Circulatory system Flashcards
What is the circulatory system?
a closed system which carries blood and dissolved substances to and from different places in the body
The Heart pumps blood and substances around the body in tubes called
blood vessels
Phases of cardiac cycle
Isovolumetric relaxation
Ventricular filling
Ventricular systole (contraction)
Morphology
base and apex
4 chambers
2 atria, 2 ventricles
the right side of the system deals with
deoxygenated blood
the left side of the system deals with
oxygenated blood
Pulmonary circulation
To and from the Lungs
Arteries
always away from heart, deoxygenated
have thick muscle and elastic fibres
the thick muscle can contract to push the blood along.
the elastic fibres allow the artery to stretch under pressure
Veins
always towards heart, oxygenated
thin muscle and elastic fibres
Three types of blood vessels
Artery
Vein
Capillary
veins have valves which act to
stop the blood from going in the wrong direction
body muscles surround the veins so that when they contract to move the body, they also
squeeze the veins and push the blood along the vessel
Capillary
link Arteries with Veins
the wall of a capillary is only one cell thick
The exchange of materials between the blood and the body can only occur through
capillaries
Capillary bed
the connection between the arteriole system and the venous systems
Smooth muscle controls the
flow
What’s in blood?
red blood cells
digested food
white blood cells
waste (urea)
platelets
hormones
plasma
carbon dioxide
oxygen
Red Blood Cells
a biconcave disc that is round and flat without a nucleus
haemoglobin
a molecule specially designed to hold oxygen and carry it to cells that need it
White Blood Cells
there are many different types and all contain a big nucleus.
the two main ones are the
lymphocytes and the macrophages
macrophages
digest micro-organisms
some lymphocytes fight disease by
making antibodies to destroy invaders by dissolving them.
others make antitoxins to break down poisons
