cardiovascular system Flashcards
what 3 components make up the cardiovascular system
the heart, blood vessels, blood
what are the functions of the cardiovascular system
nutrient and waste transport, oxygen and co2 transport, temperature maintenance, hormone circulation
discuss the flow of blood to and from the lungs
from the lungs the blood enters the left side of the heart and is pumped around the body. after oxygen is deposited to cells, the blood returns to the right of the heart which pumps it to the lungs.
how does blood help with temperature maintenance
blood distributes heat around the body- when blood passes through vessels close to skin it releases heat- cooling effect. hypothalamus regulates body temp + vaso dilation/constriction
how does blood help with hormone circulation
hormones are secreted into the bloodstream which carries them to the target tissues
what weight is the heart
250 to 350 grams approx
what is pericardium
a double walled protective sac
what are the two components of pericardium
parietal (superficial) and visceral (inner)
what lies between the two layers of pericardium
pericardial fluid
what is the function of pericardium
physical knocks, shocks, infection
what are the three layers of the heart called?
epicardium (epithelial tissue), myocardium (muscle tissue), endocardium (endothelium)
what are the 4 valves in the heart
two atrioventricular (AV) valves which are between the atria and ventricles. Mitral valve (bicuspid valve) is on the left side while the tricuspid valve is on the right side. Semi-lunar valve which are in the aorta and pulmonary artery.
describe the structure of an artery
3 layers of tissue + hollow core (lumen). Tunica interna (endothelium), tunica media (elastic + smooth muscle), tunica externa (connective tissue).
what is unusual about pulmonary veins?
they carry oxygenated blood
function of atrioventricular valve
prevent blood backflow into atrium
what are the first arteries from the aorta
coronary arteries- bring blood to heart itself
what are the carotid arteries
bring blood to neck and head
what do the subclavian arteries do
bring blood to the shoulders and arms
what brings blood to the legs
femoral arteries
what is the sinoatrial node
cluster of cardiac cells- regulate heart contraction- sends out automatic impulses which initiate heartbeats- causes the atria to contract simultaneously + excites the AV node
where does the AV node conduct impulse to
muscle in the septum
what nerve fibres initiate contraction in the left + right ventricles
purkinje fibres
what is a heart murmur
a sloshing sound that occurs when valves do not operate correctly- pig valves may be used to combat this
what is ventricular diastole
when the ventricles relax- contraction of the atria
Explain “lub dub” sounds of the heart
Lub - closing of the AV valve, start of ventricular contraction
Dub - closing pulmonary & aortic semilunar valves - end of ventricular contraction
What is blood pressure?
Force exerted by blood on artery walls
What is the diastolic pressure?
Atria filling & contracting - pressure decreases slightly -ventricular diastole
What is systolic pressure?
Contraction of ventricles - higher pressure - ventricular systole
Normal bp?
120 mmHg / 80mmHg
Explain the electrocardiogram
Electrical events if normal heartbeat - P wave before atrial contraction - QRS complex 0.2 seconds later (ventricles contract) - final event T wave - may identify arrhythmia
What is the P wave?
Activation of atria
What is the QRS complex?
Activation of the ventricle
What is the T wave?
Recovery wave
