The Sarcoplasmic Reticulum of Skeletal Muscle Functions

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You may come here because you are looking for information about the Sarcoplasmic Reticulum functions. Well, you come to the right site because here I will give you the information about the functions of sarcoplasmic reticulum and the other things related to it.

The Functions of Sarcoplasmic Reticulum of Skeletal Muscle

According to Britannica, sarcoplasmic reticulum is defined as an intracellular system of closed saclike membranes which is involved in the storage of intracellular calcium in striated (skeletal) muscle cells. On Wikipedia, sarcoplasmic reticulum is defined as a membrane-bound structure which can be found within muscle cells which is the same as the smooth endoplasmic reticulum in other cells. The main function of sarcoplasmic reticulum is to store calcium ions.

The Sarcoplasmic Reticulum of Skeletal Muscle Functions

Furthermore on Wikipedia, it is explained that calcium ion levels are kept relatively constant, with the concentration of calcium ions in a cell being 10,000 times smaller than the concentration of calcium ions outside the cell. The meaning is that small increases in calcium ions in the cell are easily detected and are able to bring about important cellular changes/

Calcium is used to create calcium carbonate and calcium phosphate. These are two compounds that the body uses to make bones and teeth. The meaning is that if there is too much calcium in the cells, it can lead to hardening or calcification of certain intracellular structures including the mitochondria where it can lead to cell death. So, it is important that calcium ion levels are controlled and are able to be released into the cell when necessary and then deleted from the cell.

The Structure of Sarcoplasmic Reticulum

According to Wikipedia, here is the explanation about the structure of sarcoplasmic reticulum. The sarcoplasmic reticulum is a network of tubules which extend throughout muscle cells where they wrap around the myofibrils but not in direct contact with the myofibrils. In the cardiac and skeletal muscle cells, there are structures named transverse tubules (T-tubules) which are extensions of the cell membrane that go into the center of the cell.

T-tubules are closely related to a  specific region of the sarcoplasmic reticulum where it is known as the terminal cisternae in skeletal muscle with a distance of roughly 12 nanometers, separating them. It is the main site of calcium release.

How about the longitudinal sarcoplasmic reticulum? It is a thinner project. They run between the terminal cisternae/ junctional sarcoplasmic reticulum. The longitudinal sarcoplasmic reticulum is the location where ion channels necessary for calcium ion absorption are most abundant.

Some Questions and Answer About Anatomy and Physiology

Here, you can read some questions and answers about Anatomy and Physiology according to Quizlet.

  • Which of these statements about skeletal muscles is false?
    A) Their fibers branch.
    B) They store nutrient reserves.
    C) They pull on tendons.
    D) They support soft tissues.
    Answer: A) Their fibers branch.
  • Which type of muscle tissue has the greatest effect on the body’s heat production?
    A) skeletal
    B) cardiac
    C) smooth
    D) All of these muscle types have about the same effect on the body’s heat production.
    Answer: A) skeletal
  • Skeletal muscle does each of these except …
    A) produce movement
    B) maintain posture
    C) ventilate the lungs
    D) pump blood
    Answer: D) pump blood
  • The capillaries that wrap around each muscle fiber are located within the …
    A) perimysium
    B) epimysium
    C) sarcolemma
    D) endomysium
    Answer: D) endomysium
  • Muscles are attached to bones by tendons or …
    A) ligaments
    B) aponeuroses
    C) perimysium
    D) superficial fascia
    Answer: B) aponeuroses
  • A thin layer of connective tissue that surrounds a muscle fascicle is called the …
    A) endomysium
    B) perimysium
    C) tendon
    D) epimysium
    Answer: B) perimysium
  • What is the function of the sarcoplasmic reticulum?
    Answer: Calcium storage/ regulation
  • The … of the cell is the organelle that contains the chromosomes – the human inheritable material.
    Answer: nucleus; houses genetic material
  • The …  are a conduit for the passage of the action potential from the sarcolemma to the sarcoplasmic reticulum.
    Answer: transverse tubules; part of coupling the action potential to contraction
  • Aerobic ATP production in all cells is performed by the …
    Answer: mitochondria; power-house of cell
  • The … is a lighter region of the sarcomere where only thick filaments are found.
    Answer: H band
  • The … marks the boundary between neighboring sarcomeres.
    Answer: Z line
  • The … is the central portion of the sarcomere.
    Answer: M line
  • The … extends from the A band of one sarcomere to the A band of the neighboring sarcomere and is the region where only thin filaments are found.
    Answer: I band
  • Which thick filament binds to actin once its active binding sites are exposed?
    A) troponin
    B) actin
    C) tropomyosin
    D) myosin
    Answer: D) myosin
  • The action potential in skeletal muscle fibers is generated by the …
    A) sarcoplasmic reticulum
    B) sarcophagus
    C) sarcoplasm
    D) sarcolemma
    Answer: D) sarcolemma
  • Titin is a(n) ….
    A) thin filament protein
    B) elastic protein
    C) calcium-binding protein
    D) tropomyosin-binding protein
    Answer: B) elastic protein
  • Sarcomere is best defined as …
    A) actomyosin proteins
    B) a storage form of calcium
    C) a repeating unit of striated muscle
    D) thick and thin filaments
    Answer: C) a repeating unit of striated muscle
  • Acetylcholine binds to its receptor in the sarcolemma and triggers …
    A) the opening of ligand-gated cation channels
    B) the opening of calcium-release channels
    C) the opening of ligand-gated anion channels
    D) the opening of voltage-gated calcium channels
    Answer: A) the opening of ligand-gated cation channels
  • What is name given to the regularly spaced infoldings of the sarcolemma?
    A) transverse or T tubules
    B) sarcoplasmic reticulum
    C) motor endplates
    D) terminal cisternae
    Answer: A) transverse or T tubules
  • The cross bridge cycle is a series of molecular events that occur after excitation of the sarcolemma. What is a cross bridge?
    A) Troponin bound to tropomyosin
    B) ATP bound to a myosin head
    C) Calcium bound to troponin
    D) A myosin head bound to actin
    Answer: D) A myosin head bound to actin

Well, that’s the information that I can give to you about sarcoplasmic reticulum and also some questions and answers related to anatomy and physiology where the questions are about muscles and sarcoplasmic reticulum can be found there and I take the information above from some online sources mentioned above.

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