Kine 2011 - Module 2

Blood and immune system.

Describe the makeup of blood.

55% of blood is plasma, which is made up of 90% H2O, 7% plasma proteins, and 3% other. 45% of blood is formed elements made up of 99% red blood cells, <1% white blood cells and platelets.

What is a hematocrit?

The measure of blood volume made up by red blood cells. Hematocrit of the average man is 45% (of 5.5L) and 42% in the average woman (of 5L).

What are the physiological roles of blood?

Carrying: oxygen, nutrients, hormones. Regualtion: body temperature and pH. Protection: clotting and immunoglobulins.

Describe plasma.

A yellow substance that contains water, electrolytes, nutrients, wastes, gases, and hormones. Also conatins the protein albumin (most abundant protein in plasma), which is responsible for carrying non-soluble substances. Albumin is also responsible for keeping osmotic pressure. Globulins also transport non-soluble substances, specifically cholesterol, iron, complement, etc. Gamma globulins are antibodies. Fibrinogen is an inactive precursor for a clot’s fibrin meshwork.

Where are the plasma proteins produced?

All plasma proteins are produced by the liver excluding the gamma globulins which are produced by white blood cells.

How many rbc on average per 1 mL.

5 billon rbc.

How does the RBC structure promotes diffusion.

Large curved surface area, extremely thin membrane, great flexibility of plasma membrane. 

Describe hemoglobin.

Found only in RBCs with a pigment containing iron. Appears red when oxygenated and blue when deoxygenated. Made up of 2 alpha and beta polypeptide chains and 4 heme groups with one iron molecule in each.

What percent of oxygen is carried by Hb and how many are found in one RBC?

98.5% of oxygen in blood is carried by Hb and 250 million can be found in one RBC.

What are three molecules hemoglobin can also combine with?

Carbon dioxide (CO2), as carbon monoxide (CO) which bind irreversibly, and nitric oxide (NO2) which is a vasodilator.

If mature RBCs do not have organelles how do they create ATP?

They are glycolytic enzymes which fuel the cell by carrying out anaerobic glycolysis.

What task does carbonic anhydrase carry out in the RBC?

Coverts carbon dioxide (CO2) and water (H2O) into carbonic acid (H2CO3) at the tissue then reverses it at the lungs.

What is the turnover of a RBC?

RBCs only last about 120 days, with about 25-30 trillion in the body at once. 2-3 million cells will be replaced per second.

At what stage of the process does a stem cell commit to becoming an RBC?

Erythroblast.

What organ removes most of the old erythrocytes?

The spleen is responsible for removing old erythrocytes from circulation.

How are blood cells produced?

Pluripotent stem cells in red bone marrow differentiate into different types of blood cells, like RBCs and WBCs. This process is called erythropoiesis.

How does the body know when to make more blood?

The kidneys will detect a lower oxygen-carrying capacity in the blood and secrete erythropoietin (EPO), which stimulates the bone marrow to produce more blood. After oxygen-carrying capacity is restored, the effects of erythropoietin are relieved.

What does blood type depend on?

Depends on the surface antigens of erythrocytes.

What is an antigen?

A large, complex molecule that triggers a specific immune response against itself when it gains entry to the body.

What antigens can occur on erythrocytes in the ABO blood types?

A and or B or none (blood type O).

What antibodies does our body naturally make?

The opposite of the antigens found on our erythrocytes. Ex: A antigen = Anti-B or Blood type O = anti-A and anti-B.

What is the CDE system or Fisher-race system?

A blood grouping system with 50 groups of antigens, with 5 primary antigen groups (D,C,E,c,e).

What makes a blood type positive or negative?

A D antigen will make a blood type positive, and no D antigen will make someone blood type negative.

What are the five major types of circulating leukocytes?

Neutrophils, esoinophils, basophils, monocytes, and lymphocytes.

What are the polymorphonuclear granulocytes and how common are they among wbc?

Neutrophil 60-70%, esoinophils 1-4%, and basophils 0.25-0.5%.

What are the mononuclear agranulocytes and how common are they among WBCs?

Monocytes 2-6% and lymphocytes 25-33%.

Describe the name polymorphonuclear granulocytes.

Polymorphonuclear (“many-shaped nucleus”) granulocytes (“granule-containing cells”).

Describe neutrophils.

The most abundant among WBCs and phagocytic specialists by engulfing and destroying bacteria intracellularly. Release web of extracellular fibers called neutrophil extracellular traps (NETs) that contain bacteria-killing chemicals.

Desscribe eosinophils.

Killing of antibody-coated parasites through the release of granule contents. Increase in circulation with allergic conditions and internal parasites (eosinophilia).

What is the theory behind why some allergic reactions happen to bee stings, peanuts, etc?

Due to eosinophils not being enganged enough they become over sensitive to things that are not dangerous.

Describe basophils.

Respondsible for chemotactic factor production. Synthesize and store histamine (important in allergic reactions) and heparin (speeds up removal of fat particles in blood). 

Describe the name monouclear agranulocytes.

Mononuclear (“single nucleus”) agranulocytes (“cells lacking granules”)

Describe monocytes.

Phagocytosis, antigen presentation, cytokine production and cytotoxicity. Emerge from bone marrow and circulate for 1-2 days; settle down in various tissue. Mature and enlarge into macrophages in resident tissue.

Describe large granular lymphocytes.

Natural killer cells (NK). Effector cells of innate immune response and extremley effective aganist virally infected cells. Release lytic granules to kill infected cells and produce cytokines to limit viral replication. 

Describe small lymphocytes.

T cells and B cells responsbile for adaptive immune response. Cytokine production, antigen recongnition, antibody production memory, and cytotoxicity.

Describe the B lymphocytes (B cells).

B cells produce antibodies as a plasma cell and are respondsible to antibody-mediated immunity (humoral immunity.

Describe T lymphocytes (T cells).

Responsible for cell-mediated immunity and do not produce antibodies. Directly destory target cells by using chemicals to punch hole in victim cell. 

What cell are all blood cells derived from?

Pluripotent hematopietic stem cells in red bone marrow. Granulocytes and monocytes are produced only in bone marrow as well.

Define immunity.

Is the body’s ability to protect itself by resisting or eliminating potentially harmful foreign invaders.

What is the immune systems job?

Defend aganist invading pathogens, removes “worn-out” cells, and identifies abonormal or mutant cells. 

Describe bacteria.

Non-nucleated, single-celled microorganisms that primarily cause tissue damage and disease. Ex. Chlamydia, salmonella, E.coli

Describe viruses.

Consists of DNA or RNA enclosed by a protein coat and cannot reproduce without invading a host cell due to being non-self-sustaining. Ex. SARS-CoV-2, HIV, HCV, Ebola

Name some other pathogenic microbes.

Fungi (Candida), Protozoan parasites (Malaria), and Helminth parasites (worms).

What is the notion of virulence.

Refers to a pathogen’s ability to cause harm and manifest in the body.

Where do T cells mature?

The thymus, located just above the heart.

What are lymph nodes?

Channels that are highly concentrated with B and T-cells respondsible for filtering waste and bacteria in the body.

What are the organs that help with internal defenses.

Bone marrow, thymus, lymph nodes, spleen, tonsils, adenoids, appendix, gut associated lymphoid tissue.

Describe the innate immune system.

Nonselectively response that defend aganist foreign material. Ex. Inflammation, NK cells, complement system, dendritic cells

Describe adaptive responses.

A selective response that targets particular invaders. Ex. Antibody-mediated immunity, Cell-mediated immunity.

When a pathogen first enters your body, how does it deal with it?

For about the first 6 days, your innate response will activate, peaking at around 2 days. Around day 3, your adaptive response will begin peaking around day 6.

What happens with a lack of a proper innate response?

Even when the adaptive response begins, there will be too many pathogens for the adaptive response to deal with.

Describe inflammation.

An innate nonspecific response to tissue injury. Recruitment of phagocytes to the injured area in order to isolate, destroy, or inactivate invaders, as well as removing debris and preparing for healing and repair.

What are the different ways your body prepares/allows for inflammation?

Resident tissue releases cytokines and chemokines. Mast cells are activated like histamine. There is localized vasodilation, increased capillary permeability, localized edema, and walling off of the inflamed area.

What cells are responsible for what during inflammation?

Emigration of leukocytes = neutrophils and monocytes. Leukocyte proliferation, marking of bacteria for destruction by opsonins, and leukocytic destruction of bacteria.

What are some of the most important cytokines?

Interleukin 1&6 and TNF.

What is the ultimate goal of the immune response?

Tissue repair. Cell division replaces lost cells with the same kind of tissue cell, while non-regenerative cells are replaced with scar tissue.

What are some diseases resulting from chronic inflammation?

Alzheimer’s disease, atherosclerosis, asthma, diabetes, and cancer.

What are the two most important innate responses in the body?

Inflammation and interferon to limit viral spread.

What are complement proteins?

Nonspecific response proteins produced by the liver that circulate in the blood in an inactive form.

What are the three ways complement proteins are activated?

Spontaneous activation on the microbial surfaces, binding to carbohydrate chains on the surface of microorganisms but not human cells, and activation by antibody binding to antigens on pathogens.

How can complement proteins destroy pathogens?

Forms membrane attack complexes (MAC) that punch a hole in the pathogen membrane by creating a channel. It can also enhance the uptake of the pathogen by phagocytes by attaching to the surface.

Describe humoral immunity.

Involves the production of antibodies by B lymphocyte derivatives known as plasma cells.

Describe cell-mediated immunity.

Involves the production of activated T lymphocytes that directly attach to unwanted cells.

What are the two classes of adaptive immunity?

Humoral immunity (antibody-mediated) and cell-mediated immunity.

Describe antigens.

Large, foreign, unique complex molecules which induce an immune response against themselves. The more complex the molecule, the greater its antigenicity. Mostly protein in nature.

What is antigenicity?

The ability of a substance to be recognized by the products of an adaptive immune response, like antibodies or T-cells.

What is immunological memory?

When the adaptive immune system recognizes a specific foreign antigen.

Describe B lymphocytes.

Responsible for humoral immunity. Function as antigen receptors and initiate B cell activation, proliferation and differentiation of antigen-specific B cells. Then take part in the secretion of the soluble form of the antibody.

Describe how antibodies take part in neutralization.

By binding and neutralizing bacterial toxins, inhibiting bacterial access to host cells, and inhibiting viral entry into host cells.

How do antibodies take part in opsonization?

By binding to pathogens, antibodies enable phagocytes to recognize and engulf pathogens through a process known as phagocytosis.

Describe T lymphocytes.

Carry out cell-mediated immunity by binding directly to targets rather than making antibodies. T cells are only activated for foreign attack only when the attack is on the surface of a cell that carries foreign antigens presented on self-antigens.

How do T cells find their targets?

The T-cell receptor is presented a peptide fragment (antigen) bound to a self protein called Major Histocompatibility Complex (MHC), which is displayed on the surface of the APCs.

Describe the CD4 cells (Helper T cells: Th)

Modulates the activities of other immune cells and secretes chemicals that amplify the activity of other immune cells.

Describe CD8 cells (Killer T cells: Tc)

Destroy host cells harbouring anything foreign and bind to viral antigen and self-antigen on the surface of the infected cell. May kill the cell directly or through enzymes that cause the cell to self-destruct.