1. Animal victims of the blue ringed octopus are often fully conscious and paralyzed as the octopus consumes them, because the venom blocks voltage-gated sodium channels causing paralysis of skeletal muscle. This means that their brain and heart are still functioning despite the fact the peripheral nervous system is failing to fire action potentials.
a) Explain why your heart would continue to beat despite being bitten by a blue ringed octopus.
b) After biting you and injecting you with venom, the octopus realizes that you are too big to eat, and slimes away. Assuming that you are not bleeding from the bite, what will cause your heart and brain to stop functioning after a number of minutes? Be very specific!
c) A surfer comes along almost immediately, before your heart and brain stop functioning and notices the blue-ringed octopus crawling away. So despite the fact that you can't talk, he cleverly deduces the cause of your predicament. What life-saving measures can the surfer administer to you?
2. If a coronary artery becomes blocked, blood flow to the heart is reduced.
a) How does lack of blood flow affect oxidative metabolism and why?
b) What will happen to the pH of the affected heart cells?
c) What will happen to levels of ATP in the affected heart cells?
d) What will happen to calcium levels in the cytosol of the affected heart cells and why?
e) What will happen to the gap junctions between the affected heart cells and other cells?
f) What will happen to the conduction of electrical signals across the affected tissue?
3. Wolff-Parkinson White syndrome is a disorder where there is a "short circuit" in the heart or an extra conducting pathway between the atria and the ventricles. Symptoms of this disorder include tachycardia and dizziness.
a) Explain why tachycardia might result in dizziness.
b) Ablation of the extra conducting tissue and beta blockers are two possible treatments of this condition. Explain how each of these treatments would alleviate symptoms.