# SFT Practice

## Describe what is occuirng in step one What is the major INPUT for step one? The major OUTCOME?
the action pontential caused the synaptic cleft to release the synaptic vesicles.

## Describe what is occuring in step two. What is the major INPUT for step two? The major OUTCOME?
the acetocoline causes the depolarization to start being sent into the t tubule

## What do these small blue dots represent? Describe what is occuirng in step three./  What is the major INPUT for step three? The major OUTCOME?
blue dots are the calcium. the (IN)depolarization at the SR will cauase the (OUT)calcium to release through the cell. 

## Describe what is occuring in step four. What is the major INPUT for step four? The major OUTCOME?

the calcium arrives at the tropanin and causes the actin to expose. This will cause the active sites to be exposed.

## Describe what is occuring in step five. What is the major INPUT for step five? The major OUTCOME?
the now available active site causes the myosin to connect to the active site

## Describe what is occuring in step six. What is the major INPUT for step six? The major OUTCOME?
Because the myosin now flips backwards because it has been attached to the active site. It uses up its stored energy to do so. Its spent ATP is gone 

## Describe what is occuring in step seven. What is the major INPUT for step seven? The major OUTCOME? What owuld happen if that input was removed???
because the myosin head no longer has the atp a new one is re-attached which it uses to release the myosin from the active site.

## Describe what is occuirng in the step eight. What is the major INPUT for step eight? The major OUTCOME?
the atp is broken down and used up as it is no longer attached to the myosin. This causes the myosin head to "reset" back

## How do we get back to a resting muscle? Where does Ca^(2+) end up? What *specifically* has changed this most directly stops the muscle from continuging to contract?
We get back to resting potential by causing the neuron to stop firing which will cause a chain in the system which will stop the process. This involves causing the synapses to stop sending vesicles to the receptors which will cause the SR to stop releasing calcium which will cause the tropinin to no longer expose active sites which will prevent the myosin from attaching to the actin. The Calcium ends up re-absorbed in the Sarcoplasmic reticulum. 
