B7 Transport in Humans Flashcards
Circulatory system
a system of tubes with a pump and valves to ensure one-way flow of blood
“Double circulation” system
one loop carries blood around the lungs in the pulmonary arteries and returns in the pulmonary veins. The other loop supplies blood at high pressure to the head and body. The aorta branches to carry blood to the head and body, and returns to the heart via the vena cava.
Atrioventricular valves
Valves in the heart which make sure that blood only flows in one direction. From the upper to lower chambers
Semi-lunar valves
2 valves found in the arteries that leave the heart., Prevent blood falling back into the heart when the lower chambers of the heart stop contracting and relax.
Bicuspid valve
2 cups. on the left side.
Tricuspid valve
3 cups. on the right side
Vein
to the heart (oxygenated blood)
Artery
Away from the heart (deoxygenated blood)
Why is the circulation of blood from the heart to the lungs and back to the heart at low pressure?
1) there is a short distance from the heart to the lungs
2) the wall on the left side is thicker, as it has a smaller volume. The right side has higher pressure as it is larger than the left
Why is lung circulation of blood at a higher pressure than the pulmonary circulation?
1) the left side is smaller than the right side. Smaller volume= higher pressure
2) the distance from the heart to body is farther = higher pressure needed
Cardiac muscles
The special type of tissue the heart is made of
Difference between cardiac muscles and skeletal muscles
Cardiac muscles- cannot be controlled by the person. Skeletal- can be contracted or relaxed at will. Skeletal muscles can stay in one position for a long time. Cardiac muscles- always contracting
Coronary heart disease
A condition which affects the vessels, the coronary arteries, which supply the heart’s muscle with blood, oxygen and nutrients. The coronary arteries become partially blocked, and decreases the heart function which causes pain in the chest, arm, neck or jaw. If the vessels become completely blocked, the some of the heart muscles can die and this is a heart attack.
How does smoking increase the chances of heart disease occurring?
Tar and nicotine increase the formation of plaque, while carbon monoxide lowers the oxygen capacity in the blood, increasing the workload of the heart. It weakens the blood vessels and tears it, causing a clot.
How to lower chances of coronary heart disease:
Eat less food with saturated fat- can lower blood cholesterol
Exercise- lowers cholesterol, high blood pressure and excess weight
Quit smoking- reduces blood pressure and damage to blood vessels
Diet- lowers cholesterol intake
Capillaries
very small. Deliver blood to cells; where exchange of materials will take place.
Features of arteries
Thick muscle wall, much elastic tissue, small lumen: diameter, not permeable, no valves
Features of veins
Thin muscle wall, little elastic tissue, large lumen: diameter, not permeable, valves in all veins
Features of capillaries
No muscle. One cell thick, no elastic tissue, large lumen: diameter, permeable, no valves
Flow of blood in an artery
Short quick bursts- high blood pressure
Flow of blood In a vein
Flows when you move, has valves to prevent back flow of blood
Hepatic artery
Delivers blood to the liver from the heart and contains a higher concentration of oxygen than the hepatic vein
Hepatic portal vein
Brings blood to the liver and flows from the small intestine. Has a very high concentration of dissolved food for a vein.
Deamination
A reaction that occurs in the liver in which excess proteins are converted into urea and sugars.
