Chapter 18 - Cardiovascular System: Blood Flashcards
What makes up the cardiovascular system?
heart and blood vessels
What do arteries do?
transport blood away from the heart
What do veins do?
transport blood toward the heart
What are capillaries & their functions?
permeable, microscopic vessels between arteries and veins
- Sites of exchange between blood and body tissues
- oxygen & nutrients exit blood
- CO2 & cellular waste enter blood
What makes up blood?
- formed elements (erythrocytes, leukocytes, platelets)
- plasma
Erythrocytes (red blood cells)
transport respiratory gases in the blood (O2 & CO2)
- most numerous
- anucleate cells appear pink or pale purple on smear
- biconcave disks
Leukocytes (white blood cells)
defend the body against pathogens
- not as numerous as erythrocytes
- larger than erythrocytes
- nucleus is very visible
Platelets
help clot the blood and prevent blood loss from damaged vessels
- cellular fragments that are much smaller than erythrocytes or leukocytes
What is plasma?
fluid portion of blood containing plasma proteins and dissolved solutes
Transportation
- formed elements, dissolved molecules, and ions throughout body
- transports O2 from & CO2 to lungs for gas exchange
- nutrients absorbed from GI tract
- hormones released by endocrine glands
- heat and waste products from systemic cells
Regulation
- body temperature, body pH, and fluid balance
Body temperature
blood absorbs heat from body cells (especially skeletal muscle) as it passes through body tissue blood vessels. Heat is then released at body surface
Body pH
blood absorbs acid and base from body cells
- contains chemical buffers that bind and release H+ ions to maintain pH until the excess is eliminated
Fluid balance
water is added to blood from GI tract and lost in urine, sweat, respired air. Constant exchange of fluid between blood plasms in capillaries & interstitial fluid surround body tissue cells. Proteins and ions in blood exert osmotic pressure to pull fluid into capillaries to help maintain fluid balance
Protection
blood contains leukocytes, plasma proteins, and other molecules to protect body
oxygen-rich blood color
bright red or scarlet
oxygen-poor blood color
dark red
Volume
average adult: 5 liters but can range 4-6
Viscosity
4 - 5 times more viscous (thicker) than water
Plasma concentration
relative concentration of solutes is typically 0.9% concentration
determines whether fluids move into or out of the plasma by osmosis
Temperature
almost 2 degrees F higher than body temperature
Blood pH
blood plasma is slightly alkaline, between 7.35 and 7.45 pH
Whole blood
both plasma and formed elements
Centrifuge
device that spins blood sample in a tube so heavier components collect at the bottom
- erythrocytes bottom layer (44% sample)
- buffy coat (leukocytes & platelets) middle layer (<1% sample)
- plasma top of sample (55% of blood)
Hematocrit
percentage of the volume of all formed elements in the blood
Blood smear
all components of the formed elements can be viewed
Composition of blood plasma
- primarily water (92%). Where formed elements are suspended & proteins/solutes dissolve
- albumin (58% of plasma proteins)
- globulins (37% of plasma proteins)
- fibrinogen (4% of plasma proteins)
- Regulatory proteins (<1% of plasma proteins)
- other solutes (1% of blood plasma)
Colloid
Opaque mixture composed of water and solute