The heart Flashcards
(18 cards)
CVS function
Bulk flow system transporting…..
– O2 & CO2
– Water & nutrients
– Metabolites & Hormones
– Heat
– Waste products
What makes up the CVS
Pump – the heart (nearly 100,000 beats / day)
* Pipes – the blood vessels
* Fluid in the system – the blood
* 2 circuits (circulation of blood)
– The Pulmonary Circuit
– The Systemic Circuit
what makes up the pulmonary circulation
Heart <–>Lungs
Pulmonary artery
Pulmonary vein
What makes up the systemic circulation
Heart <–> Rest of body
Aorta (artery)
Vena Cava (vein)
What chambers does the Vena cava supply in the heart
Right atrium and ventricle
What chambers does the pulmonary vein supply
Left atrium and ventricle
What are the types of major blood vessel and what do they do
Arteries carry blood away from the heart
– Oxygenated blood (except pulmonary artery)
* Veins return blood to the heart
– Deoxygenated blood (except pulmonary vein)
* Capillaries sites of nutrient, metabolic products
and fluid exchange
Capillaries connect arteries to veins
What are the 3 layers of arteries
Vascular endothelium - An inner, single layer of endothelium which is continuous with capillaries and veins and in contact
with the blood
A middle, thick layer of smooth
muscle and elastic fibres –> allows
the arteries to stretch and contract
An outer connective tissue coat (mostly collagen fibres)
What do the anatomical structures of arteries do
important in regulating blood flow
- The smooth muscle fibres contract or dilate to adjust the size of
the calibre (internal diameter) - Small changes in the vessel lumen can greatly affect blood
pressure and blood flow
What is the structure of veins
They have the same 3 layers as arteries
Vascular endothelium - An inner, single layer of endothelium which is continuous with capillaries and veins and in contact
with the blood
A middle, thick layer of smooth
muscle and elastic fibres –> allows
the arteries to stretch and contract
An outer connective tissue coat (mostly collagen fibres)
How do the 3 layers found in veins differ to arteries despite being the same
the middle and outer layers are much thinner.
Because veins do not regulate blood pressure and
blood flow into capillaries as arteries do
Because of the thinner layers, veins collapse if not filled with blood
What do veins contain to prevent backflow of blood
Valves
What is the structure of capillaries
Comprise a single endothelial
layer – continuous with the
vascular endothelium of arteries
and veins
What do capillaries form within tissues
capillary beds / dense networks
How are capillaries adapted for their function
Large number of capillaries –>
large surface area
Single endothelial layer –> short
diffusion distance – ideal for
exchange
What chamber of the heart is blood distributed to the rest of the body from
The left ventricle
Where is the heart found
In the thorax behind the rib cage and the sternum
Above the diaphragm
