The Cardiovascular & Respiratory System Flashcards
All 18 cards in this deck
Name, in order, the structures air passes through from the throat to the gas exchange surface in the lungs.
Trachea → bronchi → bronchioles → alveoli.
Where in the lungs does gas exchange take place?
In the alveoli (tiny air sacs).
Give three features of the alveoli that maximise gas exchange.
Large surface area; walls one cell thick; a large capillary network (good blood supply).
At the alveoli, which gas diffuses into the blood and which diffuses out?
Oxygen diffuses from the alveoli into the blood; carbon dioxide diffuses from the blood into the alveoli.
Why is each alveolus surrounded by a network of capillaries?
It gives a good blood supply, which keeps a steep concentration gradient so gases diffuse quickly.
True or false? Blood leaving the capillaries around the alveoli is deoxygenated.
False. It leaves the lungs oxygenated and travels to the heart in the pulmonary vein.
What is the function of the coronary arteries?
They supply the heart muscle with oxygenated blood.
What is a double circulatory system?
Blood passes through the heart twice for each circuit of the body: one loop to the lungs and one to the rest of the body.
Advantage: blood is pumped again at high pressure, so it flows faster to the body.What controls the natural resting heart rate?
A group of cells in the right atrium that act as a pacemaker.
True or false? An artificial pacemaker is an electrical device used to correct irregularities in the heart rate.
True. It is implanted to keep the heart beating regularly.
Name the three types of blood vessel and state what each one does.
Arteries carry blood away from the heart; veins carry blood back to the heart; capillaries allow substances to be exchanged with the tissues.
How is the structure of an artery adapted to its function?
Thick walls of muscle and elastic tissue with a narrow lumen, to withstand and maintain high pressure.
How is the structure of a vein adapted to its function?
Thin walls, a wide lumen and valves to stop blood flowing backwards, because blood is at low pressure.
True or false? All arteries carry oxygenated blood.
False. The pulmonary artery carries deoxygenated blood; arteries are defined by carrying blood away from the heart.
Name the four components of blood and give the function of each.
Plasma – transports cells, dissolved food, carbon dioxide, urea and hormones; red blood cells – carry oxygen; white blood cells – defend against pathogens; platelets – help the blood clot.
How is a red blood cell adapted to its function?
Biconcave disc shape for a large surface area, no nucleus to make room for haemoglobin, which binds oxygen.
What are the steps to calculate the rate of blood flow?
e.g. 300 cm of blood flows through a vessel in 5 minutes
- Note the volume of blood: 300 cm
- Divide the volume by the time taken:
- Rate of blood flow = 60 cm/minute
True or false? As the percentage of a coronary artery that is blocked increases, the blood flow through it increases.
False. Blood flow decreases as the percentage blockage increases (a negative correlation).