Natures wonders: how the human heart beats (Introduction)

by David Turell , Sunday, December 22, 2019, 01:19 (1588 days ago) @ David Turell

Or other primatew and mammals:

https://www.sciencedaily.com/releases/2019/12/191220074305.htm

"The heart is both a plumbing and electrical marvel. For each heartbeat, electrical waves travel across a healthy heart in a pattern that controls its filling and pumping in a tightly coordinated manner. The rate at which the impulse is propagated through the heart tissue relies on actions taking place at the molecular level in tiny protein pores present in cardiac cell membranes.

"Sodium ions -- a type of charged particles -- pass through these protein passageways in the membrane boundary between the outside and inside of the cell.

***

"The activation and quick inactivation of these voltage-gated sodium channels are part of a series of electrical and physiological events that maintain a steady heartbeat.
"Sodium channels operate in concert with calcium channels and potassium channels to drive the heartbeat at a consistent frequency for our entire lives," Zheng noted.

***

"Specifically, the NaV (Latin abbreviation for sodium, V for voltage) 1.5 channel has such an indispensable role that certain mutations in those channels can be fatal, because other sodium channels in the heart cannot compensate for their loss. These mutations can cause dangerous arrhythmias in adults and even sudden death in children and young athletes.

***

"Among the key findings from this work were:

"A description of some of the characteristics of the NaV1.5 channel that distinguish it from other sodium ion channels found in heart cells, as well as in nerve and muscle cells.

"A comparison of the conformation of an important component of the sodium ion channels that "senses" the voltage across the cell membrane and drives the channels from resting to activated states. After their rapid activation, cardiac sodium channels inactivate within 1 to 2 milliseconds, a timing that is essential to regular heart rhythm."

Comment: As a cardiologist I really enjoyed this work description. The sinus node that starts the spread of electricity is somewhat explained here. The spread of electricity is such that each of the four chambers beat in a proper sequence for proper order of pumping of the four chambers to force blood circulation, with the heart receiving returning venous blood and pumping blood out through the arteries. Not by chance. Only design can create such a mechanism. As a physician it is very easy to understand why one should believe in God.