Anatomy: Chapter 18 (Cardiovascular System-The Blood)

Describe blood in general.

-continuously regenerated fluid, connective tissue

-Moves gases, nutrients, waste, and hormones

-Transported through cardiovascular system

Describe the elements of the cardiovascular system.

-Heart: pumps blood

-Arteries: transport blood away from the heart

-Veins: transport blood toward heart

-Capillaries allow exchange between blood and body tissue

What are the two elements of the blood?

-formed elements

-plasma

What are the kinds of formed elements?

-erythrocytes

-leukocytes

-platelets

What are erytocytes?

-red blood cells

-transport respiratory gases in the blood

What are leukocytes?

-white blood cells

-defend against pathogens

-only real cell

-split into 2 classes

What are platelets?

-help form clots to prevent blood loss

-irregular, shaped cellular fragments

-150k-400k normally

-30% are stored in spleen

-circulates for 8-10 days before being broken down/recycled

What is plasma?

-fluid portion of blood

-contains plasma proteins and dissolved solutes

What are the functions of blood?

-transportation of formed elements, dissolved molecules, and ions

-regulation of body temperature

-regulation of body pH by absorbing acids and bases through chemical buffers that bind and release H

-regulation of fluid balance by pulling water back into BV

-protection from leukocytes, plasma proteins, and other molecules

What are the physical characteristics of blood?

-color

-volume

-viscosity

-plasma concentration

-temperature

-blood pH

Describe color.

-depends on oxygenation status

-oxygen-rich: bright blood

-oxygen-poor: dark red

Describe volume.

-depends on gender

-males have 5-6L

-females have 4-5L

-blood volume directly affects blood pressure

Describe viscosity.

-depends on the number of dissolved substances in the blood per fluid

-can be altered if number of substances increases or fluid decreases

Describe plasma concentration.

-number of solutes in the plasma

-regulates the flow or pull water between tissue and blood vessels

-normally is 0.09%

Describe the temperature of blood.

-1 degree C higher than body temp

-allows blood to warm tissue as it travels through the body

Describe blood pH.

-slightly alkaline (7.35-7.45)

-pH alteration can affect teh shape of proteins, denaturing them and resulting in lost function.

What is whole blood?

blood with all formed elements and plasma that can be separated by high spinning

What are the percentages of blood elements when centrifuged?

-44% erythrocytes

-

What is a hematocrit?

the percent of RBCs in blood

A child has what percent of RBCs?

30-60%

Adult males have what percent of RBCs?

42-56%

Adult females have what percent of RBCs?

38-46%

What is a blood smear?

preparation of blood for a visual analysis and macroscopic view

What are the characteristics of a blood smear?

-erythrocytes are the most numerous; anucleated, red, and biconcave

-leukocytes are larger with visual nuclei

-platelets appear as small fragments

What are the percentages of solutes in plasma?

-92% water

-7% plasma proteins

-1% molecules/ions

What is colloid osmotic pressure?

-osmotic pressure exerted by plasma proteins

-this forces fluids back into the blood and prevents fluid loss from blood capillaries

-helps maintain blood volume and blood pressure

-kidney and liver diseases leads to a loss of plasma proteins and a decrease in colloid osmotic pressure, resulting in edema or tissue swelling

What are plasma proteins?

-most produced in the liver

-others are produced by leukocytes and other organs

-albumins

-globulins

-fibrinogens

-other regulatory proteins and solutes

Describe albumins.

-58%

-exerts greatest osmotic force

-contributes to blood viscosity

-acts as transport proteins for some lipids, hormones, and ions

Describe globulins.

-37%

-alpha: transport lipids and metal ions

-beta: transport iron

-gamma: act as antibodies

Describe fibrinogens.

-4%

-function in blood coagulation (clotting)

-are converted to insoluble fibrin

What is serum?

plasma with clotting proteins removed

What are the regulatory proteins?

-

Describe the other solutes.

-electrolytes, nutrients, gases, waste products

-polar or charged substances dissolve easily

-nonpolar molecules require carrier proteins

What is hemopoiesis?

-production of formed elements

-starts with hemocytoblasts (hemopoietic stem cells)

-has the ability to differentiate into all formed elements with the help or hormones and stimulating factors

-they produce two distinct cell lines

-myeloid line

-lymphoid line

CSFs

colony-stimulating factors

What are CSFs?

growth factors and hormones that promote maturation and division of myloid and lymphoid stem cells

GM-CSF

Granulocyte-macrophage colony stimulating factor

What is GM-CSF?

affects granulocyte and monocyte formation

G-CSF

Granulocyte colony stimulating factor

What is G-CSF?

matures granulocytes

What is M-CSF?

matures monocytes

M-CSF

Macrophage colony-stimulating factor

What is thrombopoietin?

stimulates thrombocytes production

What is EPO?

-stimulates RBC production

-produced by kidneys and liver

EPO

Erythropoietin

Describe the pathway of erythropoiesis.

1: Requires iron, B vitamins, and amino acids

2: begins with myeloid stem cells, which respond to multi-CSF

3: forms progenitor cell and erythropoietin (EPO)

4: forms proerythroblast, a large nucleated cell

5: becomes erythroblast, smaller and produces hemoglobin

6: Becomes normoblast, still smaller, with more hemoglobin, anucleate

7: becomes a reticulocyte, which lacks organelles except for ribosomes that make hemoglobin

8: becomes erythrocyte, degenerated ribosomes

Order of elements in erytopoiesis.

myeloid stem cell + multi-CSF > progeneitor cell + EPO > proerytoblast > erythroblast > normoblast > reticulocyte > erythrocyte

Describe leukopoiesis.

-production of leukocytes

-involves maturation of granulocytes, monocytes, and eosinophils

What are granulocytes? What is the process of developing them?

-neutrophils

-basophils

-eosinophils

-multi-CSF and GM-CSF cause myeloid stem cell to form progenitor cell

-progenitor cell becomes a myeloblast with G-CSF that becomes a granulocyte

What are monocytes? What is the process of developing them?

-derived from myeloid stem cells

-stem cell differentiates into a progenitor cell

-M-CSF prompts progenitor cells to becomes a monoblast

-monoblast becomes a promonocyte, which matures into a monocyte

What are lymphocytes? What is the process of developing them?

-derived from lymphoid stem cells

-stem cells differentiate into B-lymphoblasts and T-lymphoblasts

-lymphoblasts mature into B-lymphocytes and T-lymphocytes

-some lymphoid stem cells differentiate directly into NK cells

What is thrombopoiesis?

-platelet production

-megakaryoblast produced from myeloid stem cell

-forms megakaryocyte under the influence of thrombopoietin, has a large size and multilobed nucleus

-megakaryocyte produces thousands of platelets

How does a megakaryocyte produce platelets?

-large cell produces proplatelets, long extensions

-these extend through the blood vessel wall into the bloodstream

-blood flow "slices" off fragments which are platelets

Describe erythrocytes.

-small, flexible cells

-anucleated

-biconcave, which allows them to create stacks called Rouleu as they pass through capillaries

-packed with hemoglobin

-transport oxygen and carbon dioxide

What is hemoglobin?

-red pigmented protein that transports oxygen and carbon dioxide molecules in the blood

-blood is oxygenated when all 4 binding sites are maximally loaded with oxygen

-blood is deoxygenated when some oxygen is lost (less than 4)

Describe the structure of hemoglobin.

-4 globulin molecules

-2 alpha

-2 beta

-each globulin has a heme group

-globin transports carbon dioxide

-heme: a carbon ring that has a Fe ion in the center

-each heme carries one oxygen molecules

What is the process of binding?

rapid attachment to oxygen molecules occurs in the lungs and rapid detachment in body tissues due to fairly weak binding.

Where does attachment to carbon dioxide molecules occur?

in body tissue

Where does detachment to carbon dioxide occur?

in the lungs

True or false: oxygen molecules bind to hemoglobin weakly, but carbon dioxide is strong

False

The production of RBCs in erythopoiesis is controlled by...

erythropoeitin (EPO)

How is EPO and erythrocyte production regulated?

-stimulus: decreased blood oxygen levels

-receptor: kidney detects decreased blood oxygen levels

-control center: kidneys release EPO into the blood

-Effector: red bone marrow myeloid cells are stimulated by EPO to increase the production and release of erythrocytes

-response: increased number of RBCs enter the circulation, blood oxygen levels increase

-negative feedback mechanism: as blood oxygen levels increase, it inhibits further EPO secretion

______________________ stimulates EPO production in the kidney.

Testosterone

Environmental factors such as altitude influence EPO levels. ________________________ at high altitude stimulate EPO production

low oxygen levels

Describe blood doping.

-used by some athletes to enhance performance

-one method is self donation of erythrocytes, with blood removal prior to competition and RBCs returned a few days prior to competition

-second method is pharmaceutical EPOs

-dangerous because of increased blood viscosity, increased heart fatigue, possible cardiovascular damage, and being banned from future competition.

What is the lifetime of RBCs?

120 days

True or false: In recycling and elimination of erythrocytes, each component has a different fate.

True

Where are RBCs degraded?

liver or spleen

What happens to globin and membrane proteins?

-gets broken down into amino acids

-amino acids get recycled for protein synthesis

What happens to iron?

-transfered to liver by transferrin proteins

-bound to storage proteins: ferritin and hemosiderin

-most is bound to ferritin and stored in liver and spleen

-transported to red bone marrow as needed for generation of erythrocytes

What happens to heme?

-converted within macrophages to biliverdin (green), to bilirubin (yellow)

-bilirubin is transported by albumin to the liver and released in bile (digestion)

-bilirubin is also converted to urobilinogen in the small intestine

-some urobilinogen is converted by the large intestine into sterocoblin (brown pigment) and excreted in feces

-some urobilinogen is absorbed back into blood and converted to urobilin (yellow pigment) and excreted by kidneys in urine

What is anemia?

-either the percentage of erythrocytes is lower than normal or oxygen-carrying capacity is reduced

-symptoms: lethargy, shortness of breath, pallor, palpitations

-some cases can be treated by pharmaceutical EPO

What is aplastic anemia?

defective red marrow due to poisons, toxins, radiation

What is congenital hemolytic anemia?

genetic defect; erythrocytes are destroyed

What is erythroblastic anemia?

large numbers of immature cells due to abnormal accelerated cell maturation

What is hemorrhagic anemia?

due to blood loss

What is pernicious anemia?

failure to absorb vitamin B12 due to lack of intrinsic factor

What is sickle-cell disease?

genetic defect, due to abnormal hemoglobin

What determines blood type?

the surface antigens projecting from erythrocyte membrane

Type A has surface antigen...

A

Type B has surface antigen...

B

Type AB has surface antigen...

AB

Type O has surface antigen...

None

What is an agglutinin?

an antibody that causes clotting in the blood

Anti-A antibodies acts on...

antigen A

Anti-B antibodies acts on...

antigen B

A person doesn't have antibodies for...

their own surface proteins

A person does have antibodies for...

antigens that are foreign to them

Type A blood has...

anti-B antibodies

Type B blood has...

anti-A antibodies

Type AB blood has...

no antibodies

Type O blood has...

both anti-A and anti-B antibodies

What is an Rh factor?

presence or absence of surface antigen D. Determines + or -

If the Rh is present...

considered positive

If the Rh is absent...

considered negative

How are anti-D antibodies acquired?

only after an Rh negative person is exposed to Rh positive blood (not born with hit). They bind to Rh antigens on RBC surface

What is aggulination?

clumping of erythrocytes

What is hemolysis?

rupture of RBCs

A+ can donate to...

A+, AB+

A+ can receive from...

A+, A-, O+, O-