Karteikarten
The Heart
Karten in diesem Stapel (25)
- 1Outline the function of the HeartThe organ that controls the circulatory system in mammals. It pumps blood around the body. Mammals have a double circulatory system, so heart must pump blood to the lungs and to the res of the body simultaneously.
- 2Describe the outside of the heartThe heart mainly consists of a dark red muscle. It is attached to four blood vessels- Pulmonary Artery, Pulmonary Vein, Vena Cava, and Aorta.
- 3Describe the inside of the heartFour main cavities: Two Atria and two Ventricles. The atria hold blood briefly, then allow it to fall into the ventricles (pump blood around heart).
- 4Heart Diagram:
- 5What does the Vena Cava do?
- 6What do the Atria do?Separated from the ventricles by the AV VALVES (Tricuspid Valves (R) and Bicuspid Valves (L)). These valves allow blood to flow downwards when the atria and ventricles relax, but close to prevent blood from flowing back up to the atria when the ventricles are contracting.
- 7What do the Ventricles do?Separated from the aorta and pulmonary artery by Semilunar Valves (Aortic and Pulmonary Valves). These prevent blood from flowing in the wrong direction back into the heart.
- 8What do the Atrial Walls do?Atrial walls are thin, as they don't need to withstand much pressure.
- 9What do the Ventricle Walls do?Ventricle walls are thicker. When ventricles contract, blood pressure inside becomes very high, and they need to be able to withstand this.
- 10Compare the walls of the left ventricle and the right ventricleThe walls of the left ventricle are thicker than those of the right of the ventricle. This is because the left side of the heart controls the systemic circuit, and the right side controls the pulmonary circuit.
- 11Why does blood in the systemic circuit need to be at a high pressure?In order to make its way around body and back to heart. Lungs are very close to the heart, containing very delicate capillaries which can break if too much pressure, so systemic circuit requires greater blood pressure than pulmonary circuit, so wall of left ventricle are thicker than of right.
- 12What is the cardiac cycle?The cycle f the beating of the heart, which consists of the three main phases: Diastole, Atrial Systole and Ventricular Systole.
- 13Describe Diastole
- 14Describe Atrial SystoleThis is the beginning of the muscle contraction. The atria contract, which pushes more blood into the ventricles.
- 15Describe Ventricular Systole
- 16Why is it important to control and coordinate the Cardiac Cycle?The heart rate needs to change to respond to various factors (i.e. increased physical activity). Also, atria and ventricles have different natural frequencies of contraction. If contractions are uncoordinated, atria and ventricles would contract asynchronously, leading to inefficient pumping.
- 17Why is the heart muscle described as being 'myogenic'?It initiates its own contraction.
This unusual property means that the heart is ably to beat even when not connected to the body. - 18How is a heartbeat initiated?SAN - located above the right atrium, generates electrical impulses in a regular fashion, which is then spread out throughout the heart.
- 19What happens one an electoral excitation has been generated by the SAN?It spreads through the atrial muscle, which then contact as part of atrial systole.
- 20Why is the wave of excitation stopped by a non-conducting disc of tissue at the base of the atria?This prevents the wave from causing the ventricles to contract too early. The only path to the ventricles is through the AV Node.
- 21What happens at the AV Node?The electrical impulse is delayed to allow the atria to fully contract. Then the wave travels down to Inter-ventricular wall through a special conducting tissue known as the Purkyne, towards the apex (base) and the ventricular muscles.
- 22What happens when the wave of excitation reaches the Ventricular muscles?It initiate the contraction. The wave them moves up the ventricles from the apex causing further contraction. IN this manner the contraction of the ventricles starts at the bottom and moves upwards, so that blood is forced upwards into the arteries during Ventricular Systole.
- 23What is an ECG?A device that measures the electrical activity of the heart. It consists of several sensors placed around the body connected to a monitor. The sensors detect the electrical signals that spread from the heart through the body to the skin.
- 24What is the PQRST shape?The ECG produces a trace of the electrical activity.
- 25—P - excitation and contraction of the atria during atrial systole
QRS complex - excitation and contraction of ventricles during ventricular systole
T - diastole phase
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- A level Biology Karteikarten am The Heart, erstellt von Sara R am 14/02/2017.
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- Sara R
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