Chapter 19 Flashcards
1
Q
What are the three components of the cardiovascular system?
A
- Blood
- The heart
- Blood vessels
2
Q
Blood
A
A liquid connective tissue that consists of cells surrounded by blood plasma.
3
Q
Interstitial fluid
A
The fluid that bathes body cells and is constantly renewed by the blood.
4
Q
What are the three general functions of blood?
A
- Transportation
- Regulation
- Protection
5
Q
Briefly describe some of the physical characteristics of blood
A
- Is denser and more viscous (thicker) than water and feels slightly sticky.
- Its temperature is ~38°C (100.4°F).
- Has a slightly alkaline pH (7.4).
- Its color varies with its oxygen content (when saturated with oxygen, it is bright red. When unsaturated with oxygen, it is dark red).
- Constitutes about 20% of extracellular fluid, and 8% of the total body mass.
- Volume is 5-6 liters (1.5 gal) in an average-sized adult male and 4-5 liters (1.2 gal) in an average-sized adult female.
6
Q
What are the two main components of blood?
A
- Blood plasma (watery liquid extracellular matrix that contains dissolved substances) (55%)
- Formed elements (cells and cell fragments - eg. RBCs and WBCs) (45%)
7
Q
Buffy coat
A
A thin layer of WBCs between the RBCs and blood plasma.
8
Q
Blood plasma
A
A straw-colored liquid in blood. Is about 91.5% water and 8.5% solutes, most of which (7% by weight) are proteins.
9
Q
Plasma proteins
A
Most produced by liver. Responsible for colloid osmotic pressure. Major contributors to blood viscosity. Transport hormones (steroid), fatty acids, and calcium. Help regulate blood pH.
10
Q
What are the three types of plasma proteins? What percentage of the plasma proteins do they make up?
A
- Albumins (54%)
- Globulins (38%)
- Fibrinogens (7%)
11
Q
Albumins
A
Smallest and most numerous plasma proteins. Help maintain osmotic pressure, an important factor in the exchange of fluids across blood capillary walls.
12
Q
Globulins
A
Large proteins (plasma cells produce immunoglobulins). Immunoglobulins (AKA antibodies) help attack viruses and bacteria. Alpha and beta globulins transport iron, lipids, and fat-soluble vitamins.
13
Q
Fibrinogen
A
Large protein. Plays essential role in blood clotting
14
Q
Antibodies
A
AKA immunoglobulins; a type of plasma protein that develops into a cell that produces gamma globulins (an important type of globulin). Produced during certain immune responses. Production of antibodies is stimulated by foreign substances (antigens) such as bacteria and viruses.
15
Q
What are the three types of formed elements?
A
- Red blood cells (RBCs)
- White blood cells (WBCs)
- Platlets
16
Q
Red blood cells (RBCs)
A
AKA erythrocytes; 4.8 million/μL in females and 5.4 million/μL in males; 7–8 μm diameter, biconcave discs, without nuclei; live for about 120 days. Hemoglobin within RBCs transports most oxygen and part of carbon dioxide in blood.
17
Q
White blood cells (WBCs)
A
AKA leukocytes; 5000–10,000/μL. Most live for a few hours to a few days. Combat pathogens and other foreign substances that enter body.
18
Q
Platelets
A
150,000–400,000/μL. 2–4 μm diameter cell fragments that live for 5–9 days; contain many vesicles but no nucleus. Form platelet plug in hemostasis; release chemicals that promote vascular spasm and blood clotting.
19
Q
Hematocrit
A
The percentage of total blood volume occupied by RBCs (Eg. A hematocrit of 40 indicates that 40% of the volume of blood is composed of RBCs). The normal range of hematocrit for adult females is ~42%; for adult males, it is 47%.
20
Q
Hemopoiesis
A
AKA hematopoiesis; the process by which the formed elements of blood develop. Before birth, hemopoiesis first occurs in the yolk sac of an embryo and later in the liver, spleen, thymus, and lymph nodes of a fetus. Red bone marrow becomes the primary site of hemopoiesis in the last 3 months before birth and continues as the source of blood cells after birth and throughout life.
21
Q
Red bone marrow
A
A highly vascularized connective tissue located in the microscopic spaces between trabeculae of spongy bone tissue. It is present mainly in bones of the axial skeleton, pectoral and pelvic girdles, and the proximal epiphyses of the humerus and femur.
22
Q
Pluripotent stem cells
A
AKA hemocytoblasts; red bone marrow cells that are derived from mesenchyme. Have the capacity to develop into many different types of cells.
23
Q
Myeloid stem cells
A
Begin their development in red bone marrow and give rise to red blood cells, platelets, monocytes, neutrophils, eosinophils, basophils, and mast cells.
24
Q
Lymphoid stem cells
A
Give rise to lymphocytes. Begin their development in red bone marrow but complete it in lymphatic tissues. Lymphoid stem cells also give rise to natural killer (NK) cells.
25
Progenitor cells
What some of the myeloid stem cells differentiate into during hemopoiesis. They are no longer capable of reproducing themselves and are committed to giving rise to more specific elements of blood.
26
Precursor cells
AKA blasts; over several cell divisions these cells develop into the actual formed elements of blood (Eg. Monoblasts develop into monocytes).
27
Hemopoietic growth factors
Hormones that regulate the differentiation and proliferation of particular progenitor cells.
28
Erythropoietin (EPO)
Increases the number of red blood cell precursors. Is produced primarily by cells in the kidneys that lie between the kidney tubules (peritubular interstitial cells).
29
Thrombopoietin (TPO)
A hormone produced by the liver that stimulates the formation of platelets from megakaryocytes.
30
Cytokines
Small glycoproteins that are typically produced by cells such as red bone marrow cells, leukocytes, macrophages, fibroblasts, and endothelial cells. They generally act as local hormones. Cytokines stimulate proliferation of progenitor cells in red bone marrow and regulate the activities of cells involved in nonspecific defenses (such as phagocytes) and immune responses (such as B cells and T cells). Two important families of cytokines that stimulate white blood cell formation are colony-stimulating factors (CSFs) and interleukins.
31
Hemoglobin
A pigment that gives whole blood its red color. Found in RBCs - each RBC contains about 280 million hemoglobin molecules. Consists of globin. Transports oxygen and carbon dioxide (a waste product of metabolism). Also plays a role in the regulation of blood flow and blood pressure.
32
Briefly describe RBC anatomy
- Are biconcave discs with a diameter of 7–8 μm.
- Have a simple structure – their plasma membrane is both strong and flexible, which allows them to deform without rupturing as they squeeze through narrow blood capillaries.
- Lack a nucleus and other organelles and can neither reproduce nor carry on extensive metabolic activities.
- Hemoglobin is found in their cytosol, and constitute ~33% of the cell's weight.
33
Briefly describe RBC physiology
- Are highly specialized for their oxygen transport function.
- Because they have no nucleus, all of their internal space is available for oxygen transport.
- Because they lack mitochondria and generate ATP anaerobically (without oxygen), they do not use up any of the oxygen they transport.
- The shape of an RBC facilitates its function – a biconcave disc has a much greater surface area for the diffusion of gas molecules into and out of the RBC than would, say, a sphere or a cube.
34
Globin
Type of protein that makes up hemoglobin molecules. Composed of four polypeptide chains (two alpha and two beta chains).
35
Heme
A ringlike nonprotein pigment that is bound to each of the four chains of globin. At the center of each heme is an iron ion (Fe2+) that can combine reversibly with one oxygen molecule, allowing each hemoglobin molecule to bind four oxygen molecules.
36
Nitric oxide (NO)
A gaseous hormone that is produced by the endothelial cells that line blood vessels. Binds to hemoglobin. Under some circumstances, hemoglobin releases NO - the released NO causes vasodilation (an increase in blood vessel diameter that occurs when the smooth muscle in the vessel wall relaxes). Vasodilation improves blood flow and enhances oxygen delivery to cells near the site of NO release.
37
What are the 14 steps involved in the recycling of RBCs?
1. Macrophages in the spleen, liver, or red bone marrow phagocytize ruptured and worn-out red blood cells.
2. The globin and heme portions of hemoglobin are split apart.
3. Globin is broken down into amino acids, which can be reused to synthesize other proteins.
4. Iron is removed from the heme portion in the form of Fe3+, which associates with the plasma protein transferrin, a transporter for Fe3+ in the bloodstream.
5. In muscle fibers, liver cells, and macrophages of the spleen and liver, Fe3+ detaches from transferrin and attaches to an iron-storage protein called ferritin.
6. On release from a storage site or absorption from the gastrointestinal tract, Fe3+ reattaches to transferrin.
7. The Fe3+–transferrin complex is then carried to red bone marrow, where RBC precursor cells take it up through receptor-mediated endocytosis for use in hemoglobin synthesis. Iron is needed for the heme portion of the hemoglobin molecule, and amino acids are needed for the globin portion. Vitamin B12 is also needed for the synthesis of hemoglobin.
8. Erythropoiesis in red bone marrow results in the production of red blood cells, which enter the circulation.
9. When iron is removed from heme, the non-iron portion of heme is converted to biliverdin, a green pigment, and then into bilirubin, a yellow-orange pigment.
10. Bilirubin enters the blood and is transported to the liver.
11. Within the liver, bilirubin is released by liver cells into bile, which passes into the small intestine and then into the large intestine.
12. In the large intestine, bacteria convert bilirubin into urobilinogen.
13. Some urobilinogen is absorbed back into the blood, converted to a yellow pigment called urobilin, and excreted in urine.
14. Most urobilinogen is eliminated in feces in the form of a brown pigment called stercobilin, which gives feces its characteristic color.
38
Erythropoiesis
The production of RBCs. Starts in the red bone marrow with proerythroblasts.
39
Proerythroblast
A precursor cell. Divides several times and produces cells that begin to synthesize hemoglobin.
40
Reticulocyte
A cell near the end of the development sequence that turns into a mature blood cell.
41
Hypoxia
An oxygen deficiency at the tissue level. Occurs if not enough oxygen enters the blood. Stimulates the kidneys to step up the release of erythropoietin - as the number of circulating RBCs increases, more oxygen can be delivered to body tissues.
42
What are the two main divisions of WBCs? What is the major difference between the two?
1. Granular leukocytes: contain cytoplasmic granules (vesicles).
2. Agranular leukocytes: don’t contain cytoplasmic granules (vesicles) that are visible.
43
What are the three types of granular leukocytes?
1. Neutrophils
2. Eosinophils
3. Basophils
44
Neutrophils
60–70% of all WBCs. 10–12 μm diameter; nucleus has 2–5 lobes connected by thin strands of chromatin; cytoplasm has very
fine, pale lilac granules. Phagocytosis. Destruction of bacteria with lysozyme, defensins, and strong oxidants, such as superoxide anion, hydrogen peroxide, and hypochlorite anion.
45
Because older neutrophils have several differently shaped nuclear lobes, they are often called ______.
Polymorphonuclear leukocytes (PMNs)
46
Eosinophils
2-4% of all WBCs. 10–12 μm diameter; nucleus usually has 2 lobes connected by thick strand of chromatin; large, red-orange granules fill cytoplasm. Combat effects of histamine in allergic reactions, phagocytize antigen–antibody complexes, and destroy certain parasitic worms.
47
Basophils
0.5–1% of all WBCs. 8–10 μm diameter; nucleus has 2 lobes; large cytoplasmic granules appear deep blue-purple. Liberate heparin, histamine, and serotonin in allergic reactions that intensify overall inflammatory response.
48
What are the two types of agranular leukocytes?
1. Lymphoctyes
2. Monocytes
49
What do monocytes differentiate into?
Macrophages
50
Some macrophages become ______, which means they reside in a particular tissue. Others become ______, which roam the tissues and gather at sites of infection or inflammation.
Fixed (tissue) macrophages; wandering macrophages
51
Lymphoctyes
Include T cells, B cells, and natural killer cells. 20–25% of all WBCs. Small lymphocytes are 6–9 μm in diameter; large lymphocytes are 10–14 μm in diameter; nucleus is round or slightly indented; cytoplasm forms rim around nucleus that looks sky blue; the larger the cell, the more cytoplasm is visible. Mediate immune responses, including antigen–antibody reactions. B cells develop into plasma cells, which secrete antibodies. T cells attack invading viruses, cancer cells, and transplanted tissue cells. Natural killer cells attack wide variety of infectious microbes and certain spontaneously arising tumor cells.
52
Monocytes
3–8% of all WBCs. 12–20 μm diameter; nucleus is kidney-or horseshoe-shaped; cytoplasm is blue-gray and appears foamy. Phagocytosis (after transforming into fixed or wandering macrophages).
53
Leukocytosis
An increase in the number of WBCs. Above 10,000/μL, is a normal, protective response to stresses such as invading microbes, strenuous exercise, anesthesia, and surgery.
54
Leukopenia
An abnormally low level of WBCs (below 5000/μL). May be caused by radiation, shock, and certain chemotherapeutic agents.
55
Emigration
AKA diapedesis; a process in which RBCs are contained within the bloodstream and WBCs leave the bloodstream. WBCs leave by rolling along the endothelium, sticking to it, and then squeezing between endothelial cells.
56
Adhesion molecules
Help WBCs stick to the endothelium.
57
What are the two types of adhesion molecules?
1. Selectins
2. Integrins
58
Chemotaxis
Chemicals released by microbes and inflamed tissues that attract phagocytes.
59
Lysozyme
An enzyme that destroys certain bacteria and strong oxidants.
60
Defensins
Proteins that exhibit a broad range of antibiotic activity against bacteria and fungi. Found in neutrophils. Defensins form peptide “spears” that poke holes in microbe membranes; the resulting loss of cellular contents kills the invader.
61
Differential white blood cell count
AKA “diff ”; a count of each of the five types of white blood cells, to detect infection or inflammation, determine the effects of possible poisoning by chemicals or drugs, monitor blood disorders and the effects of chemotherapy, or detect allergic reactions and parasitic infections.
62
What might a high and low count of neutrophils indicate?
High count: bacterial infection, burns, stress, inflammation.
Low count: radiation exposure, drug toxicity, vitamin B12 deficiency, systemic lupus erythematosus (SLE)
63
What might a high and low count of lymphocytes indicate?
High count: viral infections, some leukemias, infectious mononucleosis.
Low count: prolonged illness, HIV infection, immunosuppression, treatment with cortisol.
64
What might a high and low count of monocytes indicate?
High count: viral or fungal infections, tuberculosis, some leukemias, other chronic diseases.
Low count: bone marrow suppression, treatment with cortisol.
65
What might a high and low count of eosinophils indicate?
High count: allergic reactions, parasitic infections, autoimmune diseases.
Low count: drug toxicity, stress, acute allergic reactions.
66
What might a high and low count of basophils indicate?
High count: allergic reactions, leukemias, cancers, hypothyroidism.
Low count: pregnancy, ovulation, stress, hypothyroidism.
67
Platlet
150,000–400,000/μL. 2–4 μm diameter cell fragments that live for 5–9 days; contain many vesicles but no nucleus. Form platelet plug in hemostasis; release chemicals that promote
vascular spasm and blood clotting
68
Hemostasis
Is a sequence of responses that stops bleeding.
69
What are the three mechanisms to reduce blood loss?
1. Vascular spasm
2. Platlet plug formation
3. Blood clotting (coagulation)
70
Describe the vascular spasm mechanism
Reaction in which the circularly arranged smooth muscles in the walls of arteries and arterioles contract immediately to reduce blood loss for several minutes to several hours, during which time the other hemostatic mechanisms go into operation. The spasm is probably caused by damage to the smooth muscle, by substances released from activated platelets, and by reflexes initiated by pain receptors.
71
Describe the three stages of the platelet plug formation mechanism
1. Platelet adhesion: platelets stick to the parts of the damaged blood vessel.
2. Platelet release reaction: due to adhesion, the platelets become activated.
3. Platelet aggregation: platelets stick together. The accumulation of platelets turns into a platelet plug.
72
Fibrin-stabilizing factor
Helps to strengthen a blood clot.
73
Platelet-derived growth factor (PDGF)
A hormone that can cause proliferation of vascular endothelial cells, vascular smooth muscle fibers, and fibroblasts to help repair damaged blood vessel walls.
74
Blood clot
A gel that contains formed elements of the blood entangled in fibrin threads.
75
Clotting (coagulation) factors
Substances involved in clotting. These factors include calcium ions (Ca2+), several inactive enzymes that are synthesized by hepatocytes (liver cells) and released into the bloodstream, and various molecules associated with platelets or released by damaged tissues.
76
Serum
Straw-colored liquid that is simply blood plasma minus the clotting proteins.
77
Describe the three stages of the blood clotting (coagulation) mechanism
1. Two pathways, called the extrinsic pathway and the intrinsic pathway, lead to the formation of prothrombinase. Once prothrombinase is formed, the steps involved in the next two stages of clotting are the same for both the extrinsic and intrinsic pathways, and together these two stages are referred to as the common pathway.
2. Prothrombinase converts prothrombin (a plasma protein formed by the liver) into the enzyme thrombin.
3. Thrombin converts soluble fibrinogen (another plasma protein formed by the liver) into insoluble fibrin. Fibrin forms the threads of the clot.
78
Which pathway is faster: the extrinsic pathway or the intrinsic pathway?
Extrinsic pathway
79
Thrombosis
Clotting in an undamaged blood vessel.
80
Clot retraction
Is the consolidation or tightening of the fibrin clot.
81
What is the role of vitamin K in blood clotting?
It is required for the synthesis of four clotting factors.
82
Fibrinolytic system
Dissolves small, inappropriate blood clots; it also dissolves clots at a site of damage once the damage is repaired.
83
Fibrinolysis
Dissolution of a blood clot.
84
Plasminogen
An inactive plasma enzyme that gets incorporated into a blood clot when one is formed.
85
Plasmin
AKA fibrinolysin; the active form of plasminogen.
86
Prostacyclin
A prostaglandin that opposes the actions of thromboxane A2. Is a powerful inhibitor of platelet adhesion and release.
87
Anticoagulants
Substances present in the blood that delay, suppress, and prevent blood clotting. These include antithrombin, heparin, and activated protein C (APC).
88
Thrombus
The blood clot.
89
Embolus
A blood clot, bubble of air, fat from broken bones, or a piece of debris transported by the bloodstream.
90
Pulmonary embolism
When an embolus is lodged in the lungs.
91
Hemorrhage
The loss of a large amount of blood from the vessels. Hemostatic mechanisms can prevent hemorrhage from smaller blood vessels, but extensive hemorrhage from larger vessels usually requires medical intervention.
92
Antigens
Assortment of glycoproteins and glycolipids at the surfaces of RBCs. Occur in characteristic combinations.
93
Based on the presence or absence of various antigens, blood is categorized into different ______. Within a given ______, there may be two or more different ______. There are at least 24 ______ and more than 100 antigens that can be detected on the surface of red blood cells.
Blood groups; blood group; blood types; blood groups
94
ABO blood group
Based on two glycolipid antigens called A and B.
95
People whose RBCs display only antigen A have ______ blood. Those who have only antigen B are ______. Individuals who have both A and B antigens are ______; those who have neither antigen A nor B are ______.
Type A; type B; type AB; type O (universal donor)
96
Agglutinins
Antibodies in blood plasma that react with the A or B antigens if the two are mixed.
97
The ______ reacts with antigen A, and the ______ reacts with antigen B.
Anti-A antibody; anti-B antibody
98
Transfusion
The transfer of whole blood or blood components (red blood cells only or blood plasma only) into the bloodstream or directly into the red bone marrow.
99
Agglutination
Clumping of RBCs due to an incompatible blood transfusion.
100
Hemolysis
Rupturing of RBCs and the release of hemoglobin into the blood plasma.
101
Rh blood group
The alleles of three genes may code for the Rh antigen. People whose RBCs have Rh antigens are designated Rh+ (Rh positive); those who lack Rh antigens are designated Rh− (Rh negative). Normally, blood plasma does not contain anti-Rh antibodies. If an Rh− person receives an Rh+ blood transfusion, however, the immune system starts to make antiRh antibodies, that will remain in the blood. If a second transfusion of Rh+ blood is given later, the previously formed anti-Rh antibodies will cause agglutination and hemolysis of the RBCs in the donated blood, and a severe reaction may occur.
102
Rh factor
Rh antigen.
