Structure of the Heart and blood vessels

myogenic

feature of heart which allows it to beat by itself

coronary arteries

supply heart with oxygenated blood

chambers of heart

right atrium, right ventricles and left atrium and left ventricle

features of the atria

relatively thin walls

doesn’t need to push blood far

features of the ventricles

thicker muscular walls for bigger contraction

creating enough pressure to push blood long distances (out of the heart to the lungs and so on)

reason right ventricle pumps blood at slightly lower pressures

to prevent damage to the capillaries

moves slower so more time for gas exchange

why left ventricle has the thickest muscular wall in the heart

to ensure it can pump blood at a high enough pressure to reach all cells in the body

pulmonary vein

carries oxygenated blood from the lungs into the left atrium

vena cava

carries deoxygenated blood from the body to the right atrium

pulmonary artery

Carries deoxygenated blood away from the right ventricle to the lungs

Aorta

main artery in the body

carries oxygenated blood from the left ventricle to the rest of the body

Atrioventricular valves

valves between atria and ventricles

septum

maintains high concentration of oxygen in the blood by separating deoxygenated and oxygenated blood

maintenance of high concentration of oxygen ensures oxygen can diffuse from the blood to respiring cells

when valves open

when pressure behind it is greater than in front of it

when valves close

when pressure in front of it is greater than behind it

arteries

thick muscle so dilation and constriction can control volume of blood

thick elastic layer allows blood pressure to be maintained as it stretches and recoils in response to heartbeat

thicker walls them to stop from bursting due to the high pressure

smaller lumen

veins

relatively thin smooth muscle

lower blood pressure

contains valves

larger lumen

arterioles

thicker muscular layer than arteries limits blood flow into capillaries

thinner walls as blood flows at lower pressure

capillaries

one cell thick epithelial

narrow diameter means blood flows slower giving more time for gas exchange

how the structure of the capillaries relates to its function

walls are thin one cell thick of endothelial cells → reduces diffusion distance

capillary bed is a large network of branched capillaries → increases surface area for diffusion

small diameter/narrow lumen → reduces blood flow rate so more time for diffusion

pores in walls between cells → allows large substances through