Question

HOW IS THE HEART REGULATED AND HOW IS THAT GOING TO INFLUENCE HOMEOSTASIS.

HOW TOU DETERMINE IF SOMONE IS THE FATHER OR NOT.

Answer 1

Heart is regulated by autonomic nervous system ,ie, sympathetic and parasympathetic nervous system

There are 5 main property of heart

Inotropic effect-force of contraction

Dromotropic effect-conduction of impulse

Bathmotropic effect- contractility

Chronotropic effect-heart rate

Clonotropic effect

based on degree of sympathetic and parasympathetic outflow to heart

Function of heart is regulated

SYMPATHETIC SYSTEM

it innervates SA node ,AV node , bundle fibres , and general myocardium of heart chamber

PARASYMPATHETIC SYSTEM

it will only innervates SA node(right vagus nerve) and AV node (left vagus nerve)

Sympathetic outflow to SA node - nerve ending releases noradrenaline and it act on beta-2 receptor ,which opens ca2+ channel and results in calcium loading .which will make resting membrane Potential more towards positive (from negetive RMP )so that it is easier and faster to achieve threshold for SA node cells (normal SA node cell have ability of automaticity ie during initial time due to leaky Na+ channel sodium influx occur which slowly increases membrane Potential from negetive RMP towrds positive ,when it reaches threshold it will open voltage gated Ca2+ channel suddenly and produce action Potential)

It will increase the heart rate-positive chronotropic effect

Parasympathetic outflow to SA node- releases acetylcholine and act on M3 receptor which causes calcium reloading and block calcium loading ,which makes RMP more negetive than normal RMP

So it is very difficult and require more time to reach threshold

It will decrease the heart rate - negetive chronotropic effect

Sympathetic outflow to av node -same way it causes calcium loading and which makes conduction of impulse through gap junctions very faster ,so that conductivity is increased -positive dromotropic effect

Parasympathetic outflow to AV node - it causes calcium deloading and causes delay in transmission of impulse through AV node (nodal delay) which decreases conduction - negetive dromotropic effect

Sympathetic outflow to budle fibre -causes Ca2+ loading and produce positive bathmotropic effect

No parasympathetic effect

Sympathetic outflow to champer myocardium

It causes Ca2+ loading and increases contractility which increases force of contractions -positive inotropic effect

No parasympathetic effect

This is how heart function is regulated

In the normal heart parasympathetic outflow is dominated so that our heart rate is kept in 70 range ,(if all the nerve supply is removed heart rate will be very much greater than 70 )

Blood supply to heart -

Blood supply to heart through coronary vessels are regulated by local factors (autoregulation)

When Heart function is increased it will activate local factors and increases blood supply

Examples- when heart pumping is increased blood supply is increased because of pumping more blood and also

During contraction coronary vessels are compressed due to mechanical pressure and during relaxation it is opened so that blood supply is also increased during diastole

We can determine if someone is father or not by doing paternity test which is actually comparing the DNA of father and child . during DNA fingerprinting it will show great percentage of resemblance