What is refractory tissue?

In electrocardiography, during a cardiac cycle, once an action potential is initiated, there is a period of time that a new action potential cannot be initiated. This is termed the effective refractory period (ERP) of the tissue.

What is refractoriness of the heart?

After an action potential initiates, the cardiac cell is unable to initiate another action potential for some duration of time (which is slightly shorter than the “true” action potential duration). This period of time is referred to as the refractory period, which is 250ms in duration and helps to protect the heart.

What does refractory period mean in anatomy?

: the brief period immediately following the response especially of a muscle or nerve before it recovers the capacity to make a second response. — called also refractory phase.

What does the term refractoriness mean in medical terms?

Refractoriness. These means are used to control the excitability of such tissue as heart muscle. Prolongation of the relative refractory period causes a decrease in the frequency of heart contractions and eliminates disturbances in cardiac rhythm.

Which is the best definition of platelet refractoriness?

Definition / general Platelet refractoriness is the inability to get an adequate increase in platelet count after transfusion (Arch Pathol Lab Med 2003;127:409, Haematologica 2005;90:247)

Which is the best definition of a refractory material?

Showing or characterized by obstinate resistance to authority or control: refractory children; refractory behavior. 2. Difficult to melt or work; resistant to heat: a refractory material such as silica. 3. Resistant to treatment: a refractory case of acne. One that is refractory, especially a material that has a high melting point.

How is the degree of refractoriness of a material measured?

Refractoriness. the property by which materials and products resist high temperatures without fusing. The degree of refractoriness is expressed by the pyrometric cone equivalent— the temperature in degrees centigrade at which a trihedral pyramid of the refractory material 30 mm in height with base sides measuring 8 and 2 mm softens…