Skeletal muscle contraction

1. Describe in detail a skeletal muscle contraction starting from depolarization of the sarcolemma (plasma membrane of a muscle cell) to the muscle returning to its relaxed state. This should be as detailed as possible making sure to mention all of the molecules involved like ATP, Calcium, Troponin, Actin, Myosin, and Tropomyosin.   Also, do not forget all of the structures like T-tubule, Sarcoplasmic Reticulum, Sarcomere, and so on.
2. Below draw (or use words if you cannot draw) and explain the neuromuscular junction that exists between a nerve cell and a skeletal muscle. What kind of synapse is this, chemical or electrical?  Also, be sure to show and explain the role all of the molecules and ions involved in transferring the action potential from the nerve cell to the muscle cell.  You should list molecules and ions like: sodium, calcium, potassium, and acetylcholine (ACH).
3. Many people experience orthostatic hypotension upon standing from a seated or laying position.  This means that their blood pressure decreases rapidly.  During this event they quickly activate short term (so not the RAA pathway) mechanisms for blood pressure control.  Please explain the following:

1. Where are receptors located in the body for measuring blood pressure and how do they sense a change in blood pressure.
2. Where do the above sensors send their signals?
3. In orthostatic hypotension how does the control center in part b respond (which part of the nervous system is activated)?
4. Activation of the nervous system in part c would produce what change in blood pressure and why? For the why part of this question, you should be talking about the definition of blood pressure and how it changes in response to the nervous system change.

1. Label the following EKG’s
2. Calculate the beats per minute for each EKG strip.  Each strip represents 6 seconds.
3. Label each strip as a normal rhythm, tachycardia, or bradycardia.
4. Identify each rhythm as being a sinus rhythm or not.
5. List the steps of the Renin Angiotensin Aldosterone pathway.  In addition, what is the result with respect to blood volume and blood pressure and WHY?
6. Below describe the cardiac cycle in detail without just copying and pasting my hand-out. Be sure to explain when the two heart sounds arise during the cycle as well as both systole and diastole

Analysis Sectin

7. ____Explain why Troponin is often used as a cardiac blood marker to diagnose a myocardial infarction. A myocardial infarction is anothe same for heart attack.  During a heart attack muscle cells die.

8. ____Males do not have significantly more muscle cells than females. However, why do males muscles look larger than females and in general can oppose more force (lift heavier objects).  You must give a physiological as well as anatomical (muscle structure) explanation.

9. ____Explain how Calcium deficiencies can result in tired or weak muscles. For this you need to think about the role of calcium in a skeletal muscle contraction.
10. Years ago doctors used to give paregoric for an upset stomach and diarrhea. Paregoric is a mixture of morphine and alcohol.  It turns out that morphine binds epinephrine receptors in the GI tract.  Explain why morphine does not make the diarrhea worse since it’s binding epi receptors
11. Addison’s disease is caused by an autoimmune destruction of the adrenal cortex.  How could this put a person with Addison’s disease at risk of hypovolemic shock (Extremely low blood pressure due to low blood volume).
12. ACE inhibitors are often given to people with high blood pressure. They work by deactivating angiotensin-converting enzyme (ACE).
13. How does this lower blood pressure?
14. Where in the body do you find ACh

1. If a patient has a blood pressure of 140/85 mmHg what would be the minimum pressure needed for this patient to eject blood from their left ventricle during systole and WH
2. Little Timmy was trapped in the male’s restroom at the mall after he had inadvertently locked the door from the inside. After several hours of looking for the key the fire department was called to break down the door.  Once little Timmy was freed from the restroom the paramedics were called to make sure Timmy was ok.  Below is a list of Timmy’s signs/symptoms.  Please explain the physiological mechanisms responsible for these signs/symptoms.

• Blood pressure 150/95 (normal 120/80)
• Heart rate = 120 BPM (normal 60-100 BPM)
• Skin was pale and cold
• Urine output was low

1. Jimmy recently was in an automotive accident and suffered a ruptured chordae tendineae on his mitral valve.  His blood pressure was 95/80 and his normal blood pressure is 120/80.  Is the ruptured chordae tendineae contributing to his drop in systolic blood pressure?  If yes, why?  If not, why not?