Chapter 10 Blood Flashcards
Cardiovascular system consists of:
- Fluid – blood
- Conducting tubes – blood vessels
- Capillaries
- Arteries
- Veins - Pump – heart
Functions of Blood
- Transports O2, CO2, nutrients, hormones, wastes
- Regulates pH and ion composition by absorbing and neutralizing acids
- Restricts fluid loss at injury sites with clotting process
- Defends against toxins and pathogens with white blood cells and antibodies
- Stabilizes temperature by absorbing heat and distributing blood flow to different areas
Blood
- The only fluid connective tissue in the human body
- Components of blood
1. Formed elements - living cells (RBC, WBC, platelets)
2. Plasma - non-living matrix
Volume in body (~8% of body weight):
5 – 6 liters in average male
4 – 5 liters in average female
Physical Characteristics of Blood
- Blood is a sticky opaque fluid with a salty metal taste
- ~5 x thicker than H2O
- Oxygen-rich blood is scarlet red
- Oxygen-poor blood is dull red/blue
- pH 7.35 – 7.45 (alkaline)
- Blood temperature is slightly higher than body temperature (38°C or 100.4°F)
If blood is centrifuged
- Erythrocytes sink to the bottom Hct ~45%
- Buffy coat in the middle - leukocytes and platelets ~1%
- Plasma rises to the top ~55%
Blood Plasma
- Straw colored fluid – contains over 100 substances (proteins, ions, nutrients, gases, wastes)
- Transports organic and inorganic molecules, formed elements, heat
- Forms ~55% of whole blood volume
- Composed of:
90% water
7% plasma proteins
3% other solutes
blood plasma composed of
90% water
7% plasma proteins
3% other solutes
water
90 % of plasma volume; solvent for carrying other substances, absorbs heat
salt electrolytes
sodium-osmotic balance and pH buffering potassium- regulation of membrane calcium- permeability magnesium chloride bicarbonate
plasma proteins
albumin-osmotic balance and pH buffering
fibrinogen-clotting of blood
globulins- defense ( anti bodies and lipid transport
substances transported by blood
- nutrients
- waste products of metabolism (Urea and uric acid)
- Respiratory gases ( O2 and CO2)
- Hormones (steroids and Thyroid Hormone are carried by plasma proteins)
platelets function
blood clotting
Cell Type: Erythrocytes (red blood cells)
Function: transport O2 and help transport CO2
Cell Type: Leukocytes ( white blood cells)
Function: defense and immunity
Plasma Proteins
- Albumin
- regulates osmotic pressure
- keeps water in the blood stream
- regulates fluid volume (small assistance with pH)
*Clotting proteins/factors (fibrinogen, prothrombin)
helps to prevent blood loss when a blood vessel is injured
- Globulins:
- Antibodies - help protect the body from pathogens
- Lipid carriers - HDL’s and LDL’s
Other Plasma Solutes
*Electrolytes
Na+, K+, Ca2+, Mg2+, Cl–, HCO3–, HPO4–, SO42–
*Organic nutrients
Lipids, carbohydrates, amino acid
*Organic wastes
Urea, uric acid, creatinine, bilirubin, ammonium ions
Formed Elements - RBC
**Erythrocytes (RBCs) - ~45% (37–54%) of whole blood (termed Hematocrit)
-Main function is to carry O2 – also transport some CO2
Red Blood Cells
- RBC count is number of RBCs per microliter (cubic millimeter)
- Males: 4.5–6.3 million per µL
- Females: 4.2–5.5 million per µL
- RBCs make up about 1/3 of all cells in the human body
Functional Aspects of Red Blood Cells
1.Large surface area-to-volume ratio
Oxygen bound to hemoglobin in RBCs
Greater surface area allows for faster exchange of oxygen
- RBCs can form stacks
Allows easier flow through narrow blood vessels without jamming - Flexibility
Can bend and flex to squeeze through capillaries as small as 4 µm (nearly half the normal RBC diameter
Features of Red Blood Cells
*Filled with hemoglobin (Hb):
-Iron-containing protein that binds with oxygen
-Each RBC has ~250 million Hb molecules
14–18 g/dL whole blood in males
12–16 g/dL whole blood in females
Oxyhemoglobin – bright red
Blood with oxygen bound to hemoglobin
Deoxyhemoglobin –dark red / blue
Blood with lots of hemoglobin not bound to oxygen
Red Blood Cell Production and Recycling
-RBCs continually produced and recycled (3 million / sec)
- Short lifespan of 120 days, then:
- Plasma membrane ruptures or cell is engulfed by macrophages
*Broken down in spleen (main site) or liver
Formed Elements -
WBC -White blood cells