Logan Steele
The human body has more than 600 muscles, each serving a unique function. One such muscle is the cardiac muscle, which is also called the myocardium. It is one of the three types of vertebrate muscle tissues, the other two being skeletal muscle and smooth muscle. The cardiac muscle is found in the walls of the heart and is responsible for pumping blood through the body. It is made up of specialized cells called cardiomyocytes that can contract and relax in an alternating cycle.
| Characteristics | Values |
|---|---|
| Common name | Cardiac muscle |
| Other names | Heart muscle, myocardium |
| Type | One of three types of vertebrate muscle tissues, the others being skeletal muscle and smooth muscle |
| Location | Forms the thick middle layer of the heart, between the outer layer of the heart wall (the pericardium/epicardium) and the inner layer (the endocardium) |
| Function | Pumps blood through the body |
| Composition | Individual cardiac muscle cells (cardiomyocytes/myocytes) joined by intercalated discs, encased by collagen fibers and other substances that form the extracellular matrix |
| Contraction | Alternating cycle of contraction and relaxation; regulated by calcium ions and electrical impulses |
| Diseases | Cardiomyopathies, ischemic conditions (e.g., angina, myocardial infarction), myocarditis, coronary artery disease (CAD), congestive heart failure, hypertension, atrial septal defect (ASD), patent ductus arteriosus (PDA) |
| Exercise recommendation | WHO recommends at least 150 minutes of moderate exercise per week |
Explore related products
What You'll Learn
- Cardiac muscle is one of three types of vertebrate muscle tissues
- Cardiomyocytes are the individual cells that make up the cardiac muscle
- Coronary arteries supply blood to the cardiac muscle
- Cardiac muscle cells are striated, branched and contain many mitochondria
- Cardiovascular disease is the chronic disease of the heart or blood vessels
Cardiac muscle is one of three types of vertebrate muscle tissues
The human body has three types of muscle tissues: skeletal, smooth, and cardiac muscle. Also known as myocardium or heart muscle, cardiac muscle is an involuntary, striated muscle that forms the main tissue of the heart wall. It is the only organ in the body that is also a muscle.
Cardiac muscle forms the bulk of the heart, constituting the thick middle layer of the heart wall, between the outer layer (the pericardium) and the inner layer (the endocardium). The endocardium is not cardiac muscle, but rather simple squamous epithelial cells that form the inner lining of the heart chambers and valves. The pericardium, on the other hand, is a fibrous sac surrounding the heart, consisting of the epicardium, pericardial space, parietal pericardium, and fibrous pericardium.
The cardiac muscle is composed of individual cardiac muscle cells, known as cardiomyocytes, which are joined by intercalated discs and encased by collagen fibres and other substances that form the extracellular matrix. Cardiomyocytes are rectangular, branching cells that typically contain a single, centrally located nucleus. This nucleus is the "control centre" of the cell, containing all of its genetic material. Each myocyte contains a single nucleus surrounded by a cell membrane called the sarcolemma. The sarcolemma of cardiac muscle cells contains voltage-gated calcium channels, which skeletal muscles do not possess.
Cardiac muscle cells are highly branched and contain many mitochondria, allowing them to produce large amounts of adenosine triphosphate (ATP) and myoglobin to store oxygen to meet the metabolic demands of the body. The cardiac muscle must contract with enough force and blood to supply these demands. This is termed cardiac output and is defined as heart rate multiplied by stroke volume, which is determined by the contractile forces of the cardiac muscle and the frequency of their activation.
Testing Muscle Stim: A Beginner's Guide to Electrostimulation
You may want to see also
Explore related products
Cardiomyocytes are the individual cells that make up the cardiac muscle
Cardiomyocytes, also known as cardiac muscle cells, are the individual cells that make up the cardiac muscle. They are rectangular, tubular structures composed of chains of myofibrils, which are rod-like units within the cell. Each myofibril consists of repeating sections of sarcomeres, which are the fundamental contractile units of the muscle cells. Sarcomeres are composed of long proteins that organize into thick and thin filaments, called myofilaments. The thick myofilaments contain the protein myosin, while the thin myofilaments contain the protein actin.
The cardiac muscle, also called the myocardium, is one of three major categories of muscles found within the human body, the others being smooth muscle and skeletal muscle. It forms the thick middle layer of the heart, sandwiched between the inner endocardium and the outer epicardium (also known as the visceral pericardium). The cardiac muscle is responsible for the contractile function of the heart, enabling the pumping of blood around the body. This rapid, involuntary contraction and relaxation of the cardiac muscle are vital for pumping blood throughout the cardiovascular system.
Cardiomyocytes contain many mitochondria to produce large amounts of adenosine triphosphate (ATP) and myoglobin to store oxygen to meet the demands of muscle contraction. They also have an extensive cardiac capillary network. Each cardiomyocyte contains a single, centrally located nucleus surrounded by a cell membrane known as the sarcolemma. The sarcolemma is a specialized cell membrane found in cardiomyocytes and skeletal muscle cells. It consists of a lipid bilayer and a thin outer coat of polysaccharide material (glycocalyx) that contacts the basement membrane. The sarcolemma of cardiac muscle cells contains voltage-gated calcium channels, specialized ion channels that skeletal muscle does not possess.
Cardiac muscle cells are connected through intercalated discs, which are complex adhering structures that join the single cardiomyocytes to an electrochemical syncytium. Intercalated discs consist of three different types of cell-cell junctions: the actin filament anchoring fascia adherens junctions, the intermediate filament anchoring desmosomes, and gap junctions. Gap junctions between adjacent cardiomyocytes allow for the propagation of coordinated action potentials from one cell to the next in a phenomenon known as electrical coupling. This allows the cardiomyocytes to contract together in a synchronized fashion, enabling the heart to work as a pump.
Elongating Neck Muscles: Simple Techniques for a Supple, Strong Neck
You may want to see also
Explore related products
Coronary arteries supply blood to the cardiac muscle
The heart is made up of three layers: the pericardium, myocardium, and endocardium. The myocardium, or cardiac muscle, forms a thick middle layer between the outer layer of the heart wall (the pericardium) and the inner layer (the endocardium).
The cardiac muscle requires a constant flow of blood to provide oxygen and nutrients. Coronary arteries supply oxygen-rich blood to the cardiac muscle, and cardiac veins drain deoxygenated blood away. The coronary arteries originate from the aortic root and lie on the outer or epicardial surface of the heart. They wrap around the outside of the heart and branch off into smaller arteries, supplying blood to the entire heart muscle.
The right coronary artery supplies blood mainly to the right side of the heart, which is smaller and pumps blood only to the lungs. The left coronary artery supplies blood to the left side of the heart, which is larger and more muscular because it pumps blood to the rest of the body. The left coronary artery branches into the left anterior descending artery and the circumflex artery. The left anterior descending artery supplies blood to the front of the left side of the heart and helps send blood to the middle (septum) of the heart. The circumflex artery supplies blood to the outer side and back of the left ventricle, as well as the left atrium.
The cardiac muscle cells (cardiomyocytes) are the contractile cells of the cardiac muscle. They are rectangular, branching cells that typically contain only one centrally-located nucleus. The cardiac muscle cells are interconnected through intercalated discs, which allow for the synchronized contraction of the heart muscle.
How Muscle Shockers Aid Recovery
You may want to see also
Explore related products
Cardiac muscle cells are striated, branched and contain many mitochondria
Cardiac muscle, also known as myocardium or heart muscle, is one of the three types of vertebrate muscle tissues, the other two being skeletal muscle and smooth muscle. The myocardium forms a thick middle layer of the heart, sandwiched between the outer layer of the heart wall (the pericardium) and the inner layer (the endocardium).
Cardiac muscle cells, also known as cardiomyocytes, are striated, branched, and contain many mitochondria. They are under involuntary control, contracting in a similar manner to skeletal muscle. Electrical stimulation in the form of a cardiac action potential triggers the release of calcium from the cell's internal calcium store, the sarcoplasmic reticulum. This rise in calcium causes the cell's myofilaments to slide past each other in a process called excitation-contraction coupling.
Cardiac muscle cells contain a single, centrally located nucleus surrounded by a cell membrane called the sarcolemma. The sarcolemma contains voltage-gated calcium channels, which are specialized ion channels that skeletal muscle does not possess. The cardiac muscle cells are interconnected through intercalated discs, which contain gap junctions and desmosomes. These interconnections allow the cardiomyocytes to contract together synchronously, enabling the heart to work as a pump.
Cardiac muscle fibres are striated, with contractile proteins aligned in a regimented fashion to yield alternating light-dark patterns on light microscopic examination. The striations arise due to the arrangement of contractile units (sarcomeres) along the length of the fibre. The sarcomeres consist of thick (myosin) and thin (actin) filaments, the interactions of which form the basis of the sliding filament theory.
The Intriguing Muscular System of Slugs Unveiled
You may want to see also
Explore related products
Cardiovascular disease is the chronic disease of the heart or blood vessels
Cardiovascular disease (CVD) is a chronic disease that affects the heart or blood vessels. It is the leading cause of death worldwide and in the US, with almost half of US adults suffering from at least one form of heart disease. CVDs are a group of disorders that can affect one or many parts of the heart and/or blood vessels.
The heart is made up of three layers: the pericardium, myocardium, and endocardium. The myocardium, or cardiac muscle, is the thick middle layer of the heart. It is one of three types of muscle tissues in the body, the others being skeletal and smooth muscle. The myocardium is surrounded by the thin outer layer, the epicardium, and the inner endocardium. The endocardium is not cardiac muscle but a simple squamous epithelial layer that forms the inner lining of the heart chambers and valves. The pericardium is a fibrous sac surrounding the heart, consisting of the epicardium, pericardial space, parietal pericardium, and fibrous pericardium.
Cardiovascular diseases can involve issues with the blood vessels, such as the narrowing of blood vessels in the heart, other organs, or throughout the body. They can also involve the heart, with problems such as irregular heart rhythms, heart valves not working properly, and congenital heart defects. The cardiac muscle must contract with enough force to supply blood to the entire body, so issues with this muscle can have severe consequences.
Some of the risk factors for CVD include an unhealthy diet, physical inactivity, tobacco and alcohol use, air pollution, high blood pressure, high blood glucose, high blood lipids, and overweight and obesity. To prevent CVD, it is recommended to stop using tobacco, reduce salt and sugar intake, increase fruit and vegetable consumption, exercise regularly, and avoid harmful alcohol use.
Muscle Memory: Unlocking the Power of Physical Intelligence
You may want to see also
Frequently asked questions
Cardiovascular muscle, also known as cardiac muscle, is found in the heart.
The heart is made of cardiac muscle, which is one of three types of muscle in the body, along with skeletal and smooth muscle.
Cardiac muscle is made up of specialised cells called cardiomyocytes, which are also known as contractile myofibrils or myocytes.
Cardiomyocytes contract and relax in an alternating cycle to pump blood through the body.
Cardiovascular muscle health can be improved by regular exercise. The WHO recommends at least 150 minutes of moderate exercise per week to keep your heart healthy.
