Exam 4 Lectures Flashcards
List the three layers of connective tissue surrounding the muscles
Endomysium, perimysium and the epimysium
What does the endomysium surround
It surrounds a single muscle fiber as a thin layer of colalgen
What is the perimysium
It is a layer of connective tissue that serves as the scaffolding for nerves and blood vessels to go through and bundles each muscle fiber into a fascicle
What is the epimysium
The outermost and thickest layer of connective tissue that surrounds all of the muscle fascicles and transmits the force from the contraction to the bone
What is the sarcolema
The membrane of a muscle cell
What is a myofibril
The contractile portion of the muscle
What is a sarcomere
It is the part of the myofibril that contracts
List the cell types found in whole muscle (10)
Myocytes Satellite cells smooth muscle cells endothelial cells neurons schwann cells hemopoietic stem cells fibroblasts adipocytes immune cells
What tissues are important for force transduction
connective tissues
What and where is a satellite cell
It is a precursor myocyte that is between the basolamina and the sarcolemma
What are the types of mitochondria found in muscle cells
Subsarcolemmal mitochondria - beneath sarcolemma and responsible for Energy for transport across the membrane to the nueromuscular junction
Intramyofibrular (IMF) mitochondria - E for work of the muscle
What is the sarcoplasmic reticulum and what is its function
It is the ER of muscle cells surrounding the myofibrils that stores Ca++
What are the primary proteins of the sarcolemma
Actin and myosin
What is the A band
It is the band that spans from myosin to myosin
What is the I band
The end of the A band to the A band of the next sarcolemma
What is the Z disk
It is the length of the sarcomere that is just actin
What is the M line
The attachment protein that joins the myosins together
What is the light band
It is the I band and is actin
What is the dark band
It is the A band and is myosin
How many actin molecules is myosin in contact with
6 - it has a hexagonal shape in reality
What is the sliding filament theory and who discovered it
Huxley discovered that the length of actin and myosin does not change, but they actually slide past one another to shorten the H zone and I band during contraction
Muscle contraction (FIX THIS CARD)
1) Excitation of membrane, depolarization sarcolemma and sarcoplasmic reticulum to activate ryanodine receptors to release Ca++
2) Ca++ binds troponin to expose myosin-binding sites on the actin filaments
3) Myosin heads bind to actin, ADP is released
4) In the power stroke, the myosin head changes conformation, the filaments slide past one another
5) ATP binds to myosin, causing it to release actin
6) ATP is hydrolyzed and the myosin head returns to its resting conformation
7 ) If Ca++ is returned to the sarcoplasmic reticulum, the muscle releases
8) If Ca++ remains available, the cycle repeats and muscles contraction continues
What is the muscle biopsy technique
It is a way of examining a muscle by inserting a needle into the belly of a muscle to extract a chunk of muscle tissue. This is then frozen, sliced, stained, and examined under the microscope.
What are the two possible ways to classify muscle tissue?
1) Activity of the myosin ATPase enzyme - ST, FOG, FG
2) Myosin heavy chain - Type I, Type IIA, and Type IIB/X