The Heart and CVD Flashcards
What is systole and diastole?
Systole= period of contraction
Diastole= period of relaxation (longer than systole)
What is atrial systole?
When the heart is full of blood and ventricles are relaxed, both atria contract and blood passes down to the ventricles. The atrioventricular valves open due to blood pressure. (70% of blood passes down passively)
What is ventricular systole?
Atria relax, ventricle walls contract. Pressure of blood forces semi lunar valves open, blood passes into aorta and pulmonary arteries.
What is cardiac diastole?
The atria and ventricles relax, elastic recoil of blood lowers pressure. The coronary arteries fill.
How does the cardiac muscle receive adequate nutrients and oxygen?
Through the coronary circulation.
What are the walls and septum of the heart composed of?
Cardiac muscle.
Why is the atrial walls thinner than the ventricular walls.
Blood from the atria travel a short distance, only to the ventricles. The right ventricles is thicker as it pumps blood to the lungs and the left ventricles are the thickest as it pumps blood around the body at a long distance.
What does the term myogenic mean?
The heart tissue being able to relax and contract rhythmically at its own accord.
What causes atrial systole that leads on to ventricular systole?
Initially the heart is at cardiac diastole. The return of deoxygenated blood from the body enter the vena cava, when the atria are full they contract. Which later on leads to ventricular systole.
Which region of the heart has the highest inherent rhythm? Where is this situated?
The sino-atrial node or the pacemaker. Situated in the wall of the right atrium.
What is the structure and function of the arteries?
Arteries carry blood away from the heart. It has thick muscular walls and lots of elastic tissue to withstand high pressure (no need for valves). Elastic tissue allows the vessel to stretch to prevent damage, the recoiling pushes blood. It has a small lumen to maintain pressure.
What is the structure and function of veins?
It has a large lumen due to the low pressure of blood flow. It has thin muscular walls which contract to push blood along the vein. It has valves to avoid blood flow.
What is the structure and function of capillaries?
Wall made up of 1 cell thick endothelium, has a small lumen. No pulse, valves or muscle.
What is mass flow?
The mass transport system are used to carry raw materials from specialised exchange organs to the body cells and to remove metabolic waste. The mass transport system is the circulatory system as when the heart pumps blood around the body it supplies and disposes.
Why is water a polar molecule? What type of bond forms between water molecules?
It has an uneven distribution of charge, one side slightly negative whilst the other side is slightly positive, this makes it dipole. Hydrogen bonding forms as the negative and positive ends of the molecules attract.