cardiac physiology Flashcards
is the resting membrane potential negative or positive
negative
what functional response does an action potential cause
nerve impulse or muscle contraction
what is an action potential generated by
rapid changes in electrochemical gradients across the cell membrane like movement of ions
what is the movement of ions in and out of the cell controlled by
specific ion channels embedded in the membrane
name the 3 ions involved in membrane potential
K+, Na+, Ca2+
what is depolarisation
membrane potential gets less negative
what is depolarisation in muscles
membrane potential goes positive
what is repolarisation
potential returns to negative resting potential
what is hyperpolarisation
membrane potential becomes more negative than resting potential
how to detect and monitor action potentials generated by myocytes
electrocardiogram (ECG)
what is excitation-contraction coupling and how is it achieved
-process which an electrical action potential leads to cardiac muscle cells contracting
-achieved by converting a chemical signal into mechanical energy via contractile proteins
what is contraction of actin and myosin filaments dependent on
calcium signalling
what do gap junctions do
link cytoplasm of neighbouring cells and enable rapid passage of ions/small molecules
structural features of myocardium that help membrane potential changes
intercalated discs- tight interactions, electrical coupling, branched to extend interconnections, single nucleus, lots of mitochondria
synchronised contractions- ensures cardiomyocytes work together, syncytium cardiac muscle
gap junctions- enable rapid passage of ions/small molecules
how do intercalated discs facilitate membrane potential changes
enable tight interactions and help electrical coupling, branched fibres to extend interconnections, single nucleus, abundance of mitochondria