What is the function of blood? MAINTAIN HOMEOSTASIS IN THREE WAYS: TRANSPORT REGULATION PROTECTION

What is the function of blood? MAINTAIN HOMEOSTASIS IN THREE WAYS: TRANSPORT REGULATION PROTECTION

Components of Blood

TRANSPORT Blood maintains homeostasis by transporting: O 2 Co 2 H 2 o Nutrients Waste Hormones Heat

TRANSPORT: Plasma Plasma is the fluid portion of the blood: 92% water 7% proteins and clotting factors 1% mineral salts, sugars, fats, hormones and vitamins

TRANSPORT: Red Blood Cells Has iron containing protein called hemoglobin that binds to O 2, CO 2, or CO. No nucleus!

TRANSPORT: Red Blood Cells A genetic disease called sickle cell anemia results in RBCs with a different shape.

REGULATION Blood maintains homeostasis by keeping body temperature stable. Blood vessels can dilate or constrict to either store heat or allow more heat to leave the body.

PROTECTION BLOOD CLOTTING: via Platelets IMMUNE RESPONSE using White Blood Cells

PROTECTION: Blood Clotting Platelets initiate blood clotting and help stop blood loss.

PROTECTION: Platelets Begin the process of blood clotting by releasing enzymes that produce threads of fibrin that form the clot. No nucleus!

PROTECTION: The Immune Response

PROTECTION: The Immune System Homeostasis in an organism is constantly threatened. Failure to respond effectively can result in disease or death. The role of the immune system is to protect the body against pathogens.

Pathogens A pathogen is any disease-causing organism Pathogens include: viruses bacteria fungi parasites

PROTECTION: White Blood Cells Protect the body against infection Engulf pathogens Produce antibodies Destroy cancer cells `

White Blood Cells DIFFERENT WHITE BLOOD CELLS HAVE DIFFERENT ROLES: Destroy a pathogen by engulfing it (non-specific macrophages) Produce antibodies that attack invaders (specific B cells) Destroy infected host cells (specific killer T cells)

First Line of Defense is Non-Specific Non-Specific Defenses are barriers that keep pathogens out v Skin v Mucus v Sweat v Tears

Second Line of Defense is Non-Specific Pathogens enter the body, multiply quickly, and release toxins that activate the inflammatory response. The immune system releases chemicals that increase body temperature (fever) to slow down or stop the growth of pathogens.

Inflammation Blood vessels near the wound expand and white blood cells enter the infected tissues Macrophages engulf and destroy bacteria

Third Line of Defense is Specific Non-specific macrophages talk to specific white blood cells called T Helper cells communicate with and ACTIVATE B cells and killer T cells to fight pathogens.

Third Line of Defense is Specific White blood cells called B cells make SPECIFIC antibodies to bind to antigens. An antigen is a PROTEIN marker or tag on the surface of the cell membrane the pathogen. The antibody is a PROTEIN, too. Any cell or pathogen or allergen with non-self antigens on the surface will be seen as foreign by your immune system!

Third Line of Defense is Specific Activation of a B cell by a T-helper cell results in the B cell dividing into two subtypes of B cells called MEMORY B CELLS and PLASMA CELLS. Plasma B cells secrete antibodies!! Memory B cells stay with you forever. Antigenpresenting cell Pathogen B cell Antigen fragments MHC CD4 Memory B cells Cytokines Antigen receptor Activated Plasma cells 1 Helper T cell 2 helper T cell Secreted 3 antibodies

Why are T Helper cells so important? Let s take a closer look. T Helper cells ACTIVATE the immune system!

Displayed antigen fragment T cell MHC molecule T cell antigen receptor Antigen fragment Pathogen Host cell

Antigenpresenting cell Antigen fragment Pathogen 1 Class II MHC molecule Accessory protein (CD4) Antigen receptor Helper T cell Cytokines 2 B cell 3 3 Cytotoxic T cell Humoral immunity Cell-mediated immunity

Which types of human cells can HIV infect? HIV can infect several different types of human cells (including brain cells!) but the primary targets are T Helper cells!

Which types of human cells can HIV infect? HIV (Human Immunodeficiency Virus) infects T Helper cells. HIV infection can lead to AIDS (Aquired Immunodeficiency Syndrome).

What causes allergies? Allergies are caused by a reaction of the immune system to a harmless substance called an allergen. Histamines are produced in response to an allergen. Histamines cause increased blood flow and lead to sneezing, runny nose, etc.,

What is a vaccine? A vaccine contains a small amount of the pathogen (virus or bacteria). Vaccines do not cause disease because the pathogens are either dead or weakened. Vaccines result in ACTIVE immunity because the individual receiving the vaccine will produce antibodies against the pathogen!

What is passive immunity? Temporary!!! Transfer of antibodies v By injection of blood plasma containing antibodies v From mother to fetus through placenta v From mother to infant through breast milk

Primary immune response to antigen A Secondary immune response to antigen A Primary immune response to antigen B 10 4 Antibody concentration (arbitrary units) 10 3 10 2 10 1 Antibodies to A Antibodies to B 10 0 0 7 14 21 28 35 42 49 56 Exposure to antigen A Exposure to antigens A and B Time (days)

Amazing Blood Facts Two million red blood cells die every second. There are approximately 100,000 miles of blood vessels in the human body. Seven percent of a humans body weight is made up of blood. In the early nineteenth century some advertisements claimed that riding the carousel was good for the circulation of blood. Each day 400 gallons of recycled blood are pumped through the kidneys. By donating just one pint of blood, four lives can be saved. Blood is such a good stain that Native Americans used it for paint. The kidneys filter over 400 gallons of blood each day. The average life span of a single red blood cell is 120 days. Blood accounts for about 8% of a human's body weight. A woman has approximately 4.5 liters of blood in her body, while men have 5.6 liters. If you could stretch out all of a human's blood vessels, they would be about 60,000 miles long. That's enough to go around the world twice. Half your body s red blood cells are replaced every seven days. If all the blood vessels in your body were laid end to end, they would reach about 60,000 miles.