- 1 What is SR in muscle?
- 2 What is the role of the SR in muscle contraction?
- 3 What is the function of the sarcoplasmic reticulum in muscle cells?
- 4 Is sarcoplasmic reticulum rough?
- 5 Why is calcium necessary for muscle contraction?
- 6 What are the steps of muscle contraction?
- 7 Which muscle cells have the greatest ability to regenerate?
- 8 Which neurotransmitter is responsible for muscle contraction?
- 9 In which of the following types of muscle can calcium be released from the SR?
- 10 What does Myofibril mean?
- 11 Do humans have myoglobin?
- 12 What is the Sarcoplasm?
- 13 How does calcium get back into the sarcoplasmic reticulum?
- 14 Are sarcoplasmic reticulum present in smooth muscle?
- 15 What will happen if the sarcoplasmic reticulum of the muscle Fibre is damaged?
What is SR in muscle?
Activation of muscle contraction is a rapid event that is initiated by electrical activity in the surface membrane and transverse (T) tubules. This is followed by release of calcium from the inner membrane system, the sarcoplasmic reticulum ( SR ).
What is the role of the SR in muscle contraction?
Explanation: It is a specialized type of endoplasmic reticulum in muscles cell which primarily functions to store large amounts of Ca+2 ions for muscle contraction. When contraction is no longer needed, the SR will actively pump Ca+2 back into the SR lumen for future use.
What is the function of the sarcoplasmic reticulum in muscle cells?
The sarcoplasmic reticulum (SR) constitutes the main intracellular calcium store in striated muscle and plays an important role in the regulation of excitation-contraction-coupling (ECC) and of intracellular calcium concentrations during contraction and relaxation.
Is sarcoplasmic reticulum rough?
Characteristics. The sarcoplasmic reticulum (SR) is a type of smooth endoplasmic reticulum that abounds in the myocyte (muscle cell). The parts of the SR that are closely associated with the transverse tubules are called terminal cisternae, which is the major site of calcium release.
Why is calcium necessary for muscle contraction?
Calcium’s positive molecule is important to the transmission of nerve impulses to the muscle fiber via its neurotransmitter triggering release at the junction between the nerves (2,6). Inside the muscle, calcium facilitates the interaction between actin and myosin during contractions (2,6).
What are the steps of muscle contraction?
The process of muscular contraction occurs over a number of key steps, including:
- Depolarisation and calcium ion release.
- Actin and myosin cross-bridge formation.
- Sliding mechanism of actin and myosin filaments.
- Sarcomere shortening ( muscle contraction )
Which muscle cells have the greatest ability to regenerate?
Smooth cells have the greatest capacity to regenerate of all the muscle cell types. The smooth muscle cells themselves retain the ability to divide, and can increase in number this way.
Which neurotransmitter is responsible for muscle contraction?
(A) Neurotransmitter (acetylcholine, ACh) released from nerve endings binds to receptors (AChRs) on the muscle surface. The ensuing depolarization causes sodium channels to open, which elicits an action potential that propagates along the cell.
In which of the following types of muscle can calcium be released from the SR?
Cardiac muscle cells also depend on extracellular calcium ions, that enter through the T-tubules and triggers release of calcium ions from the SR.
What does Myofibril mean?
Myofibril, very fine contractile fibres, groups of which extend in parallel columns along the length of striated muscle fibres. The myofibrils are made up of thick and thin myofilaments, which help give the muscle its striped appearance.
Do humans have myoglobin?
In humans, myoglobin is only found in the bloodstream after muscle injury. High concentrations of myoglobin in muscle cells allow organisms to hold their breath for a longer period of time.
What is the Sarcoplasm?
Sarcoplasm is the cytoplasm of a muscle fibre. It is a water solution containing ATP and phosphagens, as well as the enzymes and intermediate and product molecules involved in many metabolic reactions.
How does calcium get back into the sarcoplasmic reticulum?
Relaxation. The calcium pump allows muscles to relax after this frenzied wave of calcium -induced contraction. Powered by ATP, it pumps calcium ions back into the sarcoplasmic reticulum, reducing the calcium level around the actin and myosin filaments and allowing the muscle to relax.
Are sarcoplasmic reticulum present in smooth muscle?
The sarcoplasmic reticulum (SR) of smooth muscles presents many intriguing facets and questions concerning its roles, especially as these change with development, disease, and modulation of physiological activity.
What will happen if the sarcoplasmic reticulum of the muscle Fibre is damaged?
In skeletal muscle, sarcoplasmic reticulum (SR) Ca2+ depletion is suspected to trigger a calcium entry across the plasma membrane and recent studies also suggest that the opening of channels spontaneously active at rest and possibly involved in Duchenne dystrophy may be regulated by SR Ca2+ depletion.