Chapter 19 - Cardiovascular System: The Blood Flashcards
What is interstitial fluid?
Fluid that bathes body cells
- constantly renewed by the blood
What are the three general functions of blood?
- Transportation - 02, C02, nutrients, wastes, hormones
- Regulation - pH, body temperature, maintain homeostasis of all body fluids
- Protection - clotting ability (protect against major blood loss), white blood cells protect against disease, antibodies, interferons
Describe the physical characteristics of blood.
- denser and thicker than water, feels sticky
- 38 degrees in temperature
- pH from 7.35 to 7.45
- 5 to 6 liters in an adult male
- 4 to 5 liters in an adult female
- 8% of total body mass
What are the components of blood?
- Blood plasma
2. Formed elements (cells and cell fragments)
What is blood?
Liquid connective tissue
- consists of cells surrounded by a liquid extracellular matrix
What are the components of blood plasma?
- 91.5% water
- 8.5% solutes
What are the blood plasma proteins?
- Albumin (regulating blood volume)
- Globulins (attack viruses & bacteria)
- Fibrinogen (help in blood clotting)
What is another name for blood plasma proteins?
Antibodies or immunoglobulins
What are antibodies and what is their function?
Plasma proteins
- Bind to the specific antigen that stimulated its production
- Disables invading antigen
What is the hematocrit?
The percentage of total blood volume occupied by RBCs
- a hematocrit of 40 would indicate 40% volume of blood is composed of RBCs
What is the normal range for the hematocrit?
38-46% in females
40-54% in males
What contributes to a higher hematocrit in males?
Testosterone
What is hemopoiesis? (hematopoiesis)
The process by which the formed elements of blood develop
Where does hemopoiesis occur before birth?
In the yolk sac of an embyro and later in the spleen, thymus and lymph nodes of the fetus
Where is the source of blood cells after birth?
Red bone marrow
What is red bone marrow?
Highly vascularized connective tissue located in the spaces between trabeculae of spongy bone tissue
Where are pluripotent stem cells derived from and what is their capacity?
Red bone marrow cells derived from mesenchyme
- have the capacity to develop into many different types of cells
What are the formed elements of blood?
- Red blood cells (whole cells)
- White blood cells (whole cells)
- Platelets (cell fragments)
In order to form blood cells, pluripotent stem cells must produce what two types of cells first?
- Myeloid stem cells
2. Lymphoid stem cells
What do myeloid stem cells give rise to?
- Red blood cells
- Platelets
- Monocytes
- Neurtophils
- Eosinophils
- Basophils
What do lymphoid stem cells give rise to?
Lymphocytes
What are progenitor cells?
Similar to a stem cell
- has a tendency to differentiate into a specific type of cell, but is already more specific than a stem cell and is pushed to differentiate into its “target” cell
- give rise to more specific elements of blood
- no longer capable of reproducing themselves
What are the CFU-designations and what does each produce?
- CFU-E: Erythrocytes (red blood cells)
- CFU-Meg: Meagkaryocytes (source of platelets)
- CFU-GM: Granulocytes (Neutrophil and monocytes)
What are precursor cells?
The next generation of blood cells (after progenitor)
- over several cell divisions they develop into the actual formed elements of blood
- monoblasts into monocytes
- eosinophilic myeloblasts intoeosinophils
- have recognizable microscopic appearances
What are hemopoietic growth factors and what do they regulate?
Hormones
- regulate the differentiation and proliferation of particular progenitor cells
What is the function of erythropoietin (EPO)?Where is it produced?
Increases the number of red blood cell precursors
Produced primarily by cells in the kidneys
What is the function of thrombopoietin (TPO)?Where is it produced?
Hormone that stimulates the formation of platelets (thrombocytes) from megakaryocytes
- produced by the liver
What is the function of cytokines?Where are they produced?
Generally act as local hormones
- stimulate proliferation of progenitor cells in red bone marrow and regulate activities of cells involved in nonspecific defenses and immune responses
- produced by red bone marrow cells, leukocytes, macrophages, fibroblasts and endothelial cells
What are the two important families of cytokines?
- Colony-stimulating factors (CSFs)
2. Interleukins
What are the colony-stimulating factors (CSFs)?
A substance secreted by bone marrow that promotes the growth and differentiation of stem cells into colonies of specific blood cells.
What are interleukins?
Any of a class of glycoproteins produced by leukocytes for regulating immune responses
What do red blood cells (erythrocytes) contain?
The oxygen-carrying protein hemoglobin
- gives it it’s red color
What is hemoglobin?
The oxygen-carrying protein in red blood cells
Describe the anatomy of red blood cells.
- biconcave discs
- plasma membrane is both strong and flexible (allows them to deform without rupturing)
- lack a nucleus and other organelles
- cannot reproduce
- do not undergo extensive metabolic activities
How do red blood cells generate ATP?
Anaerobically
- they do not use up the oxygen that they transport
Describe the physiology of red blood cells.
- RBC shape provides great surface area for diffusion
- contains hemoglobin molecules
- all the internal space inside a RBC is used for oxygen transport
What are the two parts of a hemoglobin molecule?
- Globin - protein composed of 4 polypeptide chains
2. Heme - ring-like nonprotein pigment, is bound to each chain
How many oxygen molecules attach to the iron ion that is in the center of each heme ring?
4
How many hemoglobin molecules are contained in a single red blood cell?
About 280 million hemoglobin molecules
What is the significance of red blood cells containing the enzyme carbonic anhydrase (CA)?
It catalyzes the conversion of carbon dioxide and water to carbonic acid, which dissociates into hydrogen ions and HCO3
- (an important buffer in extracellular fluid)
- allows carbon dioxide to be transported in blood plasma
How long do red blood cells live for?
120 days
- ruptured cells are removed from circulation and destroyed by fixed phagocytic marcrophages in the spleen and liver
Describe the recycling process of red blood cells.
- Marcrophages phagocytize ruptured and worn-out RBCs
- Globin and heme portions of hemoglobin are split apart
- Globin is broken down into amino acids
- Iron is removed from heme
- Iron is stored in ferritin (protein)
- Iron reattaches to transferrin
- Iron is transferred to red bone marrow
- Erythropoiesis in red bone marrows results in production of RBCs
- When iron is removed from heme, non-iron portion is converted to biliverdin then into bilirubin
- Bilirubin enter blood, transported to liver
- Bilirubin is released into bile
- Bilirubin is converted into urobilinogen in large intestine
- Some is absorbed back into blood, converted into urobilin, excreted in urine
- Most urobilinogen is eliminated in feces
What is feritin?
A protein that serves to store iron in the tissues
What is erythropoiesis?
Production of red blood cells
- starts in the red bone marrow
What is a reticulocyte?
An immature RBC without a nucleus
- develops into a mature RBC within 1-2 days after release from red bone marrow
What is hypoxia?
Cellular oxygen deficiency
- occurs if too little oxygen enters the blood
What does hypoxia stimulate?
The kidneys to step up the release of erythropoietin, which speeds up the development of proerythroblasts into reticulocytes in the red bone marrow
- as the # of circulating RBCs increases, more oxygen can be delivered to body tissues
How are leukocytes (white blood cells) different from red blood cells?
Contain a nucleus and a full complement of other organelles
- do not contain hemoglobin
How are white blood cells classified?
- Granular
- Agranular- depending on whether or not they contain cytoplasmic granules (vesicles) that are made visible during staining
What are the granular leukocytes?
- Neutrophils
- Eosinophils
- Basophils
What are the agranular leukocytes?
- Lymphocytes
2. Monocytes
What distinguishes a neutrophil?
- granules are smaller, evenly distributed and pale lilac- nucleus has 2-5 lobes, connected by thin strands of nuclear material
- as the cells age, the number of nuclear lobes increase
What distinguishes an eosinophil?
- large, uniform-sized granules
- stain red-orange with acidic dyes
- nucleus has two lobes, connected by a thin or thick strand of nuclear material
What distinguishes a basophil?
- round, variable-sized granules- stain blue-purple with basic dyes
- granules commonly obscure the nucleus which has two lobes
What distinguishes a lymphocyte?
- nucleus stains dark, is round or slightly indented- cytoplasm stains sky blue, forms a ring around nucleus
- classified as small or large based on diameter
What distinguishes a monocyte?
- nucleus is kidney-shaped
- cytoplasm stains blue-gray and has a foamy appearance
- blood is a conduit for monocytes
What do monocytes become?
Fixed (tissue) or wandering macrophages
What is the difference between fixed & wandering macrophages?
Fixed: Reside in a particular tissue
Wandering: Roam the tissues and gather at sites of infection
What are major histocompatibility (MHC) antigens?
Proteins that protrude from their plasma membranes into the extracellular fluid
- “cell identity markers” are unique to each person (except identical twins)
How many times do RBCs outnumber WBCs?
700:1
What is leukocytosis?
An increase in the number of WBCs (above 10,000 per micro litre is a normal protective response to stresses)
- due to invading microbes, strenuous exercise, anesthesia or surgery
What is leukopenia?
Abnormally low level of WBCs (below 5,000 per micro litre
What is the general function of white blood cells?
Fight pathogens that enter the body by phagocytosis or immune response
Which WBCs once they leave the bloodstream, never return?
Granular leukocytes & monocytes
- never return to bloodstream
What is emigration?
The process by which white blood cells leave the bloodstream
- also called diapedesis
How do white blood cells leave the blood stream?
Roll along the endothelium, stick to it, and then squeeze between endothelial cells
What is phagocytosis?
The process by which neutrophils & macrophages ingest bacteria & dispose of dead matter
What is chemotaxis?
A phenomenon by which different chemicals are released by microbes & inflamed tissues that attract phagocytes
What are the three kinds of lymphocytes, the major solider in immune system battles?
- B cells - destroy bacteria
- T cells - destroy viruses, fungi, cancer, bacteria
- NK (natural killer cells) - destroy a wide variety
What is a differential white blood cell count?
A count of each of the five types of white bloods cells
- to detect infection or inflammation
- determine effects of possible poisoning
- monitor blood disorders
- monitor effects of chemotherapy
- detect allergic reactions
How is a differential white blood cell count useful in diagnosis?
Each type of white blood cell plays a different role, determining the % of each type will assist in diagnosis
What kind of cells differentiate into platelets?
Hemopoietic stem cells
What is thrombopoietin?
A protein (hormone) that regulates the production of platelets
What is a megakaryoblast?
They transform into megakaryocytes, huge cells that splinter into 2000-3000 fragments
- each fragment enclosed by a plasma membrane is a platelet
How many platelets are present in each micro litre of blood?
150,000-400,000
What is hemostasis?
A sequence of responses that stops bleeding
When blood vessels are damaged or ruptured, the hemostatic response must be?
Quick, localized to the region of damage and carefully controlled in order to be effective
What are the three mechanisms that reduce blood loss?
- Vascular spasm
- Platelet plug formation
- Blood clotting (coagulation)
What is a hemorrhage?
The loss of a large amount of blood from vessels
What is a vascular spasm?
When arteries or arterioles are damages, the circularly arranged smooth muscle in their walls contracts immediately
What are the steps involved in a platelet plug formation?
- Platelet adhesion - stick to damaged blood vessel
- Platelet release reaction - extend projections and liberate contents
- Platelet aggregation - stickiness of ADP, causes a gathering
What is platelet adhesion?
The process by which platelets contract and stick to parts of a damaged blood vessel
Describe the platelet release reaction.
When platelets become activated, they extend projections and begin to liberate their contents
What is platelet aggregation?
When activated platelets release ADP, it makes other platelets in the area sticky
- causes the new platelets to adhere to the original platelets
- causes a gathering
How does a platelet plug become effective?
Initially the plug is loose, but it tightens when reinforced by fibrin threads formed during clotting
- can stop blood loss completely if the hole in the blood vessel is not too large
What is serum?
Blood plasma without the clotting proteins
What is clotting or coagulation?
A series of chemical reactions that culminate the formation of fibrin threads
What is a clot?
The gel that forms when blood is removed from the body
What is thrombosis?
Clotting in an undamaged blood vessel
- if blood clots too easily
What are the clotting (coagulation) factors?
- calcium ions
- several inactive enzymes
- various molecules associated with platelets
What are the three stages of blood clotting?
- Extrinsic and instrinsic pathways lead to the formation of prothrombinase
- Prothrombinase converts prothrombin (protein) into the enzyme thrombin
- Thrombin converts soluble fibrinogen (protein) into insoluble fibrin
- fibrin forms the threads of the clot
How quickly does the extrinsic pathway occur?
Within seconds if the trauma is severe
What occurs during the formation of an extrinsic pathway?
Tissue factor (TF) also called thromboplastin leaks into the blood from cells OUTSIDE blood vessels and initiates the formation of prothrombinase
What is tissue factor (TF) or thromboplastin?
- complex mixture of lipoproteins & phospholipids released from the surfaces of damaged cells
- in the presence of calcium ions, TF begins a sequence that results in a blood clot
How quickly does the intrinsic pathway occur?
More slowly than extrinsic pathway, several minutes
How is the intrinsic pathway different from the extrinsic pathway?
The activators for the intrinsic pathway are either in direct contact with blood or contained WITHIN the blood
- outside tissue damage is NOT needed
What marks the beginning of the common pathway?
Formation of prothrombinase
What occurs during the second stage of blood clotting?
Prothrombinase and calcium ions catalyze the conversion of prothrombin to thrombin
What occurs during the third stage of blood clotting?
Thrombin in the presence of calcium ions, converts fibrinogen (soluble) to loose fibrin threads (insoluble)
- strengthens and stabilizes the fibrin threads into a sturdy clot
Does thrombin has a positive or negative feedback?
POSITIVE!
What is clot retraction?
The process of consolidation or tightening of the fibrin clot
- as the clot retracts, it pulls the edges of the damaged vessel closer together, decreasing the risk of further damage
What vitamin is required for clot formation and why?
Vitamin K
- it is required for the synthesis of four clotting factors
What is the function of the fibrinolytic system?
To dissolve small, inappropriate clots
- also dissolves clots at a site of damage once the damage is repaired
What is fibrinolysis?
The dissolution of a clot
What is plasminogen?
The inactive precursor of the enzyme plasmin, present in blood
What is plasmin or fibrinolysin?
An enzyme, formed in the blood in some circumstances, that destroys blood clots by attacking fibrin
What is fibrin?
An insoluble protein formed from fibrinogen during the clotting of blood.
It forms a fibrous mesh that impedes the flow of blood
What are anticoagulants?
Substances that delay, suppress or prevent blood clotting
What is antithrombin?
An anticoagulant that blocks the action of several clotting factors including prothrombin
What is heparin?
An anticoagulant
- produced by mast cells and basophils
- combines with antithrombin and increases its effectiveness
What are some instances in which intravascular clots form?
- roughened endothelial surfaces of blood vessels(induce adhesion of platelets)
- when blood flows too slowly (stasis)
What is thrombosis?
Clotting in an unbroken blood vessel
What is a thrombus?
A clot in an unbroken blood vessel
- may dissolve spontaneously
What is an embolus?
A blood clot. bubble of air, fat from broken bones or a piece of debris transported by the bloodstream
What happens during a pulmonary embolism?
An embolus gets lodged in the lungs
What are agglutinogens?
An antigen that stimulates the production of an agglutinin
How is blood categorized into different blood groups?
Based on the presence or absence of various antigens
What are the two major blood groups?
- ABO
2. Rh
What is the ABO blood group based on?
Two glycolipid antigens
- A and B
What defines blood type A, B, AB & O?
Blood type A: Have antigen A
Blood type B: Have antigen B
Blood type AB: Have both antigens ( A and B)
Blood type O: Have neither antigens
What are agglutinins?
Antibodies
What are agglutinins?
Antibodies that react with A or B antigens
What are agglutinogens?
An antigen that stimulates the production of an agglutinin
What are the two kinds of antibodies in the blood?
Anti-A antibody
Anti-B antibody
What does the anti-A antibody react with?
Antigen A
What does the anti-B antibody react with?
Antigen B
If you are blood type A, what antigen type are you and what kind of antibody is present is your plasma?
Antigen A is present on red blood cells
Anti-B antibody is present in your blood plasma
** you have antibodies for any antigens that your red blood cells LACK!
What is a 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
Why would a transfusion be used?
- alleviate anemia
- increase blood volume
- improve immunity
What is agglutination and what causes it?
Clumping of red blood cells
- an incompatible blood transfusion
- antibodies in the recipient’s plasma bind to the antigens on the donated RBCs
- not the same as blood clotting
What is hemolysis?
Rupture of the red blood cells
What is agglutination and what causes it?
Clumping of red blood cells
- an incompatible blood transfusion
- antibodies in the recipient’s plasma bind to the antigens on the donated RBCs
- not the same as blood clotting
- causes hemolysis
What is hemolysis?
Rupture of the red blood cells
What blood type is the universal recipient?
Blood type AB
- do not have anti-A or anti-B antibodies in their blood plasma
- do not have antibodies to attack the donated blood
What blood type is the universal donor?
Blood type O
- have neither A or B antigens on their RBCs
- can only receive blood type O
What gives the Rh blood group it’s name?
B/c of the Rh antigen
What gives the Rh blood group it’s name?
B/c of the Rh antigen
the Rh factor
What are the two designations for Rh blood groups?
Rh positive
Rh negative
What are the two designations for Rh blood groups?
Rh positive (ppl who have Rh antigens) Rh negative (ppl who do NOT have Rh antigens)
What is the hemolytic disease of the newborn (HDN)?
Occurs if the baby is Rh+ and the mother is Rh-
- mother will make anti-RH antibodies
- if mother becomes pregnant again, and the baby is Rh+, the antibodies will attack the second baby
What is ABO blood typing?
Where the blood is tested to see if it is A, B, AB, or O
Why is blood typing important?
To ensure that antibodies aren’t created that attack the donor blood
- hemolysis would occur- agglutination would occur (clumping)
What happens during a cross-match?
The possible donor RBCs are mixed with the recipient’s serum
- if agglutination does not occur, the recipient does not have antibodies that will attack the donor RBCs
What happens during screening?
The recipient’s serum is screened against a test panel of RBCs having antigens known to cause blood transfusion reactions to detect any antibodies that may be present
What is anemia?
A condition in which the oxygen
- carrying capacity of blood is reduced
- reduced # of RBCs or decreased amount of hemoglobin
What happens when an individual has sickle-cell disease (SCD)?
Contain Hb-S
- an abnormal kind of hemoglobin
- when Hb-S gives up oxygen to the interstitial fluid, it forms long, stiff, rodlike structures that bend the erythrocyte into a sickle shape
- they rupture easily
What is hemophilia?
Inheritied deficiency of clotting in which bleeding may occur spontaneously or after only minor trauma
What is leukemia?
Refers to a group of red bone marrow cancers in which abnormal white blood cells multiply uncontrollably
- interferes with production of RBCs, WBCs and platelets
What is cyanosis?
Slightly bluish/dark-purple skin discoloration
- due to increased quantity of methemoglobin
- hemoglobin not combined with oxygen in systemic blood
What is jaundice?
Abnormal yellowish discoloration of the eyes, skin and mucous membranes
- due to excess bilirubin
What is septicemia?
“Blood poisoning”
- toxins or disease causing bacteria in the blood
