CH. 19: THE CARDIOVASCULAR SYSTEM: THE BLOOD Flashcards
1
Q
What are the three main components of the cardiovascular system?
A
blood, heart, blood vessels
2
Q
What is hermatology?
A
branch of science concerned with study of blood, blood-forming tissues, and the disorders associated with them
3
Q
What is blood?
A
a liquid connective tissue that consists of cells surrounded by a liquid extracellular matrix (blood plasma and it suspends various cells and cell fragments)
4
Q
What is interstitial fluid?
A
fluid that bathes body cells and is constantly renewed by the blood
5
Q
How does blood transport oxygen and nutrients into cells?
A
blood transports oxygen from the lungs and nutrients from the GI tract, which diffuse from the blood into the interstitial fluid and then into body cells
6
Q
How are carbon dioxide and wastes removed from cells?
A
- carbon dioxide and other wastes move from body cells to interstitial fluid to blood
- blood then transports wastes to organs- the lungs, kidneys, and skin – for elimination from body
7
Q
List and explain the three functions of blood:
A
1) Transportation: O2 from lungs to cells, CO2 from cells to lungs, nutrients from GI tract to cells, hormones from endocrine glands to cells, heat and waste products to organs for elimination
2) Regulation: homeostasis of fluids, pH through buffers, body temp, water content of cells
3) Protection: clotting to prevent blood loss after injury, WBCs and blood proteins protect against disease
8
Q
Several hormones ensure that blood volume and osmotic pressure remain relatively constant. Name three hormones that regulate how much water is excreted in urine:
A
aldosterone, antidiuretic hormone, and atrial natriuretic peptide
9
Q
What are the two components of whole blood?
A
blood plasma and formed elements
10
Q
Describe blood plasma, what is it made out of?
A
- a watery liquid extracellular matrix that contains dissolved substances (water + solutes [proteins + other])
- plasma proteins: albumins, globulins, fibrinogen (blood clotting) and others
- other solutes: electrolytes (osmotic pressure), nutrients, gases, regulatory substances, waste products
11
Q
What are the three components of the formed elements of whole blood?
A
RBCs, WBCs, Platelets
12
Q
What are the 7 types of WBCs in the formed elements of the blood? (Hint: 2 categories)
A
- Granular leukocytes: contain granules visible under a light microscope after staining (neutrophils, eosinophils, basophils)
- Agranular leukocytes: no granules visible under a light microscope after staining (T lymphocytes, B lymphocytes, natural killer cells, monocytes)
13
Q
In terms of ratios in blood, what is the hermatocrit?
A
percentage of total blood volume occupied by RBCs
14
Q
What does a significant drop in hermatocrit indicate?
A
anemia: a lower-than-normal number of RBCs
15
Q
What does a significant rise in hermatocrit indicate? (65% or higher)
A
polycythemia: a higher-than-normal number of RBCs
16
Q
What is hemopoiesis?
A
process by which the formed elements of blood develop
17
Q
What is red bone marrow?
A
a highly vascularized connective tissue located in the microscopic spaces between trabeculae of spongy bone tissue
18
Q
What are pluripotent stem cells?
A
blood cells derive from these cells in the red bone marrow
19
Q
In newborns, what colour is bone marrow? Is it active in blood cells production?
A
red and thus active in blood cell production
20
Q
As we age, the rate of blood cell formation decreases so the red bone marrow in the medullary cavity of long bones becomes ____ and is replaced by ___ bone marrow, which consists of ___ cells.
A
becomes inactive and is replaced by yellow bone marrow, which consists of fat cells
21
Q
In order to form blood cells, pluripotent cells in red bone marrow produce 2 further types of stem cells, what are they and what do they eventually produce?
A
1) myeloid cells: RBCs, platelets, mast cells, granular leukocytes (eosinophils, basophils, neutrophils), monocytes [macrophage]
2) lymphoid cells: agranular leukocytes (T lymphocytes, B lymphocytes [plasma cell], natural killer cells)
22
Q
What are progenitor cells? List 3 of them and what they produce.
A
- during hemopoiesis, some of the myeloid stem cells differentiate into them
- CFU-E produces erythrocytes (red blood cells)
- CFU-Meg produces megakaryocytes, the source of platelets
- CFU-GM produces granulocytes and monocytes
23
Q
What are precursor cells (blasts)? List 3 of them and what they produce.
A
- myeloid stem cells produce progenitor cells which produce into proerythroblasts, megakaryoblasts, eosinophilic myeloblasts, basophilic myeloblasts, myelobasts, monoblasts
- lymphoid cells produce T lymphoblasts, B lymphoblasts, NK lymphoblasts
24
Q
What are hemopoietic growth factors? Name 3, explain them and where they are produced.
A
- hormones that regulate differentiation and proliferation of particular progenitor cells
1) erythropoietin (EPO): produced by kidneys, increases number of RBC precursors
2) Thrombopoietin (TPO): produced by liver, stimulates formation of platelets from megakaryocytes
3) Cytokines: small glycoproteins produced by red bone marrow cells, they stimulate proliferation of progenitor cells in red bone marrow and regulate activities of cells involved in nonspecific defense and immune responses
25
What is another name for RBC, WBC and platelet?
erythrocyte, leukocyte, thrombocyte
26
In terms of hemopoietic growth factors, what are the two types of cytokines? Explain what they do.
1) Colony-stimulating factors (CSFs)
2) Interleukins
- they both stimulate WBC formation
27
What do RBCs contain? What do they lack?
- contain oxygen-carrying protein hemoglobin, which is a pigment that gives whole blood its red colour
- lack a nucleus and other organelles
28
What does a hemoglobin molecule consist of?
- heme: a ring-like nonprotein pigment bound to each of the 4 chains of globin (centre of each ring is iron ion that can combine reversibly with an O2 molecule, allowing each hemoglobin molecule to bind 4 O2 molecules)
- Globin: protein composed of 4 polypeptide chains (2 alpha and 2 beta chains)
29
Explain the role of hemoglobin in the maintenance of blood flow and blood pressure.
- nitric oxide binds to hemoglobin (NO is produced by endothelial cells that line blood vessels)
- the release of NO by hemoglobin causes vasodilation (an increase in blood vessel diameter that occurs when the smooth muscle in the vessel wall relaxes), which improves blood flow and oxygen delivery to cells
- bigger diameter reduces blood pressure within the blood vessels
30
RBCs contain enzyme carbonic anhydrase, which catalyzes the conversion of CO2 and H20 to carbonic acid, which dissociates into hydrogen ions and bicarbonate ions. Why is this reaction significant? (2 reasons)
1) Allows about 70% of CO2 to be transported in blood plasma from tissue cells to the lungs in form of bicarbonate ions
2) Serves as an important buffer in ECF
31
Ruptured RBCs are removed from circulation and destroyed by fixed phagocytic macrophages and breakdown products are recycled and used in metabolic processes, including formation of RBCs. Recycling occurs as follows: (14 steps)
1) Macrophages destroy RBCs
2) Globin and heme are split apart
3) Globin is broken down into amino acids
4) Iron is removed from heme in form of iron ion, which associates with plasma protein transferrin (a transporter for iron ion in bloodstream)
5) Fe3+ detaches from transferrin and attaches to an iron-storage protein called ferritin
6) On release from a storage site, Fe3+ reattaches to transferrin
7) Fe3+ - transferrin complex carried to red bone marrow, where RBC precursor cells take it up through receptor-mediate endocytosis for use in hemoglobin synthesis.
8) Erythropoeisis in red bone marrow results in the production of RBCs
9) When iron is removed from heme, the non-iron portion of heme is converted to biliverdin, and then into bilirubin
10) Bilirubin enters the blood and transported to liver
11) Bilirubin is released by liver cells into bile, which passes into small intestine and then large intestine
12) In large intestine, bacteria convert bilirubin into urobilinogen
13) Some urobilinogen is absorbed back into blood, converted to urobilin, and excreted in urine
14) Most urobilinogen is eliminated in feces in the form of stercobilin
32
Explain erythropoiesis:
- production of RBCs, starts in red bone marrow with a precursor cell called proerythroblast
- a cell near the end of the development sequence ejects its nucleus and becomes a reticulocyte
33
What does a proerythroblast do?
it divides several times, producing cells that begin to synthesize hemoglobin
34
Erythropoiesis eventually produces reticulocytes. Discuss their components and how they work.
- they retain some mitochondria, ribosomes, and endoplasmic reticulum
- pass from red bone marrow into bloodstream by squeezing between endothelial cells of capillaries
- develop into mature RBCs within 1-2 days after release from red bone marrow
35
Describe the negative feedback loop that controls the rate of erythropoiesis. Under what circumstances would you expect the rate of erythropoiesis to be increased? How would it be possible to tell if the rate of erythropoiesis is elevated?
- Erythropoiesis occurs at same pace as RBC destruction
- a drop in the oxygen-carrying capacity of blood, which leads to hypoxia can cause them to get off pace
- Hypoxia stimulates kidneys to release erythropoietin, to hurry growth of proerythroblasts into reticulocytes
- As more RBCs circulate, more O2 is transported to the tissues
- Once more O2 is in tissues, there is a decrease in kidney stimulation thus a reduction in release of erythropoietin
- rate of erythropoiesis increases when there are high levels of reticulocytes in circulation
- to tell if rate of erythropoiesis has been elevated, need to see if blood is sufficient in O2 again
36
What do leukocytes contain? What do they lack?
-nuclei and a full complement of other organelles but they do not contain hemoglobin
37
Describes neutrophils:
- granules are smaller than those of other granular leukocytes, evenly distributed, and pale lilac
- Neutrophilic (do not strongly attract either acidic or basic stain)
- Nucleus has 2-5 lobes, connected by very thin strands of nuclear material
- As cell ages, number of nuclear lobes increases
38
Describe eosinophils:
- large, uniform-sized granules within an eosinophil are eosinophilic – they stain red-orange with acidic dyes
- granules usually do not cover or obscure the nucleus, which most often has two lobes connected by either a thin strand or a thick strand of nuclear material
39
Describe basophils:
- round, variable-sized granules of a basophil are basophilic- they stain blue-purple with basic dyes
- Granules commonly obscure the nucleus, which has 2 lobes
40
Describe lymphocytes:
- nucleus stains dark and is round or slightly indented, cytoplasm stains sky blue and forms a rim around the nucleus
- An increase in the number of large lymphocytes has diagnostic significance in acute viral infections and in some immunodeficiency diseases
41
Describe monocytes:
- nucleus is usually kidney-shaped or horseshoe-shaped, and the cytoplasm is blue-gray and has a foamy appearance
- Cytoplasm’s colour and appearance are due to very fine azurophilic granules, which are lysosomes
- Migrate from blood into tissues, where they enlarge and differentiate into macrophages
- Some become fixed (tissue) macrophages, which means they reside in a particular tissue
- Other become wandering macrophages, which roam the tissues and gather at sites of infection or inflammation
42
What is leukocytosis?
- an increase in the number of WBCs
| - a normal, protective response to stresses such as invading microbes, strenuous exercise etc...
43
What is leukopenia?
an abnormally low level of WBC, caused by radiation, shock etc...
44
RBCs are contained within the bloodstream, but WBCs leave bloodstream by____.
emigration
45
What happens when WBCs undergo emigration?
WBCs roll along endothelium, stick to it, and then squeeze between endothelial cells
46
In emigration of WBCs, what do adhesion molecules do? List two examples and explain how they work.
- help WBCs stick to the endothelium
- ex: selectins stick to carbs on neutrophils causing them to slow down and roll along epithelial surface
- ex: integrins tether neutrophils to the endothelium and assist their movement through blood vessel wall and into interstitial fluid of injured tissue
47
What formed element of circulating blood and what tissue cell take part in phagocytosis? What do they do in phagocytosis?
- neutrophils and macrophages
| - they can ingest bacteria and dispose of dead matter
48
Explain chemotaxis.
when several different chemicals released by microbes and inflamed tissues attract phagocytes
49
After engulfing a pathogen during phagocytosis, a neutrophil unleashes several chemicals to destroy the pathogen. List the three chemicals:
1) enzyme lysozyme: destroys certain bacteria
2) strong oxidants (like superoxide anion)
3) defensins: proteins that exhibit a broad range of antibiotic activity against bacteria and fungi
50
Discuss eosinophils and basophils in terms of allergic reactions.
- eosinophils are believed to release enzymes, such as histaminase, that combat the effects of histamine and other substances involved in inflammation during allergic reactions (High eosinophil count = indicates an allergic condition or a parasitic infection)
- basophils intensify the inflammatory reaction and are involved in hypersensitivity (allergic) reactions
51
What do B lymphocytes do?
-effective in destroying bacteria and inactivating their toxins
52
What do T lymphocytes do?
-attack viruses, fungi, transplanted cells, cancer cells, and some bacteria, and are responsible for transfusion reactions, allergies, and the rejection of transplanted organs
53
What do natural killer cells do?
- attack infectious microbes and certain spontaneously arising tumor cells
54
What is the differential WBC count?
a count of each of the 5 types of WBCs to detect infection/inflammation, determine effects of possible poisoning by chemicals or drugs, monitor blood disorders and effects of chemotherapy, or detect allergic reactions and parasitic infections
55
Under the influence of the hormone thrombopoietin, myeloid stem cells develop into _____ ____-____ cells that in turn develop into precursor cells called _________, which transform into megakaryocytes. Each fragment of megakaryocyte, enclosed by a piece of plasma membrane is a _____ (thrombocyte).
- under the influence of the hormone thrombopoietin, myeloid stem cells develop into megakaryocyte colony-forming cells that in turn develop into precursor cells called megakaryoblasts, which transform into megakaryocytes.
- platelet
56
What do platelets contain or not contain? What do platelets do?
- has many vesicles but no nucleus
| - help stop blood loss from damaged blood vessels by forming a platelet plug (blood clotting)
57
In terms of RBCs, WBCs and platelets. Which ones have the most in number (biggest to smallest)? Which ones have nuclei? Which ones live the longest? (longest to shortest)
- RBCs, platelets, WBCs
- WBCs have nuclei
- RBCs, platelets, WBCs
58
Explain the procedure for a bone marrow transplant:
- red bone marrow from donor is removed from the iliac crest of hip bone and injected into recipient’s vein
- injected marrow migrates to recipient’s red bone marrow cavities, where donor’s stem cells multiply
59
What are some drawbacks of bone marrow transplants?
- since the recipient’s WBCs have been completely destroyed by chemotherapy and radiation, the patient is extremely vulnerable to infection
- Transplanted red bone marrow may produce T cells that attach recipient’s tissues (graft-versus-host disease)
- T cells can also attach donor transplant cells
60
What is a cord-blood transplant?
- more recent advance for obtaining stem cells
- Stem cells may be obtained from the umbilical cord shortly after birth
- stem cells are removed from the cord and then frozen
61
Name 5 advantages that stem cells from the cord have over those obtained from red bone marrow:
- easily collected
- more abundant
- less likely to cause graft-verses-host disease (match between people doesn't have to be as close so more potential donors)
- less likely to transmit infections
- can be stored indefinitely in cord-blood banks
62
What is hemostasis?
a sequence of responses that stops bleeding
63
What are the 3 mechanisms that reduce blood loss?
vascular spasm, platelet plug formation, blood clotting (coagulation)
64
Explain how a vascular spasm reduces blood loss.
- when arteries or arterioles are damaged, the circularly arranged smooth muscle in their walls contracts immediately
- this reduces blood loss for several minutes to hours
65
Explain how platelet plug formation reduces blood loss.
- Platelet adhesion (platelets stick to an injured blood vessel) causes platelets to become activated so platelet release reaction can occur
- get rid of matter in vesicles (ADP, thromboxane A2, serotonin)
- ADP and thromboxane A2 activate closeby platelets
- Serotonin and thromboxane A2 contract vascular smooth muscle to reduce blood flow through damaged vessel
- ADP makes other platelets sticky, so they stick to first platelets that were activated (platelet aggregation)
- buildup and adhesiveness form platelet plug.
- loose plug but gets tighter as fibrin threads form during clotting
66
Explain how blood clotting reduces blood loss.
- network of insoluble protein fibers called fibrin in which the elements of blood are stuck
- involves clotting factors such as calcium ions, some inactive enzymes and several molecules related to platelets or freed by injured tissues.
- extrinsic pathway and intrinsic pathway lead to formation of prothrombinase
- Once prothrombinase is formed, the steps are the same for both pathways, and together these 2 stages are the common pathway
- Prothrombinase converts prothrombin (a plasma protein formed by the liver) into the enzyme thrombin
- Thrombin converts soluble fibrinogen (another plasma protein formed by the liver) into insoluble fibrin
- Fibrin forms the threads of the clot
67
Explain the extrinsic pathway in blood clotting. What is thrombplastin/tissue factor (TF)?
- tissue protein that leaks into the blood from cells outside blood vessels and initiates the formation of prothrombinase
- complex mixture of lipoproteins and phospholipids released from the surfaces of damaged cells
- in the presence of Ca2+, TF begins a sequence of reactions that ends up activating clotting factor X
- once factor X is activated, it combines with factor V in the presence of Ca2+ to form the active enzyme prothrombinase, completing the extrinsic pathway
68
Explain the intrinsic pathway in blood clotting.
- contact with collagen fibers activates clotting factor XII which begins a sequence of reactions that eventually activates clotting factor X
- platelet phospholipids and Ca2+ can also participate in the activation of factor X
- once factor X is activated, it combines with factor V to form the active enzyme prothrombinase, completing the intrinsic pathway
69
Explain the common pathway in blood clotting.
- formation of prothrombinase marks the beginning of the common pathway
- in the 2nd stage of blood clotting, prothrombinase and Ca2+ catalyze the conversion of prothrombin to thrombin
- 3rd stage: thrombin, in the presence of Ca2+, converts fibrinogen, which is soluble, to loose fibrin threads, which are insoluble
- thrombin also activates factor XIII (fibrin stabilizing factor), which strengthens and stabilizes the fibrin threads into a sturdy clot
- plasma contains some factor XIII, which is released by platelets trapped in the clot
70
Thrombin is involved in the common pathway in blood clotting, what are its 2 positive feedback effects?
1) involves factor V, it accelerates the formation of prothrombinase, which accelerates the productions of more thrombin
2) thrombin activates platelets, which reinforces their aggregation and the release of platelet phospholipids
71
What is clot retraction in blood clotting?
the consolidation or tightening of the fibrin clot
72
What does the fibrinolytic system do?
dissolves small, inappropriate clots; it also dissolves clots at a site of damage once the damage is repaired
73
What is fibrinolysis?
dissolution of a clot
74
When a clot is formed, an inactive plasma enzyme called ____ is incorporated into the clot. Both body tissues and blood contain substances that can activate it to ___ or ____ (an active plasma enzyme). Once plasmin is formed, it can dissolve the clot by digesting fibrin threads and inactivating substances such as ___.
- when a clot is formed, an inactive plasma enzyme called plasminogen is incorporated into the clot
- both body tissues and blood contain substances that can activate plasminogen to plasmin or fibrinolysis (an active plasma enzyme)
- fibrinogen
75
Clot formation is localized because...
fibrin absorbs thrombin into the clot and due to the dispersal of some of the clotting factors by the blood, their concentrations are not high enough to allow spreading
76
Endothelial cells and WBCs produce a prostalglandin called ____ (powerful inhibitor of platelet adhesion and release) that opposes the actions of _______ __
endothelial cells and WBCs produce a prostalglandin called prostacyclin (powerful inhibitor of platelet adhesion and release) that opposes the actions of thromboxane A2
77
What are anticoagulants? Name 4 and explain them:
- substances that delay, suppress, or prevent blood clotting
1) antithrombin: blocks the action of XII, X, and II (prothrombin)
2) heparin: produced by mast cells and basophils, combines with antithrombin and increases its effectiveness in blocking thrombin
3) activated protein C (APC): inactivates the 2 major clotting factors not blocked by antithrombin and enhances activity of plasminogen activators
4) Warfarin (Coumadin): acts as an antagonist to vitamin K and thus blocks synthesis of 4 clotting factors
78
What is thrombosis?
clotting in an unbroken blood vessel (usually a vein)
79
What is a thrombus?
the clot itself in an unbroken blood vessel, may dissolve spontaneously
80
What is an embolus?
-a blood clot, bubble of air, fat from broken bones, or a piece of debris transported by the bloodstream
81
What is a pulmonary embolism?
- when an embolus lodges in the lungs
82
What are the two major blood groups?
ABO, Rh
83
What is the ABO blood group made up of? What are the 4 different blood types?
- based on 2 glycolipid antigens called A and B
- people whose RBCs display only antigen A have type A blood
- those who have only antigen B are type B
- individuals who have both A and B antigens are type AB
- those who have neither antigen A nor B are type O
84
Blood plasma contains antibodies called agglutinins that react with the A or B antigens if the two are mixed. They are the?
-these are the anti-A antibody, which reacts with antigen A, and the anti-B antibody, which reacts with antigen B
85
You do not have antibodies that react with the antigens of your own RBCs, but you do have antibodies for any antigens that your RBCs lack. True or False?
True
86
Explain agglutination:
- an antigen-antibody response in which RBCs become cross-linked to one another
- When these antigen-antibody complexes form, they activate plasma proteins of the complement family
- complement molecules make the plasma membrane of the donated RBCs leaky, causing hemolysis (rupture of the RBCs) and the release of hemoglobin into the blood plasma
