The German philosopher Christian von Wolff coined the term in the Latin form "teleologia" in in his work Philosophia rationalis, sive logica.
Polygenic inheritance The transport system 6.
The coronary arteries supply heart muscle with oxygen and nutrients. The right atrium collects blood from the superior and inferior vena cava and the left atrium collects blood from the pulmonary veins.
This blood then flows into the right and left ventricle which pump the blood into the arteries. The direction of the blood flow is controlled by the atrioventricular valves and semilunar valves. When the atria contract the blood flows through the atrioventricular valves which are open, into the ventricle.
At this stage the semilunar valves are closed so the ventricle fills with blood. The ventricles then contract which causes a rise in pressure. This rise in pressure first causes the atrioventricular valves to close preventing back flow of blood into the atria.
Then the semilunar valves open allowing the expulsion of blood into the arteries. As this happens, the atria start to fill with blood again. The ventricles stop contracting leading to a fall in pressure which causes the semilunar valves to close, preventing back flow of blood from the arteries.
When the ventricular pressure drops below the atrial pressure the atrioventricular valves open again and the cycle repeats. Atria collect blood from veins.
Atria contract, atrioventricular valves open. Blood is pumped into ventricles. Ventricle contracts, atrioventricular valves close and semilunar valves open.
Blood is pumped into arteries, semilunar valves close. The heart muscle can contract by itself, without the stimulation of a nerve.
This is called myogenic muscle contraction. The region that initiates each contraction is found in the wall of the right atrium and is called the pacemaker. Every time the pacemaker sends out a signal, a heartbeat results.
The pacemaker is under the influence of nerves and adrenaline. One nerve carries messages from the medulla of the brain to the pacemaker and speeds up the beating of the heart.
Another nerve carries messages from the medulla of the brain to the pacemaker and slows down the beating of the heart. Finally, adrenaline epinephrine is carried by the blood and once it reaches the pacemaker it signals it to increase the beating of the heart.
Heart muscle can contract by itself myogenic muscle contraction. One nerve carries messages from the brain to the pacemaker to speed up the beating of the heart. One nerve carries messages from the brain to the pacemaker to slow down the beating of the heart.
Adrenaline signals the pacemaker to increase the beating of the heart. Arteries have a thick outer layer of longitudinal collagen and elastic fibers to avoid leaks and bulges. They have a thick wall which is essential to withstand the high pressures.
They also have thick layers of circular elastic fibres and muscle fibres to help pump the blood through after each contraction of the heart.
In addition the narrow lumen maintains the high pressure inside the arteries. Veins are made up of thin layers with a few circular elastic fibres and muscle fibres. This is because blood does not flow in pulses and so the vein walls cannot help pump the blood on.
Veins also have thin walls which allows the near by muscles to press against them so that they become flat. This helps the blood to be pushed forwards towards the heart. There is only a thin outer layer of longitudinal collagen and elastic fibres as there is low pressure inside the vein and so little chance of bursting.
Finally, a wide lumen is needed to accommodate the slow flowing blood due to the low pressure.Why the change?
While the new IB syllabus covers much the same content as the old syllabus, the style has changed significantly: The old syllabus was organised into dot points, each of which included a specific command term that identified the level of knowledge required.
IB Biology notes on The transport system. The transport system Draw and label a diagram of the heart showing the four chambers, associated blood vessels, valves and the route of blood through the heart. Mitochondrial Biology in Heart and Skeletal Muscle (J1) joint with the meeting on Mitochondria in Aging and Age-Related Disease (J2) Scientific Organizers: E.
Dale Abel and Andrea L. . biology. If you’re studying the life cycles of living organisms, you’ve come to the right place.
We break down the processes of everything from bacteria to blue whales. Teleology or finality is a reason or explanation for something in function of its end, purpose, or goal. It is derived from two Greek words: telos (end, goal, purpose) and logos (reason, explanation).
A purpose that is imposed by a human use, such as that of a fork, is called extrinsic. Natural teleology, common in classical philosophy but controversial today, contends that natural entities.
The Heart. The heart is a pump that circulates blood all around the body. It is approximately the size of a human fist and is located just to the left of the centre of a human’s chest.