Muscle Phsyiology - Cardiac muscle and Smooth muscle Flashcards
What system is the cardiac muscle under the influence of ?
Autonomic nervous system
(Para and sympathetic)
What does the cardiac muscle act as to allow for rapid communication ?
Acts as a functional syncytium.
This means that the gap junctions allow rapid communication between cells.
This means if you stimulate one cardiac muscle fibre, you stimulate them ALL, and they contract as a single unit.
What does sympathetic nervous stimulation do to the heart rate ?
Increase the heart rate
How does the heart muscle contract ?
++ DIFFERS FROM SKELETAL MUSCLE
Calcium-induced calcium release !!!
Once the dihydropyridine receptor is open, calcium enters into the cardiac muscle fibre.
This is the only difference between cardiac and skeletal muscle.
What is the frank-starling law of the heart
- The force of contraction is directly proportional to the initial length of muscle fibres within the physiological limits.
- The greater the preload (stretch) the greater the force.
Think of the rubber band example explain in class.
What is end diastolic volume ?
End-diastolic volume is the amount of blood that is in the ventricles before the heart contracts.
Whats the end systolic volume ?
The end-systolic volume (ESV) is referred to as the volume of blood in the left or right ventricle at the end of the systolic ejection phase.
What is the refractory period ?
TThe refractory period is a state of recovery that occurs after a neuron fires an action potential. During this period, another action potential cannot be easily produced.
Because of this, cardiac muscle cannot be tetanized.
