What function does blood perform?
Carry oxygen throughout the body
What % of human's body weight does blood account for?
What is blood composed of?
Fluid (plasma) along with several types of cells (erythrocytes, leukocytes, plaetlets)
What are the components of plasma?
- Mostly water (90 - 93%)
- Waste products;
- Various hormones
98.5% of oxygen transported in th blood is bound to what?
Hemoglobin, a protein found only in erythrocytes (red blood cells)
What is the most abundant type of cells found in the blood, and what % of the body's blood cells do they make up?
Erythrocytes -- red blood cells. Make up 99% of blood's cells
What does hemoglobin carry?
Carries about 30% of the carbon dioxide transported by the blood
What is hematocrit?
Measure of the percentage of the blood's volume that is composed of erthrocytes.
What is the average hematocrit in women and men? Why are they different?
- Women = 42%;
- Men = 45%;
- Difference exists because male hormone testoterone affects production of erythrocytes
What are other effects of lower hematocrit levels in women?
- Reduced hemoglobin content;
- About 14 g/1000 mL of blood compared to men's 16 g/100 mL of blood
What are leukocytes where are they located and what's their function?
- White blood cells;
- Part of body's immune system;
- Function os to destroy potentially infectious agents the enter the body
What are platelets and what is their function?
- Fragments of larger cells;
- Function is to accumulate and form a plug where damage has occured to the wall of the blood vessel to prevent loss of blood
What effects does exercise have on the blood?
- Induces hyperemia;
- Cardiovascular drift
What is hyperemia and what does this do for exercise?
- Increase in the volume of blood delivered to the working muscles;
- Greater delivery of oxygen and nutrients;
- Efficient removal of carbon dioxide and metabolic by-products such as lactate
What is cardiovascular drift and what does this do for exercise?
- Movement of plasma out of the blood vessels into surrounding tissue;
- Prevents overheating of the body by having more water available for sweating;
- Increases during exercise in hot environments;
What does cardiovascular drift cause a decrease in and what is the result?
Causes a decrease in total volume of blood in the vasculature, resulting in decreased stroke volume and increased heart rate even though exercise remains constant
What is hemoconcentration?
- Another result of cardiovascular drift;
- Causes elevation in hematocrit and hemoglobin values
Long term training is associatd with what positive adaptations of the blood?
- 1) Production of erythrocytes significantly increases
- 2) Plasma volume increases resulting in hemoglobin and hematocrit decrease
- 3) Oxygen-carrying capacity of blood increases because of 1&2
What is runner's anemia?
The result of decreased hemoglobin and hematocrit in well-conditioned athletes. Should not be considered a negative.
What are advantages of increased plasma in trained individual?
- 1) At rest, higher SV and lower HR
- 2) During exercise, enhances capacity for thermoregulation (ie running in hot/cold environments)
- 3) During submaximal training, higher SV and lower HR than untrained individuals
- 4) Max SV and cardiac output are more impressive in trained individuals