Question

read the paragraphs and answer the following questions

PART 1: Death of a small town An unknown chemical has been added to the drinking water of a small community in central California causing the death of all who have ingested the water. The victims are all in a state of rigor mortis, their bodies contorted with their skeletal muscles in a "locked" or contracted position at the time of death. Although rigor mortis is a common consequence of death, it usually occurs several hours after death. In the case of all of these townspeople, however, rigor mortis set in very rapidly after death. Pet dogs and cats were also found in the same condition. You are an investigator that has been sent to investigate the cause of death. You are to determine the possible mechanism by which death occurred, based on the evidence collected by various members of your investigation team. Your final explanation must account for the five pieces of evidence provided and demonstrate your knowledge of how skeletal muscles function at the molecular level. You may refer to your text and notes as needed (please do not use internet resources - you should be able to figure this out!). Evidence 1: One of the victims has his arms flexed in death. You take a biopsy of the biceps and triceps muscles (antagonistic muscles of the upper arm) and compare these to a muscle at resting length using a high-power microscope. You find that, in both of the victim's muscles, the A bands are the same width but the I bands and H zones are shorter, in comparison to the resting muscle. What does this condition mean about the state of contraction of the victim's two muscles? Is this condition expected or unusual? Evidence 2: One of the victims has his arms flexed in death. You take a biopsy of the biceps muscle and prepare it for viewing with the electron microscope. Usually, about 15-25% of the myosin heads are in contact with myosin- binding sites on the actin thin filament as cross-bridges. However, in your victim's muscle, you find a much higher percentage of cross-bridges. What could have caused this to occur? Evidence 3: Flura II is a calcium-indicating fluorescent dye. When you give a lab rat some of the town's drinking water, it dies within a few minutes. You euthanize (humanely kill) a "control" rat so it dies at approximately the same time. A biopsy of the skeletal muscle (gastrocnemius) from each rat is treated with Flura II. You find that the rat that drank the town's water has a significantly higher level of intracellular calcium in the gastrocnemius than does the control rat, based on the level of Flura II fluorescence.

please read the paragraphs and answer the questions

Answer 1

1) Tetrodotoxin is a lethal poison caused mainly due to consumption of fish (puffer and porcupine),shell fish, crabs and octopus that contains neurotoxins . The toxic effects starts from 10-15 minutes after consuming toxic effect. Marshal along with his friends ate dinner in a fish restaurant after eating bad fish he developed symptoms of toxicity, his Bp dropped to 90/50.

2) Tetrodotoxin mainly acts at nervous system. It is a potent sodium channel blockers, it blocks sodium channels in nerve cells by blocking sodium ions. As a result tetrodotoxin alters normal transmission of nerve signals between body and the brain. It finally end up with paralysis of muscles involves in voluntary function like respiratory muscles (diaphragm and intercostal muscles), Death occurs due to total cessation of breathing.

3) TTX acts on action potential and reduces peripheral vascular resistance ( force exerted by blood flow in arteries). Hypotension and bradycardia results from disruption in action potential. Atropine blocks parasympathetic nervous system thereby increasing heart rate. Atropine controls the excessive vagal stimulation and thus it helps in treatment of bradycardia and heart block.

4) Antidote is a medicine that helps to neutralizes the effect of toxic effects occurs due drug or substance poisoning. Activated charcoal can be effective in treating TTX poison.

- This eliminates poison by trapping chemicals and preventing them to adhere / absorbed into the body.

- Activated charcoal absorbs drug in the intestine and thereby preventing entry of toxins into systemic circulation.

- It also contains laxative " sorbitol " that facilitates cleaning stomach contents by inducing diarrhea.