Understanding cardiac physiology – the SARCOMERE

[ CAR SHOCK ABSORBER ANALOGY – to sarcomere ]

The SARCOMERE, the basic functional unit (contractile unit) of muscle, in this case cardiac muscle,

can be thought of as a shock absorber.

shckabsbr001

the shock absorber (a common day item in our lives)  at its extremes can represent

the sarcomere at its extremes.

shckabsbr002

SEVERE DEHYDRATION

the above pair of shock absorbers would represent severe dehydration.

(piston pair pictured above – entitle “severe dehydration”).

There is practically no more room for the pistons to be pushed together.

CONGESTIVE HEART FAILURE

(piston pair picture below that – entitled “congestive heart failure”).

There is practically no more room to pull the pistons apart.

 

[ HAND GRASP ANALOGY – to sarcomere ]

shckabsbr003

pictured above :

baby grasping hand – analogous to congestive heart failure.

barely any grip left.

hand shake – analogous to good grasp (Goldilocks zone).

good grasp.  Good allowance for give or take of the grip.

rescuer’s grip – analogous to severe dehydration.

not very good at contracting anymore.  However, plenty of room for give.

starling curve 004

Such is the sarcomere :

A grip between actin and myosin filaments.

For purposes of our discussion, the sarcomere should be in the Goldilocks zone

allowing for enough give or take – to handle the “fluid bumps in our lives as we

indulge in liquid intake or neglect”.

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