cardio physiology Flashcards
Describe the blood flow through heart
- blood enters the hart through a vein
- blood enters atrium
- blood flows through an atrioventricular valve
- blood enters a ventricle
- blood flows through a semilunar valve
- blood leaves the heart through an artery
describe deoxygenated blood
- high in carbon
- low in oxygen
- dark red in colour
describe oxygenated blood
- high in oxygen
- low in carbon dioxide
- bright red in colour
what is the cardiac cycle?
it is a series of alternating contractions and relaxations of the hearts atria and ventricles in order to pump blood through the body
what is the order of the cardiac cycle? 1-5
- electrical depolarisation of the heart chamber
- contraction of the heart chamber
- increased pressure inside the heart chamber
- heart valve opens
- blood flows through open valve
where does your heart beat start and the rate is set?
SA node of the right atrium
what is depolarisation ?
cardiac muscle contracting
what is repolarisation?
cardiac muscle relaxing
what is Atrial systole?
contraction of the atria
what is Atrial diastole?
relaxation of the atria
what is ventricular systole?
contraction of the ventricles
what is ventricular diastole?
relaxation of the ventricles
what happens during the ventricular filling phase?
- atria contracts
- P wave on ECG (atrial depolarisation)
- blood moves from atria into ventricles
what happens during the ventricular systole phase?
- ventricles contract
- QRS complex on ECG
- first heart soul ‘lub’
- isovolumetric contraction
- semilunar valves open
- blood is ejected into arteries
- AV valves close
what happens during the isovolumetric relaxation phase?
- T wave on ECG
- ventricles relax
- isovolumetric relaxation
- semilunar valve close
- second heart sound ‘dub”
what is cardiac output?
the volume of blood pumped out f each ventricle in one minute
what is blood volume?
the amount of blood in the cardiovascular system
what is your blood pressure?
the pushing force that blood exerts on blood vessel walls
what is the stroke volume?
the amount of blood pushed out of a ventricle each time it contracts
what is venous return?
the amount of blood returning to the heart through the veins
what can increase heart rate?
- sympathetic stimulation (fight or flight)
- female gender
- exercise
- increased blood volume
- younger age
what can decrease heart rate?
- parasympathetic stimulation (resting and digesting)
- decreased thyroid hormone secretion
- larger body size
- lower body temperature
what is baroreceptors?
blood pressure receptors
what is venous return?
the amount of blood returning through the veins, to the right atrium of the heart
what is preload?
it is how much a ventricle wall is stretched
what is contractility?
how forceful the heart contracts
what is after load?
the blood pressure in the aorta
what increases stroke volume?
- sympathetic stimulation
- increased blood volume
- increased end diastolic volume
- exercise
- vasodilation
what decreases stroke volume?
- decreased venous return
- low blood calcium concentration
- increased end systolic volume
- high blood potassium concentration
- high arterial blood pressure
how do you work out cardiac output?
cardiac output = heart rate x stroke volume
= beats/mins x mL/beat
= mL/min
what would cause stroke volume to decrease?
haemorrhage
what are the nine important plus points?
- superficial temporal artery (temples)
- facial artery (jaw)
- common carotid artery (neck)
- Brachial artery (joins of the arm)
- radial artery (wirst)
- femoral artery (crouch)
- popliteal artery (back of knee)
- posterior tibial artery (ankel)
- dorsalis pedis artes (foot)
