The cellular mechanisms of cardiac muscle
Located in the superior posterolateral wall of the right atrium
What is the sinoatrial (SA) node?
Represents/highlights ventricular depolarisation in an ECG (mostly reflects left ventricle depolarisation)
What is the QRS complex?
Made up of 6 polypeptide chains - 2 heavy and 4 light
What is a myosin molecule?
The foxglove plant
What are cardiac glycosides derived from?
Limiting the information shared (to the required/necessary individuals/groups) to only what is necessary to address the issue
What is (maintaining) confidentiality?
The name of the complex which covers the active sites on the actin filament in a relaxed muscle
What is the troponin-tropomyosin complex?
During this time interval a 2nd stimulus can’t generate a new action potential in a depolarised cardiomyocyte (accuracy required or only half points)
What is the effective refractory period?
This subunit of the troponin complex binds strongly with calcium ions, playing a key role in muscle contraction
What is troponin C?
2 examples of cardiac glycosides
What are digoxin and digitoxin?
(Digitoxin is a phytosteroid and is similar in structure and effects to digoxin, though the effects are longer-lasting. Unlike digoxin, which is eliminated from the body via the kidneys, it is eliminated via the liver, and so can be used in patients with poor or erratic kidney function. While several controlled trials have shown digoxin to be effective in a proportion of patients treated for heart failure, the evidence base for digitoxin is not as strong, although it is presumed to be similarly effective.)
The ethical duty that requires doctors to act on concerns about colleagues is outlined in this GMC document
What is "Good Medical Practice"?
What is excitation-contraction coupling?
Allows the heart muscle to relax and prevents permanent contraction (tetany)
What is the plateau phase // absolute refractory period?
It is the time interval in which no new AP can be generated as the fast Na+ channels are deactivated (plateau phase)
The plateau phase of the myocardial AP is longer than the actual contraction. This allows the heart muscle to relax and prevents permanent contraction (tetany).
Sites of strong adhesion that help keep the muscles cells connected when they contract
What are desmosomes?
Digitalis compounds increase the activity of this nerve, contributing to their parasympathomimetic effects.
What is the vagus nerve?
(Parasympathomimetics are a class of drugs that stimulate the parasympathetic nervous system, mimicking the effects of acetylcholine)
This is the primary responsibility of a doctor when they believe a colleague's conduct or competence is being negatively affected
What is protecting/maintaining patient safety?
This feature of cardiac myocytes ensures that muscle contraction spreads quickly through the heart
What is the interwoven arrangement of cardiac myocytes?
Indicates/signifies ventricular re-polarisation in an ECG
What is the T-wave?
The backbone of actin filaments is composed of this double-stranded, helical protein molecule
What is F actin?
The major side effect of digitalis compounds is this
What is cardiac arrhythmia (especially atrial tachycardia and atrioventricular block)?
When a doctor is concerned about a colleague’s competence, they are advised to first raise the issue to these individuals/teams
What is a supervisor, clinical lead, or patient safety team?
This term refers to a single cell or cytoplasmic mass containing several nuclei, formed by the fusion of cells
What is a syncytium?
The upstroke and depolarisation of pacemaker cells is caused by the opening of these
What are L-type Ca2+ channels?
(Extra information: In other muscle cells and neurons, it is by fast Na+ channels)
Allow cardiac myocytes to contract in a wave like manner so the heart can work like a pump
What are intercalated discs?
2 conditions which can be treated/helped by the use of cardiac glycosides
What is heart failure and atrial fibrillation?
This GMC principle requires doctors to be open and honest with patients if something goes wrong with their care, especially if it causes harm or distress
What is duty of candour?