structure of the cardiovascular system Flashcards
what is the cardiovascular system
blood transportation network
the heart pumps blood through blood vessels
blood carries nutrients, oxygen and waste products to and from cells
what are the two circulatory systems
- pulmonary circulation
- systemic circulation
what is pulmonary circulation
the flow of blood between the heart and the lungs
deoxygenated blood enters the lung capillaries and then exits oxygenated through the diffusion of O2 in the alveolus
what is systemic circulation
the flow of blood between the heart and all organs and tissues
oxygenated blood is distributed to the brain, skin, kidneys, muscles, liver and then back to the heart deoxygenated
where is the heart located
within the middle mediastinum
situated obliquely, with 2/3rds of the heart left to the mid-sternal line and 1/3rd to the right
sits within the pericardiumw
what is the pericardium
fluid filled sac that surrounds the heart and its great vessels
what are the layers of the pericardium
- fibrous pericardium
- serous pericardium
what is the fibrous pericardium
tough connective tissue
prevents overfilling
what is the serous pericardium
parietal layer
visceral layer
allows movement
what are the layers of the heart wall
epicardium
myocardium
endocardium
what is the epicardium
the outer layer of the heart wall
what is the myocardium
the middle layer of the heart wall
cardiac muscle
between the myocardium and endocardium is the subendochondrial layer which is loose connective tissue containing small blood vessels and nerves, and the branches of the impulse conducting system
what is the endocardium
the inner layer of the heart wall
what are the purkinje fibres
distribute excitatory activity for ventricular contraction
what is the flow of deoxygenated blood
vena cava
right atrium
tricuspid valve
right ventricle
pulmonary valve
pulmonary artery
lungs
what is the flow of oxygenated blood
lungs
pulmonary vein
left atrium
mitral valve (bicuspid)
left ventricle
aortic valve
aorta
what are the types of atrioventricular valve
tricuspid > right atria and right ventricle
mitral > left atria and left ventricle
what happens to the atrioventricular valves during diastole
diastole occurs when the heart muscles relax as it fills with bloof
AV valved open during ventricular diastole due to relaxed papillary muscles
what happens to the atrioventricular valves during systole
systole occurs when the heart muscles contract and blood is pumped out
AV valves close during ventricular systole due to contraction of papillary muscles creating tension of chordae tendinae
what is the function of the semilunar valves
prevent backflow of blood into the ventricles
what are the types of semilunar valve
pulmonary > right ventricle and pulmonary trunk
aortic > left ventricle and aorta
what is the function of the conduction system of the heart
generates and transmits impulses to produce coordinated contractions
what are the components of the conduction system of the heart
sinoatrial node
atrioventricular node
atrioventricular bundle - bundle of His
purkinje fibres
what is the process of the conduction system of the heart
excitation signal is created by the sinoatrial node
the wave of excitation spreads across the atria, causing them to contract
upon reaching the atrioventricular node, the signal is delayed
signal is conducted into the bundle of His, down the intraventricular septum
the bundle of His and the purkinje fibres spread the wave of impulses along the ventricles, causing them to contract
what are the arteries of the heart
arteries of the heart supply the heart with oxygenated blood
left and right coronary arteries emerge from the aortic sinus of the ascending aorta
what are the veins of the heart
veins drain the heart of deoxygenated blood
drain into the coronary sinus which then empties into the right atrium
what are the types of blood vessels
arteries
veins
capillaries
what is the function of arteries
carry blood from the heart and distribute it around the body
relatively high pressure
what is the function of veins
return blood to the heart
low pressure
what is the function of capillaries
connect arterial and venous sides of circulation
exchange of materials
what is the structure of a blood vessel
three layers
1. tunica intima
2. tunica media
3. tunica adventitia
what is the tunica intima
a single layer of cells
what is the tunica media
smooth muscle
what is the tunica adventitia
outer connective tissue
arteries vs veins
share the same 3 layers
arteries have thicker walls and smaller lumen due to higher blood pressure - thicker tunica media
veins often contain valves
