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Why do the ventricles of the heart contract from the base upwards?
Wiki User
∙ 7y ago
Because where the blood leaves the chambers are at the top. Try squeezing all the toothpaste out of a toothpaste tube by pushing down end with the hole. Not very effective. If you squeeze from the flattened end much more of the toothpaste will come out much more efficiently. (If you really must try this do it over a sink)
Wiki User
∙ 7y ago
Wiki User
∙ 15y agoi am not 100% sure, but i would guess its to get the blood to a higher point of the body, therfore making it easier to circulate downwards due to gravity
Wiki User
∙ 13y agobecause blood leaves from the top of the heart. imagine a tooth paste tube, if you squeeze from the bottom more tooth paste comes out, so its more effective.
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Do arteries have valves to allow blood to flow away from the heart?
No, they're aren't any valves in the arteries.
How blood is prevented from flowing from the ventricles back into the atria?
There are two factors that prevent flow of blood fronm arteries to ventricles 1. presence of semi-lunar valve at the base of pulmonary arch and systemic arch 2. The pressure difference b/w ventricles and artries. The pressure in ventricles is lower than that of arteries and according to Equation of contunity fluid never flows from higher pressure to lower pressure
Which valve guards the base of the aorta and opens when the ventricles are contracting?
Aortic semilunar valve
During the heart attack cardiac muscle cell are deprived of their blood supply yet the ventricles are full of blood. Why?
The heart is a pump that both circulates blood and uses it to obtain oxygen and nourishment. Circulating blood enters the Atria (top chambers), is pumped to the Ventricles (bottom chambers) and out. Every time the heart contracts or beats, this happens. Blood for nourishment enters the heart muscle via the coronary arteries, which are attached to the base of the Aorta (the vessel that leaves the Left Ventricle, and pumps blood to the body). When you have a heart attack, the heart is either quivering like a bowl of jello, or at a standstill. There is blood still in the chambers, but no pressure to push the blood into the coronary arteries. The heart muscle dies.
Is the apex of the heart on the second rib?
The base of the heart.
Do the ventricles contract at the apex or at the base of the heart?
Not really sure what you mean by the base, the ventricles contract from the Apex (which is at the bottom) upwards.
How does the heart stop blood from flowing the wrong way when the heart muscle contracts?
It has valves. The TRICUSPID valve between the right atrium and right ventricle and the BICUSPID valve between the left atrium and left ventricle. These valves open as the atria contract and close as the atria relax. The heart also has two SEMI-LUNAR valves at the base of the pulmonary artery and the aorta to prevent back flow from the arteries too. They open as the ventricles contract and close as the ventricles relax. Hope this helps :) Kim Walsh x
Do arteries have valves to allow blood to flow away from the heart?
No, they're aren't any valves in the arteries.
Can someone help you decipher your EKG report It says sinus tachycardia borderline AV conduction delay and probable left atrial abnormality.?
sinus tachycardia = rapid heartbeat borderline av conduction delay = a slight delay in the conduction of electrical impulse from the atria, at the top of the heart, to the ventricles, at the base of the heart. The ventricles are the chambers that do the pumping of blood to the lungs and to the body. The atria are the two "collecting" chambers for the blood returning to the heart from the lungs and from the body. The electrical impulse of a heartbeat starts in the right atrium, travels across to the left atrium and down to the top of the ventricles. This causes the atria to contract and push blood through heart valves into the chambers of the heart called Ventricles. The contraction then has a slight pause as the impulse "stimulates" the atrioventricular node to pass the impulse down to the base of the right and left ventricles. When the impulse passes the AV node, the ventricles contract and push the blood out to the lungs to be oxygenated and to the body. A slight delay in the conduction of the impulse is normal but it is only a fraction of a second. Any delay in the conduction which is longer than the "normal" fraction of a second is considered an abnormal av conduction delay. Probable Left Atrial abnormality = some kind of abnormal size, shape, structure, or electrical conduction in the chamber at the top of the left side of the heart. Remember that the atria are chambers for collecting blood returning to the heart. The left atrium is the chamber for collecting blood which is returning from the lungs. This is freshly oxygenated blood. The blood travels from the lungs to the left atrium. When the atria contract, the blood is pushed from the left atrium into the left ventricle. When the ventricles contract, the blood is then pumped from the left ventricle out into the aorta (the largest artery in your body) and then on to the furthest reaches of your body.
What are the three structures found in the heart?
The heart has three surfaces: anterior, inferior and posterior. The anterior, sternocostal surface, the inferior or diaphragmatic surface and the base of the heart, the posterior surface.
What starts the electrical activity of the heart?
The sinoatrial (SA) node (known as the heart's pacemaker) in the wall of the right atrium is where electrical signals originate and lead to contraction. It sets the rate of contraction; at rest this is about 70 to 80 bpm (beats per minute). The SA node causes the atria to contract (down from the top), forcing blood into the ventricles. The SA node can also be influenced by external sources (such as exercise, increased adrenaline, or drugs) that can increase or decrease the force of contraction (heart rate).The atrioventricular (AV) node passes the electrical signals from the atria to the ventricles, then to the bundle of His. If the SA node is damaged, the AV node takes over its functions.The bundle of His (also known as the atrioventricular bundle) is a tissue within the ventricular septum. It splits to form the right and left bundle branches. The bundle of His passes the electrical signals to the Purkinje fibers.The Purkinje fibres pass the electrical signals to the myocardium (heart muscle) in the ventricles. The ventricles contract (up from the bottom), pushing blood into the aorta and pulmonary arteries.Electrical conduction system of the heart is the class, a subclass of body partSA Node (causes contraction of atria) to AV Node ( delay from SA to AV allows atria to contract before ventricles), to Bundle of His (atrioventricular bundle) where the fibers branch into twos and carry impulses down the center of the heart to both ventricles and at base of heartfurther branching into Purkinje Fibers, which trigger muscle fibers of ventricles to contract.
Which heart chamber is mainly at the base of the heart?
The heart is approximately conical in shape. It is well tilted that its apex is directed forwards, downwards and to the left and the base directed upwards and backwards. The apex is mainly formed by the left ventricle while the base is mainly posterior part of left atrium.
In the expression 64 what is the base?
Could be any base from 7 upwards.
How blood is prevented from flowing from the ventricles back into the atria?
There are two factors that prevent flow of blood fronm arteries to ventricles 1. presence of semi-lunar valve at the base of pulmonary arch and systemic arch 2. The pressure difference b/w ventricles and artries. The pressure in ventricles is lower than that of arteries and according to Equation of contunity fluid never flows from higher pressure to lower pressure
Which valve guards the base of the aorta and opens when the ventricles are contracting?
Aortic semilunar valve
What structure of the conduction system helps to cause the constriction of the ventricles and extend from the atrioventricular node?
The conduction speed slows when it reaches the bundle of His, and then speeds up as it travels along the Purkinje fibres to the base of the ventricles.
During the heart attack cardiac muscle cell are deprived of their blood supply yet the ventricles are full of blood. Why?
The heart is a pump that both circulates blood and uses it to obtain oxygen and nourishment. Circulating blood enters the Atria (top chambers), is pumped to the Ventricles (bottom chambers) and out. Every time the heart contracts or beats, this happens. Blood for nourishment enters the heart muscle via the coronary arteries, which are attached to the base of the Aorta (the vessel that leaves the Left Ventricle, and pumps blood to the body). When you have a heart attack, the heart is either quivering like a bowl of jello, or at a standstill. There is blood still in the chambers, but no pressure to push the blood into the coronary arteries. The heart muscle dies.
