Cardiovascular system Flashcards
(24 cards)
What does the pulmonary circuit do?
-Carries blood to and from gas exchange surfaces of lungs.
What does the systemic circuit do?
-Carries blood to and from the body.
Name the three types of blood vessels?
- Arteries; carries blood away.
- Veins; carry blood to heart.
- Capillaries; Networks between arteries and veins.
Explain capillaries?
- Exchange vessels.
- Exchange materials between blood and tissues.
- E.g. dissolved gases, nutrients and wastes.
Name the two pumps in the system?
- Heart; filled with blood and has cardiac muscles contracting,
- Muscle; Contraction squeezes veins, especially in lower limbs.
Name the four chambers of the heart?
- Right atrium; collects blood from systemic circuit.
- Right ventricle; pumps blood to pulmonary circuit.
- Left atrium; collects blood from pulmonary circuit.
- Left ventricle; pumps blood to systemic circuit.
Anatomy of the heart?
- Pointed tip = apex!!
- Surrounded by pericardial sac.
- Sits between 2 pleural cavities.
Internal anatomy of the heart? (valves)
- Valves lie between atria and ventricle. Atrioventricular valves. Left is bicuspid (2) and right is tricuspid (3).
- Permit blood flow in one direction.
Name the blood vessels in to the right atrium?
- Blood flow from body enters here.
- Superior vena cava; receives blood from head, neck, upper limbs.
- Inferior vena cava; receives blood from trunk and lower limbs.
- Coronary sinus; Cardiac veins return blood to coronary sinus.
Explain the right ventricle in detail?
- Tricuspid valve prevents back flow of blood.
- Blood flows out in to pulmonary circuit through semi-lunar valve and in to the left and right pulmonary arteries in to the lungs.
Name the blood vessels in to the left atrium?
- Blood from lungs into left and right pulmonary veins.
- They deliver to left atrium.
- Blood passes through the bicuspid valve.
Explain the left ventricle in detail?
- Larger than right as muscle is thicker+more powerful.
- Blood leaves through ascending aorta passing through the semi-lunar valve (or aortic).
- Ascending aorta turns and becomes descending aorta.
What is the coronary circulation?
- Supplies blood to muscle tissue of heart.
- Coronary arteries and cardiac veins.
What is a heartbeat?
- A single contraction of the heart.
- Entire heart contracts, atria and then ventricle.
- SA generates 80-100 AP per minute.
Name the structures of the conducting system?
- Sinoatrial node- wall of right atrium.
- Atrioventricular node- junction between atria and ventricles.
- Conducting cells; throughout myocardium.
- Electrocardiogram (ECG).
Impulse conduction through the heart?
- SA node in right atrium sends stimulus to the AV node.
- Delay at AV, atrial contraction begins.
- Impulse travels along septum and branches in to purkinje fibres, to papillary muscles of right ventricle.
- Impulse is distributed throughout ventricular myocardium, atrial contraction completed.
What is the cardiac cycle?
- The period between the start of one heartbeat and the beginning of the next.
- Includes contraction and relaxation.
Name the 4 key phases of the cardiac cycle?
- Atrial systole; contraction.
- Atrial diastole; relaxation.
- Ventricular systole; contraction.
- Ventricular diastole; relaxation.
Describe the phases of cardiac cycle?
- Atrial systole begins, small amount of blood into relaxed ventricles.
- Atrial diastole begins, ventricular systole pushes AV valves closed, pressure rises and exceeds pressure and so semi-lunar valves open, blood flows out.
- Ventricular diastole causes ventricles to relax and blood flowing back causes semi-lunar valves to close.
- Ventricular diastole means all chambers relax and ventricles fill.
What is the cardiac output?
-Millilitres of blood per minute.
What is the stroke volume?
-Millilitres of blood per heart beat.
What is the heart rate?
-Beats per minute.
How do you calculate cardiac output?
Heart rate x stroke volume.
How is blood pressure affected?
- Rises during systole (contraction)
- Falls during diastole (relaxation)
