Flashcards
controlling the heart
Cards in this deck (22)
- 1Heart rateNumber of times the heart beats per minute
- 2Cardiovascular control centrecontrols heart rate, located in medulla oblongata, recieves impulses about CO2 levels in blood, sends impulses via accelerator nerve (sympathetic NS) or vagus nerve (parasympathetic NS) to SAN to increase or decrease heart rate.
- 3stroke volumevolume of blood pumped out of the left ventricle every time the ventricle contracts (ventricular systole). cardiac output x heart rate = stroke volume
- 4cardiac outputstroke volume x heart rate = cardiac output. stroke volume per minute.
- 5SANSinoatrial node - group of specialisd muscle fibres in the heart wall which initiate the heart beat (aka pacemaker)
- 6Bundle of Hisspecialised fibres in the heart carry impulses from AVN to ventricle tips, ensure ventricle contracts in a way that squeezes blood upwards through arteries
- 7AVNAtrioventricular node - area of specialised tissue in the wall of the heart between the atria and ventricles. coordinates the heart beat. impulse from SAN is delayed briefly here (0.13 seconds)
- 8cardiac cycleone complete cycle of the heart - systole and diastole
- 9electrocardiogramgraphic record of electrical activity of the heart
- 10Purkyne fibresspecialised muscle fibres running between right and left ventricles, conducting impulses making the ventricles contract
- 11myogenicmuscle which can contract without being stimulated to do so by a nerve (heart is initiated by SAN instead and these are muscle fibres rather than nerves)
- 12QRS complexwave of depolarisation resulting in conraction of ventricles
- 13R waverepresents depolarisation of left ventricle (just before the right ventricle)
- 14P wavedepolarisation of the atria (from right to left)
- 15Q wavedepolarisation of the bundle of His
- 16T waveventricular relaxation/repolarisation (
- 17S waveend of depolarisation/contraction of right ventricle
- 18QT intervallength of time between beginning of Q wave (depolarisation of bundle of His) and the end of the T wave (repolarisation of ventricles)
- 19order of depolarisation and repolarisation (3 stages)atrial depolarisation (right to left)
ventricular depolarisation (left to right)
ventricular repolarisation - 20U waveoccurs in 50-75% population
- 21Adrenaline role on heart rateproduced by adrenal glands when we are stressed or frightened, increases stroke volume and heart rate which increases cardiac output, dilates blood vessels supplying muscles, stimulating conversion of glycogen to glucose.
- 22Anginapain in chest when heart muscle doesn't revieve enough oxygen-rich blood. If coronary heart muscles can't supply enough oxygen then the heart muscle respires anaerobically, producing lactic acid
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- AS - Level Biology (Topic 7) Flashcards on controlling the heart, created by Alice Storr on 17/04/2017.
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- Alice Storr
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