Basic Cardiology -I
Contents
- 1 S A Node is present at -
- 2 ‘funny’ current denotes ionic flow through channels activated in -
- 3 Plateau phase in cardiac action potential results from-
- 4 Which isoforms of ryanodine receptor is expressed mostly in myocardium?
- 5 Which is the major cellular mediator of calcium-induced calcium release?
- 6 Phospholamban [ 52-amino acid ] regulates the --------- pump in cardiac muscle cells?
- 7 In familial forms of the Dilated cardiomyopathy[DCM] which of the following is most common association?
- 8 Which of the following mediate the release of calcium ions from the sarcoplasmic reticulum and endoplasmic reticulum in muscle contraction?
- 9 All of the following are the antagonist of Ryanodine receptor EXCEPT?
- 10 All of the following are TRUE about Malignant hyperthermia EXCEPT?
S A Node is present at -
S A Node is located at the junction of the crista terminalis in the upper wall of the right atrium and the opening of the superior vena cava.
‘funny’ current denotes ionic flow through channels activated in -
I[f] Current or ‘funny’ current denotes ionic flow through channels activated in hyperpolarized cells (−60 mV or greater), unlike other time- and voltage-dependent channels activated by depolarization.
Plateau phase in cardiac action potential results from-
Phase 2 - is also known as the "plateau" phase due to the membrane potential remaining almost constant, as the membrane slowly begins to repolarize.
This is due to the near balance of charge moving into and out of the cell.
During this phase delayed rectifier potassium channels (Iks) allow potassium to leave the cell while L-type calcium channels (activated by the influx of sodium during phase 0) allow the movement of calcium ions into the cell.
Which isoforms of ryanodine receptor is expressed mostly in myocardium?
RyR1 is primarily expressed in skeletal muscle RyR2 is primarily expressed in myocardium (heart muscle) RyR3 is expressed more widely, but especially in the brain.
Which is the major cellular mediator of calcium-induced calcium release?
The RYR2 ryanodine receptor isoform is the major cellular mediator of calcium-induced calcium release (CICR) in animal cells.
Phospholamban [ 52-amino acid ] regulates the --------- pump in cardiac muscle cells?
Phospholamban [ 52-amino acid ] regulates the calcium (Ca2+) pump in cardiac muscle cells
In familial forms of the Dilated cardiomyopathy[DCM] which of the following is most common association?
DCM -most common form of its transmission is an autosomal dominant pattern
Which of the following mediate the release of calcium ions from the sarcoplasmic reticulum and endoplasmic reticulum in muscle contraction?
Ryanodine receptors mediate the release of calcium ions from the sarcoplasmic reticulum and endoplasmic reticulum, an essential step in muscle contraction.
All of the following are the antagonist of Ryanodine receptor EXCEPT?
Antagonists of RyR : Ryanodine locks the RyRs at half-open state at nanomolar concentrations, yet fully closes them at micromolar concentration. Dantrolene - clinically used antagonist Ruthenium red - Antagonist Procaine - Local anesthesia
SURAMIN -Direct Activator of RyR - Agonist
All of the following are TRUE about Malignant hyperthermia EXCEPT?
Malignant hyperthermia - Autosomal dominant
Defect is typically located on - long arm of chromosome 19 involving the ryanodine receptor.
Major Cause of Trigger for Malignant hyperthermia - Drugs used primarily in general anesthesia
Most common triggering agents are volatile anesthetic gases -
- halothane, sevoflurane, desflurane, isoflurane, enflurane
- Depolarizing muscle relaxants suxamethonium and decamethonium used primarily in general anesthesia
