What are the three main distribution functions of blood?
Delivery of O2 (from lungs) and nutrients (digestive tract) to all body tissues
Transport metabolic wastes from cells to lungs (CO2) or kidneys (urine)
Transport hormones (from glands to target organ)
What are the three regulatory functions of blood?
Regulate body temperature, pH balance, and fluid volume.
How does blood help regulate body temperature?
Via absorption and distribution of heat
How does blood help regulate pH balance?
RBC and other substances in plasma help to prevent sudden changes in pH.
How does blood help regulate fluid volume?
Substances (such as Na+ and Cl-; proteins) help to retain water to maintain proper balance between blood volume and tissue cells.
What are the protective functions of blood?
Protects against blood loss via clotting mechanisms
Protects against infection via antibodies, WBC, and other immune proteins.
What is the optimal pH range for blood?
Between 7.35-7.45
At what pH level does acidosis occur?
Below 7.35
At what pH level does alkalosis occur?
Above 7.45
How much does blood compose of the total body weight?
Approximately 8%
What is the average volume of blood in the body?
Males: 5-6L
Females: 4-5L
What percentage does solvents compose in plasma composition?
90% water
What are the dissolved solutes in plasma?
Nutrients, wastes, salts, respiratory gases and proteins.
What proteins compose plasma?
Albumin (60%), Globulins (36%), Clotting Proteins (4%)
What is the function of Albumin?
Transport lipids and is the main contributor of osmotic pressure.
How much of plasma protein does Albumin account for?
Some 60%
What is the function of globulins?
Transport lipids and are released during immune responses
What are the functions of clotting proteins?
Forms fibrin threads of blood clots.
What do the formed elements of blood consist of?
Erythrocytes, leukocytes, and platelets.
Of erythrocytes, leukocytes, and platelets, which ones are true cells?
Only leukocytes.
Erythrocytes lack a nucleus and platelets are cell fragments.
Most types of formed elements survive in the bloodstream for how long?
Only a few days.
Small cells, about 7.5 µm in diameter, biconcave discs with depressed centers
Erythrocytes
Mature erythrocytes are anucleate (lack nucleus) and represent bags of ____?
hemoglobin.
What percentage does hemoglobin make up an erythrocyte?
97%
What is the purpose of erythrocytes?
They transport respiratory gases via hemoglobin (Hb)
What is the structural composition of hemoglobin?
Red heme pigment bound to globular protein.
Globin consists of 4 polypeptide chains (2 alpha, 2 beta) with the heme pigment molecule located at the center.
What does the heme molecule bind to?
Binds reversibly to oxygen molecules
When oxygen binds to iron (heme molecule), the hemoglobin assumes a three-dimensional shape and becomes ruby red. This is called
oxyhemoglobin
When oxygen detaches from iron and resumes its former shape. This occurs in body tissue.
Deoxyhemoglobin.
About 20% of the carbon dioxide transported in the blood combines with hemoglobin, but it binds to globin's amino acids instead of the heme group. This is called
Carbaminohemoglobin
Blood cell formation is called
hematopoiesis
Red blood cell formation is called
Erythropoiesis
Where does erythropoiesis occur?
Largely in red marrow of bones (head of humerus, femur, sternum, and pelvin girdles)
Precursor cells that reside in red bone marrow and give rise to erythrocytes
Hemocytoblasts (stem cells)
How does red blood cell production occur?
Via hormonal control.
The kidneys produce erythropoietin which stimulate production.
What are the steps for EPO production?
1. Kidney cells become hypoxic (O2 availability is inadequate)
2. Increased EPO production circulates to red marrow
3. Increased RBC production
What are the causes for hypoxia?
1. Exercise induced
2. Hemorrhage
3. High altitude
4. Respiratory distress (ex., pneumonia, emphysema)
What controls the rate of erythopoiesis?
The ability to transport enough oxygen to meet tissue demands.
What are the nutritional requirements for erythropoiesis?
Iron, B complex vitamins (B12, folic acid), amino acids
What is the lifespan of new erythrocytes in the bloodstream?
100 to 120 days.
Aged and damaged RBC are engulfed by what?
Macrophages in the liver, spleen, and bone marrow.
Abnormal excess of RBC which increases blood viscosity is called
Polycythemia
Polycythemia vera results from
Bone marrow cancer
Secondary polycythemia occurs if
There is a decrease is O2 in the atmosphere (as in high altitudes) or an increase in EPO (either naturally or artificially)
A condition in which the blood's oxygen-carrying capacity is too low to support normal metabolism
Anemia
Hemorrhagic anemia results from
Blood loss
Hemolytic anemia results from
Red blood cell rupture
Iron-deficiency anemia results from
Hemorrhage (secondary result of) or low Fe (iron) in diet
Pernicious anemia results from
Vitamin B12 deficiency (not absorbed in GI tract)
Sickle-cell anemia results from
Genetically altered hemoglobin molecules create sickle-shaped RBCs under conditions of low oxygen availability.
Thalassemia anemia results from
Genetically one hemoglobin chain is absent or faulty and causes RBCs to be thin and delicate.
Aplastic anemia results from
Failure of RBC production.
The only formed elements that are complete cells, with nuclei and the usual organelles; White blood cells
Leukocytes
How much of total blood volume do leukocytes account for?
1%.
Unlike RBC, WBCs are not confined to the bloodstream and are able to be transported across the body in a process called
Diapedesis
What are the two major categories of leukocytes?
Granulocytes and agranulocytes.
What are the difference between granulocytes and agranulocytes?
Granulocytes contain obvious membrane-bound cytoplasmic granules.
List leukocytes in the order of most abundant to least abundant.
Neutrophils, lymphocytes, monocytes, eosinophils, basophils.
Never Let Monkeys Eat Bananas
Which leukocytes are considered granulocytes?
Neutrophils, eosinophils, basophils.
What percentage do neutrophils make up of WBC population?
Roughly 50-70%.
How many nuclei do neutrophils typically have?
3-6.
What is the function of neutrophils?
Phagocytize bacteria
Attracted to inflammation
What percentage do eosinophils account for?
2-4%.
What are some characteristics of eosinophils?
Nucleus usually has two lobes connected by a broad band of nuclear material (resembles ear muffs); Stain brick red to crimson with acid dyes;
What is the main function of eosinophils?
Kills parasitic worms and play a complex role in allergies and asthma.
Reduce allergy reactions via breakdown of antibody complexes.
Rarest of WBC, accounting for only .5-1% of the leukocyte population
Basophils
Characteristics of basophils
Cytoplasm contains large, course, histamine-containing granules that have an affinity for the basic dyes (basophil = base loving) and stain purplish-black. The deep purple nucleus is generally U or S shaped with one or two constrictions.
What is the function of basophils?
Release histamine and other mediators of inflammation; contain heparin, an anticoagulant.
Accounting for 25% or more of WBC population (1500-3000 ul), these are the second most numerous leukocytes in the blood
Lymphocytes
Characteristics of lymphocytes
Large, dark-purple nucleus that occupies most of the cell volume; nucleus is normally spherical; surrounded by a thin rim of pale-blue cytoplasm; classified by size as small, medium, or large.
What is the function of lymphocytes?
Play a crucial role in immunity. T cells function in the immune response by acting directly against virus-infected cells and tumor cells. B cells give rise to plasma cells, which produce antibodies that are released in the blood.
What percentage of WBCs do monocytes account for?
3-8% (100-700 ul)
Characteristics of monocytes?
Largest of leukocytes (average diameter of 18 um); an abundant pale-blue cytoplasm and a darkly staining purple nucleus, which is often U shaped or kidney shaped.
What is the main function of monocytes?
Phagocytosis
Help activate lymphocytes.
Literally "white blood," refers to a group of cancerous conditions involving overproduction of abnormal white blood cells.
Leukemia
With leukemia, what happens to the white blood cells?
They remain unspecialized and proliferate out of control, impairing normal red bone marrow function.
An abnormally low white blood cell count, commonly induced by drugs, particularly glucocorticoids and anticancer drugs.
Leukopenia
What are platelets?
Cytoplasmic packets of enzymes.
What is the function of platelets?
Clot formation.
What happens during the first step in homeostasis?
Damaged blood vessel responds to the injury by constricting, exposing collagen fibers.
What occurs during the second step in homeostasis?
Platelets stick together forming a plug that temporarily seals the break in the vessel wall. A plasma protein causes platelets to swell, form spiked processes, and become stickier. This allows for a bridge to form between platelets and collagen fibers.
What occurs during the third step in homeostasis?
Coagulation occurs. It reinforces the platelet plug with fibrin threads that act as a "molecular glue" for the aggregated platelets.
Blood is transformed from a liquid to a gel in a multistep process that involves a series of substances called
Clotting factors, or procoagulants.
Process of enzymatic clot breakdown once healing has occurred; this "clean-up" is continual.
Fibrinolysis.
What types of hemophilia exist?
A, B, and C; These are linked to X-chromosome genetic disorders that result in inadequate clotting mechanisms.
What is the management for hemophilia?
Transfusions and control over activity to prevent injury. Can be treated with genetically engineered clotting factors IX or VII.