adaptive immune response

what is innate immunre response

The rapid but nonspecific, which consists of a variety of specialized cells and soluble factors

what is adaptive immune response

relatively slow but very specific and effective immune response controlled by lymphocytes

what r lymphocytes

type of WBCs (leukocytes) that pkays a key role in controlling immne response

where do blood cells, including immune cells, originate from

arise from bone marrow from hematopoietic stem cels

what is special about hematopoiietic stem cells

are present throughout adulthood, allowing for continuous differentiatin f blood cells to replace those lost to age or function

what are the three clases of immune cells based on function

phagocytic cells, lymphocytes, cells containing cytroplasmic granueles

what is the role of lymphocytes

specifically coordinate the activities of adaptive immunity

what do phagocytic cells do

which ingest pathogens to destroy them

what do cells containt cytoplasmic granukes do

help mediate immune responses against parasites and intracellular pathogens such as viruses

what are the primary cells of adaptive immune respinse

lymphocytes

what are the two basic types of lymphocytes

T and B cells

how r b cells and t cells distinguished from each other

by surface protein markers and the moleucles they secrete

b and t cells have

large central nucleus surrounded by thin layer of cytoplas

where does b cells mature

rbm

where does t cells mature

thymus

where do both b and t cells develop

bone marrow

where are b cells and t cells found

blood stream, lymph, secondary lymphoid organs like teh spleen and lymph nodes

what r b cells

immune cells that function primarily by producing antibodies.

what antibody

any of the group of proteins that binds specifically to pathogen-associated molecules known as antigens.

what antigen

a chemical structure on the surface of a pathogen that binds to T or B lymphocyte antigen receptors.

what happens when b cells activated by antigen

B cells differentiate into cells that secrete a soluble form of their surface antibodies.

what r plasma cells

activated b cells

what t cell

plays a central role in cell mediated immunity, helping to regulate immune responses and fight infections

what do differnt t cells types have the ability to

either secrete soluble factors that communicate with other cells of the adaptive immune response or destroy cells infected with intracellular pathogens.

what plasma cell

a B cell that has differentiated in response to antigen binding, and has thereby gained the ability to secrete soluble antibodies.

what is distincitve about the morphology of plasma cells

contain a large amout of cytoplasma packed with rough endoplasmic reticulum, which is the protein synthesizing machiner

what is role of natural killer (NK)

partcipate in the innate immune response and are among the bodys first lines of defense against viruses and certain types of cancers

what do NK and cytoxic cells have in common

shares the same mech. but in adaptive immune response

priamry function of b lympocytes

generates diverse antibodies

primary function of t lymphocytes

secretes chenical messengers

primary function of plamsa cell

secretes antibodyes

primary functin of nk cell

destroys virally infected cells

what r primary lymphoid organs

bone marrow and thymus gland

defone primary lypmhoid organs

where lymphocytes mature, proliferate, and are selected, which enables them to attack pathogens without harming the cells of the body.

where r blood cells made during embronic develop

yolk sacs, spleen, lypmph nodes, and liver but later bone marrow takes over most hematopoietic functions

what is function of rbm

site of hematopoiesis, where blood cells r produced

wat is thymocyte

immature t cell that leaves bone marrown and matures largerly in the thymus gland

what is yellow bone marrow

site of energy storage, which consists largerly fat cells

what is thymus

thymus gland is a bilobed organ found in the space between the sternum and the aorta of the heart

what holes thymus gland tofether to aorta

Connective tissue holds the lobes closely together but also separates them and forms a capsule.

what divides the thymus into lobules

connective tissue capsules via textensions called trabeculae

what r 2 main regions of thymus

cortex and medulla

what cells r found in cortex of thymus

contain large numbers of thymocytes, epithelial cells, macrophages, and dendritic cells

what happens to thymocytes in medulla

thymocytes migrate to medulla b4 leaving thymus

where do lyphocytes mount immune responses

from secondary lymphoid organs

what is a naive lympocyte

one that has left primary lymphoid organ and entered a secondary lymphoid organ and has yet to encounter a antigen to responsd to

what r examples of secondary lympphoid organs

lymph nodes, spleen, and lymphoid nodukes

what are geminal centers

sites of rapidly divifing and differentiating b lymphocytes

what do all secondary lymphoid organs tissues contain

The presence of lymphoid follicles, the sites of the formation of lymphocytes, with specific B cell-rich and T cell-rich areas, An internal structure of reticular fibers with associated fixed macrophages, Germinal centers

function of lymph nodes

remove debris and oathogens from lymph, acting as filters of the lymph

what happens to bacteria that infect the intersistial fluid

bacteria are taken up by lymphatic caps and transported to a regional lymph node, where they are internalized and killed by dendritic cells and macrophages

what type of immune responses occur in lymph nodes

adaptive immune responses mediated by t cells, b cells, and accessory cells