The heart Flashcards
Describe the circulatory system
A system composed of blood vessels, valves and a pump from the heart
Describe the single circulation of a fish
Blood flowing once during a complete body circuit
Describe the double circulation of a mammal
Blood flowing through the heart twice during a complete circuit
Advantages of a double circulation
Oxygenated and deoxygenated blood kept separate, lungs not damaged due to low pressure of pump, oxygen supply fast
Where is blood pumped away from the heart
In arteries
Where does blood return to the heart
In veins
Describe the functioning of heart
The atria contract pushing blood into the ventricles
The valves open due to the pressure of blood and the ventricles contract to push blood into the arteries
The valves close to prevent blood flowing back
Ways of monitoring heart rate
ECG, pulse rate and listening to the valves movement
Describe the effect of physical activity on the pulse rate
During exercise the heart beats faster due to higher heart contraction
Oxygen supplied faster
Carbon dioxide removed faster
Describe coronary heart disease
Blockage of coronary arteries
Risk factors of chd
Diet
Lack of exercise
Age
Genetics
Smoking
Sex
Role of diet in reducing chd
A healthy diet will reduce chd, a high and sugary diet will increase chd
The role of exercise in reducing chd
Regular exercise raises the blood circulation, blood pressure kept at a healthy level
Explain the effect of physical activity on the heart rate
During physical activity the heart needs more energy for the contraction of muscles: it beats faster
Describe the structure of arteries
Thick walls for high blood pressure
Small lumen
No valves present
Describe the structure of veins
Wide for blood flow, thin walls due to low pressure, valves to ensure a one way flow
Structure of capillaries
Narrow, one layer of cells so that it is easy for substances to pass through
Function of capillaries due to their structures
Large surface area for gas exchange, short diffusion distance for easy supply of oxygen and removal of waste products
List the components of blood
Red blood cells, plasma, white blood cells, platelets
Function of red blood cells
Transport of oxygen due to haemoglobin
Function of white blood cells
Antibody production and phagocytosis
Function of platelets
Blood clotting
Function of plasma
Transport of blood cells, nutrients, hormones and carbon dioxide
Function of lymphocytes
Antibody production
