Cardiorespiratory System- Blood

Question 1

What is blood?

Answer 1

• A form of fluid connective tissue
• About 4 times more viscous than water
• The temperature of blood is about 1 degrees celsius higher than measured body temperature

Question 2

What is whole blood?

Answer 2

• Can be separated into its liquid and cellular components using a machine called a centrifuge
• Components include, erythrocytes, buffy coat and plasma

Question 3

What are erythrocytes?

Answer 3

• Called red blood cells
• Form the lower layer of separated whole blood (formed element)
• Average about 44% of a blood sample
• Lack nuclei and organelles, meaning they have a reduced life span of 120 days (cannot repair itself when damaged)
• Structure enables them to carry respiratory gases proficiently between tissues and the lungs
• They are normally small and disc shaped which allows respiratory gases to be loaded and unloaded rapidly
• Filled with hemoglobin proteins

Question 4

What is a buffy coat?

Answer 4

• Makes up the middle layer of separated whole blood
• Thin and slightly gray-white layer composed of cells called leukocytes (white blood cells) and cell fragments called platelets
• Forms less than 1% of a blood sample

Question 5

What is plasma?

Answer 5

• Yellow coloured liquid made up of water, proteins and other solutes
• Water makes up 92% of plasma total volume
• Plasma proteins make up 7% of plasma total volume
• When plasma proteins are removed, the remaining fluid is called serum
• Lies between the buffy coat and erythrocyte layers in separated whole blood
• Generally makes up 55% of a blood sample

Question 6

What are formed elements of blood?

Answer 6

• Erythrocytes and buffy coat (leukocytes and platelets)
• Refer to them as elements instead of cells because platelets are fragments broken off from a larger cell
• Combined with the liquid plasma, it creates whole blood

Question 7

How does blood transport?

Answer 7

• Moves numerous elements and compounds throughout the body
• Erythrocytes and plasma carry oxygen from the lungs to body cells and then transport the carbon dioxide produced by the cells back to the lungs to diffuse from the body
• Plasma also transports nutrients that have been absorbed from the GI tract and hormones that are secreted by the endocrine glands
• Lastly plasma carries some waste products from the cells to organs such as kidneys where they are removed

Question 8

How does blood regulate?

Answer 8

• Regulates many body functions including temperature
• Plasma absorbs and distributes heat throughout the body
• If the body needs to be cooled, blood vessels in the dermis dilate and dissipate the excess heat through integument
• If the body needs to conserve heat, the dermal blood vessels constrict and warm blood is sent quickly to deeper blood vessels in the body
• Blood also helps regulate pH levels in the body’s tissues by containing plasma that has compounds and ions that may be distributed to the fluid bathing cells within the tissues to help maintain normal levels.
• Blood also maintains normal fluid levels in the cardiovascular system by maintaining a constant exchange of fluid between blood plasma and interstitial fluid. Blood contains molecules to prevent excess fluid loss from plasma (maintings level blood pressure)

Question 9

What is blood acidosis and alkalosis?

Answer 9

• Acidosis: when blood pH levels are low and depresses the CNS (leads to coma or death)
• Alkalosis: when blood PH levels are high and it causes a hyper excited nervous system and causes convulsions

Question 10

How does blood protect?

Answer 10

• Leukocytes help guard against infection by mounting an immune response if a pathogen or antigen (foreign substance to the body) is found
• Antibodies are molecules that can bind to antigens until the immune system destroys or removes the antigen. They are transported in blood plasma
• Platelets and plasma proteins protect the body from blood loss by forming blood clots

Question 11

What are the plasma protein types?

Answer 11

• They all buffer against pH changes and regulate blood pH

- Albumins, globulins, fibrinogen and regulatory proteins

Question 12

What are albumin plasma protiens?

Answer 12

• Smallest and most abundant plasma proteins (58%)
• Regulate water movement between blood and interstitial fluid by providing some of the plasma solutes to drive osmosis
• Act as transport proteins that carry ions, hormones and some lipids in the blood

Question 13

What are globulin plasma proteins?

Answer 13

• Second largest group of plasma proteins (37%)
• Smaller alpha-globulins and larger beta-globulins primarily bind, support and protect certain water-insoluble molecules, hormones and ions
• Gamma-globulins (antibodies), are soluble proteins produced by some of our immune cells to protect the body against pathogens that may cause disease

Question 14

What are fibrinogen plasma proteins?

Answer 14

• Make up about 4% of plasma proteins
• Responsible for blood clot formation
• Following trauma to the walls of blood vessels, fibrinogen is converted into long, insoluble strands of fibrin, which help form blood clots

Question 15

What are regulatory plasma proteins?

Answer 15

• Very minor class of plasma proteins (less than 1%)

- Include enzymes that accelerate chemical reactions and proenzymes that are inactive precursors of enzymes

Question 16

What are the other solutes found in blood plasma?

Answer 16

• Electrolytes (sodium, potassium and chloride ions), nutrients, respiratory gases, some hormones and waste products
• These solutes make up less than 1% of blood plasma
• The level of these solutes vary depending on whether the blood is oxygenated or deoxygenated, and whether selected hormones are secreted into the blood

Question 17

What are the differences between plasma and interstitial fluid?

Answer 17

• Plasma is a type of extracellular fluid, meaning it is found outside of cells
• Both have similar concentrations of most dissolved products with the exception of plasma proteins
• Plasma has higher dissolved oxygen content because the cells take up the oxygen from interstitial fluid during energy production
• Plasma has lower dissolved carbon dioxide content because cells produce it during energy production in interstitial fluid
• The difference in these concentrations ensures that oxygen and carbon dioxide will readily diffuse between the blood and interstitial fluid

Question 18

What is hematocrit?

Answer 18

• The percentage of the volume of all formed elements in the blood
• Values vary depending on the age and sex of the individual
• Formed elements in blood can be viewed by preparing a blood smear
• Erythrocytes make 99% of formed elements whereas, leukocytes make up less than 0.01% and platelets less than 1%

Question 19

What is hemoglobin?

Answer 19

• 280 million red-pigmented protein that fill an erythrocyte (red blood cell)
• Transports oxygen and carbon dioxide
• When blood is maximally loaded with oxygen it is oxygenated and has a bright red colour
• When blood is darker and even perceived as blue, the oxygen was lost and carbon dioxide is gained during respiratory gas exchange, making it deoxygenated blood
• Each hemoglobin molecule consists of 4 polypeptide chains called globins… 2 are alpha chains and 2 are beta chains
• Each alpha and beta polypeptide chain contains a non protein or heme group that is shaped like a ring with an iron ion in its center (each hemoglobin has 4 rings, meaning 4 iron ions!)
• Oxygen binds to the iron ions for transport in the blood

Question 20

Where is oxygen in higher concentrations in the body?

Answer 20

• Higher concentration in the lungs compared to blood, meaning oxygen diffuses from the lungs into the blood
• Higher concentration in the blood compared to interstitial fluid, meaning oxygen diffuses from the blood to interstitial fluid
• This is why the oxygen binding to the iron molecules in hemoglobin is loose, so that rapid exchange can occur (carbon dioxide attaches to the globin weakly as well… not to iron!)

Question 21

What forms free amino acids after broken down in liver by macrophages?

Answer 21

• Dead erythrocyte membrane proteins and globin proteins

- Some of which the body uses for protein synthesis to make new erythrocytes

Question 22

What are the blood types?

Answer 22

• The plasma membrane of an erythrocyte has numerous molecules called surface antigens that project from the plasma membrane
• Most common group of antigens is the ABO blood group which has 2 surface antigens A and B and are accompanied by specific antibodies that travel in blood plasma
• The absence or presence of either determines blood type
• Type A: has erythrocytes with surface antigen A only and anti-B antibodies in blood plasma
• Type B: has erythrocytes with surface antigen B only and anti-A antibodies in blood plasma
• Type AB: has erythrocytes with surface antigens A and B and neither A or B antibodies in its blood plasma
• Type O: has erythrocytes with neither surface antigen A nor B but has both A and B antigens in its blood plasma

Question 23

What are leukocytes?

Answer 23

• Part of the buffy coat in whole blood
• Help initiate immune response and defend the body against pathogens
• Are true cells in that they contain a nucleus and cellular organelles (unlike formed elements in the blood)
• Are larger than erythrocytes and do not contain hemoglobin
• Are remarkably flexible and enter the tissue through a process called diapedesis where they leave the vessel by squeezing through endothelial cells of the blood vessel wall
• Chemotaxis is a process where leukocytes are attracted to the site of infection by molecules released by damaged or dead cells or invading pathogens
• A reduced number of leukocytes is called leukopenia which is a condition that may result in viral or bacterial infection or certain types of leukemia
• An elevated number of leukocytes is called leukocytosis which is often an indicator of infection, inflammatory reaction or extreme physiological stress
• Divided into two types based on the presence or absence of visible organelles called granules when stained and viewed: granulocytes and agranulocytes

Question 24

What are granulocytes and agranulocytes (leukocytes)?

Answer 24

• Granulocytes: Include neutrophils, eosinophils and basophils
• Agranulocytes: Include lymphocytes and monocytes

Question 25

What are platelets?

Answer 25

• Part of the buffy coat of whole blood
• Irregular, membrane inclosed cellular fragments that are really small
• Produced in red bone marrow by cells called megakaryocytes (large and have a multilobed nucleus and do not leave the bone marrow)
• Platelets first form the plug of a blood clot and then are reinforced by fibrin strands from the blood plasma
• Thrombocytopenia is an abnormally small number of platelets

Question 26

What is hematopoiesis?

Answer 26

• Production of formed elements in red bone marrow
• Begins with pluripotent stem cells called hemocytoblasts which produce 2 lines of blood cell development:
• Myeloid line forms erythrocytes, megakaryocytes and all leukocytes except lymphocytes
• Lymphoid line produces lymphocytes

Hemopoiesis involves several colony stimulating factors
– Multi-colony-stimulating factor increases formation of erythrocytes and other formed elements
– Granulocyte-macrophage colony-stimulating factor increases formation of granulocytes and monocytes
– Granulocyte colony-stimulating factor stimulates formation of granulocytes
– Macrophage colony-stimulating factor stimulates production of monocytes
– Thrombopoietin stimulates production of megakaryocytes
– Erythropoietin stimulates production and maturation of erythrocyte progenitor and erythroblast cells

Question 27

What is erythropoiesis?

Answer 27

• Erythrocyte production
• Normally they are produced at a rate of about 3 million per second, controlled by the hormone erythropoietin
• Process begins with a myeloid stem cell that forms a progenitor cell
• Progenitor cell then forms a proerythroblast which is a large nucleated cell
• Proerythroblast becomes erythroblast which is slightly smaller that produces hemoglobin in its cytoplasm
• Erythroblast becomes a normoblast with more hemoglobin in its cytoplasm. At the end of this stage the nucleus is ejected
• Eventually a cell called a reticulocyte is produced and it has only ribosomes but continues to produce hemoglobin
• This whole process from a myeloid stem cell to reticulocyte takes about 5 days
• The reticulocyte then enters blood circulation and matures after 2 days into an erythrocyte

Question 28

What is thrombopoiesis?

Answer 28

• Thrombopoiesis is production of platelets
• Megakaryoblast forms from myeloid stem cell
• It matures into a megakaryocyte
• Each megakaryocyte produces thousands of platelets

Question 29

What is leukopoiesis?

Answer 29

• Leukopoiesis is production of leukocytes
• Granulocyte maturation: All granulocytes derive along myeloid line from myeloblasts
• Monocyte maturation: Monocytes derived from myeloid stem cell that differentiates into a monoblast which then becomes a promonocyte which becomes a monocyte
• Lymphocyte maturation: Lymphocytes derived from lymphoid stem cells along lymphoid line
• Stem cells differentiate into B-lymphoblasts and T-lymphoblasts
• Some stem cells differentiate directly into NK cells