zone control-direct the blood to particular regios of the body
they can glow bigger. CCS gurantees that each cell of the body is within about 2 cells widths of a blood capillary (short diffusion distances)
Other functions of circulatory systems
heat distribution throughout the body and temperature control
distribution of hormones
immune system function (wbc pagocytizing pathogens)
pH control
cellular waste removal
Advantages of keeping oxy and deoxy separate
allows the arterial blood of mammals to provide the maximum amount of oxygen to tissues. This means that those tissues can achieve higher metabolisms and be more active at all times.
blood is composed of
plasma
leukocytes-fight pathogens
eythrocytes (contain protein hemoglobin) transport oxigen and carbon dioxide
platelets
hematocrit
the volume of blood that is composed of red blood cells
usually between 40% and 65% among vertebrates
Anemia refers to
lower than normal levels of hemoglobin
cause by lack of sufficient iron FE
hemapoietic stem cells
make the two kinds of cells in red bone marrow
biconcave shape
shape of red blood cell because of no nucleus
efficien shape for increse surface area to facilitate the loading and unloading of oxygen
myogenic heart
can initiate their beating themselves using sinoatrial node
Sinoatrial node SA
pacemaker
a collection of modified cardiak cells that have an inherently unstable resting membrane potential