3a.3 - The Circulatory System Flashcards
Describe the circulatory system in humans (4)
- Double circulatory system
- First pumps deoxygenated to lungs the returns to heart
- Second pumps oxygenated to other organs
- Blood gives away it’s oxygen and deoxygenated returns to heart
What do heart valves do? (2)
- Keep blood flowing around the body
- Prevent backflow
What are the four chambers in a heart?
- Right atrium
- Right ventricle
- Left atrium
- Left ventricle
How does the heart use it’s four chambers? (4)
- Blood flows into the two atria from the vena cava and the pulmonary vein
- Atria contracts, pushing blood into ventricles
- Ventricles contract, forcing the blood into pulmonary artery and the aorta, out of the heart
- Floes to organs through arteries and returns in veins
What is the function of the arteries?
Carry blood away from the heart
What is the function of capillaries?
Involved in the exchange in materials at the tissues
What is the function of veins?
Carry blood to the heart
What type of blood does the right side of the heart carry?
Deoxygenated
What type of blood does the left side of the heart carry?
Oxygenated
What type of blood vessel carries blood under high pressure?
Arteries
What are the three types of blood vessel?
- Arteries
- Capillaries
- Veins
Describe the structure of an artery (3)
- Thick walls
- Contain thick layers of muscle
- Contain elastic fibres
What do arteries branch into?
Capllaries
What is the job of the capillaries?
Carry blood really close to every cell to exchange substances with them
Describe the structure of capillaries (3)
- Permeable walls
- Thin cell wall
- Very small
What do capillaries join up to form?
Veins
What type of blood vessel carries blood under low pressure?
Veins
Describe the structure of veins (3)
- Bigger lumen
- Valves
- Thinner walls
What is the job of the red blood cells?
Carry oxygen from the lungs to all cells in the body
Describe the features of a red blood cell (3)
- Biconcave shape
- No nucleus
- Contains haemoglobin
What does haemoglobin do? (2)
- In the lungs, combines with oxygen to produce oxyhaemoglobin
- In body tissues, splits back up to release oxygen
What do white blood cells do?
Protect against diseases
What do platelets do?
Helps blood clot
Describe the features of a platelet
- Small fragments of cells
- No nucleus
What does plasma contain? (7)
- Red and white blood cells
- Platelets
- Nutrients like glucose and amino acids
- Carbon dioxide
- Urea
- Hormones
- Antibodies and antitoxins
Why is artificial blood used? (2)
- More energy is needed for a transfer to take place
- Patient has lost a lot of blood
What are the advantages of artificial blood? (3)
- Doesn’t need refrigerating
- No need for blood matching
- Carries much more oxygen
What are the disadvantages of artificial blood? (3)
- Expensive
- Doesn’t mix well with normal blood
- Side effects
How do stents work? (3)
- Pushed up to an artery enclosed around a balloon
- Balloon inflates and mesh remains inflated
- Balloon is pulled out
Why would stents be needed?
If oxygen flow to the heart is interrupted, it can cause a heart attack
What are the advantages of stents? (3)
- Better than death
- No need for general anaesthetic
- No need for open heart surgery
What are the disadvantages of stents? (3)
- Causes pain
- Cholesterol could build back up if there is no change to diet
- Causes an irregular heartbeat
What can cause circulation to go wrong? (3)
- Experiences heart failure
- High blood pressure
- Coronary heart disease
Describe how the artificial heart is different from a normal heart (3)
- Made like pumps
- Tubes that leave the body
- Needs an external power supply
What are the advantages of artificial hearts? (2)
- Keeps you alive
- People can be mobile
What are the disadvantages of artificial hearts? (4)
- Lasts three years
- Backpack is heavy
- Battery can run out
- Complications with surgery
What are the symptoms of an faulty valve? (2)
- Tired and listless
- De-oxygenated blood mixes with oxygenated
What are the advantages of artificial heart valves? (2)
- High success rate
- Prolong life
- Last 20 years
What are the disadvantages of artificial heart valves?
- May need blood thinners
- Complications in surgers
