LYMPHATIC SYSTEM/IMMUNITY

Mariah Rosette S. HandomonBS Nursing – I (Human Anatomy & Physiology Lecture)

Lymphatic SystemO Is a vast collection of cells and biochemicals that travel in

lymphatic vessels, and the organs and glands that

produce them. (Hole’s 2012)

O Includes a network of vessels that assist in circulating

body fluids, closely associated with the cardiovascular

system. (Hole’s 2012)

O Plays a crucial role in circulation by draining the fluids that

pour out into the extracellular space during capillary

exchange and returning them to the blood. (Norris &

Seigfried 2011)

O A drainage network through. (Norris & Seigfried 2011)

O It removes toxins, helps transports fats, and stabillizes

blood volume despite environmental stress. (Norris &

Seigfried 2011)

Lymphatic System – Second Major Function

O It enables us to live in the world with different types

of organisms, some of which take up residence in

or on the human body and may cause infectious

diseases.

O Cells & Biochemicals of Lymphatic System launch

both generalized and targeted attacks against

“foreign” particles, enabling the body to destroy

infectious micro-organisms and viruses.

Immune System

O Consist of variety of components: the Lymphatic

System, a body-wide network of vessels and

organs through which flows an important body

fluid called lymph; a variety of very peculiar cell

types; and several types of biological molecules,

some of them just as peculiar.

ANATOMY & PHYSIOLOGY OF THE LYMPHATIC SYSTEM

Lymphatic PathwaysLymphatic

Capillaries Lymphatic Vessels

O Are microscopic, closed-

ended tubes. They extend

into interstitial spaces,

forming complex networks

that parallel those of blood

capillaries.

O Formed by a single layer of

simple squamous epithelial

cells. Thin walls allows

tissue fluid to enter

lymphatic capillaries.

O Once it is inside the

lymphatic capillaries it is

called lymph.

O The walls of lymphatic

vessels are similar to those

of veins, but thinner. Like

veins, lymphatic vessels

have flap-like valves that

help prevent backflow of

lymph.

O The larger lymphatic vessels

lead to specialized organs

called lymph nodes.

(Moles 2012)

Lymphatic PathwaysLymphatic Trunks &

Collecting Ducts

O Drain lymph from the lymphatic vessels, are named for the regions they serve.

O They join one of two collecting ducts- the thoracic duct or the right lymphatic duct.

THORACIC DUCT – larger and longer collecting duct. It receives lymph from the lower limbs and abdominal regions, t left upper limb, and left side of the thorax, head and neck and empties into the left subclavianvein near the junction of the left jugular vein.

RIGHT LYMPHATIC DUCT –

receives lymph from the right

side of the head and neck, right

upper limb, and right thorax,

and empties into the right

subclavian vein near the

junction of the right jugular

vein.

O After leaving the two

collecting ducts, lymph

enters the venous system

and becomes part of the

plasma just before blood

returns to the right atrium. (Moles 2012)

Lymphatic

Capillary

Afferent lymphatic

vessel

Lymph node

Efferent lymphatic

vessel

Lymphatic Trunk

Collecting Duct

Subclavian Vein

Lymphatic Pathway(Moles 2012)

Structures of the Lymphatic System

Lymphatic Vessels

O Are thin tubules that carry

lymph.

O Form a network very similar

to the venous system.

O (Lymph Capillaries,

Lymphatic Vessels,

Lymphatic Ducts)

Lymphatic Ducts

O Largest of the lymphatic

vessels , drain into two

large veins.

O Located on the right side of

your neck near your right

clavicle, drains lymph for the

right arm and right half of the

body above the diaphragm

into the right subclavian vein.

The thoracic duct also called

the left lymphatic duct, which

runs through the middle of

your thorax, drains lymph

from everywhere else into

the left subclavian vein.

(Norris & Seigfried

2011)

Structures of the Lymphatic System

Lymph Nodes

O Are bean-shaped structures located along the lymph

vessels.

O Dense clusters of lymph nodes are found in the mouth,

pharynx, armpit, groin all through the digestive system, all

through the digestive system, and other locations.

O Each lymph node is encapsulated (covered) by a fibrous

connective tissue capsule.

O Nodule – numerous extensions that divide the node

internally into structures. It is filled with meshlike network of

fibers which lymphocytes and macrophages adhere.

O Also provide a safe and nurturing environment for

developing lymphocytes. (Norris & Seigfried 2011)

Structures of the Lymphatic System

Splendid Spleen

O A solid organ, located to the left of and slightly posterior to

the stomach.

O Roughly oval in shape, normally measuring about 1 by 3 by

5 in (3 by 8 by 13 cm) and weighing about 8 ounces

(23grams).

O Spleen’s structure is similar to the kidney , to the liver and

the lymph nodes. Enveloped by fibrous capsule.

O It has hilus, a spot where several diff. vessels cross the

capsule.

O Divided into functional subunits by outgrowths of the

capsule’s fibrous tissue.

(Norris & Seigfried

2011)

Structures of the Lymphatic System

“T” Cells

O Thymus Gland - overlies the heart and straddles

the trachea, sitting just posterior to the sternum. It

produces thymosin, a hormone that stimulates the

differentiation and maturation of T Cells.

(Norris & Seigfried

2011)

Body Defenses against Infection

Innate (Nonspecific) Defenses

PATHOGEN – presence and multiplication of disease-causing agent. Includes viruses, bacteria, fungi and protozoans.

The human body can prevent the entry of pathogens or destroy them if they enter. Some mechanisms are quite general and protect against many types of pathogens, providing innate (nonspecific) defense. These mechanisms include species resistance, mechanical barriers (enzyme action, interferon, and complement), natural killer cells, inflammation, phagocytosis, and fever.

Other defense mechanisms are very precise, targeting specific pathogens and providing adaptive (specific) defense, or immunity.

Specific Resistance – refers to the fact that a given type of organism, or species (such as the human species homo sapiens) may be resistant to the diseases that affect other species because its cells do not have receptors for the pathogens or its tissues do not provide the temperature or chemical environment that a particular pathogen requires.

(Mole’s 2012)

MECHANICAL BARRIERS –prevents the entrance of infectious agents. These barriers provide a first line of defense. Skin, Mucous Membranes lines the passageway of the respiratory, digestive, urinary, reproductive systems.

CHEMICAL BARRIERS –

Enzymes in the body fluid. Lymphocytes and fibroblasts produce hormonelike peptides called interferons in response to viruses or tumor cells.

Complement group of proteins, in plasma and other body fluids, that interact in an expanding series of reactions or cascade.

NATURAL KILLERS (NK)

CELLS – small population of

lymphocytes different from the

lymphocytes that provide

adaptive (specific) defense

mechanisms. NK cells defend

the body against various

viruses and cancer cells by

secreting called perforins.

INFLAMMATION - tissue

response to injury or infection,

producing localized redness,

swelling, and pain,. The

redness result of blood

vessels dilation that increases

blood flow and volume of the

affected tissues.

pus– a thick fluid formed by

infection.

Adaptive (Specific) Defenses, or Immunity

PHAGOCYTOSIS – removes foreign particles from the lymph as it moves from the interstitial spaces to the bloodstream.

FEVER – body temperature elevated above an individuals normal temperature due to an elevated set point. It is defense, it makes the body inhospitable to certain pathogens.

IMMUNITY – third line of defense. Is resistance to specific pathogens or to their toxins or metabolic by-products. Lymphocytes and Macrophages that recognize and remember

Specific foreign molecules carry out adaptive immune responses.

ANTIGENS – are protiens, polysaccharides, glycoproteins or glycolipids, usually located on cell’s surface. Most effective in eliciting an immune response are large and complex, with few repeating parts.

LAMPHOCYTE ORIGINS

T Lymphocytes or T Cells-reside in lymphatic organs and are particularly abundant on lymph nodes, thoracic duct, and white pulp of the spleen.

B Lymphocytes or B Cells-abundant in lymph nodes, bone marrow, and intestinal lining.

Thank