A&P2 Chapter 16: Blood

Leukocytosis is a WBC count above ___ per cubic mm. Is leukocytosis a dangerous condition?

-11,000 cells/cubic mm -The condition is not dangerous, because it is a normal response to an infection in the body.

What is the ratio of erythrocytes to leukocytes? What is the average number of leukocytes per cubic mm?

A WBC to RBC ratio is 1:100. The average number of leukocytes are 4,000 to 11,000.

What single stem cell produces all of the formed elements?

Hematocytoblasts

What are the formed elements of blood? Why are erythrocytes and platelets not considered true cells?

The formed elements of blood include the erythrocytes, leukocytes and platelets. The erythrocytes aren't considered true cells because they contain no nuclei or organelles. The platelets aren't considered true cells because they are only cell fragments.

What is the primary function of leukocytes? Where do leukocytes typically operate?

The primary function is defense against various diseases and bacteria. The leukocytes typically operate outside the capillary walls of blood vessels (use of blood vessels to get to the site of infection).

What is hematopoiesis?

The production of all formed elements-RBC's, WBC's and platelets.

Platelets are also called ___.

Thrombocytes

Name the 5 steps of the clotting process.

-Clot Formation -Clot Stabilization -Clot Retraction -Clot Dissolution -Clot Restriction

-What type of tissue is blood? -What 3 components make-up the connective tissue of blood?

-Connective Tissue -Cells, Fibers and a Matrix The cells (formed elements) consist of erythrocytes, leukocytes and platelets. The fibers consist of fibrin (only apparent in clotting). The matrix is the background material in which all cells and fibers are found, the plasma.

What are the 5 major chemical components of plasma?

-Electrolytes -Plasma Proteins (Albumin, Alpha/Beta/Gamma Globulin's and Fibrinogen) -Nutrients (Organic) -Respiratory Gases -Hormones

What are 3 special dietary requirements necessary for erythropoiesis?

-Iron -Folic Acid -Vitamin B12

To get to the site of infection, leukocytes undergo margination, diapedesis and are drawn to foreign invaders by positive chemotaxis through amoeboid movement. Explain the various terms: margination, diapedesis, positive chemotaxis and amoeboid movement.

-Margination: The process of existing WBC's in the blood stream becoming attached to receptors extending from the capillary wall (prompted by the release of chemicals, through the destruction of outside pathogens). The WBC's then perform a process of detaching and rolling along the inner margin of the capillary wall, to the area of diapedesis. -Diapedesis: The process of WBC's squeezing through a hole in the capillary lining and leaving the blood vessel, after margination. -Positive Chemotaxis: The process of WBC's orientating to the source of action after leaving the blood vessel (directing movement), via released chemicals. -Amoeboid Movement: The movement of a WBC, involving extending the cytoplasmic process and then dragging the cell in the required direction.

Name the various leukocytes, erythrocytes and platelets in the order of relative size (from smallest to largest).

-Platelet -Erythrocyte -Neutrophil -Eosinophil -Basophil -Lymphocyte -Monocyte

Name the 3 major functions of blood, and give examples of each function.

-Regulation: The regulation of body heat (distribution of warm blood), blood pH and adequate fluid volume (salts and proteins). -Protection: The prevention of the spread of infection and blood loss. -Distribution: The distribution of oxygen/carbon dioxide, nutrients/waste (cells/kidneys) and hormones to cells (the site of production to the site of action).

What are the common differences/similarities between the extrinsic and intrinsic path of coagulation?

-The extrinsic path is used if damage occurs to the tissues, is quicker than the intrinsic path with fewer steps (shortcut with thromboplastin), contains platelet factor 3 (PF3)/calcium and requires a few pro-coagulants. -The intrinsic path is used if injury occurs to the endothelium, is slower than the extrinsic path with many steps (no shortcut), contains platelet factor 3 (PF3)/calcium and requires all the pro-coagulants.

Answer the following questions about hemoglobin: -What is the function of hemoglobin? -What 3 chemical components make-up the hemoglobin molecule? -How much oxygen can a single hemoglobin molecule bind? How much oxygen can a RBC bind?

-The function of hemoglobin is the transportation of oxygen to various tissues. -The hemoglobin molecule consists of 4 polypeptide (globin) chains (2 alpha and 2 beta), 4 heme groups and 4 iron atoms located in the center of each heme group. -A single hemoglobin molecule can bind 4 oxygen oxygen molecules. A single RBC can bind 1 billion molecules of oxygen.

In platelet plug formation...What initially causes the platelets to adhere to the broken blood vessel? What chemical draws more platelets to the site of injury? What does the substance serotonin accomplish? What does the substance thromboxane A2 accomplish?

-The platelets initially adhere to the exposed collagen on the blood vessel's outermost surface. -The chemical ADP draws more platelets to the site of injury, a chemical attractant for platelets. -The substance seratonin enhances the vascular spasm, promoting vasoconstriction. -The substance thromboxane A2 is a short-lived prostaglandin derivative, that further enhances the vascular spasm.

How does oxyhemoglobin, deoxyhemoglobin (reduced hemoglobin) and carbaminohemoglobin differ from each other?

-The term oxyhemoglobin refers to an oxygenated RBC. The RBC has moved through the lungs, diffusing oxygen into the RBC where it binds to the hemoglobin (via the heme group). -The term deoxyhemoglobin refers to a deoxygenated RBC. The oxygen has detached from the hemoglobin and entered the bodily tissues. -The term carbaminohemoglobin refers to carbon dioxide binding with the hemoglobin (via the globin's amino acids). The formation also occurs more readily when the hemoglobin is in the reduced state (deoxyhemoglobin).

What is the role platelets play in hemostasis via: the vascular spasm, platelet plug formation, coagulation and clot retraction?

-Vascular Spasm: platelets release seratonin, which enhances the vascular spasm and promotes vasoconstriction -Platelet Plug Formation: platelets accumulate in the collagen, releasing ADP to attract more platelets to eventually form a plug -Coagulation: platelets reinforce the plug, through aggregated platelets -Clot Retraction: platelets secrete platelet-derived growth hormone (PDGF), which stimulates smooth muscle and connective tissue growth

What is the general structure of a blood vessel?

A blood vessel's innermost layer is endothelium (tunica interna). A blood vessel's middle layer is smooth muscle (tunica media). A blood vessel's outer covering is made of collagen (tunica externa).

Describe red bone marrow. Specifically, where in the bone is red marrow typically found? In which bones does blood formation usually occur?

A bone's inner marrow contains reticulated cells/fibers, fats, hematocytoblasts (undifferentiated stem cells, that can become a RBC, WBC or platelet) and cells in various stages of development. The red bone marrow is typically found in flat bones (containing large amounts of spongy bone). The bones include the sternum, cranial cap, ilium (hip) and the heads of the femur/humerus.

What is anemia? What are the signs and symptoms of anemia?

A condition in which the blood's oxygen-carrying capacity is too low to support normal metabolism. The signs and symptoms are fatigue, paleness/coldness and shortness of breath.

What does it mean when a hematocytoblast becomes committed? What causes the hematocytoblast to become committed?

A hematocytoblast becoming committed refers to the cell being on a path, to become one type of cell (RBC, WBC or platelet). The hematocytoblast becomes committed when specific receptor proteins become apparent in the plasma membrane, the receptors are receptive to a specific hormone which directs the maturation path.

How is a platelet related to a megakaryocyte?

A platelet is a pinched-off portion of the plasma membrane, of a megakaryocyte (with granules).

Describe a red blood cell (RBC) in terms of shape, size and intracellular components.

A red blood cell's shape is a bi-concave disc, a flattened disc with a depressed center. A red blood cell's size is roughly 7.5 micrometers in diameter and 2.5 micrometers in width. A red blood cell contains no intracellular components, aside from hemoglobin (a bag of hemoglobin).

What is a reticulocyte? What percentage of RBC's are reticulocytes, under normal circumstances?

A reticulocyte is a collapsed RBC with granules (leftover ribosomes, which will eventually degenerate). 1-2% of RBC's are reticulocytes.

What are the relative life spans of the formed elements?

Granulocytes: Hours to a Few Days Platelets: Few Days Erythrocytes: 4 Months (120 Days) Monocytes: Months Lymphocytes: Hours to Years (Fighting Infection or Providing Immunity)

What is hemostasis? What are the 3 stages of hemostasis?

Hemostasis is the stoppage of bleeding at the blood vessel. The 3 stages of hemostasis are the vascular spasm, platelet plug formation and blood clotting.

Describe the 3 stages in red blood cell formation.

Phase 1: The hematocytoblast creates ribosomes used for protein production. Phase 2: The protein in production is hemoglobin, polypeptide chains are created that comprise the hemoglobin. The cell begins to produce large amounts of hemoglobin. Phase 3: The cell ejects all organelles, leaving only hemoglobin. The high amount of hemoglobin leaves no room for any organelles.

How do RBC's generate ATP?

RBC's generate ATP through anaerobic respiration (glycolysis), because RBC's don't contain mitochondria. RBC's don't use the oxygen the cells carry.

What is the difference between adult hemoglobin and fetal hemoglobin?

The adult hemoglobin contain 2 alpha and 2 beta polypeptide chains. The fetal hemoglobin contains 2 alpha and 2 gamma polypeptide chains. The gamma chains allow the fetus to pick up oxygen from the mother's hemoglobin, one year after birth fetal hemoglobin dissipates.

How plentiful are platelets per cubic mm? How large are platelets? What is the function of platelets?

The amount of platelets is roughly 250,000 to 500,000. The platelets are 60 micrometers in diameter. The function of platelets is to aid in the stoppage of bleeding (clotting).

What cell lineage are platelets derived from?

The cell lineage of megakaryocytes give rise to platelets.

What are the chemical reactions of the final common path in coagulation?

The chemical reactions of the final common path are (5 important reactants): PROTHROMBIN ACTIVATOR coverts to PROTHROMBIN, which converts to THROMBIN, which converts to FIBRINOGEN, finally converting to FIBRIN.

What chemical substance, from which structure is involved in clot retraction?

The chemical substance is platelet-derived growth factor (PDGF) and is secreted by the platelets.

Describe the process of clot formation.

The clot formation processes liquid blood into a semi-solid gel. The process is fast, localized and controlled. A cascade of chemical reactions leads to the production of the fibrous protein fibrin. The fibrin traps RBC's, WBC's, plasma proteins, clotting factors and platelets in a mesh-like gauze. *Remember: The blood's fibers are only apparent during the repair of a damaged blood vessel-clotting!

How is the clot restricted to the site of injury?

The clot is restricted through anti-thrombin III (inhibits the act of thrombin), heparin (inhibiting clot formation of neighboring cells) and the presence of anti-coagulants. A continuous blood flow dilutes and removes the existing clotting factors from the area.

What are the two conditions in which polycythemia might occur?

The condition of polycythemia means an excess amount of erythrocytes, essentially raising blood viscosity. The two conditions in which polycythemia might occur are chronic hypoxia and a form of bone marrow cancer.

What is the vascular spasm?

The constriction of a blood vessel, by the contraction of the smooth muscle (rapid vasoconstriction-less blood is being sent to the injured vessel, to lessen blood loss).

What is blood coagulation?

The formation of a blood clot.

What is the fate of the three components of hemoglobin, when a RBC dies?

The globin molecules (polypeptide chains) of hemoglobin are broken down into individual amino acids, for reuse in building different proteins. The nitrogen-containing heme groups are eliminated (excreted from the body). The iron atoms are saved, stored and bound to proteins in the liver/plasma.

Leukocyte production is under hormonal control. What are the hormones called that oversee leukocyte production? Where do the hormones act for production? What can stimulate the hormone's secretion?

The hormonal control is in reference to interleukins and colony stimulating factors (CSF's). The hormones target the committed cells of the bone marrow. The chemicals released at the site of infection can stimulate the hormone's secretion.

Where is the hormone produced that regulates RBC production (erythropoietin)? What does the hormone act upon, to stimulate RBC production?

The hormone erythropoietin is produced in the kidneys and liver (a small amount is always present in the blood, to sustain production at a basal rate). The hormone acts upon red bone marrow, to stimulate the production of red blood cells (stimulating already committed RBC's to mature rapidly).

The production of RBC's is under hormonal control. What is the name of the hormone responsible for RBC production? What are the results of too few or too many RBC's being produced?

The hormone responsible for RBC production is erythropoietin. The result of too few RBC's being produced is enhanced erythropoietin production. The result of too many RBC's being produced is depressed erythropoietin production.

What effect does testosterone have on erythropoietin (the hormone that controls the production of RBC's)?

The hormone testosterone enhances the kidney's production of erythropoietin (EPO) (raises basal levels).

What substances, from which structures are involved in the dissolution of the clot?

The plasma protein plasminogen (inactive within the clot) is activated into plasmin, a fibrin-digesting enzyme (a clot buster) to assist in disolution. Also, the tissue-plasminogen activator (tPA) is released from the endothelial cells to assist in the dissolution of the clot.

How is a platelet plug formed through the positive feedback process?

The positive feedback process that forms a platelet plug includes: platelets coming into contact with collagen on the outermost layer of the blood vessel-the platelets then adhere to the collagen and change shape, becoming sticky-the platelets then begin to secrete ADP to attract more platelets...more platelets continue to arrive until a platelet plug is formed.

Describe the process of clot stabilization.

The process is a dynamic situation in which loose fibrin fibers are anchored together at points of contact (a conglomeration of fibrin fibers, producing a tight knit piece of gauze). The process requires: Calcium, Thrombin and Factor XIII. The process traps plasma proteins, clotting factors, erythrocytes, platelets and leukocytes in a web of fibers leading to the stoppage of bleeding/healing of damaged tissues.

Describe the process of clot retraction.

The process is the edges of the cut vessel being pulled closer together, as the actin/myosin within the platelets contract (the collecting platelets form a bridge, connecting the edges). The platelets secrete platelet-derived growth factor to stimulate the growth of smooth muscle and connective tissue (endothelial cells also regenerate at the same time-characteristic feature is regeneration).

What is erythropoiesis?

The production of red blood cells (RBC's).

What reactants are in clot stabilization?

The reactants required are: -Calcium -Thrombin -Fibrin Stabilizing Factor (FSF) (Factor XIII)

What is blood doping?

The removal of blood (1-2 liters at a time, up to 5 liters total) to induce hypoxia. The loss of blood stimulates EPO (erythropoietin) release and in a few weeks, normal blood volume is restored. The process happens progressively until the total amount is reached, then the blood is thawed and re-infused before the athletic event. The goal is to boost performance in endurance events, by increasing the oxygen-carrying capacity of blood. The dangers of blood doping are increased blood viscosity, a decrease in cardiac output and an increase in blood pressure.

What is the stimulus that causes the release of erythropoietin?

The stimulus is hypoxia (low oxygen levels in the blood). Hypoxia can be caused by hemorrage (loss of blood), high altitudes, exercise and/or blood doping.

Blood and an Anti-Coagulant are spun down in a centrifuge tube. Describe the resulting layers observed in the tube, and the composition of each layer.

The three layers are: -Erythrocytes (the bottom layer): 45% of whole blood (the hematocrit) -Plasma (the top layer): 55% of whole blood -Buffy Coat (the middle layer): <1% of whole blood (leukocytes and platelets)

What are the 2 subcategories of leukocytes? What are the types of cells belonging to each category of leukocytes?

The two subcategories are granulocytes and agranulocytes. Granulocytes: Neutrophils, Eosinophils and Basophils Agranulocytes: Monocytes and Lymphocytes

What are the two varieties of lymphocytes? What are the functions of the two different varieties?

The two varieties of lymphocytes are: B-Lymphocytes and T-Lymphocytes. B-Lymphocytes: produce antibodies and establish direct contact with the pathogen, effectively immobilizing and neutralizing the pathogen for ineffectiveness T-Lymphocytes: kill the body's infected cells when pathogens bypass antibodies and enter cells, to prevent the spread of infection/amp up the body's immune response

Describe the vascular spasm in the process of blood clotting.

The vascular spasm is the constriction of the blood vessel by contraction of the smooth muscle (to reduce blood volume to the injured area) via stretched smooth muscle, released chemicals from the endothelium/platelets and pain receptor reflexes.

What hormone stimulates the production of thrombocytes?

Thrombopoietin

What is a normal value for a RBC count (per cubic mm) and hemoglobin (grams per 100ml of blood), for men/women?

Women: RBC is 4.3-5.2 and Hemoglobin is 12-16 Men: RBC is 5.1-5.8 and Hemoglobin is 13-18