Types of muscles

The Muscle fibers consist of a single muscle cell. They help to control the physical forces within the body. When grouped together, they can facilitate organized movement of your limbs and tissues. There are several types of muscle fiber, each with different characteristics. Keep reading to learn more about these different types, what they do, and more. Each one of your skeletal muscles is made up of Each muscle fiber contains smaller units made up of repeating thick and thin filaments. This causes the muscle tissue to be striated, or have a striped appearance. Skeletal muscle fibers are classified into two types: type 1 and type 2. Type 2 is further broken down into subtypes. • Type 1. These fibers utilize oxygen to generate energy for movement. Type 1 fibers have a higher density of energy-generating organelles called mitochondria. This makes them dark. • Type 2A. Like type 1 fibers, type 2A fibers can also use oxygen to generate energy for movement. However, they contain less mitochondria, making them light. • Type 2B. Type 2B fibers don’t use oxygen to generate energy. Instead, they store energy that can be used for short bursts of movement. They contain even less mitochondria than type 2A fibers and appear white. Smooth muscle Unlike skeletal muscles, smooth muscles aren’t striated. Their more uniform appearance gives them their name. Smooth muscle fibers have an oblong shape, much like a football. They’re also Cardiac muscle Similar to skeletal muscles, cardiac muscl...

Overview A muscle strain is an injury to a muscle or a tendon — the fibrous tissue that connects muscles to bones. Minor injuries may only overstretch a muscle or tendon, while more severe injuries may involve partial or complete tears in these tissues. Sometimes called pulled muscles, strains commonly occur in the lower back and in the muscles at the back of the thigh (hamstrings). The difference between a strain and a sprain is that a strain involves an injury to a muscle or to the band of tissue that attaches a muscle to a bone, while a sprain injures the bands of tissue that connect two bones together. Initial treatment includes rest, ice, compression and elevation. Mild strains can be successfully treated at home. Severe strains sometimes require surgical repair. Symptoms Signs and symptoms will vary, depending on the severity of the injury, and may include: • Pain or tenderness • Redness or bruising • Limited motion • Muscle spasms • Swelling • Muscle weakness When to see the doctor Mild strains can be treated at home. See a doctor if your symptoms worsen despite treatment — especially if your pain becomes intolerable, or you experience numbness or tingling. Causes Acute strains can be caused by one event, such as using poor body mechanics to lift something heavy. Chronic muscle strains can result from repetitive injuries when you stress a muscle by doing the same motion over and over. Risk factors Participating in contact sports — such as soccer, football, hockey, b...

Muscle types There are three types of muscle in the body: • smooth muscle – found in the internal organs and blood vessels - this is involuntary • cardiac muscle – found only in the heart - this is involuntary • skeletal muscle – attached to the skeleton - this is voluntary Involuntary muscles are not under our conscious control which means we can't make them contract when we think about it. Voluntary muscles are under our conscious control so we can move these muscles when we want to. Muscle fibre types There are two different types of skeletal muscles: • slow twitch, also known as type I - oxidative • fast twitch, also known as type II - glycolytic Each type of muscle fibre has different characteristics which are shown in the table: Type I Type II Speed of contraction Slow Fast Force produced Low Medium/high Resistance to fatigue High Medium/low Colour Red White Energy system Aerobic Anaerobic Endurance cyclists need a high percentage of type I fibres so that their muscles can work for the duration of a race without getting tired. These muscles are red in colour because of the amount of capillaries that transport the oxygenated blood to the working muscles. Sprinters need a high percentage of type II fibres which allow their muscles to contract very quickly. Fast muscle contractions give runners power and enable them to maintain a high speed over a short distance. However, this type of muscle tires very quickly, meaning sprinters are not able to run at this speed for ver...

\( \newcommand\) • • • • • • • • • Muscle contractions are defined by changes in the length of the muscle during contraction. Key Points • Isotonic contractions generate force by changing the length of the muscle and can be concentric contractions or eccentric contractions. • A concentric contraction causes muscles to shorten, thereby generating force. • Eccentric contractions cause muscles to elongate in response to a greater opposing force. • Isometric contractions generate force without changing the length of the muscle. Key Terms • Isometric: A muscular contraction in which the length of the muscle does not change. • isotonic: A muscular contraction in which the length of the muscle changes. • eccentric: An isotonic contraction where the muscle lengthens. • concentric: An isotonic contraction where the muscle shortens. A muscle fiber generates tension through actin and myosin cross-bridge cycling. While under tension, the muscle may lengthen, shorten, or remain the same. Although the term contraction implies shortening, when referring to the muscular system, it means the generation of tension within a muscle fiber. Several types of muscle contractions occur and are defined by the changes in the length of the muscle during contraction. Concentric Contractions A concentric contraction is a type of muscle contraction in which the muscles shorten while generating force, overcoming resistance. For example, when lifting a heavy weight, a concentric contraction of the biceps ...

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Facts You Should Know: The Human Body Quiz Rotation is one of the most-important actions of the cervical (neck) Side bending also is an important action of the cervical spine. The sternocleidomastoid muscles are involved in cervical side bending. The posterior scalene muscles, located on the lower sides of the neck, ipsilaterally bend the neck to the side and elevate the second rib. The splenius capitis and splenius cervicis also assist in neck side bending. The Get a Britannica Premium subscription and gain access to exclusive content. Neck flexion refers to the motion used to touch the chin to the chest. It is accomplished primarily by the sternocleidomastoid muscles, with assistance from the longus colli and the longus capitis, which are found in the front of the neck. Neck The back Multiple muscles in the back function specifically in movements of the back. The erector spinae muscles, for example, extend the back (bend it backward) and side bend the back. The semispinalis dorsi and semispinalis capitis muscles also extend the back. The small muscles of the vertebrae (the multifidi and rotators) help rotate, extend, and side bend the back. The quadratus lumborum muscle in the lower back side bends the lumbar spine and aids in the inspiration of air through its stabilizing affects at its insertion at the 12th

Muscle atrophy is the wasting or thinning of muscle mass. It can be caused by disuse of your muscles or neurogenic conditions. Symptoms include a decrease in muscle mass, one limb being smaller than the other, and numbness, weakness and tingling in your limbs. Disuse atrophy can be reversed with exercise and a healthy diet. Symptoms and Causes What are the symptoms of muscle atrophy? The symptoms of muscle atrophy differ depending on the cause of your condition. The most obvious sign of muscle atrophy is reduced muscle mass. Other signs of muscle atrophy may include: • One arm or one leg is smaller than the other. • Weakness in one arm and or one leg. • • Trouble walking or • • Facial weakness. • Gradual What does muscle atrophy feel like? If you have muscle atrophy in your limbs, you may feel tingling, numbness or weakness in your arms and legs. If you have atrophied muscles in your face or throat, your What causes muscle atrophy? The cause of muscle atrophy depends on the type you have. Disuse (physiologic) atrophy is caused by not using your muscles enough. If you stop using your muscles, your body won’t waste the energy it needs to take care of them. Instead, your body will start to break your muscles down, which causes them to decrease in size and strength. Disuse atrophy may affect you if you: • Lead a • Are malnourished. • Don’t get enough • • Are on best rest. • Have a genetic disorder such as • Can’t move your limbs due to a • Have age-related atrophy (sarcopenia)...