Heart

The valves of the heart prevent backflow into the arteries. As a result, the heart can efficiently pump the correct amount of blood to the tissues of the body efficiently and rhythmically. -Cheers The valves of the heart prevent backflow into the arteries. As a result, the heart can efficiently pump the correct amount of blood to the tissues of the body efficiently and rhythmically. -Cheers

The atrio-ventricular valves (or A-V valves) are exactly what their name implies. They are valves located between the atria and ventricles. Since there are two atria and two ventricles, it follows naturally that there must be two A-V valves. The one on the right is called the TRICUSPID valve and the one on the left is called the MITRAL valve.

Your resting heart rate is how many times your heart beats per minute while you are at "rest". The best time to check this is upon awakening in the morning, before walking around, eating, or having caffeine. While there is some debate on this topic it seems that a healthy heart rate is: Between 60 and 75 beats per minute for men Between 60 and 80 beats per minute for women. The fitter you are the lower your heart rate will be. Some professional athletes have a resting heart rate as low as 30 beats per minute! On the other hand, if you have a heart rate over about 80 beats per minute then you should seek medical advice regarding your health and diet as you may need to make some changes.

Right Antrium

Sympathetic innervation of the heart is from cardiac accelerator nerves descending from the uppermost thoracic sympathetic ganglia and the cervical sympathetic ganglia. Parasympathetic innervation comes from the vagus nerve (Cranial Nerve X). These nerves continue into the walls of the heart and provide autonomic innervation, which can only modify the rate and contractility of the heart.

Inside the heart, intrinsic pacemaking comes from the sinoatrial node, which automatically paces the heart due to the existence of "funny currents" (seriously, that's what they're called) that depolarize the node. The SA node is located in the right atrium and the depolarization follows tracks to the left atrium and the atrioventricular node. The AV node can automatically depolarize, but it does so at a lower rate than the SA node, so the SA node overrides the AV nodal rhythm.

From the AV node, the electrical signal goes through Bundles of His and Purkinje Fibers to deliver a wave of depolarization to the cardiac muscle. These cells are modified cardiac myocytes between the endocardium and the myocardium specialized for the transmission of electrical impulse. Technically, these are not nerves, though they function similar to nerves.

Beyond that, there are gap junctions between cardiac myocytes in the intercalated disks that allow for the coordinated contraction of cardiac muscle. In other words, the cells are arranged like a net and the depolarization and contraction of one cell leads to the depolarization and contraction of the cells next to it that have not yet been depolarized.

You have three layers of heart. Outer is pericardium. Middle is myocardium. Inner is endocardium. The middle layer function in blood pumping, mainly.

For an average lifetime, a heart beats for 4 000 000 000 times without stopping.

r atrium r ventricle pulomanry artery lung capillaries pulmonary vein l atrium l ventricle aorta

hi ppl, mammalian means the heart of a mammal - so when u ask whhy is a mammal's heart called a double pump - its not the same thing. they are not answering the question why is it CALLED a double pump, they think you mean whzt is a double pump used for , what are the advantages.. etc. x just to let you knoww x

the spingoream thaleum in old roman language but is actually called the charta sacta

The left ventricle is the heart chamber that pumps the blood through the aorta to the rest of the body.

The blood in veins is not under direct pressure from the heart. It has little valves inside to prevent blood from flowing backwards away from the heart. These valves inside the veins prevent the backflow of blood in veins. They encourage the one-directional flow of blood to the heart.

The aorta receives blood from the Aortic Valve. The Aortic Valve gets blood from the left ventricle.

Heart has two sides (4chambers) separated by a septum.One side it collects the impure blood ie from all the parts of our body and pumps it to lungs. At lungs through alveoli the co2 diffuses out and oxygen enters the blood. this pure blood (oxygenated blood) enters the other side of heart from where it is pumped to all body parts AND cycle continues.

Two hormones that affect heart rate are epinephrine and norepinephrine. Both are actively involved with the body's stress response system. These hormones cause the body to increase heart rate so that oxygenated blood can reach muscles faster to promote more muscle strength and endurance.

The left and right ventricles, which when they contract pump blood into the systemic and pulmonary curcuits.

Heart valves are what allow your heart to act as a pump. There are 4 of them in your heart. A bicuspid (also known as mitral valve), which divides your left atrium (upper portion of the heart) from the left ventricle (lower/larger and more muscular portion). A tricuspid valve, on the right side of your heart divides the right atrium from the left ventricle in a similar manner as I explained for the left, the only difference (in regards to structure) is that this valve has the flaps on it (hence "TRIcuspid) as opposed to two (BIcuspid). Lastly, there is an aortic valve on the left side, and a pulmonic valve on the right. The left side of the heart receives oxygenated blood into the left atrium via the pulmonary veins. The left atrium contracts, sending the blood through the mitral valve into the left ventricle. Immediately following this, the left ventricle contracts and sends the blood out through the aortic valve, into the aorta and out to the rest of your body.

The right side of the heart receives used up / deoxygenated blood from the superior and inferior vena cava (SVC and IVC), into the right atrium. The right atrium then contracts and pushed the blood through the tricuspid into the right ventricle. The right ventricle then contracts and pushes the blood through the pulmonic valve into the pulmonic artery out to the lungs to pick up more oxygen! Although I separated the processes of left and right contraction, they actually occur simultaneously.

So as I indicated above, there are four chambers. In order for your heart to effectively pump blood it must open and close valves at different times during contraction so as to generate enough pressure to push blood through the vessels of your body. If there were not valves, there would be no pressure, and consequently, there would be no circulation.

The deoxygenated blood goes into the lungs through pulmonary artery from the right ventricle.

the oxygenated blood again enters the heart from the lungs by pulmonary veins to the left atrium.

Nothing much. You just get tired. Sometimes it happens when you're too fat, that's why fat people sometimes walk slower and you can hear them panting. If you are very very fit, your heart goes a bit slower, so when you are running it speeds up later, giving you more energy to run. That is why all (most) runners are so skinny.

The blood turns red once it has come into contact with oxygen. This is why your veins appear blue, purple, etc, but when you cut yourself the blood is red. Not sure about details, but oxygen changed the color.