Biol 102 The Blood Lecture Notes

Chapter 7: Blood

Circulatory System Overview:

 Consists of heart (pump), blood vessels, and blood
 Picks up nutrients from digestive system
 Exchanges gases with respiratory system
 Delivers nutrients and O2 to every cell
 Carries CO2 to lungs for removal
 Carries wastes and excess water to urinary system
 Carries metabolic wastes to liver for removal
 Helps regulate body temperature

The Composition and Functions of Blood:

 Blood is a specialized connective tissue consisting of
– Specialized cells and cell fragments
– Watery solution of ions, molecules
 Blood has three primary functions
– Transportation of nutrients, waste, hormones
– Regulation of body temperature, water volume, pH
– Defense against infections and bleeding

 Plasma (makes up 55% of whole blood)
– Water
– Electrolytes (ions)
– Proteins (albumins, globulins, clotting proteins)
– Hormones
– Gases
– Nutrients and wastes
 Formed elements (makes up 45% of whole blood)
– Red blood cells (RBCs)
– White blood cells (WBCs)
– Platelets

Plasma Consists of Water and Dissolved Solutes:

 Plasma: liquid portion of the blood
 90% water
 10% dissolved solutes
– Proteins
– Hormones
– Ions
– Amino acids

, – Carbohydrates
– Vitamins
– Metabolic wastes

 Plasma proteins
– Albumins: maintain osmotic balance with interstitial fluid
– Globulins: diverse group of proteins
– Alpha
– Beta globulins: important transport functions
– Bind to lipid-forming lipoproteins
– HDL: high-density lipoproteins
– LDL: low-density lipoproteins (“bad cholesterol”)
– Gamma globulins: antibodies that are part of the body’s defenses against
infections
– Clotting proteins
Red Blood Cells (Erythrocytes) Transport Oxygen and Carbon Dioxide:

 Make up almost half the blood volume
 5 million/mm3
 Functions: transport oxygen (O2) and carbon dioxide (CO2)
 Packed with hemoglobin, a protein which transports O2
 Hemoglobin molecule includes heme groups that each have iron atoms to which O2
binds
 Origin: stem cells in the bone marrow
 Life span: 120 days in humans
 Control of production: erythropoietin (hormone)

Hematocrit and Hemoglobin Reflect Oxygen-Carrying Capacity:

 Hematocrit: the percentage of whole blood that consists of red blood cells
– Men: 43–49% Women: 37–43%
 Hemoglobin measurement
– Men: 14–18 gm% Women: 12–14 gm%
 Low hematocrit or hemoglobin may indicate anemia
 High hematocrit may be response to high elevation (less O2 available in atmosphere)
 Very high hematocrit is risky because of increased blood viscosity

Blood Cells and Platelets Originate From Stem Cells:

 Stem cells in bone marrow divide continually throughout the life of an individual
 These stem cells produce all of the types of blood cells