Ch 7 - The Lymphatic and Immune Systems

Question 1

What are microbes?

Answer 1

Microscopic organisms, such as bacteria, viruses and protists

Question 2

What are the bodies three lines of defense against pathogens?

Answer 2

1. Barriers to entry
2. Innate immunity
3. Adaptive immunity

Question 3

What are examples of barriers to entry for pathogens?

Answer 3

1. Skin
2. Mucous membranes of body cavities
3. Chemical barriers, such as oil glands in the skin that contain chemicals that weaken or kill bacteria
4. Acid pH of the stomach
5. Acidity of the vagina
6. The flora (microbes) that reside in the mouth, intestine and other areas, which prevent pathogens from taking up residence

Question 4

What is innate immunity?

Answer 4

The first-responders, such as phagocytic white blood cells in tissues: neutrophils, monocytes (that become macrophages and dendritic cells), mast cells, and in blood: monocytes, basophils

Question 5

What is adaptive immunity?

Answer 5

Acquired defenses: B- and T-cells

Question 6

What is bacteria, and what is its stucture?

Answer 6

Single-celled prokaryotes that don’t have a nucleus. Have flagella (the tail to help them move), and some have hairs on their surface to help them stick to things, called fimbriae

Question 7

What is plasmid?

Answer 7

An accessory ring of DNA in bacteria that often carries resistant genes to antibodies

Question 8

What is a pilus?

Answer 8

An elongated, hollow tube on the surface of bacteria that’s used to transfer DNA to other bacterial cells

Question 9

What is a capsule, and how does it help bacteria survive?

Answer 9

The cell wall of some bacteria is surrounded by a capsule, which has a thick, gelatinous consistency. It helps bacteria stick to surfaces and makes it harder for phagocytic WBCs to take them up and destroy them.

Question 10

Bacteria can release _____ that inhibit cellular metabolism.

Answer 10

Toxins

Question 11

What are viruses, and what is their structure?

Answer 11

They bridge the gap between the living and non-living. They’re acellular (not composed of cells), and they lack the ability to acquire and use nutrients. Once the virus is attached to a cell, its DNA or RNA enters the cell. Then it codes for the creation of protein units that the virus’s capsid is made up of. A virus relies on the host’s enzymes and ribosomes for its own production. There are two parts to a virus: the outer capsid shell composed of protein units, as well as the inner core of nucleic acid that contains the genetic info it needs to reproduce itself by latching onto cells.

Question 12

What are prions?

Answer 12

Infectious particles made strictly of proteins (no nucleic acid/DNA), which cause a group of degenerative diseases of the nervous system called “wasting” diseases. For example, CJD, or mad cow disease, is caused when a normally-beneficial prion goes rogue and folds into new shapes. It has the ability to fold other prions into new shapes too, causing disease.

Question 13

What needs to happen to a prion in order for it to stop functioning as a beneficial “housekeeper” in the brain?

Answer 13

It’s proteins would need to change shape, which is what happens in wasting diseases. When proteins change physical structure, they cannot carry out their regular functions effectively anymore. And due to that reason, disease can occur.

Question 14

What is the lymphatic system composed of? Which organs?

Answer 14

1. Lymphatic vessels
2. Red bone marrow
3. Thymus
4. Spleen
5. Lymph nodes
6. Lymphatic ducts
7. Tonsils, appendix, intestines (Peyer’s patches)

Question 15

What are the 4 main functions of the lymphatic system?

Answer 15

1. Lymphatic capillaries absorb excess tissue fluid & return it to the bloodstream
2. In the small intestine, lymphatic capillaries (called lacteals) absorb fats in the form of lipoproteins and transport them to the bloodstream
3. Production, maintenance and distribution of lymphocytes (B- and T-cells) (in red bone marrow and the thymus)
4. Defends the body against pathogens (in lymph nodes, the spleen, peyer’s patches, etc.)

Question 16

Where do B-cells and T-cells form and mature?

Answer 16

Both form in red bone marrow. B-cells mature there, whereas T-cells travel to the thymus and mature there.

Question 17

How do we ensure that our bodies don’t produce any lymphocytes that will react with our own cells?

Answer 17

Any B cell that reacts with the cells of the body is removed in the bone marrow and doesn’t enter circulation. Any T cells that react with the individual’s cells will die in the thymus and also never make it into circulation.

Question 18

What are the primary lymphatic organs?

Answer 18

1. Red bone marrow

2. Thymus

Question 19

What are the secondary lymphatic organs?

Answer 19

1. Spleen

2. Lymph nodes

Question 20

How are lymph nodes different from lymphatic nodules?

Answer 20

Lymph nodes are contained inside a capsule where they can filter lymph. Lymphatic nodules, like the tonsils, are NOT surrounded by a capsule.

Question 21

What are peyer’s patches?

Answer 21

A type of lymphatic nodule. Peyer’s patches are located in the intestinal wall and in tissues within the appendix

Question 22

What role does the spleen play in the lymphatic system?

Answer 22

Filters blood due to containing macrophages that are like powerful vacuum cleaners that engulf pathogens and debris, such as old worn-out RBCs.

Question 23

How is immunity defined?

Answer 23

It is the capability of killing or removing foreign substances, pathogens and cancer cells from the body.

Question 24

What are the two types of immunity?

Answer 24

1. Adaptive = is initiated and amplified by exposure
2. Innate = no recognition that an intruder has attacked before. This is our basic first line of defense to quickly start attacking invaders without knowing what type of invader they are

Question 25

What are monocytes?

Answer 25

Monocytes are in the blood normally. But when there is a pathogen invasion, they seep out of the blood vessel and transform into macrophages (more powerful than neutrophils) and dendritic cells. These two types of cells can then destroy pathogens in the tissue/tissue fluid.

Question 26

Which cells release histamines, and what effect does that have?

Answer 26

Released by mast cells in tissues, and tissue cells also release histamines. Histamine causes capillaries to dilate, and in effect, this causes blood pressure to decrease

Question 27

What is anaphylactic shock and how can it be handled?

Answer 27

An immediate allergic response as a result of an allergen entering directly into the blood stream (i.e. bee stings and penicillin shots). It’s a sudden and life-threatening drop in blood pressure due to increased permeability of the capillaries by histamine. Taking epinephrine can counteract this reaction until medical help is available.

Question 28

How do WBCs react when pathogens enter the body?

Answer 28

1. WBCs move out of the bloodstream into the surrounding tissue.
2. Neutrophils come in first to phagocytize debris, dead cells and bacteria
3. If neutrophils are overwhelmed, they release cytokines
4. The cytokines attract monocytes, which transform into dendritic cells and macrophages
5. Macrophages enlist the help of lymphocytes (B and T cells) to carry out adaptive defense mechanisms

Question 29

What is the complement system, or complement?

Answer 29

These are plasma proteins that “complement” certain immune responses.

1. Some will bind to mast cells and trigger histamine release
2. Others will attract phagocytes to the scene
3. Other complement proteins join to form a membrane attack complex that produces holes in bacterial surfaces so fluids will enter the bacteria, causing it to burst
4. Interferons are proteins produced by virus-infected cells to warn other non-infected cells to start producing substance to combat the virus/replication

Question 30

What is the adaptive immunity defense process?

Answer 30

1. B-cells becomes activated by attaching to free-floating antigens
2. At the same time, macrophages are breaking down antigens and presenting a protein on its surface (MHC II protein)
3. T helper cells attach to these MHC II proteins, and start releasing cytokines. They also start activating more T helper cells
4. The release of the cytokines stimulates B cells to clone itself
5. Most of the cloned B cells become plasma cells, which output antibodies to a specific antigen. Others become memory cells
6. T cytotoxic cells attach to MHC I proteins and destroy them

Question 31

What is defense by B cells called?

Answer 31

Humoral immunity, or antibody-mediated immunity because activated B cells become plasma cells that produce antibodies

Question 32

What is defense by T cells called?

Answer 32

Cell-mediated immunity, because they destroy infected cells.

Question 33

What is apoptosis, and what happens if it fails to occur after a pathogen has been wiped out?

Answer 33

The process of programmed cell death. If this doesn’t occur, there’s potential for an autoimmune response or for T cell cancers.

Question 34

What’s an example of an antigen-presenting cell?

Answer 34

Macrophages

Question 35

What are monoclonal antibodies?

Answer 35

When B-cells turn into plasma cells and start cloning the same antibodies to combat a specific pathogen.

Question 36

What is an immune complex?

Answer 36

A clump of antigens and antibodies that attract white blood cells

Question 37

What are the different types of antibodies?

Answer 37

1. IgG = main antibody in circulation; binds to pathogens, activates complement, enhances phagocytosis by WBCs
2. IgM = Activates complement. Clumps cells
3. IgA = Prevents pathogens from attaching to epithelial cells in digestive and respiratory tract
4. IgD = found on surface of immature B cells. Signifies readiness of a B cell
5. IgE = found as antigen receptors on mast cells in tissues. Responsible for immediate allergic response (+ histamine release) and protection against parasitic worms

Question 38

What are human MHCs, and why are they important for immune responses?

Answer 38

HLAs, or human leukocyte antigens. They’re proteins found on all of our body cells. Each human has a different combination. Important because T cells can see the antigen protein and the self protein (HLA) side by side and determine if it needs to attack antigens that seem to be foreign.

Question 39

What is HIV?

Answer 39

A virus that causes AIDS that infects helper T cells and other cells fo the immune system, which makes the individual susceptible to infections that eventually kill them.

Question 40

What is active vs. passive immunity?

Answer 40

Active = the individual alone produces antibodies against an antigen (either naturally or by being vaccinated).

Passive = being injected with antibodies or immune cells to combat a disease.

Question 41

What is the role of cytokines?

Answer 41

They regulate WBC formation and/or function. They’re signaling molecules produced by macrophages, T cells and others.

Question 42

How does our immune system react to cancer cells and why?

Answer 42

Most cancer cells carry an altered protein on their cell surface, so they should be attacked by cytotoxic T cells.

Question 43

Which antibody is involved in allergic reactions?

Answer 43

IgE, which attach to receptors in mast cells in the tissue and basophils in the blood. These cells release histamines.

Question 44

What is xenotransplantation?

Answer 44

Using animal organs instead of human organs for transplants

Question 45

What is autoimmune disease?

Answer 45

When cytotoxic T cells attack the body’s own cells.

Question 46

What is rheumatoid arthritis?

Answer 46

An autoimmune disease where the joints are chronically inflamed, and it’s thought that antibody-complexes, complement system, neutrophils, T cells and macrophages are all involved in the destruction of cartilage in the joints.

Question 47

What is lupus?

Answer 47

When a person’s central nervous system is damaged as a result of the patient producing high levels of anti-DNA antibodies. This interferes with tissues throughout the body, since all cells contain DNA.

Question 48

What is multiple schlerosis (MS)?

Answer 48

When T cells attack the myelin sheath covering nerve fibers, causing CNS dysfunction, double vision, and muscular weakness.