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- This article provides a comprehensive look at the heart's structure with a detailed, labeled diagram and realistic photos, guiding you through each part and its role in the circulatory system. Heart Anatomy in Basic Terms The heart is a crucial organ that functions as the body's pump, ensuring blood circulation throughout the body.
www.verywellhealth.com/heart-anatomy-8654202
Aug 26, 2024 · The heart is a fist-sized organ in the chest that is responsible for pumping blood. It has four chambers: two upper chambers (atria) and two lower chambers (ventricles). These chambers are separated by valves to keep blood flowing in the proper direction.
- Heart Anatomy: Labeled Diagram and Quick Reference
Understanding its basic anatomy is crucial to understanding...
- Heart Anatomy: Labeled Diagram and Quick Reference
Oct 31, 2024 · Passage of blood through the left atrium, bicuspid valve, left ventricle, aorta, tissues of the body, and back to the right atrium constitutes the systemic circulation. Blood pressure is greatest in the left ventricle and in the aorta and its arterial branches.
- The Editors of Encyclopaedia Britannica
- In humans, the heart is situated between the two lungs and slightly to the left of center, behind the breastbone. It rests on the diaphragm, the mu...
- The heart consists of several layers of a tough muscular wall, the myocardium. A thin layer of tissue, the pericardium, covers the outside, and ano...
- The pumping of the heart, or the heartbeat, is caused by alternating contractions and relaxations of the myocardium. These contractions are stimula...
- The rhythmic noises accompanying the heartbeat are called heart sounds. The two distinct sounds are heard, a low, slightly prolonged “lub” (first s...
Sep 4, 2024 · Your circulatory system’s three basic functions are: Move blood throughout your body. Bring oxygen and nutrients to your organs, muscles and tissues. Remove waste products like carbon dioxide and your organs’ chemical byproducts. Day and night, even while you’re asleep, your heart moves blood through your body in a circuit.
Nov 10, 2024 · The heart is a muscular organ that pumps blood throughout the body via the circulatory system. It is approximately the size of a fist and consists of four chambers: two atria and two ventricles. The heart is composed of specialized muscle tissue, known as myocardium , and is encased within a double-layered protective sac called the pericardium .
- Overview
- The heart and its function
- The arteries and their function
- The veins and their function
- The blood and its function
- How the circulatory system works
- Symptoms of poor circulation
- Conditions that affect the circulatory system
The heart and blood are major parts of the circulatory system. All components contribute to oxygen and nutrient delivery throughout your body.
Combined with the cardiovascular system, the circulatory system helps fight off disease, helps the body maintain a normal body temperature, and provides the right chemical balance for the body to achieve homeostasis, or a state of stability among all its systems.
The circulatory system consists of four major components:
•heart
•arteries
•veins
Heart wall
There are three layers of the heart wall. The epicardium is the heart wall’s outer layer, the myocardium is the middle — and muscular — layer, and the endocardium is the heart’s innermost layer.
Chambers
The heart has four chambers: the right and left atria, and the right and left ventricles. Together, they make up the heart’s internal cavity. The four chambers play an important role in circulation. The atria receive blood from the veins, while the ventricles push blood out of the heart. Because the ventricles have to be much stronger to perform this pumping activity, their myocardial layers are thicker than those of the atria.
Arteries carry blood away from the heart.
The artery walls have three layers: tunica intima (inner), tunica media (middle), and tunica externa (outer).
The middle layer is usually the thickest. It’s made up of smooth muscle that changes the size of the artery to regulate blood flow.
There are three main types of arteries. They get smaller and smaller the further they are from the heart.
Elastic arteries
The aorta and pulmonary arteries are the elastic arteries. They receive blood directly from the heart and need to be elastic to accommodate the surge and contraction as blood pushes through with each heartbeat.
The blood moves back to the heart through veins.
The blood travels from the capillaries into the venules, which are the smallest veins. As the blood moves closer to the heart, the veins get larger and larger.
Like the arteries, veins have walls made up of layers called the tunica intima, tunica media, and tunica externa. There are some important differences between the arteries and veins:
•In veins, the walls have less smooth muscle and connective tissue.
•The walls of veins are thinner than artery walls.
•Veins have less pressure and can hold more blood than arteries.
Plasma
About 55 percent of the blood is plasma. Plasma is what makes blood liquid. Plasma moves blood cells through the body by way of the circulatory system. It also carries hormones, nutrients, antibodies, and waste products. Plasma is made up of: •water •salts •sugar •fat •protein
Red blood cells
Red blood cells, also called erythrocytes, make up about 40 to 45 percent of the blood’s volume. These cells have no nucleus, which means they can easily change shape as they move through the body’s arteries and veins. Red blood cells contain a protein called hemoglobin. It carries oxygen from the lungs to the rest of the body and returns carbon dioxide to the lungs, where it’s exhaled.
White blood cells
White blood cells, also called leukocytes, make up just 1 percent of the blood. They protect the body from infection. There are five major types of white blood cells. Most white blood cells are neutrophils, which live for less than 1 day. Neutrophils are the body’s immediate response team. Types of lymphocytes include B lymphocytes (B cells) and T lymphocytes (T cells). B lymphocytes make antibodies, while T lymphocytes regulate other immune cells and target infected cells and tumors. The other major types are basophils, eosinophils, and monocytes.
Oxygen enters the bloodstream through tiny membranes in the lungs that absorb oxygen as it’s inhaled. As the body uses oxygen and processes nutrients, it creates carbon dioxide, which your lungs expel as you exhale.
The circulatory system works thanks to constant pressure from the heart and valves throughout the body. This pressure ensures that veins carry blood to the heart and arteries transport it away from the heart. (Hint: To remember which one does which, remember that that “artery” and “away” both begin with the letter A.)
There are three different types of circulation that occur regularly in the body:
•Pulmonary circulation. This part of the cycle carries oxygen-depleted blood away from the heart, to the lungs, and back to the heart.
•Systemic circulation. This is the part that carries oxygenated blood away from the heart and to other parts of the body.
•Coronary circulation. This type of circulation provides the heart with oxygenated blood so it can function properly.
There are many symptoms of poor circulation, including:
•chest pain
•dizziness or feeling faint
•shortness of breath
•pain, weakness, or numbness in the limbs
•swollen limbs
There are several conditions that can affect the heart and circulatory system, including:
•Peripheral arterial disease. In peripheral arterial disease, blood flow in the arteries of the legs is restricted. This is usually due to buildup of plaque in the arteries.
•Arteriosclerosis. In arteriosclerosis, plaque buildup in the blood vessels becomes calcified and hard. The arteries are less flexible, leading to higher blood pressure, stroke, heart damage, and kidney damage.
•Heart attack. During a heart attack, a blockage of blood flow to the heart muscle leads to death of heart muscle tissue. It’s also known as a myocardial infarction.
•Angina. In angina, the heart muscle isn’t getting enough blood. This leads to crushing chest pain, fatigue, nausea, and shortness of breath.
•Mitral valve conditions. In mitral valve prolapse, mitral valve stenosis, or mitral valve regurgitation, problems with the mitral valve cause oxygenated blood in the heart to flow backward, or blood flow to be slowed down or constricted.
The heart is a hollow, muscular organ that pumps oxygenated blood throughout the body and deoxygenated blood to the lungs. This key circulatory system structure is comprised of four chambers.
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Jun 11, 2024 · Understanding its basic anatomy is crucial to understanding how it functions. This article provides a comprehensive look at the heart's structure with a detailed, labeled diagram and realistic photos, guiding you through each part and its role in the circulatory system.
