The Circulatory System: Blood Flashcards
(42 cards)
0
Q
How many liters of blood are in an average adult?
A
5 liters, but can range from 4-6
1
Q
Common Functions of Blood
A
- Transport (O2, CO2, nutrients, waste, hormones, stem cells)
- Protection (prevent spread of infection, WBCs destroy microorganisms and cancer cells, produce antibodies, platelets secrete factors for clotting etc)
- Regulation (fluid distribution, pH, body temperature)
2
Q
Blood Components
A
- Formed elements (cells, platelets)
- Fluid elements of the matrix (plasma)
3
Q
Formed Element Classifications
A
- Erythrocytes
- Platelets
- Leukocytes
- Granulocytes:
- Neutrophils
- Eosinophils
- Basophils
- Agranulocytes
- Lymphocytes
- Monocytes
- Granulocytes:
4
Q
Hematocrit
A
The percentage of total volume made up by the erythrocytes (usually 37-52%)
5
Q
Components of Blood in a Centrifuge Sample (%)
A
Top to Bottom:
- Plasma (47-63%)
- WBCs and platelets (“Buffy coat,” 1% or less)
- Erythrocytes (37-52%)
6
Q
Plasma Components
A
- Water
- Three Categories of Proteins:
1) Albumin
- transports solutes
- buffers pH of plasma
- viscosity and osmolarity
2) Globulins
- alpha, beta, gamma
- transport, clotting, immunity
3) Fibrinogen
- precursor of clotting fibrin - Nutrients
- Electrolytes
- Hormones
- Nitrogenous wastes
- Gases
7
Q
5 Types of Leukocytes
A
Granulocytes
- Neutrophils
- Basophils
- Eosinophils
Agranulocytes
- Lympocytes
- Monocytes
8
Q
Serum
A
When the blood clots and solids are removed, remaining fluid is serum
Serum is essentially plasma without the clotting protein fibrinogen
9
Q
Origin of Plasma Proteins
A
The liver produces all plasma proteins but gamma globulin which are generated by plasma cells (connective tissue cells that are descending from B lymphocytes)
10
Q
Viscosity
A
The resistance of a fluid to flow based in the cohesion of its particles
- Blood viscosity is determined by the level of plasma proteins and formed elements
11
Q
Osmolarity
A
The total molarity of dissolved particles that cannot pass through the blood vessel wall
- If blood molarity is too high (with respect to tissue molarity), the bloodstream will retain too much water which will increase blood volume and blood pressure
- If blood molarity is too low, the bloodstream will release too much water into the tissues, resulting in edema and low blood pressure
- Osmoreceptors in the brain detect changes in osmolarity to govern the release of ADH and stimulate thirst
12
Q
pH of Blood
A
7.35-7.45
13
Q
Hemopoiesis
A
- Tissues that produce blood cells are called hemopoietic tissues (mainly myeloid tissue aka red bone marrow, and lymphoid tissue such as the tonsils and thymus)
- Hemopoietic stem cells (HSCs, aka pluripotent stem cells or PPSCs) in the bone marrow give rise to all formed elements
- Most HSCs remain in the bone marrow but some go on to form colony-forming units (CFUs)
14
Q
Internal Structure of Erythrocytes
A
- During maturation, erythrocytes lose their organelles and this contain no nucleus or mitochondria and rely on anaerobic respiration (they transport oxygen and therefore must not consume it)
- Cytoplasm contains hemoglobin
15
Q
Lifespan of Erythrocytes
A
~120 days
- Are phagocytosed by macrophages in the spleen, liver, bone marrow
16
Q
Structure of Hemoglobin
A
- Four protein chains called globins: 2 alpha and 2 beta chains
- Heme group containing ferrous ion (Fe++) that binds O2 to form oxyhemoglobin
- The globin portion binds CO2 to form carboaminohemoglobin
- Adult hemoglobin (HbA) and fetal hemoglobin (HbF) differ in structure; HbF had two gamma rather than best chains and binds oxygen with a higher affinity
17
Q
Erythropoiesis
A
- Stimulated by hypoxia (low blood O2), the kidney and liver release erythropoietin (EPO)
18
Q
Primary and Seconary Polycythemia (Polycthemia Vera)
A
- Excess RBCs
- Primary is cancer of the erythropoietic line of the red bone marrow
- Secondary is from all other causes
- Higher blood volume, BP, viscosity
19
Q
Anemia
A
- Very low RBCs or hemoglobin
- Caused by inadequate erythropoiesis/hemoglobin, hemorrhagic anemia, hemolytic anemia
Iron-Deficiency Anemia
- small, pale RBCs
Pernicious Anemia
- deficiency of intrinsic factor to absorb B12
Aplastic Anemia
- destruction of bone marrow
20
Q
Sickle-Cell Disease
A
- A recessive allele modifies hemoglobin so the cells are tapered and agglutinate, blocking blood vessels and causing pain to oxygen-deprived areas
- Heterozygous are trait carriers who exhibit limited symptoms and demonstrate resistance to malaria
21
Q
Agglutination Terms for Blood Types
A
Agglutinogens – Antigens
Agglutinins – Antibodies
22
Q
Universal Donor versus Recipient
A
AB = recipient (contains neither anti-A or -B agglutinins)
O = donor (contains both anti-A and -B)
23
Q
Rh Factor
A
Group of antigens: C, D, E (D is the most common)
- Blood type is + or - based on presence or absence of D antigen
- Blood does not contain anti-D antibodies but will develop them upon exposure to Rh+ blood
24
Rh Factor and Pregnancy
- Rh- mother may be exposed to baby's Rh+ blood during birth and will produce anti-D antibodies
- During a second Rh+ pregnancy, these antibodies can cross the placenta resulting in hemolysis
- Known as erythroblastosis fetalis or hemolytic disease of newborn
- Can be combated by injecting mother beforehand with globulins that intercept Rh+ antigens before she produces antibodies
- ex RhoGAM, passive immunization
25
Leukocyte Order of Abundance
N > L > M > E > B
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Neutrophils
- Bacterial infections
- Nucleus consists of 2-5 lobes
- Called polymorphonuclear Leukocytes (PMNs)
- Reddish to violet granules
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Eosinophils
- Allergies, parasitic infections, collagen diseases, diseases of spleen and CNS
- Bilobed nucleus
- Rosy to orange granules
28
Basophils
- Secrete histamine and heparin
- Abundant dark violet granules
- Histamine widens blood vessels to accelerate the flow of blood to injured tissues and makes them more permeable to neutrophils and clotting proteins
- Heparin inhibits blood clotting and promotes mobility of other WBCs
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Lymphocytes
- Large nucleus with thin strip of cytoplasm
- Large, medium, and small varieties
- Medium and large typically in fibrous connective tissue, not usually circulating in blood
30
Monocytes
- Inflammation and viral infections
- Largest WBC
- Kidney- or U-shaped nucleus
- Cytoplasm contains fine granules
- Transform into macrophages in the tissue that destroy dead or dying host cells as well as foreign cells, pathogenic chemicals, etc
- Macrophages are called Antigen-presenting cells (APCs) because they display antigen fragments to alert the immune system
31
Leukopenia versus Leukocytosis
Leukopenia = Low WBC
- Lead, arsenic, mercury poisoning, radiation sickness, certain infectious diseases, glucocorticoids and certain anti-cancer drugs
Leukocytosis = High WBC
- Dehydration or emotional responses
32
Leukopoiesis
HSCs differentiate into distinct CFUs:
- Myeloblasts ultimately form the granulocytes
- Monoblasts form monocytes
- Lymphoblasts form lymphocytes
33
Leukemia
Cancer of hemopoietic tissues - can be classified as myeloid or lymphoid, acute or chronic
- Myeloid leukemia is marked by overproduction of granulocytes
- Lymphoid leukemia overproduces monocytes and lymphocytes
- Acute appears and progresses rapidly while chronic appears and progresses slowly
34
Thrombopoiesis
- Some HSCs have receptors for thrombopoietin released by the kidneys and liver and become megakaryoblasts
- Megakaryoblasts become megakaryocytes with multilobed nuclei and multiple chromosome sets
- Platelets are fragments of the megakaryocytes
35
Hemostasis
= cessation of bleeding
- Three mechanisms:
1) Vascular spasm
- Constriction of blood vessel, lasts until other two mechanisms can take over
2) Platelet plug formation
- Platelets detect exposed collagen fibers and form a platelet plug and undergo degranulation of serotonin, thromboxane, ADP
3) Blood clotting
- One of the most complex processes in the body
- Fibrinogen is converted to fibrin to collect more fibrin, blood cells and platelets
36
Platelet Granules Released in Platelet Plug Formation
Serotonin + Thromboxane = vasoconstriction and spasm
ADP + Thromboxane = plug formation
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Two Pathways for Conversion of Fibrinogen to Fibrin
1) Extrinsic Mechanism - clotting factors released from source(s) other than blood - the damaged tissue (ex Thromboplastin)
2) Intrinsic Mechanism - clotting factors found in the blood itself
38
Fibrinolysis
- Dissolution of a clot
| - Plasmin dissolves fibrin through a positive feedback loop
39
Hemophilia
- A blood clotting disorder where blood fails to clot due to lack of clotting factors
- Pain and joint immobility can result from hematomas (masses of clotted blood in the tissues)
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Thrombosis
- Abnormal clotting of blood in an unbroken blood vessel
- A thrombus (clot) may cause blockages/break off to form an embolus that enters the bloodstream
- If a vessel that supplies O2 to a vital tissue is blocked, infarction ( or tissue death) may result
- ex Deep vein thrombosis pulmonary embolism
41
Citrate or EDTA as Anticoagulants
Citrate and EDTA are salts that bind Ca++ so it cannot participate in blood clotting
