Myoneme

Last updated

A myoneme (or spasmoneme) is a contractile structure found in some eukaryotic single-celled organisms, particularly Vorticella . [1] It consists of a series of protein filaments that shorten rapidly upon exposure to calcium. Although the shortening can be up to 100 lengths per second, faster than any muscle, the relaxation time is several seconds (compared to approximately one tenth of a second for muscle). The myonemes of Acantharea also display slow contraction and undulation movements. [2]

Related Research Articles

<span class="mw-page-title-main">Bodybuilding</span> Control and development of musculature

Bodybuilding is the use of progressive resistance exercise to control and develop one's muscles by muscle hypertrophy for aesthetic purposes. It is distinct from similar activities such as powerlifting because it focuses on physical appearance instead of strength. An individual who engages in this activity is referred to as a bodybuilder.

<span class="mw-page-title-main">Human leg</span> Lower extremity or limb of the human body (foot, lower leg, thigh and hip)

The human leg, in the general word sense, is the entire lower limb of the human body, including the foot, thigh or sometimes even the hip or gluteal region. However, the definition in human anatomy refers only to the section of the lower limb extending from the knee to the ankle, also known as the crus or, especially in non-technical use, the shank. Legs are used for standing, and all forms of locomotion including recreational such as dancing, and constitute a significant portion of a person's mass. Female legs generally have greater hip anteversion and tibiofemoral angles, but shorter femur and tibial lengths than those in males.

<span class="mw-page-title-main">Larynx</span> Voice box, an organ in the neck of amphibians, reptiles, and mammals

The larynx, commonly called the voice box, is an organ in the top of the neck involved in breathing, producing sound and protecting the trachea against food aspiration. The opening of larynx into pharynx known as the laryngeal inlet is about 4–5 centimeters in diameter. The larynx houses the vocal cords, and manipulates pitch and volume, which is essential for phonation. It is situated just below where the tract of the pharynx splits into the trachea and the esophagus. The word ʻlarynxʼ comes from the Ancient Greek word lárunx ʻlarynx, gullet, throat.ʼ

<span class="mw-page-title-main">Rib cage</span> Bone structure that protects the vital organs and major blood vessels

The rib cage is an enclosure that comprises the ribs, vertebral column and sternum in the thorax of most vertebrates, protects vital organs such as the heart, lungs and great vessels.

<span class="mw-page-title-main">Scapula</span> Bone that connects the humerus (upper arm bone) with the clavicle (collar bone)

The scapula, also known as the shoulder blade, is the bone that connects the humerus with the clavicle. Like their connected bones, the scapulae are paired, with each scapula on either side of the body being roughly a mirror image of the other. The name derives from the Classical Latin word for trowel or small shovel, which it was thought to resemble.

<span class="mw-page-title-main">Muscle car</span> High-performance car

Muscle car is a description according to Merriam-Webster Dictionary that came to use in 1966 for "a group of American-made two-door sports coupes with powerful engines designed for high-performance driving." The Britannica Dictionary describes these as "an American-made two-door sports car with a powerful engine."

<span class="mw-page-title-main">Lumbricals of the hand</span> Muscles in the central compartment of the hand

The lumbricals are intrinsic muscles of the hand that flex the metacarpophalangeal joints, and extend the interphalangeal joints.

<span class="mw-page-title-main">Adrenergic receptor</span> Class of G protein-coupled receptors

The adrenergic receptors or adrenoceptors are a class of G protein-coupled receptors that are targets of many catecholamines like norepinephrine (noradrenaline) and epinephrine (adrenaline) produced by the body, but also many medications like beta blockers, beta-2 (β2) agonists and alpha-2 (α2) agonists, which are used to treat high blood pressure and asthma, for example.

<span class="mw-page-title-main">Hyoid bone</span> Bone situated in the neck between the chin and the thyroid cartilage

The hyoid bone is a horseshoe-shaped bone situated in the anterior midline of the neck between the chin and the thyroid cartilage. At rest, it lies between the base of the mandible and the third cervical vertebra.

<span class="mw-page-title-main">Mr. Olympia</span> Recurring sporting event

Mr. Olympia is the title awarded to the winner of the professional men's bodybuilding contest at Joe Weider's Olympia Fitness & Performance Weekend—an international bodybuilding competition that is held annually and is sanctioned by the IFBB Professional League. Joe Weider created the contest to enable the Mr. Universe winners to continue competing and to earn money. The first Mr. Olympia was held on September 18, 1965, at the Brooklyn Academy of Music, New York City, with Larry Scott winning his first of two straight titles.

<span class="mw-page-title-main">Subclavian artery</span> Major arteries of the upper thorax, below the clavicle

In human anatomy, the subclavian arteries are paired major arteries of the upper thorax, below the clavicle. They receive blood from the aortic arch. The left subclavian artery supplies blood to the left arm and the right subclavian artery supplies blood to the right arm, with some branches supplying the head and thorax. On the left side of the body, the subclavian comes directly off the aortic arch, while on the right side it arises from the relatively short brachiocephalic artery when it bifurcates into the subclavian and the right common carotid artery.

<span class="mw-page-title-main">Skeletal muscle</span> One of three major skeletal system types that connect to bones

Skeletal muscles are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of muscle tissue, and are often known as muscle fibers. The muscle tissue of a skeletal muscle is striated – having a striped appearance due to the arrangement of the sarcomeres.

<span class="mw-page-title-main">Gluteus maximus</span> Largest and most superficial of the three gluteal muscles

The gluteus maximus is the main extensor muscle of the hip. It is the largest and outermost of the three gluteal muscles and makes up a large part of the shape and appearance of each side of the hips. It is the single largest muscle in the human body. Its thick fleshy mass, in a quadrilateral shape, forms the prominence of the buttocks. The other gluteal muscles are the medius and minimus, and sometimes informally these are collectively referred to as the glutes.

<span class="mw-page-title-main">Human musculoskeletal system</span> Organ system that gives humans the ability to move by using their muscular and skeletal systems

The human musculoskeletal system is an organ system that gives humans the ability to move using their muscular and skeletal systems. The musculoskeletal system provides form, support, stability, and movement to the body.

<span class="mw-page-title-main">Muscles of mastication</span> Muscles in the zygomatic arch that close the jaw

There are four classical muscles of mastication. During mastication, three muscles of mastication are responsible for adduction of the jaw, and one helps to abduct it. All four move the jaw laterally. Other muscles, usually associated with the hyoid, such as the mylohyoid muscle, are responsible for opening the jaw in addition to the lateral pterygoid.

<span class="mw-page-title-main">Quadriceps</span> Group of human leg muscle

The quadriceps femoris muscle is a large muscle group that includes the four prevailing muscles on the front of the thigh. It is the sole extensor muscle of the knee, forming a large fleshy mass which covers the front and sides of the femur. The name derives from Latin four-headed muscle of the femur.

<span class="mw-page-title-main">Scalene muscles</span> Muscles on the sides of the neck

The scalene muscles are a group of three pairs of muscles in the lateral neck, namely the anterior scalene, middle scalene, and posterior scalene. They are innervated by the third to the eight cervical spinal nerves (C3-C8).

<span class="mw-page-title-main">Iliopsoas</span> Joined psoas and the iliacus muscles.

The iliopsoas muscle refers to the joined psoas major and the iliacus muscles. The two muscles are separate in the abdomen, but usually merge in the thigh. They are usually given the common name iliopsoas. The iliopsoas muscle joins to the femur at the lesser trochanter. It acts as the strongest flexor of the hip.

<span class="mw-page-title-main">Abdomen</span> Part of the body between the chest and pelvis

The abdomen is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the torso. The area occupied by the abdomen is called the abdominal cavity. In arthropods it is the posterior tagma of the body; it follows the thorax or cephalothorax.

<span class="mw-page-title-main">Pharyngeal arch</span> Embryonic precursor structures in vertebrates

The pharyngeal arches, also known as visceral arches, are structures seen in the embryonic development of vertebrates that are recognisable precursors for many structures. In fish, the arches are known as the branchial arches, or gill arches.

References

  1. Alexander, R.M.N. (1979). The Invertebrates . Cambridge University Press. p.  68. ISBN   9780521293617 . Retrieved 2015-02-26.
  2. Febvre, Jean (1981). "The Myomene of the Acantharia (Protozoa): a new model of cellular motility". BioSystems. 14 (3–4): 327–336. doi:10.1016/0303-2647(81)90039-3. PMID   7199949.