Chapter 16- Lymphatic and immune systems

why does transplant rejection happen?

This happens because your body starts to recognize that organ as foreign and starts to reject it

allergies

an exaggerated immune response to a harmless substance

Antigen

any molecule that triggers an immune response.

interpheron

chemical that interferes with the course of that virus protein released from virus-infected cells that helps protect nearby cells from invasion

what do B-cells do?

create antibodies

Explain the beneficial results of inflammation.

include stimulating the body's defense system to begin fighting the infection while instigating measures to contain the pathogen. The inflammatory response also includes processes that clean up and repair the damaged tissue.

2 main phagocytes

neutrophils and macrophages

complement proteins

puncture holes in the plasma membrane so then the cell is not able to control what enters/exits the cell.

What are pathogens?

something that can generate disease -bacteria -viruses

The body's 3rd line of defense against infection

specific defenses final wall (also called immune response) -produced by B-cells & T-cells This occurs when the body retains a memory of a pathogen after defeating it. If exposed to the same pathogen in the future, the body can quickly recognize it, targeting a response at this one specific invader.

functions of the lymphatic system

- Return tissue fluid to the blood stream - Fat transportation - Immunity : defense against pathogens and other foreign material

Describe what a vaccine is and what it does

-A vaccine is made from antigens that are not harmful -helps us create memory so we'll be ready if we do encounter that virus -After getting vaccinated, you develop immunity to that disease, without having to get the disease first.

antibody that helps attribute to your allergy response

-IGE function= enhances inflammation -histamine=triggers inflammation both work hand in hand to trigger that response

the location and function of the lymph nodes

-Lymph nodes lie along lymphatic vessels -Lymph nodes filter lymph (remove pathogens and other foreign material) -Besides cleansing lymph, lymph nodes also serve as sites for final maturation of some types of lymphocytes and monocytes.

the location and function of Peyer's patches

-Peyer's patches are lymphatic nodules residing in the small intestines -Its function includes monitoring intestinal bacteria populations and preventing the growth of pathogenic bacteria in the intestines

Cellular immunity

-cytotoxic t-cells -targets intracellular antigens (viruses)

Humoral immunity

-obtained from B-cells & antibodies -targets extracellular antigens (bacteria and viruses)

the location and function of tonsils

-tonsils are accumulations of lymphatic tissue -the 1st line of defense as part of the immune system

THE BODY AT WORK: 4 classes of immunity

1. Natural active immunity: occurs when the body produces antibodies or T cells after being exposed to a particular antigen. 2. Artificial active immunity: This results when the body makes T cells and antibodies against a disease as a result of a vaccination (such as for tetanus or influenza). By injecting a vaccine containing dead or weakened (attenuated) pathogens, the recipient's body produces an immune response without actually developing the illness. 3. Natural passive immunity: This form of immunity results when a fetus acquires antibodies from the mother through the placenta, or when a baby acquires them through breastfeeding. 4. Artificial passive immunity: This form of immunity involves obtaining serum from a person or animal that has produced antibodies against a certain pathogen and then injecting it into someone else. This is typically used in emergencies for the treatment of rabies and botulism.

Antibody functions

1. Opsonization coating antigen with antibody enhances phagocytosis 2. neutralization -blocks adhesion of bacteria and viruses to mucosa -blocks active site of toxin 3. Activation of complement *Gives you the green light that you're ready to go -hangs out in our body until light turns on -has to be activated before it can start poking holes 4. Agglutination -enhances phagocytosis & reduces # of infectious units to be dealt with *groups them together so, instead of having to take a bunch of little bites, it can just take 1 big bite

key features of B-cells & T-cells

1. Specificity- they know exactly what they're looking for 2. Memory- they will remember if they've encountered that pathogen before

Describe the activation of B-cells and T-cells

1. The immune process begins when a phagocyte (such as a macrophage, reticular cell, or B cell) ingests an antigen. 2. The phagocyte, called an antigen-presenting cell (APC), displays fragments of the antigen on its surface—a process called antigen presentation—which alerts the immune system to the presence of a foreign antigen. When a T cell spots the foreign antigen, it binds to it. 3. This activates (or sensitizes) the T cell, which begins dividing repeatedly to form clones: identical T cells already sensitized to the antigen. Some of these T cells become effector cells (such as cytotoxic T cells and helper T cells), which will carry out the attack, while others become memory T cells. 4. The cytotoxic T cell binds to the surface of the antigen and delivers a toxic dose of chemicals that will kill it. 5. Helper T cells support the attack by secreting the chemical interleukin, which attracts neutrophils, natural killer cells, and macrophages. It also stimulates the production of T and B cells.

the process of phagocytosis

1. When a phagocyte encounters a microorganism, it sends out membrane projections called pseudopods. 2. The pseudopods envelop the organism, forming a complete sac called a phagosome. 3. The phagosome travels to the interior of the cell and fuses with a lysosome, which contains digestive enzymes. 4. The digestive enzymes from the lysosome destroy the microorganism. 5. The waste products are then released from the cell.

2 groups of antigens

1. foreign antigens which originate from outside the body 2. autoantigens which originate within the body

signs of inflammation

1. heat 2. redness 3. swelling 4. pain

rheumatoid arthritis

A chronic inflammatory disorder affecting many joints, including those in the hands and feet **Autoimmune disorder

THE BODY AT WORK: anaphylaxis

A severe, immediate allergic reaction that affects the whole body is called anaphylaxis. Anaphylactic shock occurs when symptoms worsen to the point that circulatory shock and even sudden death may occur. Mild anaphylaxis can often be relieved with antihistamines. Anaphylactic shock, however, is a medical emergency, requiring emergency treatment with epinephrine.

Compare and contrast active and passive immunity

Active immunity: -Immunity that results when the body manufactures its own antibodies or T cells against a pathogen -Active immunity is permanent, or at least long lasting Passive immunity: -immunity that results when someone receives antibodies from another person or animal -In passive immunity, the body doesn't develop a memory for the pathogen, so the immunity lasts only a few months

phagocytosis

the engulfing and destruction of bacteria

complement proteins

Complement proteins are a group of proteins in the blood that, through a cascade of chemical reactions, participate in nonspecific immunity.

Types of T-cells and their function

Cytotoxic T-cell: destroyers, poisonous, kill virus's immediately and attack cancer cells Helper T-cells: help to activate B and T-cells

The body's 1st line of defense against infection

External Barriers (try to stop pathogen on the way in) 1. skin, mucous membranes 2. secretions -lactic acid and fatty acids (skin) -mucus -Tears, saliva, stomach acid -Vomiting, urination, and defecation 3. resident bacteria

Describe the process of fever and explain its role in fighting infection

Fever is an abnormal elevation of body temperature. Elevated body temperature inhibits the reproduction of bacteria and viruses. The process of fever involves: 1. As neutrophils and macrophages phagocytize bacteria, they secrete a fever-producing substance called a pyrogen. The pyrogen stimulates the anterior hypothalamus to secrete prostaglandin E (PGE). 2.PGE resets the body's set point for temperature. For example, it may raise it from a normal of 98.6° F (37° C) to 102° F (39° C). 3.When the set point rises, the body needs to generate heat, which it does through shivering and constricting blood vessels in the skin. The result: chills and cold, clammy skin. 4.The temperature rises until it reaches its new set point, where it remains as long as the pathogen is present. 5.When the pathogen is no longer a threat, the phagocytes stop producing the pyrogen and the body's set point for temperature returns to normal. When this happens, the body needs to lose the excess heat, which it does through sweating and dilating blood vessels in the skin. The result: warm and flushed skin.

Describe how the Human Immunodeficiency Virus (HIV) causes disease in humans

HIV causes disease in humans because the virus invades helper T cells, eventually destroying them. Because helper T cells are a key player in both humoral and cellular immunity, their loss places the host at risk for infections and cancers that a healthy immune system easily rebuffs.

Describe the formation and flow of lymph

Lymphatic vessels are filled with lymph: a clear, colorless fluid similar to plasma but with a lower protein content. Lymph originates in the tissues as the fluid left behind following capillary exchange. Lymph is dumped back into the blood.

The body's 2nd line of defense against infection

Non specific defenses (they are always present and ready to go) 1. Phagocytes (macrophages) 2. inflammation 3. complement proteins 4. fever (our immune system works better @ a higher temp.) 5. interferon

autoimmunity

when your immune system starts to react against your own normal healthy proteins so it starts to attack itself

the location and function of the spleen

The spleen filters the blood