The Lymphatic System

The Lymphatic System

The Lymphatic System

Carries essential nutrients to the cells

Collects cellular waste

Plays an important role in the immune system of the

body

Lymph

A fluid that fills the spaces

between the blood vessels and the

body cells (interstitial fluid)

Derived from blood, mainly plasma

Made up mostly of water and

circulates in the lymphatic

vessels

Functions of the System

To collect excess lymph and

return it to the blood

circulation, along with any

waste that may be collected

To carry elements of the

immune system such as

antibodies and WBC that will

neutralize antigens (viruses

& bacteria)

To transport molecules such as

fats

Lymphatic Vessels

Similar to blood vessels, they are located near them

They carry lymph and return it to the blood by emptying it into two subclavian veins near the heart (right vein for upper body, left vein for lower body)

Lymph circulates as a result of the contracting of the muscles on the lymphatic vessels (like blood in veins).

Lymph Nodes AKA Ganglions

Small round structures found along lymph vessels

Found in 4 areas:

Groin, neck, armpits, abdomen

During an infection such as tonsillitis or the flu, lymph nodes swell and harden

Lymph is filtered by lymph nodes, which are filled with white blood cells that attack bacteria and viruses

They make WBC

Organs of Lymphatic System

Spleen: in abdomen

Tonsils: in mouth

Thymus: underneath heart

Bone marrow: in long

bones

These organs are filled with

WBC that filter blood and

collect harmful bacteria and

viruses

Spleen

The spleen filters blood. It destroys old worn red

blood cells. It has WBC that attack viruses and

bacteria

The Immune System

Includes vessels and organs of the lymphatic system as

well as other structures or cells, such as white blood

cells, which help to protect the body

Immunity: ability of the human body to protect

itself against foreign antigens

Antigens are viruses, bacteria, abnormal cells or any

other substances that can trigger a reaction of the

immune system

Antibody: substance produced by certain white blood

cells and that is able to neutralize a specific antigen

Non-Specific Immunity

Human body’s ability to protect itself against a wide range

of antigens (white blood cells)

Skin acts as a barrier and is one of the mechanisms of

non-specific immunity

Your lymph nodes or glands become swollen when you are

sick because they are working to make cells to fight infections.

White blood cells move outside of capillaries through a

process called diapedesis and enter the lymphatic system

to reach the site of infection, the white blood cells will

circle the antigens and form pseudopods

Once they reach the pathogen they surround and destroy it

through phagocytosis

Diapedesis

Phagocytosis

Specific Immunity

Human body’s ability to protect itself against a

particular antigen using specific antibodies

Immunity can be acquired in two ways:

Natural acquisition: being exposed to an infection

like chicken pox.

Cells of immune system have a memory of the antibodies

produced by white blood cells to fight against the antigen

causing the infection. If the antigen enters the body again,

body can produce the specific antibodies quicker, and the

person will not develop the illness again

Specific Immunity

Immunity can be acquired in two ways:

Artificial acquisition: being given a vaccine. Vaccines contain

dead/weakened antigens which trigger the production and

memory of antibodies without causing the illness. Vaccinated

person has immunity to that illness if they would encounter it.

**Vaccines do not cure you of diseases – you need to be

vaccinated BEFORE getting sick!

Basically…

General immunity is like an on-going security system

Specific immunity is like someone’s picture being posted

and being banned from entering a building

Vaccines

Substance that, when introduced into an organism, stimulates the immune system; which then manufactures specific antibodies and immunizes the individual against a given disease.

What are they used for?

To protect the health of the people that receive them which will prevent them from developing diseases with dangerous consequences

How does it work?

They contain antigens (bacteria, viruses, virus fragments, etc.) that are weakened and cannot transmit disease. The body still produces antibodies to eliminate these antigens that will be effective against the real disease.

Vaccines

Cowpox and Smallpox – The First Vaccine

Herd Immunity

Vaccines before travelling to certain countries

Refreshing vaccines

The Difference between Antibiotics and

Vaccines

Antibiotics cure disease by killing or injuring bacteria

Although antibiotics are useful in a wide variety of

infections, it is important to realize that antibiotics only

treat bacterial infections.

Antibiotics are useless against viral infections (for

example, the common cold) and fungal infections (such as

ringworm).