Topic 6- Structure of skeletal muscles Flashcards
What makes up skeletal muscles?
Striated muscle
What is a straited muscle made up of?
Muscle fibres
What does each muscle fibre contain + surrounded by?
-contains an organised arrangement of contractile proteins in the cytoplasm
-contains many nuclei
-surrounded by a cell surface membrane
What is the sarcolemma?
Cell membrane of the fibre
What is the sarcoplasm?
Muscle cytoplasm
What does the carcoplasm contain?
-Many mitochrondia (sit of aerobic respiration to generate ATP) to provide ATP for contraction
-Myofibrilis- protein fillanments (actin+ myosin) that cause contraction
What is the sarcoplasmic reticulum (SR)?
Endoplasmic reticulum in the fibre
The sarcolemma has many deep tube-like projections that fold in from its outer surface which run close the SR. What are these known as?
transverse system tubules/T tubules
What do membranes of the SR contain and for what purpose?
-protein pumps
-transport calcium ions into the lumen of the SR
What are thick fillaments made up of?
Myosin
What are thin fillaments made up of?
Actin
What creates the different types of bands and lines?
The myosin and actin are arranged in a particular order
What is the H band?
Myosin
What is the I band
Actin
What is the A band
-Areas of myosin
-Areas where myosin and actin overlap
What is the M line?
Where myosin attaches
What is the Z line?
Where actin attaches
What is the sarcomere?
The section of myofibril between 2 Z lines
