hapter 17 Blood
(I) Blood Is the liquid tissue of transport in humans Average human has 5-6 liters of blood Blood is composed of: red blood cells white blood cells platelets plasma
(A) Plasma Consists of 90% water Plasma contains: proteins antibodies nutrients enzymes hormones clotting factors
(B) Red Blood Cells
(B) Red Blood Cells Also called Erythrocytes 30 trillion rbc s in human body O2 from lungs to body cells CO2 to the lungs from the body cells Lack a nuclei when mature Contain hemoglobin
Hemoglobin An Fe-containing protein in which O 2 binds to. O 2 binds to hemoglobin, oxyhemoglobin CO 2 binds to hemoglobin, Carboxyhemoglobin
(C) White Blood Cells
(C) White Blood Cells 60 billion white blood cells in the body WBC s are larger than RBC s WBC s contain a nucleus Main purpose is to fight off disease
Types of White Blood Cells Phagocytes Lymphocytes
Phagocytes Engulf and destroy bacteria at the site of infection by the process of phagocytosis This is the normal defense against disease for the body
Lymphocytes Produce antibodies which act against foreign molecules known as antigens (anti-body generators) An antigen-antibody reaction is referred to as an immune response
(D) Platelets Are smaller than RBC s and WBC s Play a key role in blood clot formation 1.5 trillion platelets in the blood
Blood serves as a transport medium that helps to maintain homeostasis for all cells of the body Ex: hormones are secreted into blood to help regulate certain activities in the body
(II) Blood Clotting Clotting involves a series of enzyme-controlled reactions Platelets rupture and release an enzyme that initiates the clotting reaction The enzymes produce fibrin (comes from fibrinogen) which forms a network of strands that trap red blood cells and platelets to form a clot When a wound has healed, other enzymes are activated and dissolve the fibrin clot Pus- forms at the site of an infected wound. It is the WBC s that have died after engulfing the bacteria
(III) Immunity The capacity of the body to resist a specific disease (become immune to it) Two Types: Active Immunity Passive Immunity
Active Immunity Results when antibodies are produced by the body in response to a foreign substance (antigen) in the body Ex: A person gets chicken pox 1. Antibodies are produced by the body (lymphocytes) to fight the disease-causing organism (antigen) 2. After the illness is over, antibodies against the disease remain in the blood and protest against re-infection
Passive Immunity Develops when an individual receives antibodies from an outside source (medication) This provides temporary immunity to a particular disease However, the borrowed antibodies are gradually destroyed and the immunity they provide ends
(IV) Blood Types Blood Type A B AB O Antigen A B A and B none Antibodies In plasma anti-b anti-a none anti-a and anti-b
Transfusion- when a person receives blood from an outside source Blood Type Recipient (can receive) Type A Type B Type AB Type O type A,O type B,O type A, B, AB, O type O
Keep in mind: The person receiving the blood, look at the antibody for their blood type and the person donating the blood, look at the antigen for their blood type Type O- universal donor Type AB- universal recipient
Disorders of Blood
Anemia A condition in which blood cannot carry sufficient amounts of oxygen to body cells This is due to reduced amounts of hemoglobin and/or red blood cells
Sickle-Cell Anemia Anemia more prevalent in African-Americans This is due to malformed RBC s (sickle shape)
Sickle-Cell Anemia
Leukemia A form of cancer in which the bone marrow produces non-functional white blood cells (far too many)
(VI) Human Lymphatic System
Intercellular Fluid All cells of the body are bathed in a colorless, watery fluid called intercellular fluid (ICF) All substances exchanged between the blood and the body cells must diffuse through the ICF Excess ICF is drained from the tissues by vessels of the lymphatic system
Lymphatic System 1. Excess ICF is returned back to the blood by a system of vessels called the lymphatic system 2. Tiny lymph vessels are present in all body tissue
3. Excess ICF diffuses into lymph vessels and is now called lymph 4. These small lymph vessels join larger lymph vessels and ultimately join into the thoracic duct, which is the largest lymphatic vessel in the body
5. Lymph from the thoracic duct is emptied into a large vein in the neck 6. It is in this way that fluid lost from the blood is returned to the blood 7. Lymph vessels in the villi of the small intestine are called lacteals
8. Major lymph vessels have enlarged regions called lymph nodes in which lymphocytes (WBC s) destroy bacteria and other foreign substances from the lymph before the fluid is returned back into the blood