Logan Steele
Muscle & Fitness is an American fitness and bodybuilding magazine founded in 1935 by Canadian entrepreneur Joe Weider. It was originally published under the title Your Physique and has since been renamed several times before acquiring its current name in 1980. The magazine offers exercise and nutrition tips, and features professional bodybuilders and entertainers such as Dwayne Johnson, who was named the Man of the Century in 2015. Similar magazines include Muscle and Health, Iron Man Magazine, and MuscleMag.
| Characteristics | Values |
|---|---|
| Number of muscles in the human body | More than 600 |
| Types of muscles | Skeletal, smooth, and cardiac |
| Skeletal muscle composition | 30-40% of total body mass |
| Skeletal muscle control | Voluntary |
| Smooth muscle control | Involuntary |
| Cardiac muscle cells | Rely on blood and electrical supply to deliver oxygen and nutrients |
| Muscle composition | Small fibers woven together |
| Muscle functions | Moving, sitting still, standing up straight, pumping blood, giving birth, digesting food, etc. |
| Muscle fatigue | Loss of oxygen, glucose, or ATP, and build-up of waste products like lactic acid and ADP |
| Muscle recovery | Requires extra oxygen intake to restore muscle cells to their resting state |
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What You'll Learn
- Skeletal muscle is the most common type of muscle in the body
- Cardiac muscle is responsible for the rhythmic contractions of the heart
- Smooth muscle is an involuntary muscle that lines the inside of some organs
- Muscles are made of thousands of small fibres woven together
- There are more than 600 muscles in the human body
Skeletal muscle is the most common type of muscle in the body
The human body has over 600 muscles, which can be grouped by their location or the type of movement they enable. These muscles support almost every part of the body, and they make up about half of a person's body weight. Skeletal muscle is the most common type of muscle in the body. It is also known as striated muscle due to its striped appearance. This striated appearance is caused by the arrangement of the sarcomeres.
Skeletal muscle is part of the voluntary muscular system, which means that it moves when you want it to. It is controlled by the somatic nervous system. Skeletal muscles are attached to bones by tendons, which are tough connective tissues. These muscles support the body's weight and enable movement. They also play a role in maintaining posture and joint position. Skeletal muscle tissue is made up of elongated multinucleate muscle cells called muscle fibres. Each muscle contains thousands of fibres, and these fibres can be red or white.
Skeletal muscle has a wide range of functions. Its primary function is contraction, but it also functions as an endocrine organ by secreting myokines, which are believed to mediate the health benefits of exercise. Skeletal muscle also produces body heat. Contraction of these muscles is responsible for 85% of the body's heat. Additionally, skeletal muscle can store and release energy for metabolism.
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Cardiac muscle is responsible for the rhythmic contractions of the heart
The human body is composed of hundreds of muscles, which are soft tissues that enable movement. There are three types of muscle tissue in vertebrates: skeletal muscle, cardiac muscle, and smooth muscle.
Cardiac muscle, also called the myocardium, is one of the three major categories of muscles found within the human body. It is made up of sarcomeres that allow for contractility. The heart is made up of three layers: the pericardium, myocardium, and endocardium. The endocardium is not cardiac muscle and forms the inner lining of the heart chambers and valves. The pericardium, on the other hand, is a fibrous sac surrounding the heart. The cardiac muscle is responsible for the contractility of the heart, which results in its pumping action. This muscle must contract with enough force to supply the metabolic demands of the entire body.
Cardiac muscle cells, or cardiomyocytes, are considerably shorter and smaller in diameter compared to skeletal muscle cells. They are striated, branched, and contain many mitochondria, which provide energy for the contractions of the heart. Each cardiomyocyte contains a single, centrally located nucleus surrounded by a cell membrane known as the sarcolemma. The sarcolemma contains voltage-gated calcium channels, which are specialized ion channels not found in skeletal muscle. Cardiac muscle cells also contain branched fibres connected via intercalated discs, which help support the synchronized contraction of the muscle.
The contractions of the heart (heartbeats) are controlled by specialized cardiac muscle cells called pacemaker cells, which directly control heart rate. This property is known as autorhythmicity and is unique to cardiac muscle. The pacemaker cells respond to signals from the autonomic nervous system (ANS) to speed up or slow down the heart rate. Myocardial conduction cells initiate and propagate the action potential (the electrical impulse) that travels throughout the heart and triggers the contractions that propel blood.
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Smooth muscle is an involuntary muscle that lines the inside of some organs
The human body is composed of various muscles that work together to help us move, breathe, and stay alive. There are over 600 muscles in the human body, and they can be grouped by their location, such as chest, leg, or back muscles, or by the type of movement they enable. Muscles are tissues, and there are three types of muscle tissue: skeletal muscle, cardiac muscle, and smooth muscle.
Smooth muscle has a unique structure, consisting of thick and thin filaments that give it a non-striated appearance. It contains high amounts of actin and myosin, which are proteins that enable muscle contraction. Smooth muscle can be divided into two types: single-unit and multi-unit. Single-unit smooth muscle, also known as visceral smooth muscle, is found in the walls of internal organs and lines blood vessels. It can contract and relax without input from a motor neuron, allowing for coordinated contractions and relaxations.
Smooth muscle plays a crucial role in maintaining blood pressure and flow, regulating airways in the lungs, and facilitating motility and nutrition collection in the gastrointestinal system. Its ability to be contracted and controlled involuntarily is essential for the nervous system to regulate many of the body's subsystems. For example, during exercise, the nervous system adjusts blood pressure without conscious thought. Smooth muscle is also important in the disease process, such as in the treatment of asthma and gastric emptying.
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Muscles are made of thousands of small fibres woven together
The human body has more than 600 muscles, which help us do everything from breathing to running marathons. These muscles are made of thousands of small fibres woven together, stretching and pressing together to move our organs and body.
Muscles are pieces of soft tissue throughout our bodies. They are constructed of skeletal muscle tissue, blood vessels, tendons, and nerves. Skeletal muscles are part of the musculoskeletal system and work with our bones, tendons, and ligaments to support our weight and move us. Tendons attach skeletal muscles to bones all over the body.
Skeletal muscles are voluntary, meaning they move when you think about moving that part of the body. They are striated, consisting of elongated, multinucleate muscle cells called muscle fibres. Each skeletal muscle fibre is a single cylindrical muscle cell, and an individual skeletal muscle may be made up of hundreds or thousands of muscle fibres bundled together and wrapped in a connective tissue covering. Each muscle fibre can contain from hundreds to thousands of nuclei.
Other types of muscles include smooth muscles and cardiac muscles. Smooth muscles are involuntary muscles that line the inside of some organs, such as the female and male reproductive systems, the urinary system, the respiratory system, and the digestive system. Cardiac muscles, on the other hand, make up the middle layers of the heart.
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There are more than 600 muscles in the human body
The human body has more than 600 muscles, accounting for roughly half of a person's body weight. These muscles are made of thousands of small fibres woven together, allowing them to stretch and press together to move your organs and body. They run in all directions and work together to move you.
There are three types of muscle tissue in vertebrates: skeletal, smooth, and cardiac. Skeletal muscles are the most common type of muscle in the body. They are voluntary muscles, meaning you control how and when they work. Skeletal muscles work with your bones, tendons, and ligaments to support your weight and move you. Tendons attach skeletal muscles to bones all over the body.
Smooth muscles, on the other hand, are involuntary muscles that line the inside of some organs. They perform essential functions like moving waste through your intestines and helping your lungs expand when you breathe. Smooth muscles play a role in various body systems, including the reproductive, urinary, respiratory, and digestive systems.
Cardiac muscle, also known as myocardium, makes up the mass of the heart and is responsible for its rhythmic contractions. Like smooth muscle, cardiac muscle is involuntary and works without conscious intervention.
Muscles are vital for various functions, from pumping blood throughout the body to helping lift heavy objects. They also play a role in generating body heat through muscle contractions, contributing to our natural body temperature.
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Frequently asked questions
Muscles are pieces of soft tissue throughout your body that help you do everything from holding your body still to running a marathon. There are more than 600 muscles in the human body.
There are three types of muscle tissue in vertebrates: skeletal muscle, cardiac muscle, and smooth muscle. Skeletal muscles are the most common type of muscle in the body and are voluntary muscles, meaning you control how and when they work. Cardiac and smooth muscles are involuntary muscles that your autonomic nervous system controls.
Muscles provide the tug on the bones needed to bend, straighten, and support joints. They also help with digesting food and getting rid of waste. They move and support your organs. They also store and release energy that your body uses as part of your metabolism. The final function of muscle tissue is the generation of body heat.
Muscles get their signals to contract and relax from the brain. Muscle tissue contains special contractile proteins called actin and myosin which interact to cause movement. Skeletal muscles work together with bones and joints to form lever systems.
