Skip to main content

Heart

We see and hear about hearts everywhere. A long time ago, people even thought that their emotions came from their hearts, maybe because the heart beats faster when a person is scared or excited. Now we know that emotions come from the brain, and in this case, the brain tells the heart to speed up. The heart is a muscular organ about the size of a closed fist that functions as the body’s circulatory pump. It takes in deoxygenated blood through the veins and delivers it to the lungs for oxygenation before pumping it into the various arteries (which provide oxygen and nutrients to body tissues by transporting the blood throughout the body). The heart is located in the thoracic cavity medial to the lungs and posterior to the sternum.
The heart wall is made of 3 layers: epicardium, myocardium and endocardium.
Epicardium. The epicardium is the outermost layer of the heart wall and is just another name for the visceral layer of the pericardium. Thus, the epicardium is a thin layer of serous membrane that helps to lubricate and protect the outside of the heart. Below the epicardium is the second, thicker layer of the heart wall: the myocardium.
Myocardium. The myocardium is the muscular middle layer of the heart wall that contains the cardiac muscle tissue. Myocardium makes up the majority of the thickness and mass of the heart wall and is the part of the heart responsible for pumping blood. Below the myocardium is the thin endocardium layer.
Endocardium. Endocardium is the simple squamous endothelium layer that lines the inside of the heart. The endocardium is very smooth and is responsible for keeping blood from sticking to the inside of the heart and forming potentially deadly blood clots
The heart contains four (4) chambers: the right atrium, left atrium, right ventricle, and left ventricle. The atria are smaller than the ventricles and have thinner, less muscular walls than the ventricles. The atria act as receiving chambers for blood, so they are connected to the veins that carry blood to the heart. The ventricles are the larger, stronger pumping chambers that send blood out of the heart. The ventricles are connected to the arteries that carry blood away from the heart.
Valves of the Heart
The heart functions by pumping blood both to the lungs and to the systems of the body. To prevent blood from flowing backwards or “regurgitating” back into the heart, a system of one-way valves are present in the heart. The heart valves can be broken down into two types: atrioventricular and semilunar valves.
Atrioventricular valves. The atrioventricular (AV) valves are located in the middle of the heart between the atria and ventricles and only allow blood to flow from the atria into the ventricles. The AV valve on the right side of the heart is called the tricuspid valve because it is made of three cusps (flaps) that separate to allow blood to pass through and connect to block regurgitation of blood. The AV valve on the left side of the heart is called the mitral valve or the bicuspid valve because it has two cusps. The AV valves are attached on the ventricular side to tough strings called chordae tendineae. The chordae tendineae pull on the AV valves to keep them from folding backwards and allowing blood to regurgitate past them. During the contraction of the ventricles, the AV valves look like domed parachutes with the chordae tendineae acting as the ropes holding the parachutes taut.
Semilunar valves. The semilunar valves, so named for the crescent moon shape of their cusps, are located between the ventricles and the arteries that carry blood away from the heart. The semilunar valve on the right side of the heart is the pulmonary valve, so named because it prevents the backflow of blood from the pulmonary trunk into the right ventricle. The semilunar valve on the left side of the heart is the aortic valve, named for the fact that it prevents the aorta from regurgitating blood back into the left ventricle. The semilunar valves are smaller than the AV valves and do not have chordae tendineae to hold them in place. Instead, the cusps of the semilunar valves are cup shaped to catch regurgitating blood and use the blood’s pressure to snap shut.

Comments

Post a Comment

Followers

Popular posts from this blog

Environmental Hazards in the Workplace

Workplace safety is crucial for maintaining a healthy and efficient environment. Environmental hazards can pose significant risks, affecting health, productivity, and overall well-being. Understanding and mitigating these hazards is essential for creating a safe work environment. Let’s explore seven common environmental hazards that can impact employee health and safety: Chemical Hazards: These can be found in various workplaces, including construction sites, factories, laboratories, and offices. Examples include exposure to hazardous chemicals like lead or asbestos. Prevention Tips: ·        Use proper ventilation systems. ·          Implement strict safety protocols for handling and storing chemicals. ·          Provide personal protective equipment (PPE) like gloves and masks. Biological Hazards: These arise from exposure to living organisms that can cause disease or illn...
Post a Comment
Read more

Incredible Benefits of Getting a Good Night's Sleep

In today's fast-paced world, where we often find ourselves juggling multiple responsibilities and tasks, sleep is often sacrificed in the pursuit of productivity. However, this approach is counterproductive, as sleep plays a crucial role in our overall well-being. A good night's sleep is not just a luxury; it's a necessity that offers a wide range of benefits for our physical, mental, and emotional health.  Let us delve into the incredible benefits that come with prioritizing and getting the sleep we need. Enhanced Cognitive Function: Sleep is essential for optimal brain function. During sleep, the brain consolidates memories, processes information, and clears out unnecessary neural connections. This enhances our ability to learn, make decisions, solve problems, and think creatively. A good night's sleep ensures that your mind is sharp, focused, and ready to tackle challenges effectively. Improved Mood and Emotional Well-being: Lack of sleep is closely linked to m...
5 comments
Read more

Health Benefits of Teff Grain

Teff Grain  Scientifically known as Eragrostis tef, is a tiny grain widely used in Africa but is beginning to gain popularity in the United States. It is used in a similar way as millet or quinoa, but the grain’s small size means that it cooks very rapidly, thus using less fuel and being more viable as a dietary staple for countries with limited resources.  It’s a protein-rich staple food of the African nation that has received a great deal of attention lately, and versatile applications make it an ideal “superfood” that people from Hollywood to the Horn of Africa are clamoring for. It’s amazing how many nutrients are packaged in such a small grain, but the mineral, vitamin, fiber, and organic compounds found in teff grain make it an ideal nutritional source for millions of people already. The most common use of teff is making flour and bread, but it can basically be used in the same way as any other cereal grain. Health Benefits of Teff Grain Relieves Menstrual Probl...
Post a Comment
Read more