Skelatal Muscle Pathway is finally here!!!! Remember a picture explains a thousand words and this picture once my explanation is posted will, practically tell you how it works! (Sorry for being 1day late) To see a picture of how easy this is and with it's explanation stay and read if your not interested no need for you to stay so you can leave the thread. This is a post for people to expand their knowledge and ask question. And if I have many grammer errors remember I am a Med major not an English major!. Before we start I will state I will not be starting from the brain. The point in which I start will be starting from the Neuro musclular junction also known as the (Axon Terminal) and terms that I will use to explain will be listed now: Acetylcholine - is a Neurotrasmitter, a neurotransmitter is basically a signal sent from the brain. I will Refer to Acetylchline as (ACH)!!! I made it shorter! Axon Terminal - releases (ACH) via "(ACH) vessicals" basically a container that holds and transports Neurotransmitters. ACH Receptor - binds to (ACH) This receptor is known as a (Nicotinic receptor) T-Tubule -- a "T-Tubule" is a deep invagination of a sarcolemma. Sarcolemma - plasma membrane of skelatal muscle and cardiac muscle cells. Sarcoplasmic reticulum - I will refer to this as (SR) look! I made it shorter!! The duty of the SR is to Store calcium Ions and to release them. in my picture calcium will look like this (Ca2+) Sarcomere - is a basic component of a muscle a Sacomere is composed of "thick" Filimints and "Thin" Filiments. Thick filiments - these filliment are composed of Myosin. (myosin is a protien fun fact) Thin Filliments - "thin filliments" are composed of Actin, Tropomyosin and Troponin. Actin - Actin posses the myosin binding site. This is were actin and myosin bind. Myosin will bind to Actin and "pull" on Actin causing a "power stroke" contraction. Tropomyosin - Covers myosin binding site on Actin. Troponin - stabilizes tropomyosin in the "blocking" position. Troponin will bind to Ca2+ ions. End plate potential - will be called a EPP. An EPP is an electrical signal (to make this simplar I will not state the full definition) Action Potential - will be called an AP. An AP is a short lasting event / electrical signal sent down a membrane. M-line - this marks the center of a Sarcomer. Z-disk - "Z-disk" marks the end of a sarcomere. Dihydropyridine receptor - ha! I'm not spelling that all the time so it will be called (DHP receptor) this is a voltage gate receptor which means once it receives a electrical signal it will send a signal to the Ryanodine channel Ryanodine channel - is a channel that once it receives a signal from DHP receptor it will release Ca2+ ions from the SR. Picture here!!!!!!!!!! Steps of a Contraction! 1) once ACH binds to the ACH receptor soduim Na+ will rush into the cell. 2) Na+ rushing into the cell will cause an electrical signal known as an EPP be sent. 3)EPP will be turned into an AP while it goes down the T-Tubule the electrical signal will be sent to the DHP receptor. 4) DHP receptor will send a signal to the Ryanodine channel. 5) Once Ca2+ is released by the SR, Ca2+ will bind to Troponin. 6)The Ca2+ Troponin complex will move Tropomyosin "out of the way" exposing The myosin binding sites on Actin. 7)Myosin binds to Actin. 8)"Powerstoke" Z-disks are moved together causing the contraction. How skelatal muscle relaxes 1) ATP will bind with myosin head = Myosin will detach from Actin. 2) ATP will "slide back" to relaxed length. 3) ATP is hydrolized (hydrolized means breaking down.) By Myosin ATPase -> this will "re-cocks" Myosin head into the energized state for the next muscle contraction. 4) ATP Hydrolysis requires MG2+ (this is magnesium.)
Hmmm I'll be reposting this tomorrow I did not like how the picture came out I'll be making a new picture on the white board color to help understand mod lock please
Will be reposted tomorrow with hopefully a picture that is easier to understand. And less writing on it.