Refractory periods of the heart
Chp. 12 Obj. 3Emily dzvonik
START
What are "Refractory Periods"?
Periods concerning the ionic composition of the cells during different phases of the action potential and the ability of the cells to accept a stimulus.
Simply Put:
A period of time during which a cell is incapable of repeating an action potential.
What does 'Refractory' mean?
Define refractory
The term refractory simply means to resist. If it helps, think of refractory periods as resistant periods!
Refractory Periods
Three different periods
Nonrefractory Period
Relative Refractory Period
Absolute Refractory Period
Nonrefractory
All the cells are in their resting or polarized state - ready to respond!
Relative
The time in which repolarization is almost complete and where a strong stimulus may cause depolarization of some cells.
Absolute
The ionic composition of the cells is not in place to recieve a stimulus.
Some cells may respond!
Cells can not respond to a stimulus!
All cells are ready to respond!
+INFO
+INFO
+INFO
Check Your Understanding!
Check Your Understanding!
Absolute Refractory Period
Absolute refractory
> Occurs during phases 0, 1, 2 and half of 3 > Ionic composition of cells is not in place to receieve a stimulus > Cells can NOT respond to a stimulus
The cells can ABSOLUTELY NOT respond to a stimulus!
Relative Refractory Period
Graph!!
Relative refractory
> Repolarization is almost complete > A strong stimulus may cause depolarization of some cells > Some cells may respond normally, some abnormally, and some not at all > Second half of phase 3
Nonrefractory Period
Nonrefractory
> All of the cells are in their resting or polarized state > All cells are ready to respond to a stimulus in a normal fashion > Phase 4
Check Your Understanding!
Absolute vs. Relative
Causation of refractory periods
Video
Absolute vs. Relative:> Definition> Causation > Illustration
Check Your Understanding!
Questions?!
Works Cited
Citations
- https://books.lib.uoguelph.ca/human-physiology/chapter/bioelectricity-of-the-heart/
- https://www.youtube.com/watch?v=_nXqX3hSx9E
Refractory Periods
Emily Dzvonik
Created on November 8, 2023
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Transcript
Refractory periods of the heart
Chp. 12 Obj. 3Emily dzvonik
START
What are "Refractory Periods"?
Periods concerning the ionic composition of the cells during different phases of the action potential and the ability of the cells to accept a stimulus.
Simply Put:
A period of time during which a cell is incapable of repeating an action potential.
What does 'Refractory' mean?
Define refractory
The term refractory simply means to resist. If it helps, think of refractory periods as resistant periods!
Refractory Periods
Three different periods
Nonrefractory Period
Relative Refractory Period
Absolute Refractory Period
Nonrefractory
All the cells are in their resting or polarized state - ready to respond!
Relative
The time in which repolarization is almost complete and where a strong stimulus may cause depolarization of some cells.
Absolute
The ionic composition of the cells is not in place to recieve a stimulus.
Some cells may respond!
Cells can not respond to a stimulus!
All cells are ready to respond!
+INFO
+INFO
+INFO
Check Your Understanding!
Check Your Understanding!
Absolute Refractory Period
Absolute refractory
> Occurs during phases 0, 1, 2 and half of 3 > Ionic composition of cells is not in place to receieve a stimulus > Cells can NOT respond to a stimulus
The cells can ABSOLUTELY NOT respond to a stimulus!
Relative Refractory Period
Graph!!
Relative refractory
> Repolarization is almost complete > A strong stimulus may cause depolarization of some cells > Some cells may respond normally, some abnormally, and some not at all > Second half of phase 3
Nonrefractory Period
Nonrefractory
> All of the cells are in their resting or polarized state > All cells are ready to respond to a stimulus in a normal fashion > Phase 4
Check Your Understanding!
Absolute vs. Relative
Causation of refractory periods
Video
Absolute vs. Relative:> Definition> Causation > Illustration
Check Your Understanding!
Questions?!
Works Cited
Citations