9: Transport in animals Flashcards
Describe the circulatory system
A system of blood vessels with a pump and valves to ensure one-way flow of blood
Describe the single circulation of a fish
heart –> gills –> tissues –> heart
- blood passes through the heart ONCE
DEOxygenated blood from body to heart, Oxygenated blood from gills to tissues, to heart
Describe the double circulation of a mammal
- blood passes through the heart TWICE
Pulmonary Circulation (deoxygenated blood)
- RHS Heart > lungs > LHS Heart
- Lower Pressure
Systemic Circulation (oxygenated blood)
- LHS Heart > Body > RHS Heart
- Higher Pressure
Explain the advantages of a double circulation
- increases pressure = flow rate of blood supply to tissues ALSO INCREASED!!
- delivers greater blood flow to tissues around the body - mammals are large = need blood to be supplied to their tissues quickly
- need to maintain high body temperature
Explain the relative thickness of the muscle walls of the left and right ventricles
- right ventricle (thinner): forces blood to the lungs
- left ventricle (thicker): more muscular due to it having to pump blood at a HIGHER pressure that overcomes greater resistances
Explain the relative thickness of the muscle walls of the ATRIA compared to those of the ventricles
- atria have less muscular walls
- only forces blood INTO the ventricles
- ventricles contract and pump the blood out into the arteries at a HIGHER pressure
Explain the importance of septum
It prevents deoxygenated blood on the right side mixing wth the oxygenated blood on the left side
Describe the functioning of the heart (including contraction of muscles of the atria (A) & ventricles (V) and the action of the valves)
- muscle walls of A and V are relaxed
- blood flows into the A from the vena cava (RHS heart) and the pulmonary vein (LHS heart) = A fills with blood
- muscle walls of A contract = increases the pressure in the atria
- pressure in A is HIGHER than pressure in V –> blood is pushed from A to V
- muscle walls of A relax & V contract = increases pressure in V
- WHEN pressure of V is higher than A: atrrio=ventricilar valves are forced closed
- WHEN pressure in V is > than pressure in vessels = semi-lunar valves are open
- blood is pushed OUT of V into blood vessels (RHS = pa, LHS = aorta)
- V RELAX & pressure in blood vessels is HIGHER than V
- semi-lunar valves are forced shut which prevents backflow of blood into V
Where is blood pumped away from the heart?
Into arteries & returns to the heart in veins
How can the activity of the heart be monitored?
ECG, pulse rate & listening to the sound of valves closing (lub dub)
What is the effect of physical activity on heart rate?
More exercise = higher ur heart rate
Describe coronary heart disease & possible risk factors
the blockage of coronary arteries
- diet, lack of exercise, stress, smoking, genetic predisposition, age, sex
What are the roles of diet and exercise in reducing the risk of coronary heart disease?
DIET
- limiting how much saturated & trans fat you eat is an important step to reduce your blood cholesterol & lower risk of CHD
EXERCISE
- reduces you risk of having a heart attack –> the heart benefits from exercise
Describe the structure of arteries
- STRONG, thick walls: comes out of the heart at HIGH pressure
- elastic fibres in wall that stretch and recoil: helps push blood along, MAINTAINS its pressure
- narrow space in the centre: for blood to flow along
- muscle can contract & relax: controls pressure & volume of blood flow
Describe the structure of veins & how it is related to the pressure of the blood they transport
- THIN walls: blood is at a lower pressure (more space for blood to flow)
- bigger lumen: help blood flow
- have (semi-lunar) valves at intervals: help keep blood flowing in the RIGHT DIRECTION (prevent backflow, back to heart)
