ECG Flashcards
(295 cards)
describe the passage of blood through the heart
deoxygenated blood from the body arrives from cranial vena cava
right atrium
tricuspid valve
right ventricle
pulmonary valve
pulmonary artery to the lungs
pulmonary vein from the lungs
left atrium
mitral valve
left ventricle
aortic valve
aorta to systemic circulation
what is the purpose of the heart beating?
pump blood around the body and lungs
what is myocardium made up of?
cardiac muscle
is heart contraction governed by nerve impulse?
no - contracts automatically
what is the process of heart contraction controlled by?
electrical impulses
what relating to the heart is controlled by the autonomic nervous system?
heart rate
what part of the nervous system controlls heart rate?
autonomic
what are the 2 branches of the autonomic nervous system?
sympathetic
parasympathetic
what effect does the sympathetic nervous system have on heart rate?
increases HR
what effect does the parasympathetic nervous system have on heart rate?
slows
how does the parasympathetic nervous system slow heart rate?
release of acytylcholine
how does the sympathetic nervous system increase heart rate?
releases catecholamines to accelerate HR
what catecholamines increase HR?
adrenaline
noradrenaline
what are the 2 types of cardiac cells?
electrical cells
myocardial cells
what is the role of electrical cells within the heart?
conduction system of the heart
spontaneously generate and respond to electrical impulses
transmit electrical impulses
how are electrical cells distributed throughout the heart?
orderly fashion throughout the heart
where are myocardial cells found?
within the walls of the atrium and ventricles
what is the role of myocardial cells?
responsible for contraction and stretch of the heart
what is required for the heart to function properly?
coordinated contraction of both atria and ventricles
what is coordinated atrioventricular contraction?
coordinated contraction of both atria and ventricles to expel blood into aorta and pulmonary artery
what do cardiac muscle cells require to contract?
electrical stimulus
what state are cardiac cells in when relaxed?
polarised
what happens to cardiac cells when stimulated by an electrical impulse?
cells start to depolarise
what area of the heart must be depolarised first in order to allow the heart to function properly?
two atria