The Lymphatic and Immune System

Fluid that is found outside the circulatory system and also outside cells is

A. lymph.

B. plasma.

C. interstitial fluid.

D. intracellular fluid.

C. interstitial fluid.

These lymph system structures are designed to ensure that foreign cells meet with lymphocytes. As such, they serve as outposts of the immune system.

A. lymph nodes.

B. lymph capillaries.

C. lymphatic ducts.

D. lymphatic trunks.

A. lymph nodes.

Members of this kingdom are eukaryotic and unicellular. Some of them are pathogenic.

A. Archaea

B. Bacteria

C. Protista

D. Fungi

C. Protista

All of the following are part of the first line of defense of the immune system EXCEPT

A. phagocytes

B. native bacteria

C. mucous membranes

D. intact skin

A. phagocytes

These leucocytes kill by "touch killing." They contact a foreign cell and release perforins and they also cause apoptosis.

A. B cells

B. neutrophils

C. helper T cells

D. NK (natural killer) cells

D. NK (natural killer) cells

What are the three parts of the lymphatic system?

lymph vessels/ lymphatics

lymph

lymph nodes

interstitial fluid

fluid in the tissues between cells

What are the functions of our lymphatic system?

- Transports lymph and "junk" from the tissues back to the cardiovascular system.

- Filters the lymph fluid in lymph nodes to destroy pathogens as part of the immune system.

- Nourishes cells in the lymphatic system.

(Transport fats from the small intestine)

What are the jobs of the lymphatic vessels?

- The lymphatic vessels provide a one-way system that carries lymph back toward the heart

What are the types of lymphatic vessels?

- Lymph vessels (lymphatics) include the lymphatic capillaries, collecting vessels, (trunks,) and ducts.

Lymphatic capillaries are similar to blood capillaries, except:

- they are very permeable (take up cell debris, pathogens, and cancer cells) and

- they have endothelial cells that overlap to form one-way minivalves, that are anchored by collagen filaments, to preventing their collapse

Lymphatic collecting vessels are similar to veins, except that they

- have thinner walls, with more internal valves

- anastomose [uh-nas-tuh-mohz] more frequently

Right lymphatic duct drains

the right upper arm and the right side of the head and thorax

Thoracic duct drains

the rest of the body

Lymphatic ducts empty into venous circulation where

at the junction of the internal jugular and subclavian veins on its own side of the body

What causes lymph to move through the lymphatic vessels?

- the respiratory pump

- the muscular pump

What are the main warriors of the immune system

Lymphocytes

2 main types of lymphocytes

T and B cells

T cells

that manage the immune response AND attack and destroy foreign cells

B Cells

that produce plasma cells which secrete antibodies

Monocytes

circulate for a few days in the blood. They then move to the tissues where they turn into...

macrophages

Monocytes that move to the tissues

that phagocytize foreign substances and help activate T cells

What is lymphoid tissue?

a type of connective tissue that is filled with reticular cells and fibers. It is filled with lymphoid cells.

Function of lymphoid tissue?

- Provides a proliferation site for lymphocytes

- Furnishes a surveillance vantage point. When foreign protein is picked up, it ends up in lymphatic tissue which can then defend the body against it.

Function of lymph nodes

filter lymph (macrophages then destroy microorganisms and debris) AND as part of the immune system, the lymphocytes are activated and mount a defensive attack

Functions of the spleen

- Site of lymphocyte proliferation and immune surveillance and response

- Cleanses the blood of aged cells and platelets and debris

- Stores breakdown products of RBCs (e.g., iron) for later reuse

- Stores blood platelets

- Has a fibrous capsule and trabeculae (internal divisions)

- Contains lymphocytes, macrophages, and huge numbers of erythrocytes

Function of the thymus

T (thymus) lymphocyte maturation

structure of the thymus

- Its size changes with age

- Increases in size from infancy and is most active during childhood

- Stops growing during adolescence and then gradually atrophies

Describe the structure and function of the tonsils

- Simplest lymphoid organs

- Form a ring of lymphatic tissue around the pharynx

- Contain tonsillar crypts that trap and destroy bacteria and particulate matter.

- Lymphoid cells are exposed to this material and protect us from it.

What are Peyers patches? Where are they found and what is their function?

- are clusters of lymphoid follicles that are found in the wall of the distal portion of the small intestine

- They destroy bacteria, and thereby prevent them from breaching the intestinal wall

What kingdoms belong to the domain Prokaryote

Archaea

Bacteria

What kingdoms belong to the domain Eukaryote

Protista

Plantae

Fungi

Animals

Witch Domain and Kingdoms are pathogenic

Bacteria

Protista

Fungi

Animals

Unicellular Eukarya

Protista (algae, slime molds, protozoans)

Multi Cellular Eukarya

Plantae

Fungi

Animals

Eukarya, Multicellular, Autropic

Plantae(Moss, ferns, conifers, flowering plants)

Eukarya, Multicellular,Heterotropic, External digestion

Fungi (yeast, Mushrooms)

Eukarya, Multicellular,Heterotropic, internal digestion

Animals (sponges, worms, arthropods, vertebrates)

No nucleus

No nuclear membrane

1 chromosome

Loop chromosomes

Prokaryote

Nucleus

Nuclear Membrane

several chromosomes

Rod chromosomes

Eukaryote

- Not living

- Not cells

- Made of genetic material (DNA or RNA) wrapped in a protein coat

Viruses

- Entamoeba histolytica (amoebiasis/ amoebic dysentery)

- Plasmodium (malaria)

- Giardia lamblia

- Trypanosoma brucei (African sleeping sickness)

- Toxoplasma gondii (toxoplasmosis)

Protozoal diseases

Athletes foot

Ringworm

Nail infections

Thrush

Fungal diseases

Roundworms

Tapeworms

Lice

Fleas

Animal diseases

- Act against any organism that is attacking the body.

- The first line of defense keeps pathogens from entering the body.

Innate (nonspecific) defenses

Innate (nonspecific) defenses - first line

surface barriers

Innate (nonspecific) defenses - Second line

internal cells and chemicals

Innate (nonspecific) defenses - first line (Surface barriers)

Physical

- Intact skin - keratin

- Mucous membranes (with cilia)- on the - systems that open to the body's surface.

Chemical

- Enzymes

- pH

- Lysosomes in fluid secretions (tears, saliva, sweat, mucus with lysosomes)

Biological

- Native bacteria - "Good bugs"

What five groups of cells and chemicals are included in this second line of defense in Innate (nonspecific)?

- Necessary if microorganisms invade deeper tissues

- Phagocytes - neutrophils and macrophages

- Natural killer (NK) cells

Inflammatory response (macrophages, mast cells, WBCs, and inflammatory chemicals)

- Antimicrobial proteins (interferons and complement proteins)

- Fever

What are NK (natural killer) cells?

NK cells are lymphocytes that kill virus-infected cells AND cancer cells.

To what do NK cells respond and how do they do so?

They kill by secreting perforins to damage the cell membrane AND they cause apoptosis (programmed cell death.)

Apoptosis changes include:

- chromatin condensation

- nuclear fragmentation

- chromosomal DNA fragmentation

- blebbing (forming an irregular bulge in the plasma membrane)

- cell shrinkage

What is the role of antimicrobial proteins (interferons and complement?)

- A cells that has a virus in it is dead.

- Viral-infected cells are activated to secrete interferons (IFNs.) IFNs enter neighboring cells causing them to produce antiviral proteins that block viral reproduction

Complement proteins do what

insert into bacterial membranes and form a pore that causes the cell to burst.

The adaptive (Specific) immune system

- Is specific - one specific cell will target one specific pathogen

- Is systemic

- Has memory - The system will also "remember" that it has encountered this pathogen before

hapten

An incomplete antigen (hapten) does not directly trigger an immune response, but does when it binds to proteins in the body. They cause hypersensitivities.

complete antigen

A complete antigen can trigger an immune response.

What is an antigen?

- Cells have proteins, polysaccharides, glycoproteins, and glycolipids on their surfaces.

- These molecules act as antigens when they cause an immune response.

- The body learns to recognize its own antigens as "self." MHC are "self" proteins.

- Our body will attack cells with "non-self" antigens.

What is an antigen determinant

Antigenic determinants are the regions of the antigen that cause the immune system response.

What is an MHC

(major histocompatibility complex) markers are self-antigens. These are cell surface proteins that act that the body "feels" and recognizes a cell as "self."

B lymphocytes target

Bacteria and molecules in exteracellular enviroment

T lymphocytes target

body cells infected by viruses

abnormal or cancerous cells

transplanted tissues

B lymphocytes mature were

Bone marrow

T lymphocytes mature were

Thymus Gland

Active cells of B lymphocytes

Effector Cells

Memory cells

Active cells of T lymphocytes

Toxic 8 1

Cytotoxic --> CD8 --> MHC 1

Help 4 Z

Helper Cells --> CD4 --> MHC 2

Naïve cells

have not been exposed to their (non-self) antigen.

Effector cells

fight against the current pathogen.

Memory cells

"remember" the current pathogen for the next infection.

What 2 lessons do B and T cells have to learn to me mature

Immunocompetence

and

Self- Tolerance

Immunocompetence

they must be able to recognize and bind to a specific antigen

Self- Tolerance

they must be unresponsive to self antigens

Antigen-Presenting Cells (APCs)

- engulf antigens

- They then present fragments of antigens on their surface attached to MHC proteins so that they can be recognized by T cells

The three major types are dendritic cells

Macrophages

B Cells

Adaptive Immunity

Uses lymphocytes, APCs, and specific molecules to identify and destroy nonself substances

Adaptive Immunity depends on

- Recognize antigens by binding to them

- Communicate with one another so that

the whole system mounts a specific response

Antigen challenge

is the first encounter between an antigen and a naive immunocompetent lymphocyte.

Antigen challenge occurs where

It usually occurs in the spleen or a lymph node

What is clonal selection

- B cell is activated when antigens bind to its surface receptors and cross-link them

- Receptor-mediated endocytosis of cross-linked antigen-receptor complexes occurs

- Stimulated B cell grows to form a clone of identical cells bearing the same antigen-specific receptors(T cells are usually required to help B cells achieve full activation)

First exposure to a specific antigen

Lag period: three to six days

Peak plasma antibodies: 10 days

Antibody levels decline: after 10 days

Secondary exposure to a specific antigen

Lag period: hours

A Peak plasma antibodies: 2-3 days

Antibody level decline: after weeks to months

Antibodies bind with greater affinity

What is immunological memory?

Immunological Memory -or- Fool me once, shame on you; fool me twice, shame on me.

Natural immunity

acquired in the regular course of life due to exposure to a pathogen

Artificial immunity

acquired by man's means

Active immunity

memory cells are produced

Passive immunity

antibodies are received

What is an antibody

Proteins secreted by plasma cells (effector B cells)

Capable of binding specifically with antigen detected by B cells

IgM

First antibody released - early infection

Potent agglutinating agent

Activates and fixes complement

IgA

In mucus and other secretions (saliva, sweat, intestinal fluids, milk)

Helps prevent entry of pathogens

MHC (major histocompatibility complex) markers

are self-antigens. These are cell surface proteins that act that the body "feels" and recognizes a cell as "self."

Dendritic cells are able to obtain other cells' endogenous antigens by

- Engulfing dying virus-infected or tumor cells

- Importing antigens through temporary gap junctions with infected cells

How do helper T cells work?

Once primed by APC presentation of antigen, they

Help activate T and B cells

Induce T and B cell proliferation

Activate macrophages and recruit other immune cells

Without TH, there is no immune response

How do cytotoxic T cells work

Directly attack and kill other cells

Tc cell releases perforins and granzymes by exocytosis

Perforins create pores through which granzymes enter the target cell

Granzymes stimulate apoptosis

cytotoxic T cells target

Virus-infected cells

Cells with intracellular bacteria or parasites

Cancer cells

Foreign cells (transfusions or transplants)