explain how heart rate is controlled by the heart itself and by the ANS

When you are cold, your blood vessels contract. However, your heart rate and blood pressure increases. Explain. What is the physiological function of increasing heart rate?

Your grandfather was told that his SA node (pacemaker) has stopped functioning. Explain how his heart is still beating at a rate of 40 to 50 times per minute. Are the atria stimulated to contract? Explain.

Vern, suffering from cardiac arrhythmias, is brought into the emergency room of a hospital. The doctors hook him up to an ECG. He begins to exhibit a decreased R to R interval, and as a result loses consciousness. His anxious partner asks you why he has lost consciousness. a.How would you respond? What is wrong with him, and why did it cause a loss of consciousness. The partner then responds that Vern took nitroglycerine because he was experiencing chest pain known as angina. One of the major side effects of the medication is that the patient will notice a severe headache. b. What does nitroglycerine do? c. How is it administered? d.How does it distribute through the body? e.What is the target cell and mechanism of action on the heart? f. What causes the headache? g.Could the drug have caused the arrhythmia?