Functions
Transport of gases, nutrients, and waste products
Transport of processed molecules
Transport of regulatory molecules
Regulation of pH and osmosis
Maintenance of body temperature
Protection against foreign substances
Clot formation

Composition
Plasma 55%, formed elements 45%

Plasma
Pale yellow, 91% water, 9% other substances
Colloid: liquid containing suspended substances that don’t settle out of solution
Almost all of the plasma proteins are produced by the liber or blood cells
Albumins
Regulate movement of water between the tissues and the blood
Maintain blood colloid osmotic pressure
Bind and transport other molecules in the blood
Globulins
Part of immunity
Protection against microorganisms
Fibrinogen
Formation of blood clots
Plasma volume stays relatively constant

Formed Elements
Process of blood cell production: hematopoiesis
Confined primarily to red bone marrow
All of the formed elements of the blood are derived from a single population of stem cells called hemocytoblasts
Different growth factors determine the type of formed element derived from the stem cells and how many formed elements are produced

Red Blood Cells
Passively moved by forces that cause the blood to circulate
Biconcave structure to increase surface area which allows for gases to move in and out of the cell quicker
Main component is hemoglobin (about 1/3)
After birth hemoglobin picks up oxygen from the air in the baby’s lungs
Transports oxygen
RBC production is stimulated by low blood O2 levels which typically results from decreased numbers of RBC, decreased or defective hemoglobin, diseases in the lungs, high altitude, inability of the CV system to deliver blood to tissues and increased tissue demands for O2
Low blood O2 levels stimulates RVC production by increasing the formation of the glycoprotein erythroprotein
When blood O2 levels decrease, erythroprotein production increases which increases RBC production

White Blood Cells
Lack hemoglobin (which gives pigment) but have a nucleus
Protect the body against invading microorganisms and remove dead cells, and debris from the body
Neutrophils
60-70% of WBC nuclei are lobed first of the WBC to respond to infection secrete lysozymes which can destroy certain bacteria survive 1-2 days after leaving the circulation
Eosinophils
2-4% of WBC two-lobed nucleus leave the circulation to enter the tissues during an inflammatory reaction response to allergic reactions reduce inflammatory response by producing enzymes that destroy inflammatory chemicals like histamine
Basophils
20-25% smallest originate in red bone marrow roles in immunity
Monocytes
3-8% largest remain in circulation for about 3 days increase in the number of monocytes is often associated with chronic infection

Platelets
Minute fragments of cells consisting of a small amount of cytoplasm surrounded by a plasma membrane

* Blood Grouping
Transfusion: transfer of blood or blood components from one person to another
Infusion: introduction of a fluid other than blood i.e saline, or glucose solution into the blood
Surfaces of RBC have molecules called antigens and the plasma includes proteins called antibodies

ABO Blood Group
Type A
Type A antigens
Type B antibodies
Type B
Type B antigens
Type A antibodies
Type AB
A and B antigens
Neither antibody
Type O
Neither A or B
Both antibodies
Universal donor because they can usually give blood to other ABO blood types without causing a transfusion reaction
Genes for antigens found on chromosome 9
AB example of co-dominance where both traits can be expressed at the same time

Rh Blood Group
Rh- positive if they have a certain Rh antigen on the surface of their red blood cells, negative if they don’t
Found on chromosome 1
Rarest combination is AB-
Antibodies against the Rh antigen don’t develop unless an Rh- negative person is exposed to Rh-positive blood