Chapter 18 Study Guide

Question 1

What are the three main functions of the circulatory system? Be able to describe the functions in a single word and be able to further explain what that single word means relative to the circulatory system.

Answer 1

1) Transport: of O_2, CO_2, nutrients, wastes, hormones, and stem cells
2) Protection: Hemostasis and immune system
3) Regulation: Fluid balance, stabilizes pH of ECF, and temperature control

Question 2

What are the major components of the circulatory system?

Answer 2

Heart, blood vessels, and blood

Question 3

What components make up blood? What primary tissue did they originate from? Define the matrix and formed elements.

Answer 3

1) Plasma and the seven types of formed elements
2) Blood is a liquid connective tissue; all of the several blood cell types originate in the connective tissue of bone marrow
3) Plasma: extracellular matrix of blood
4) Formed elements: blood cells and cell fragments

Question 4

Which of the formed elements are not all cells? The ratio of formed elements to plasma is measured using what test?

Answer 4

1) Platelets are cell fragments
2) Hematocrit test measures the ratio of formed elements to plasma

Question 5

List physical properties of blood including viscosity, color, pH, location of blood components when centrifuged, and volume

Answer 5

Viscosity: Whole blood 4.5 to 5.5 times as viscous as water; plasma is 2.0 times as viscous as water
Color: Red
pH: 7.35-7.45
When centrifuged: RBCs on bottom, the a buffy coat of WBCs and platelets, then plasma on top (55% of volume)

Question 6

1) What is the composition of components in blood plasma? (include the percents of each)
2) What are some nutrients?
3) What are some some waste products.

Answer 6

1) Composition: 55% plasma, 45% RBCs, 1% WBCs and platelets
2) Nutrients: Glucose, vitamins, fats, cholesterol, phospholipids, and minerals
3) Wastes: Urea (nitrogenous waste)

Question 7

What are the three main proteins in plasma and what are their functions? Which protein is most abundant?

Answer 7

1) Albumins: smallest and most abundant
-Functions in maintaining osmotic pressure and transports hydrophobic substances
2) Globulins
-Alpha and beta: transports hydrophobic substances
-Gamma globulins = antibodies
3) Fibrinogen
-Fibrinogen can be converted to Fibrin (blood clot)

Question 8

Can you explain blood viscosity and what component of blood contributes most to the viscosity? What issue(s) arise if blood viscosity is too high or too low?

Answer 8

1) Defined as the resistance of a fluid to flow, resulting from the cohesion of its particles
2) RBCs affect blood viscosity; polycythemia and cause viscosity issues; anemia can cause viscosity issues.
3) An RBC or protein deficiency reduces viscosity and causes blood to flow too easily, whereas an excess causes blood to flow too sluggishly. Either of these conditions puts a strain on the heart that may lead to serious cardiovascular problems if not corrected.

Question 9

Can you define blood osmolarity? What issue(s) arise if blood osmolarity is too high or too low?

Answer 9

1) Osmolarity of blood: the total molarity of those dissolved particles that cannot pass through the blood vessel wall
2) If the blood osmolarity is too high, the bloodstream absorbs too much water. This raises the blood volume, resulting in high blood pressure and a potentially dangerous strain on the heart and arteries.
3) If its osmolarity drops too low, too much water remains in the tissues. They become edematous (swollen) and the blood pressure may drop to dangerously low levels because of the water lost from the bloodstream.

Question 10

Where does the production of blood originate?

Answer 10

Stem cells in red bone marrow

Question 11

1) Differentiate hematopoiesis from erythropoiesis.
2) Differentiate between myeloid hemopoiesis and lymphoid hemopoiesis.

Answer 11

1) Hemopoiesis is the creation of blood cells, and erythropoiesis is specifically the creation of red blood cells.
2) Blood formation in the bone marrow and lymphatic organs is called, respectively, myeloid and lymphoid hematopoiesis.

Question 12

Are you able to describe the structure and function of erythrocytes (red blood cells)? What gives the RBC it’s color?

Answer 12

1) Functions: To carry oxygen from the lungs to the tissues and to pick up and transport carbon dioxide from the tissues to the lungs.
2) Structure: They’re biconcave Discs with thick rim. Flexible; can change shape. No nucleus or organelles
3) Color: Nonprotein moiety (red-colored pigment) that binds O2 to ferrous ion (Fe) at the center of the heme groups

Question 13

Can you describe the structure of hemoglobin?

Answer 13

1) Four protein chains: globins
-Adult HB has two alpha and two beta chains
-Fetal Hb contains two alpha and two gamma chains
-Globins bind CO2 (5% of CO2 in blood)
2) Four heme groups
-Nonprotein moiety (red-colored pigment) that binds
-O2 to ferrous ion (Fe) at its center

Question 14

What are the 3 functions of hemoglobin?

Answer 14

1) O2 loading in lungs: Produces oxyhemoglobin (ruby red)
2) O2 unloading in tissues: Produces deoxyhemoglobin or reduced hemoglobin (dark red)
3) CO2 loading in tissues: 20% of CO2 in blood binds to Hb; leads to carbaminohemoglobin

Question 15

What is the hematocrit range for men? For women? Why are the ranges for men and women different?

Answer 15

1) Values are lower in women:
-Normal levels of hematocrit for men range from 41% to 50%. Normal level for women is 36% to 48%
2) This is because:
-Androgens stimulate RBC production
-Women have periodic menstrual losses
-Hematocrit is inversely proportional to percentage of body fat

Question 16

Are you able to define clinical measurements as it relates to RBC and hemoglobin quantities? If a range is given regarding RBC and hemoglobin, whose values tend to be lower? Men or Women and why?

Answer 16

1) Ranges:
-Men’s normal ranges: RBCs: 4.6–6.2 x 1012/L Hemoglobin: 120–160 g/L
-Women normal ranges RBCs: 4.2–5.1 x 1012/L Hemoglobin: 120–160 g/L
2) Women’s RBC levels tend to be lower because:
-Androgens stimulate RBC production
-Women have periodic menstrual losses

Question 17

What hormone stimulates erythropoiesis and what organ produces the hormone? What was the stimulus for the hormone to be released?

Answer 17

1) Kidney production of erythropoietin stimulates bone marrow to perform erythropoiesis
2) Stimulus: A drop in RBC count causes hypoxemia detected by kidney; this could be due to:
-Low levels O2 (hypoxemia)
-High altitude
-Increase in exercise
-Loss of lung tissue in emphysema

Question 18

What is the life cycle of an erythrocyte, i.e what cell did it start from, and the stages until it is an erythrocyte? How long does it take?

Answer 18

1) Development of RBCs takes 3 to 5 days
1}) Reduction in cell size, increase in cell number, synthesis of hemoglobin, and loss of nucleus; first committed cell is called an erythrocyte colony-forming unit
2) Has receptors for erythropoietin (EPO) from kidneys
3) Erythroblasts (normoblast) multiply and synthesize hemoglobin
4) The nucleus is discarded to form a reticulocyte; named for fine network of endoplasmic reticulum
-0.5% to 1.5% of circulating RBCs are reticulocytes
5) Then matures to mature erythrocyte

Question 19

1) How long does a RBC circulate in the body on average?
2) What is the significance of an increase in reticulocytes?

Answer 19

1) Up to 120 days
2) An increase in reticulocytes could indicate anemia due to red blood cells being destroyed earlier than normal (hemolytic anemia) Bleeding or a blood disorder in a fetus or newborn (erythroblastosis fetalis)

Question 20

Nutritionally, what is needed to perform erythropoiesis?

Answer 20

Iron, folic acid, vitamin B12, vitamin C

Question 21

1) Can you explain erythrocyte death and disposal?
2) What organs are involved in the demise of the RBC?
3) What happens to the globin of hemoglobin?
4) What happens to the iron?
5) What happens to the heme of hemoglobin?

Answer 21

1) RBCs rupture (hemolysis) in narrow channels of spleen and liver
2) Macrophages mainly in spleen but also in liver
3) Globins hydrolyzed into amino acids
4) Iron removed from heme and recycled
5) Heme pigment excreted
-Heme pigment converted to biliverdin (green)
-Biliverdin converted to(yellow)
-Liver removes bilirubin (& biliverdin) and secretes into bile
-Bile released into small intestine
-Bacteria of large intestine convert pigments into urobilinogens

Question 22

Can you define gastroferritin, ferritin and transferrin? What element is bound to them and why does this element have to be bound?

Answer 22

1) In the stomach, Gastroferritin binds Fe^(2+) and transports it to small intestine
2) Absorbed into blood and binds to transferrin for transport to bone marrow, liver, and other tissues
3) Stored in Liver as ferritin

Question 23

Define and describe polycythemia and its different types

Answer 23

1) Polycythemia: an excess of RBCs
2) Primary polycythemia: Cancer of erythropoietic cell line in red bone marrow
3) Secondary polycythemia: From dehydration, emphysema, high altitude, or physical conditioning
Increased blood volume, pressure, viscosity; can lead to embolism, stroke, or heart failure

Question 24

Define anemia and describe its main causes and consequences

Answer 24

1) Anemia: a lack of RBCs
2) Causes: Inadequate erythropoiesis or hemoglobin synthesis due to things such as: Kidney failure, iron-deficiency anemia, pernicious anemia, hemorrhagic anemias from bleeding, hemolytic anemias from RBC destruction
3) Consequences:
-Tissue hypoxia and necrosis
-Patient is lethargic; shortness of breath; necrosis of brain, heart, or kidney
-Blood osmolarity is reduced, producing tissue edema
-Blood viscosity is low
-Pressure drops and heart race; cardiac failure may ensue

Question 25

Can you determine an incompatibility between a mother and fetus in Rh blood type?

Answer 25

Rh negative mother with anti-Rh antibodies, and baby with Rh positive blood

Question 26

Describe the different types of leukocytes

Answer 26

1) Neutrophils: acute infections, aggressively antibacterial
2) Eosinophils: parasitic infections and allergies, stain orange
3) Basophils: release histamines and heparin, stain purple
4) Lymphocytes: huge nucleus, b-cells and t-cells
5) Monocytes: chronic infections, viral infections and inflammation, leave blood stream and transform into macrophages

Question 27

1) What cell type did all the leukocytes begin with?
2) What is the significance of differentiating to a colony-forming unit?
3) Which leukocyte type migrates to the thymus?

Answer 27

1) Begin as Hemopoietic stem cells (HSCs) in the bone marrow
2) Each colony-forming unit develops into a particular type of WBC
3) T-lymphocytes migrate to the thymus

Question 28

Name and define the 3 types of leukocyte disorders; describe their causes and effects

Answer 28

1) Leukopenia: low WBC count: below 5,000 WBCs/μL
-Causes: radiation, poisons, infectious disease
-Effects: elevated risk of infection
2) Leukocytosis: high WBC count: above 10,000 WBCs/μL
-Causes: infection, allergy, disease
3) Leukemia: cancer of hemopoietic tissue usually producing a very high number of abnormal, circulating leukocytes

Question 29

Can you describe the difference between a total WBC count and a differential WBC? Which is more useful and why?

Answer 29

Total WBC count is less useful than differential WBC count, because differential WBC count allows you to see which leukocyte type is abnormal

Question 30

1) Define hemostasis.
2) How does the body control bleeding for small vessels?

Answer 30

1) Hemostasis: the cessation of bleeding
2) Vascular spasm: Vasoconstriction of a broken vessel

Question 31

Platelets are small fragments of cells called _________ and their function is to:

Answer 31

megakaryocytes; aid in clotting and stop bleeding

Question 32

Define thrombopoesis

Answer 32

The formation of platelets in bone marrow

Question 33

What are the three hemostatic mechanisms and which involve platelets? Of the three hemostatic mechanisms, which is the most immediate?

Answer 33

1) Vascular spasm, platelet plug formation, and blood clotting (coagulation); all 3 involve platelets
2) Vascular spasm is the most immediate protection against blood loss

Question 34

Describe vascular spasm

Answer 34

Most immediate protection against blood loss
Causes: Pain receptors, smooth muscle injury, platelets release serotonin (vasoconstrictor)
Vasoconstriction of a broken vessel

Question 35

Describe platelet plug formation

Answer 35

Intact vessels have a smooth endothelium coated with prostacyclin (platelet repellant)
Broken vessel exposes collagen
Platelet pseudopods stick to the collagen and to each other
Pseudopods contract - draw together a platelet plug
Platelets degranulate releasing chemicals that attracts more platelets
Positive feedback loop

Question 36

Describe blood clotting (coagulation)

Answer 36

last and most effective defense against bleeding
Conversion of fibrinogen into insoluble fibrin threads (framework of clot)
Procoagulants (clotting factors) in plasma
Activate one factor and it will activate the next to form a reaction cascade

Question 37

What is the last and most effective defense against bleeding?

Answer 37

Blood clotting/ coagulation

Question 38

Be able to differentiate between the extrinsic mechanism of coagulation and the intrinsic mechanism of coagulation.

Answer 38

1) Extrinsic pathway
-Factors released by damaged tissues
-Faster
2) Intrinsic pathway
-Initiated by platelets
-Slower

Question 39

Clotting factors are proteins produced by which organ? Is blood clotting a negative feedback mechanism or a positive feedback mechanism? What element is required?

Answer 39

1) Clotting factors are proteins produced by the liver
2) Blood clotting is a positive feedback mechanism
3) Calcium required for either pathway

Question 40

Whether extrinsic or intrinsic, they converge to the identical final three steps. Describe these steps

Answer 40

1) Factor x is converted to prothrombin activator
2) Prothrombin activator: Converts prothrombin to thrombin
3) Thrombin: Converts fibrinogen into fibrin monomers; monomers covalently bind to form fibrin polymer

Question 41

Define fibrinolysis. Why do you need fibrinolysis?

Answer 41

1) Fibrinolysis: dissolution of a clot, usually using plasmin (a fibrin-dissolving enzyme that breaks up the clot)
2) It’s needed because eventually the tissue is repaired and the clot is no longer needed

Question 42

What are the three mechanisms you have in the body that prevent inappropriate clotting?

Answer 42

1) Prostacyclin-coated endothelium repels platelets
2) Thrombin diluted and washed away by flowing blood
-Heart slowing in shock can result in clot formation
2) Natural anticoagulants
-Heparin (from basophils and mast cells)
-Antithrombin (from liver)

Question 43

Know the difference between the clotting disorders including hemophilia, thrombus and embolus. For a pulmonary embolism, where would the clot most likely originate from?

Answer 43

1) Hemophilia: family of hereditary diseases characterized by deficiencies of one factor or another
2) Thrombus: abnormal clotting in unbroken vessel
3) Embolus: anything that can travel in the blood and block blood vessels
-Infarction (tissue death) may occur; MI or stroke
4) Pulmonary embolism: 650,000 Americans die annually of thromboembolism; would originate from right heart (*)