Structure of the Cardivascular System Flashcards
What is the cardiovascular system composed of?
heart
blood
blood vessels
Give the 5 functions of the cardiovascular system?
Transporting oxygen and removing carbon dioxide
Transporting nutrients (e.g. glucose) and removing wastes (e.g. urea)
Fighting disease (A mode of transport for WBC)
Transporting hormones
Regulating body temperature
What do arterial branches of the aorta supply?
oxygenated blood to all parts of the body
What does deoxygenated blood leave the organs in and what do they unite to form and where does this lead to?
Leaves in the veins . These unite to form the vena cava, which returns blood to the heart.
Describe what happens to blood pressure as blood moves away from the heart?
a decrease in blood pressure
What are the 3 types of blood vessels?
Arteries (and arterioles)
Veins (and venules)
Capillaries
Describe the structure of an artery?
Outer layer of connective tissue containing elastic fibre.
Middle layer - thick smooth muscular layer
Inner layer - elastic fibres
Lining of endothelium
Narrow lumen
Describe the structure of a vein?
Outer layer of connective tissue containing elastic fibre.
Middle layer - thin smooth muscular layer
Inner layer - elastic fibres
Lining of endothelium
Wide lumen
Valves
Give 3 structural differences between an artery and a vein?
An artery has a narrower lumen whereas a vein has a wider lumen
An artery has a thick muscular layer whereas a vein has a thin muscular layer
An artery doesn’t have valves whereas a vein does
Give 2 functional differences between an artery and a vein?
An artery carries blood away from the heart
A vein carries blood back to the heart
(Arteries mainly carry oxygenated blood.)
(Veins mainly carry deoxygenated blood.)
What do valves do?
prevent the backflow of blood
What do arteries branch into ?
smaller arteries called arterioles
What is blood returned to veins from?
smaller veins called venules
When does vasoconstriction occur?
when the smooth muscle in the walls of the arterioles contract which reduces blood flow.
When does vasodilation occur?
when the smooth muscle relaxes which increases blood flow to an area
What are capillaries composed of?
endothelial cells
Describe the walls of capillaries?
the walls are only one cell thick
What do capillaries allow?
the exchange of substances between blood and living tissues through their thin walls.
In terms exchange of materials in a capillary bed, what does blood arrive in?
arteriole at higher pressure than the blood in the capillaries
As blood is forced into the narrow exchange vessels, what does it undergo?
a form of pressure filtration and much of the plasma (containing small dissolved molecules like glucose, amino acids and essential ions) is squeezed through the thin walls. The liquid is called tissue fluid.
How does tissue fluid differ from blood plasma ?
it contains little or no plasma protein
What is tissue fluid?
the liquid which forms around cells after the process of pressure filtration. It contains all the same components of blood plasma other than plasma proteins.
In terms exchange of materials in a capillary bed, what does blood leave in?
venule at low pressure
What happens after the exchange of materials with the body cells?
the tissue fluid to blood/circulatory system by OSMOSIS
