contraction

Examples of contraction in the following topics:

• Types of Muscle Contractions: Isotonic and Isometric

  • Muscle contractions are defined by the changes in the length of the muscle during contraction.
  • Several types of muscle contractions occur and they are defined by the changes in the length of the muscle during contraction.
  • A concentric contraction is a type of muscle contraction in which the muscles shorten while generating force, overcoming resistance.
  • A yielding contraction occurs when a muscle contraction is opposed by resistance.
  • An overcoming contraction occurs when a muscle contraction is opposed by an immovable object.

• ATP and Muscle Contraction

  • ATP is critical for muscle contractions because it breaks the myosin-actin cross-bridge, freeing the myosin for the next contraction.
  • Muscles contract in a repeated pattern of binding and releasing between the two thin and thick strands of the sarcomere.
  • When the actin is pulled approximately 10 nm toward the M-line, the sarcomere shortens and the muscle contracts.
  • Therefore, without ATP, muscles would remain in their contracted state, rather than their relaxed state.
  • With each contraction cycle, actin moves relative to myosin.

• Futures and Forward Contracts

  • Standardized contracts allow investors to buy and sell futures contracts on organized exchanges.
  • You could sell your futures contract on the derivatives market if you no longer want the contract.
  • Contract size is 10,000 barrels of petroleum with a contract price of $75 per barrel.
  • On the other side of the contract, the bank benefits from this contract.
  • If a speculator bought this contract from the Malaysian bank, then he or she loses approximately $250,000 on this contract if the contract matured today.

• Interactions of Skeletal Muscles

  • Skeletal muscle contractions can be grouped based on the length and frequency of contraction.
  • The time between the stimulus and the initiation of contraction is termed the latent period, which is followed by the contraction period.
  • At peak contraction the muscle relaxes and returns to its resting position.
  • After contraction the muscle relaxes back to a resting level of tension.
  • If the frequency of these contractions increases to the point where maximum tension is generated and no relaxation is observed then the contraction is termed a tetanus.

• Contract Manufacturing

  • In contract manufacturing, a hiring firm makes an agreement with the contract manufacturer to produce and ship the hiring firm's goods.
  • A contract manufacturer ("CM") is a manufacturer that enters into a contract with a firm to produce components or products for that firm .
  • In a contract manufacturing business model, the hiring firm approaches the contract manufacturer with a design or formula.
  • Mutual Benefit to Contract Site: A contract between the manufacturer and the company it is producing for may last several years.
  • Compare the benefits and risks of employing a contract manufacturer (CM)

• Review Your RFI, RFP and Contract Language

• Velocity and Duration of Muscle Contraction

  • Skeletal muscle contractions can be broadly separated into twitch and tetanic contractions.
  • In a twitch contraction, a short burst of stimulation causes the muscle to contract, but the duration is so short that the muscle begins relaxing before reaching peak force.
  • If the stimulation is long enough, the muscle reaches peak force and plateaus at this level, resulting in a tetanic contraction.
  • Twitch contractions are short in duration and though they have high velocity, they begin resting before reaching peak force.
  • Tetanic contractions, which are long in duration, reach peak force and plateau.

• Mechanism and Contraction Events of Cardiac Muscle Fibers

  • The gap junctions spread action potentials to support the synchronized contraction of the myocardium.
  • In cardiac, skeletal, and some smooth muscle tissue, contraction occurs through a phenomenon known as excitation contraction coupling (ECC).
  • The actual mechanical contraction response in cardiac muscle occurs via the sliding filament model of contraction.
  • The pathway of contraction can be described in five steps:
  • This removal of the troponin complex frees the actin to be bound by myosin and initiates contraction.

• Abnormal Contractions of Skeletal Muscle

  • Involuntary muscle contractions are referred to as spasms, and can be due to abnormal activity of the nerve or the muscle.
  • In medicine, a spasm is a sudden, involuntary contraction of a muscle, a group of muscles, or a hollow organ, or a similarly sudden contraction of an orifice .
  • There are a variety of other causes of involuntary muscle contractions, which may be more serious, depending on the cause.
  • Examples of spasms include muscle contractions due to abnormal nerve stimulation, or abnormal activity of the muscle itself.
  • Spasmodic muscle contraction may be due to a large number of medical conditions, including the dystonias.

• Excitation–Contraction Coupling

  • Excitation–contraction coupling is the connection between the electrical action potential and the mechanical muscle contraction.
  • Excitation–contraction coupling is the physiological process of converting an electrical stimulus to a mechanical response.
  • It is the link (transduction) between the action potential generated in the sarcolemma and the start of a muscle contraction .
  • This diagram shows excitation-contraction coupling in a skeletal muscle contraction.
  • Explain the process of excitation-contraction coupling and the role of neurotransmitters