Where do skeletal muscles come from?
The skeletal muscles of the torso and limbs arise from the mesoderm of the somites, while those of the head arise from the mesoderm of the somitomeres which contribute to the branchial (pharyngeal) arches. They form by the fusion and elongation of numerous precursor cells called myoblasts. Some stem cell precursors of myoblasts remain in an adult animal; they are located between the sarcolemma and basement membrane of mature muscle cells, and are called satellite cells. Since each myoblast contributes its nucleus to the muscle cell, skeletal muscle fibers are all multinucleated, the longest having 200 or more nuclei.
How do muscle cells form?
Muscle cells form by the fusion and elongation of numerous precursor cells called myoblasts. Some stem cell precursors of myoblasts remain in an adult animal, located between the sarcolemma and basement membrane of mature muscle cells, and these are called satellite cells in this setting. Since each myoblast contributes its nucleus to the muscle cell thus formed, skeletal muscle fibers are all multinucleated, the longest having 200 or more nuclei. The skeletal muscles of the torso and limbs arise from the mesoderm of the somites, while those of the head arise from the mesoderm of the somitomeres, which contribute to the branchial (pharyngeal) arches.
How does postural control work?
Postural strategies coordinate sensory input from the visual, vestibular and somatosensory systems with motor activity. Therefore, postural control is dependent on the ability of the individual to interpret this sensory information and execute an appropriate motor response. An accurate motor response requires strength, flexibility and coordination, all of which (among other things) are influenced by muscle tone, joint range of motion and biomechanical relationships. Postural strategies can be divided into those that are engaged to maintain quiet balance, such as standing and sitting, and those engaged during active movement. Both require synchronized activity of muscle groups in response to sensory input and, to varying degrees, both are dependent on feedback and anticipatory control. Ghez (1991) uses the tasks of reaching for a cup and catching a ball to compare these two control mechanisms. In reaching for a cup, feedback control would compare visual and somatosensory information concerning the position of your arm in space with the location of the cup. Any necessary adjustments will be made on the basis of this information. Processing and responding to sensory information in a feedback loop is relatively slow; it takes almost as much time to process the information as to execute the movement. Feedback mechanisms are used to maintain or modulate slow movements or sequential acts. Actions requiring very rapid responses rely on feedforward control. Information is processed to anticipate the needed response. An example of feedforward control can be illustrated by reviewing the act of catching a ball. Visual information is used to assess the anticipated trajectory of the ball, its placement and the time until it reaches you. These visual cues will also be used to ready the musculoskeletal system by assuming an appropriate posture for impact ( Ghez 1991 ). When a new task is being learned, feedback control will dominate the process. Once learned, feedforward control is involved with the initiation of the task, while feedback control is used to fine-tune the end movements ( Ghez & Krakauer 2000 ).
What is the sarcoplasmic reticulum?
Within each fiber is a longitudinal network of tubules called the sarcoplasmic reticulum (SR), analogous to the endoplasmic reticulum of other cells ( Figure 21-2 ). Release of Ca 2+ from the SR is a the key step in coupling the sarcolemma action potential to activation of contraction. SR membranes bear large numbers of Ca 2+ pump proteins whose role is to pump Ca 2+ into the lumen of the SR where it is sequestered until the fiber is stimulated. Crossing the SR perpendicular to the cell axis are transverse tubules (T-tubules), which are invaginations of the sarcolemma. They conduct the action potential into the interior of the cell which triggers the release of Ca 2+ from SR.
How many nm are in muscle fibers?
Muscle fibers contain long cylindrical myofibrils (typically 1–2 μm in diameter) aligned longitudinally and consisting of interpenetrating arrays of thin myofilaments (6–7 nm in diameter) and thick filaments (15–16 nm in diameter). These structures are the contractile apparatus of the fiber ( Figure 21-3 ).
What is the size of skeletal muscle cells?
Individual muscle cells, or fibers, are elongated, roughly cylindrical, and usually unbranched, with a mean diameter of 10–100 μm. The plasma membrane of muscle fibers is called the sarcolemma, and fibers are surrounded by structural filaments of the extracellular matrix which are often described as forming a basement membrane.
Where are mitochondria located in muscle cells?
Muscle cells contain many mitochondria which are often present as reticulum-like structures extending longitudinally in the fiber near the sarcolemma, rather than as discrete ellipsoidal organelles found in many other cells. These provide much of the high-energy phosphate needed to power contraction and to operate the Ca 2+ pumps that control the cytosolic calcium concentration. Different types of skeletal muscle fibers differ considerably in the extent and organization of both their SR and mitochondria.
What are the functions of the trunk muscles?
Trunk muscles have a few very important functions; they contribute to the protection of the thoracic and abdominopelvic viscera and they assist essential body activities such as breathing, movement, defecation and micturition. Key facts about muscles of the trunk. Anterior thoracic muscles.
Which muscles are deep?
Deep: Transversospinal muscles (semispinalis, multifidus, rotatores longus and brevis) Deepest: Interspinales, intertransversarii and levatores costarum. This article will give you an overview of the torso musculature and serve you as a hub from which you can hop into more detailed topics related to trunk anatomy.
What are the muscles of the thoracic cage?
The muscles of the thoracic cage are the pectoralis major, pectoralis minor, serratus anterior, subclavius, intercostal (external, internal and innermost ), subcostal and transversus thoracis muscles, including the diaphragm.
What muscles cover the anterolateral part of the trunk?
Anterior trunk muscles. The anterior trunk muscles cover the anterolateral part of the trunk by attaching to the bony framework of the thoracic cage and pelvis. These muscles are grouped into the muscles of the thoracic cage and the muscles of the abdominal wall .
What is the central part of the body to which the head and limbs are attached?
Ventral trunk muscles (overview) The trunk (torso) is the central part of the body to which the head and the limbs are attached. Except for the brain, the trunk houses all the vital organs of the human body.
Which layer of the vertebrae contains the massive erector spinae?
The intermediate layer contains the massive erector spinae muscles. They lie in a groove on either side of the vertebral column in the space between the spinous processes of the vertebrae and the angles of the ribs. The erector spinae group contains three muscles, located from lateral to medial, as follows: iliocostalis, longissimus and spinalis.
Which muscle is located in the intermediate layer of the vertebral column?
The intermediate layer contains the massive erector spinae muscles. They lie in a groove on either side of the vertebral column in the space between the spinous processes of the vertebrae and the angles of the ribs. The erector spinae group contains three muscles, located from lateral to medial, as follows: iliocostalis, longissimus and spinalis.
What is the torso?
The torso is the middle section of the human body. The torso includes the majority of the upper body with the exception of the head, neck, and arms. This important part of the body contains key organs and muscles. Let's take a closer look.
What are the organs of the torso?
For example, the digestive system consists of the gallbladder, stomach, jejunum, ileum, duodenum, colon, and liver. The spleen is part of the lymphatic system, and the pancreas belongs to both the endocrine and digestive systems.
What are the four muscles that control the pace, depth, and intensity of breathing?
The muscle group commonly called abdominals, or abs, is made up of four sets of muscles, including rectus abdominis, transverse abdominis, and the internal and external obliques.
What muscles control the ribcage?
Two sets of intercostal muscles, internal and external, lie between the ribs that make up the ribcage. Along with the diaphragm, these muscles control breathing. The external intercostals contract the ribcage and the internal intercostals release it. These movements allow humans to breathe in and out. By contracting or releasing more, these muscles control the pace, depth, and intensity of breathing.
Which muscles control movement of the arm?
The latissimus dorsi muscle control movement at the junction of the shoulder and the arm. These muscles allow people to move their arms to and from the body. The teres major and minor alongside the latissimus dorsi allow the arms to rotate.
Which muscle group allows you to move your arms up and down?
This large muscle group allows people to move their arms up and down and rotate their arms. When humans breathe in deep, the pectoralis muscles help to raise up the ribs allowing even more air into the lungs. This is the muscle group that fitness enthusiasts target when they want to build a more muscular chest.
Which muscles support the shoulder?
Many muscles of the torso support shoulder motion. The trapezius is a large set of muscles that sits on both sides of the back. This muscle gives added support to the scapula, more commonly known as the shoulder bone. A strong trapezius leads to better posture, and this muscle group helps the neck bear the weight of the skull. The rhomboid muscles, in the back, support shoulder rotation and allow people to squeeze their shoulders together. The rotator cuff muscles lie in the inner workings of the scapular, stabilizing the shoulder joint and supporting a healthy range of motion for the shoulders.
Pulled Muscle in the Chest
A pulled muscle in the chest can result in muscle spasms. Anyone can have a pulled muscle in their chest.
Injury to the Chest Wall
Injuries to the chest wall/muscle can actually be fairly common among athletes. There are twelve pairs of ribs in the chest and each one of them is separated by a bundle of veins, an artery, and an intercostal nerve.
Stress Fractures in the Chest
Typically, stress fractures are seen in athletes, due to the excess strain of their training or playing sports can cause stress on the ribs.
Spasm of the Coronary Artery
The human heart is comprised of muscles that help the heart to pump in the oxygen that the body requires to properly function.
Esophageal Spasm
Another cause of spasms in the chest area that does not have a cardiac cause is esophageal spasms. In this type of spasm, the muscles in the esophagus have some abnormal contractions that result in significant chest pain.
Fibromyalgia & Spasms in the Chest
Fibromyalgia is a condition that is characterized by chronic fatigue. This causes some severe muscle pain, and does, in fact, affect the muscles in the shoulders, chest, and neck- as well as others.
Imbalance of Electrolytes and Dehydration
Believe it or not, electrolytes such as chloride, magnesium, potassium, and sodium actually play a vital role in the contraction and relaxation of your muscles.
What is the torso of a vertebrate?
Klaus Vedfelt/Digital Vision/Getty Images. The torso is the main part of the body to which the neck and limbs attach, and it is a common feature of all vertebrates. The torso holds the body’s major internal organs except for the brain. Often, scientists refer to either the lower torso or the upper torso for better clarity.
What organs are in the upper torso?
In most vertebrates, the upper torso holds the lungs, heart, windpipe and esophagus. These organs reside in and are protected by the rib cage. The lower torso holds the large intestine, small intestine, stomach, liver, kidneys, pancreas, gall bladder, spleen and appendix.
What bones are in the lower torso?
Additionally, male vertebrates hold their testis inside the lower torso, while female vertebrates carry their ovaries and uterus inside the lower torso. Sometimes, the lower torso is called the abdomen. The primary bones of the torso include the rib cage, spinal column, clavicle and shoulder bones. Many different muscles cover ...
Do snakes have flexible torsos?
The torso often moves in and out with breathing movements or, for some vertebrates, their heartbeat. The torso of most animals is not very flexible, as seen in humans, dogs and whales. By contrast, a few animals, such as snakes, have remarkably flexible torsos. ADVERTISEMENT.
What Constitutes the Torso?
The torso is the centre chamber of the human body and is crucial for the majority of key activities. The torso contains the heart and lungs, two vital organs that humans cannot survive without.
Torso Muscle Embryology
Numerous important muscle groups are present in the torso. The sternocleidomastoid muscle is located at the edge of the torso and connects the clavicle to the temporal bone in the back of the skull. This crucial muscle allows humans to tilt their necks and shift their heads side to side.
Torso Bone Anatomy
Along the midline of the torso, the spine houses the delicate nerves of the central nervous system. At the rear of this anatomical region is the scapula. The scapula collaborates with strong back and chest muscles to support the full range of motion of the arms and shoulders.
Organs within the Core
The thoracic organs are essential components of major organ systems. The digestive system, for instance, includes the gallbladder, stomach, jejunum, ileum, duodenum, colon, and liver. The spleen is a component of the lymphatic system, while the pancreas is a component of both the endocrine and digestive systems.
Equivalents of Torso
There are numerous scientific and common synonyms for torso. The torso is often referred to as the trunk. Due to the hosting of numerous key muscles, some refer to the torso as the figure, physique, or build of an individual. In common parlance, the torso is typically referred to as the chest, abdomen, or stomach.
Additional Anatomical Regions of the Human Body
The anatomical regions are the neck, torso, abdomen, upper and lower extremities. The head and neck comprise the cervical region, often known as the cephalic region. The thorax is the upper portion of the chest, whereas the abdominal region contains the stomach. The arms and legs are the upper and lower extremities, respectively.
What is the torso?
English Language Learners Definition of torso. : the main part of the human body not including the head, arms, and legs. See the full definition for torso in the English Language Learners Dictionary.
What is the meaning of torso?
Definition of torso. 1 : the human body apart from the head, neck, arms, and legs : the human trunk. 2 : a sculptured representation of the trunk of a human body. 3 : something (such as a piece of writing) that is mutilated or left unfinished.
Where are the torso muscles located?from kenhub.com
The next set of torso muscles are found in the intercostal spaces between the ribs. The intercostal muscles consist of a group of three layered muscles, from superficial to deep: external, internal and innermost intercostals. The fibres of the external intercostal muscles originate from the inferior border of the ribs.
What are the main muscles in the torso?from graphdiagram.com
The torso also harbours many of the main groups of muscles in the body, including the: 1 pectoral muscles 2 abdominal muscles 3 lateral muscle 4 epaxial muscles
What are the muscles of the thoracic cage?from kenhub.com
The muscles of the thoracic cage are the pectoralis major, pectoralis minor, serratus anterior, subclavius, intercostal (external, internal and innermost ), subcostal and transversus thoracis muscles, including the diaphragm.
What is the deep layer of the spine?from kenhub.com
Deep layer. The deep layer of back muscles are a group called the transversospinalis muscles. From superficial to deep, these include semispinalis, multifidus and rotatores. These muscles are located underneath the erector spinae, occupying the space between the spinous and transverse processes of the spine.
How many skeletal muscles are there in the human body?from graphdiagram.com
This is a table of skeletal muscles of the human anatomy. There are around 640 skeletal muscles within the typical human body.
What is the superficial layer of the back?from kenhub.com
Superficial layer. The superficial layer of intrinsic back muscles is made up of the spinotransversales muscles, which are splenius capitis and splenius cervicis. They are located on the anterolateral aspects of the neck. Splenius capitis is a deep, broad muscle found in the floor of the posterior triangle of the neck.
Where does the posterior superior serratus originate?from kenhub.com
Serratus posterior superior - originates from the nuchal ligament and spinous processes of vertebrae C7-T3. It inserts on the superior borders of ribs 2-5, elevating them. It is innervated by the 2nd to 5th intercostal nerves.
