Ch. 18 - Blood Flashcards
Blood
continuously regenerated CT that moves gases, wastes, and hormones. Transported through cardiovascular system
Arteries transport blood
away from the heart
Veins transport blood
towards the heart
Capillaries
very small vessels that allow for exchange between blood and body tissues.
General Composition of blood
Blood is made up of formed elements and plasma. Formed elements include erythrocytes, leukocytes, and thrombocytes.
Erythrocytes
red blood cells that transport respiratory gases in the blood. It is small and flexible. Lacks a nucleus or organelles and is just packed with hemoglobin. biconcave disc and can stack in a single file called Rouleau.
Leukocytes
white blood cells that defend against pathogens. Contain a nucleus and organelles; no hemoglobin. Motile and flexible. Most are in tissues, not blood. 5 types divided into 2 classes.
Thrombocytes
platelets; help form clots to prevent blood loss
Plasma
fluid portion of the blood; contains plasma proteins and dissolved solutes.
Functions of Blood
transportation, protection, regulation of body conditions
Transportation
blood transports formed elements, dissolved molecules, and ions. Carries o2 and co2 and transports nutrients, hormones, heat, and waste
Protection
leukocytes, plasma protein, and other molecules protect against pathogens. platelets and certain plasma proteins protect against blood loss
Regulation of body conditions
regulates body temp by absorbing heat from body cells and releasing it at dermal capillaries. Regulates pH by absorbing acid and bases from body and neutralizing it using buffers. Regulates fluid balance by adding water by GI tract, losing it through urine, respiration, and skin. blood proteins help maintain osmotic balance.
Color of Blood
Oxygen rich is bright red and o2 poor is dark red
Volume of Blood in average adult
5 liters
Viscosity of blood
about 4-5 times thicker than water. Depends on amount of dissolved and suspended substances. Viscosity increases with # of RBCs and if fluid amount decreases.
Osmosis of Blood
plasma concentration determines the direction of osmosis across capillary walls. During dehydration plasma becomes hypertonic and fluid is drawn from tissues
Blood Temp
blood is 1C higher than body temp and warms areas through which it travels
Blood pH
slightly alkaline; between 7.35-7.45. Crucial for normal plasma protein shape (avoiding denaturation)
Centrifuged blood
whole blood (plasma and formed elements) separated into parts by a centrifuge.
Erythrocytes are lower red layer (44%)
Plasma is straw colored at top of sample (55%)
Buffy coat
very thin 1% middle layer with gray-white color. Composed of leukocytes and platelets.
Hematocrit
percentage of volume of all formed elements. clinical def: % of only erythrocytes. 42-56% of adult males and 38-46% for females. Testosterone causes more erythropoietin secretion by kidney.
Medical vs. Clinical definition of hemocrit
medical: percentage of all formed elements
clinical: percentage of erythrocytes
colloid
blood is a colloid or a substance microscopically dispersed evenly throughout another substance. Contains dispersed plasma proteins that exert colloid osmotic pressure.