Prop of Cardiac Muscle - lecture 1 - S Roe Flashcards
Approx how many beats does the average heart do a day?
115,000
What is the average daily volume of blood pumped per day?
8,000L
What are the 5 properties needed for Cardiac muscle?
Reliability Efficiency & Economy Redundancy Automatic and Co-ordinated Controllable depending on demand.
What is the name of the cell in the heart muscle?
Cardiac Myocyte - the develop from myoblasts. Held together by intercalated disks.
Why is the cardiac muscle cell branched?
To allow for it to pull in from many different directions.
The heart is said to work functionally as a Syncitium. What does this mean?
That the heart should work as if its only one cell. If you do something to one cell it happens to them all.
How are intercalated disks held together?
Tough tight junctions (to withstand pressure) Gap junctions to allow the passage of ions for electrical stimuli.
What is pacemaker tissue?
This is the conducting tissue i.e. SA Node, AV Node, Bundle of his and punki fibers
What ions move to create a action potential in pacemaker and non-pacemaker tissue?
NA, K, Cl
What is the resting potenital for non pacemaker tissue?
-92 mV RMP
What can you tell from the 2 peaks of the cardiac potential of a pacemaker tissue.
It tell us that it is autonomic
What happens at phase 0 of Non-pacemaker tissue?
Na+ channels open
Whay happens in phase 1 of non-pacemaker tissue?
Na+ channels closee and K+ and Cl+ channels open
What happens in phase 2 of Non-pacemaker tissue?
Slow prolonged opening of Cl+ channels
what happens in phase 0 of pacemaker tissue?
Long lasting Ca+ channels open and open at -40mv
What happens in phase 3 non pacemaker tissue?
There are 2 K+ channels (Ikr & Iks). The first 1 Ikr this allows potassium to leak in holding the plataeu and then the other channels open reversing this and letting K+ flood out of the cell making it more negative.
What is phase 4 in Non-pacemaker tissue?
Resting membrane potential
What phases are missing in Pacemaker cells?
1 & 2
What happens in phase 3 of pacemaker cells?
Potassium comes back in
Where does the Basal Caloric get its energy?
60% fats
35% oxidation of Carbs
5% oxidation of amino acids & ketone bodies
