The Lymphatic System and Immune Response, Schemes and Mind Maps of Anatomy

Download The Lymphatic System and Immune Response and more Schemes and Mind Maps Anatomy in PDF only on Docsity!

THE LYMPHATIC SYSTEM

COMPILED BY HOWIE BAUM

THE LYMPHATIC SYSTEM – ALSO CALLED THE

LYMPH OR IMMUNE SYSTEM

 Protects the body from invasion by bacteria or other germs.

 The active part of the system is lymph fluid.

 It drains into networks of tiny capillaries in tissue spaces that unite to form larger vessels called lymphatics.

 Lymph nodes (lymph glands) are the filtering and storage areas of the system, and they are scattered along the routes of the lymphatics.

 Unlike blood, lymph is not pumped; instead it moves passively as lymphatics are compressed by contraction of surrounding muscles during movement.

 Lymph fluid contains large numbers of specialized white blood cells, particularly lymphocytes, which protect the body against non-self material such as invading microorganisms.

https://www.youtube.com/watch?v=JRkLDKrDtDY

THE AUXILIARY IMMUNE

SYSTEM

Many organs have a role in protecting the body against invading microbes.

Together they can be termed the auxiliary immune system, since they supplement the true internal immune system.

Physical mechanisms of protection are provided by structures such as the skin and microscopic hairs, while defenders such as gastric enzymes and useful bacteria protect by chemical means.

Immunity is the body’s defense system against infection and disease.

White blood cells play a key role.

Some rush to attack any harmful microbes that invade the body.

Other white blood cells become specialists, adapted to fight particular pathogens.

All of them work to keep the body as healthy as possible.

IMMUNCE CELLS EATING BACTERIA 1.5 MIN https://www.youtube.com/watch?v=iZYLeIJwe4w

White blood cells , also called leukocytes, defend the body against disease.

They normally account for only 1% of circulating blood volume but increase during infection or inflammation.

Neutrophils are the most common type, comprising 60% to 70% of all white blood cells.

Neutrophils are phagocytes, cells that consume invading pathogens.

A Macrophage is a large phagocytic cell found in stationary form in the tissues or as a mobile white blood cell, especially at sites of infection https://www.youtube.com/watch?v=w0-0Bqoge2E (USE LOW SPEED)

Phagocytes of humans and other animals are called "professional" or "non-professional" depending on how effective they are at phagocytosis.

The professional phagocytes include many types of white blood cells (such as neutrophils, monocytes, macrophages, mast cells, and dendritic cells).

The main difference between professional and non- professional phagocytes is that the professional phagocytes have molecules called receptors on their surfaces that can detect harmful objects, such as bacteria, that are not normally found in the body

The process begins when chemicals from a pathogen, or damaged tissue, attract a phagocyte.

The phagocyte binds to the microbe, envelopes it, and then eats it.

Enzymes within the phagocyte kill and digest the pathogen.

The video shows a human polymorphonuclear leukocyte (neutrophil) crawling among red blood cells, notable for their dark color and principally spherical shape.

The neutrophil is "chasing" Staphylococcus aureus (Staph) microorganisms.

https://www.youtube.com/watch?v=Z_mXDvZQ6dU (make loud at end)

Activated B cells multiply to produce large numbers of clones, most of which become plasma cells.

Plasma cells produce antibodies that recognize antigens on foreign microbes.

The antibodies act as tags to identify the invaders.

This is called an antibody- mediated response.

T cells, activated by antigens presented by phagocytes, multiply then seek out and destroy infected cells.

This is called a cell-mediated response.

LYMPH NODES

The lymph nodes (or “glands”) are vital to the body’s defense system – they produce and hold immune cells (lymphocytes) that protect the body from disease.

Lymph nodes are scattered throughout the body and also concentrated in groups.

Each node is a mass of lymphatic tissue divided into compartments by partitions of connective tissue known as trabeculae.

Lymph fluid from most tissues or organs flows through one or more lymph nodes, where it is filtered and cleaned, before draining into the venous bloodstream.

Lymph nodes vary in diameter from 1 to 25mm ( 1/25 to 1in), although they can swell during infection or illness. Covered in a fibrous capsule, they contain sinuses, where many scavenging white blood cells, called macrophages, ingest bacteria as well as other foreign matter and debris.

Lymphocyte - Chief immune cell, with large nucleus that almost fills the cell; either B or T, depending on development.

Neutrophil - Granulocyte (having many small particles in the cytoplasm) with a multi-lobed nucleus; engulfs pathogens.

Eosinophil - Granulocyte that is important during allergic reactions; B-shaped nucleus; destroys antigen– antibody complexes.

LOCAL INFECTION

If harmful microbes enter body tissues, both the inflammatory and immune responses act swiftly to limit their spread.

The infection may be confined to a naturally defined site, such as the boundary between two sets of tissues.

White blood cells and invaders, living and dead, accumulate, along with fluids, toxins, and general debris.

The resulting mixture is known as pus , and if it gathers in a localized area, this is an abscess.

As the pus collects, it puts pressure on surrounding structures.

This may cause discomfort and pain, especially if the surroundings have no flexibility, as in a tooth abscess.

Microbes gain access through a decayed region of enamel and dentine, infect the pulp, and spread into the root, where pus collects.

As pus presses on the pulp nerves, it causes the pain of toothache.