Lecture 8 Flashcards
What are the three types of muscles on the human body
Smooth Muscle
Cardiac Muscle
Skeletal muscle
What are all muscles made up od?
Cells called ‘fibers’
What are some jobs the muscle has
Develop force (contraction)
Provide voluntary control over major openings.
Convert energy (in part) to heat to maintain core temperature (eg. shivering)
What do fibers (muscle cells) gather together to form?
Fibers gather into bundles called fascicles.
Fascicles are further bundled into Muscles
What is a sarcomere
A sarcomere is an individual contractile unit of muscle
What are myofibrils
Myofibrils are made up of repeating units known as sarcomeres
What are the two types of filaments that comprise most of skeletal muscle
Actin (thin filament)
Myosin (thick filament)
What is the sarcolemma?
The plasma membrane of the muscle cell
What is the plasma membrane of the muscle cell
The Sarcolemma
Where does signal to contract move along in the skeletal muscle
When skeletal muscle is receiving a signal to contract, this signal moves along the sarcolemma
What is the function of the transverse tubules
The transverse tubules are pathways that lead down from the sarcolemma deep into the muscle cell.
This allows the signal to penetrate down into the cell and activate all at once
What is the role of the sarcoplasmic reticulum
The role of the sarcoplasmic reticulum is to store calcium. it keeps calcium outside of the cell until the muscle needs to contract
What is Excitation-Contraction Coupling
The pairing of a signaling event (excitation of the muscle cell) with a mechanical event (contraction of the muscle cell)
What is the function of the voltage-gated sensor? (DHPR)
Receives signals from the t-tubules and interacts with the ryanodine receptor
What is the function of the SR calcium-ATPase (SERCA)
An active calcium pump that uses ATP to move Ca2+ back into the Sarcoplasmic reticulum against its concentration gradient.
This ends excitation
What is the function of the ryanodine receptor (RyR)?
A passive calcium channel on the Sarcoplasmic reticulum that can open to allow Ca2+ into the cell
What happens when calcium diffuses throughout the cell
It activates the myofilaments and thus causes contraction
How does the SERCA allow the muscle to relax
It burns ATP to produce energy to pump calcium back into the Sarcoplasmic Reticulum against its gradient. The removal of calcium from the cell stops the signaling event and allows the muscle to relax.
