Cardiovascular system: blood

Blood

• continuously regenerated connective tissue

  • moves gases, nutrients, wastes, and hormones

Arteries

transport blood away from the heart

Veins

transport blood towards the heart

capillaries

allow exchange between blood and body tissue

Blood components: formed elements

• erythrocytes (red blood cells): transport respiratory gases

• leukocytes (white blood cells): defend against pathogens

• platelets: help form blood clots

Plasma

Fluid portion of blood

• contains plasma portents and dissolved solutes

Primary functions of blood

1. transport

2. protection

3. regulation of body conditions

Transportation

transports formed elements, dissolved molecules, gasses and ions

protection

• leukocytes, plasma proteins, and other molecules protect against pathogens

• platelets and certain plasma proteins protect against blood loss

Regulation of body contiditons

• body temperature

blood absorbs heat from cells and heat is realized a skin in blood vessels

• body pH

  • blood absorbs acids and bases from body cells acting as a buffer (can accept and donate H+ ions maintaining a pH in a solution)

• Fluid balance

  • water is added to blood from GI tract and lost through urine, skin, respiration

  • fluid is exchanged between blood and interstitial fluid - driven by osmotic pressure

Characteristics of blood

Color, volume, viscosity, plasma, temperature, blood ph

color

depends on degree of oxygenation

• rich is bright red

• poor is dark red

volume

about 5 liters in adult

viscosity

blood is 4-5 times thicker than water

• depends on amount of dissolved and suspend substances relative to amount of fluid

  • viscosity increase if erythrocyte number increases

  • viscosity increase off amount of fluid decreases

Plasma concentration of solutes

proteins and ions

• determines the direction osmosis across capillary walls

temperature

• blood is 1 c higher than measured body temp

• warms tissues as it moves through

blood ph

slightly basic

• pH between 7.35 and 7.45

• crucial to maintain protein shape

centrifuged blood

plasma (55)

• straw colored liquid at top

buffy coat (1)

• very thin, grey whie

erythrocytes (44)

• lower, red

Hematocrit

Percentage of RBCs in sample

Blood smear

thin layer of blood placed on microscope slides and stained

Erthrocytes

most numerous

• pink, enucleate, biconcave discs

• transport o2 and co2

• lifespan 120 days

leukocytes

• larger than ery

• varied in form, noticeable nucleus

• lifespans - varies from hours to years

platelets

• small fragments of cells

• hemostasis

• lifespan 8-10 days

Composition of blood plasma

extracellular fluid

• water 92

• plasma proteins 7

• dissolved molecules and ion 1

similar composition to interstitial fluid but plasma has higher protein concentration

Colloid osmotic pressure

plasma proteins exert colloid osmotic pressure

• pulls fluid back into the vessels

• prevents loss of fluid from blood as it moves though capillaries

  • helps maintain blood volume and blood pressure

Plasma proteins in blood

Albumins, globulins, fibrinogens. regulatory proteins ( also contains cations (na, k, ca, h) and anions (cl, bicarb, phosphate), dissolved electoryles)

Albumins

58%

• exert greatest colloid osmotic pressure

• act as carrier proteins form some lipids, hormones, and ions

Globulins

37%

• smaller alpha-globulins and larger beta-globulins

  • transport some water-insoluble mocleuces, hormones, metals, ions

• gamma-globulins (antibodies)

  • part of body defenses

fibrinogens

4%

• aids in blood clot formation

  • following trauma → converted into insoluble fibrin strands

  • serum is plasma clotting proteins removed

regulatory portents

<1%

• includes enzymes and hormones

what is another term of leukocyte? what is their primary function?

immune cells, white blood cells

Is the ph of blood basic or acidic and why does it matter?

slightly basic, crucial to maintain protein shape

after centrifuging blood into its components, the middle layer is composed of leukocytes and platelets is know by what name? what percentage?

buffy coat, 1%

Would a malnourished person eating inadequate amounts of protein have blood with high or low colloid osmotic pressure?

low osmotic pressure

what type of plasma protient has an immune function?

gamma-globulins

Hemopoiesis

production of formed elements

• occurs in red bone marrow

Hemocytoblasts

stem cells for formed elements

• produced two different lines

  • myeloid line, forms erythrocytes, all leukocytes except lymphocytes, and megakaryocytes

  • lymphoid line forms only lymphocytes

colony-stimulating factors (CSFs)

stimulating hemopoiesis

• growth factors/ hormones responsible for the division and maturation of hemopoietic stem cells

  • secreted in response to a decrease of formed elements in the blood or other changes in blood homeostasis

  • target hemocytoblasts

Erythropoiesis

red blood cell production

• hemocytoblasts differentiates into myeloid stem cell

• multi-CSF differentiates stem cell to a progenitor cell

Hemocytoplasts

hemocytoblasts (multi-CFS)

→ progenitor cell (EPO)

• → proerythroblast (EPO)

  • → erythroblast

    • → normoblast

      • → reticulocyte

        • → erythrocyte

Leukopoiesis

production of leukocytes

• involves maturation of granulocytes, monocytes, lymphocytes

granulocytes

myeloid stem cell (cultivation-CSF)

→ progenitor cell (GM-CSF)

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