Medical Post Graduation | Physiology

Refractory period in the ventricles corresponds to the

ক

Period of ventricular contraction

খ

Period of ventricular action potential

গ

QRS complex of ECG

ঘ

PR interval of ECG

ঙ

ST segment of ECG

Refractory period in the ventricles

ক

Decreases during sympathetic stimulation of the heart

খ

Corresponds to the period of ventricular contraction

গ

Corresponds to the QRS complex of ECG

ঘ

Corresponds to the period of ventricular action potential

ঙ

Is shorter than the skeletal muscle

Absolute refractory period in the ventricles

ক

Corresponds to the period of ventricular depolarization.

খ

Corresponds to the period of ventricular contraction.

গ

Is the period when the ventricles are completely unexcitable.

ঘ

Is shorter than the corresponding atrial muscle.

ঙ

Decrease during stimulation of the vagus nerve to the heart.

Plateau phase in the action potential of cardiac muscle

ক

Is due to slow Ca+ -Na channel

খ

Coincides with ventricular systole

গ

Results in prolonged refractory period

ঘ

Is due to efflux of K+

ঙ

Is due to fast sodium channel

Plateau (phase2) of the action potential in cardiac muscle

ক

Coincides with ventricular systole

খ

Results in prolonged refractory period

গ

Is due increased calcium ion influx

ঘ

Coincides with PR interval of ECG

ঙ

Is due to efflux of K+

Plateau in the cardiac muscle

ক

Is due to opening of slow calcium-sodium channel

খ

Results in prolonged refractory period

গ

Coincides with ventricular systole

ঘ

Is due to K+ efflux

ঙ

Is due to opening of transient calcium channel

The factors causing dilatation of blood vessels are

ক

Nitric oxide

খ

Prostacyclin

গ

Endothelin-I

ঘ

Angiotensin-II

ঙ

Neuropeptide Y

Coronary vasodilators released during cardiac muscle ischemia are:

ক

Adenosine

খ

Potassium ion

গ

Hydrogen ion

ঘ

Sodium ion

ঙ

Bicarbonate ion

Factors causing vasodilatation are

ক

Increased K+

খ

Serotonin

গ

NO

ঘ

Angiotensin-II

ঙ

Endothelin-I

Metarterioles and precapillary sphincters relax due to

ক

Sympathetic inhibition

খ

Hypercapnia

গ

Baroreceptor reflex

ঘ

Local tissue hypoxia

ঙ

Circulating epinephrine

The velocity of blood flow is

ক

Close to zero in ascending aorta daring early diastole

খ

Higher in arteries than in arterioles

গ

Inversely proportional to cross sectional area of blood vessels

ঘ

Higher in capillaries than in arterioles

ঙ

Higher in venules than in the arterioles

Tendency to turbulence flow is directly proportional to

ক

Diameter of the blood vessel

খ

Density of blood

গ

Velocity of blood flow

ঘ

Viscosity of blood

ঙ

Elasticity of vessel wall

Viscosity of blood is

ক

A function of friction between molecules of flowing blood

খ

A contributing factor to peripheral resistance

গ

A determining factor of blood flow

ঘ

Increased in anemia

ঙ

Increased in hypoproteinemia

Total peripheral resistance is inversely proportional to

ক

Cross sectional area of blood vessels

খ

Radius of blood vessels

গ

Velocity of blood flow

ঘ

Viscosity of blood

ঙ

Length of blood vessels

Velocity of blood flow is

ক

Higher in the arteries than in the arterioles

খ

Close to zero in ascending aorta during early diastole

গ

Inversely proportional to the cross sectional area of blood vessels

ঘ

Higher in the venules than in the arterioles

ঙ

Higher in the veins than in the arteries

Medical Post Graduation | Physiology | Cvs physiology