2. Breathing & Circulation Flashcards
What is the circulatory system’s main function?
- To get food and oxygen to every cell in the body.
- To carry waste products to where they can be removed.
What is the circulatory system made up of?
- Heart
- Blood vessels
- Blood
What type of circulatory system do humans have?
A double circulatory system - two circuits joined together.
What does each of the two circulatory circuits do?
1st - Pumps deoxygenated blood to the lungs to take in oxygen and then returns it to the heart.
2nd - Pumps oxygenated blood all around the body, providing oxygen, and then returns it to the heart.
What is the heart made of?
Muscle tissue.
What is the function of the heart?
To pump blood around the body.
What does the heart have to prevent backflow?
Valves.
How many chambers does the heart have?
4 - Right atrium, right ventricle, left atrium, left ventricle.
What is the path of the blood starting in the right atrium?
Right atrium -> Right Ventricle -> Pulmonary Artery -> Lungs -> Pulmonary Vein -> Left Atrium -> Left Ventricle -> Aorta -> Body -> Vena Cava
What controls your resting heart rate?
Pacemaker
What is the heart’s pacemaker and where is it?
A group of cells in the right atrium wall.
How does the heart’s pacemaker work?
The group of cells in the right atrium wall produces a small electric impulse which spreads to the surrounding muscle cells, causing them to contract.
What is done if the heart’s natural pacemaker doesn’t work properly (e.g. the patient has an irregular heartbeat)?
An artificial pacemaker is used
What is an artificial pacemaker?
A small device implanted under the skin which has a wire that goes to the heart. It produces an electric current to keep the heart beating regularly.
What are the three types of blood vessel?
- Arteries
- Capillaries
- Veins
What is the function of arteries?
Carry blood away from the heart to the organs and tissues.
What is the function of capillaries?
Carry blood very close to every cell in the body to exchange substances with them.
What is the function of veins?
Carry blood back to the heart from the organs and tissues.
Define the heart.
A four chambered muscle pump that pumps blood under pressure around the body.
Why are there valves in the heart?
To prevent backflow of blood.
When you exercise, what does the body need to do?
- Get more oxygen and glucose to the muscles to supply energy
- Remove CO2 at a faster rate
How do muscles contract?
They use oxygen and glucose to release energy, which is used to contract the muscles.
How does the body respond to exercise?
- Increases breathing rate
- Breathing more deeply
- Increase in heart rate
- Heart contracts more powerfully (increased stroke volumes)
- Blood is diverted to muscles
How does the resting heart rate of an unfit person compare to a fit person?
An unfit person has a higher resting heart rate.
How does the heart rate of an unfit person change during exercise compared to a fit peerson?
An unfit person’s heart rate goes up more during exercise than a fit person’s.
How long does it take for an unfit person to recover compared to a fit person?
It takes longer for an unfit person to recover than a fit person.
How is some glucose stored in muscles and liver?
As glycogen.
Where is glycogen stored?
Mostly in the liver, but also in each muscle.
What happens when vigorous exercise uses up glucose rapidly?
Some of the glycogen in converted back to glucose to provide more energy.
What happens when you do exercise and your body cannot supply enough oxygen to muscles?
The muscles start doing anaerobic respiration instead of aerobic respiration.
What does anaerobic mean?
Without oxygen
What is anaerobic respiration?
The incomplete break down of glucose (without oxygen) to produce lactic acid and energy.
What is the word equation for anaerobic respiration?
Glucose -> Lactic Acid (+ Energy)
What is the symbol equation for anaerobic respiration?
C6H12O6 -> 2C3H6O3 (+ Energy)
What are the problems with anaerobic respiration?
1) It produces lactic acid which:
- Builds up in the muscles and gets painful
- Causes muscle fatigue and the muscles stop contracting efficiently
2) It is not as efficient as aerobic respiration (i.e. less energy released)
What are the advantages of anaerobic respiration?
It allows the muscles to keep contracting for longer.
How do plants and some microorganisms respire without oxygen?
They produce ethanol and CO2 (instead of lactic acid, like humans).
Apart from humans, who can respire without oxygen?
Plants and some microorganisms.
What is oxygen debt?
The amount of oxygen that has to be added to the blood adter exercise in order to oxidise the lactic acid in the muscles.
Why do you keep breathing heavily after exercise?
To repay the oxygen debt from anaerobic exercise. Breathing heavily provides oxygen to oxidise the lactic acid in the muscles.
When the oxygen debt is being repaid, what does oxidisng the lactic acid produce?
CO2 and water.
After exercise, how long do the pulse and breathing rate stay high?
Until the body detects that the levels of lactic acid and CO2 in the body are no longer at a high level.
What is the function of the atria?
They contract and push the blood into the ventricles.
What is the function of the ventricles?
They contract and push the blood into the pulmonary artery and aorta.
What are the features of an artery?
- Thick, elastic, muscular walls
- Relatively small lumen
What are the walls of an artery made of?
Muscle and elastic fibres
What are the features of a capillary?
- Very narrow
- Thin, permeable walls (1 cell thick)
- Very small lumen
What are the features of a vein?
- Thin, elastic, muscular walls
- Relatively large lumen
- Valves
What do arteries branch into?
Arterioles and then capillaries .
What to capillaries join up into?
Venules and then veins.
What is the blood pressure like in arteries?
High
What is the blood pressure like in veins?
Low
Where are capillaries found?
Organs (lungs) and tissues
What do capillaries supply and take away?
Supply: Food and oxygen
Take away: Waste like CO2
Why do arteries have their specific features?
- Thick, muscular wall -> Resist high blood pressure
- Elastic fibres in wall -> Allow artery to stretch and spring back
Why do veins have their specific features?
- Thin, muscular walls -> Lower pressure than in arteries
- Relatively large lumen -> Help blood flow
- Valves -> Prevent backflow
Why do capillaries have their specific features?
- Very narrow -> Can reach every cell
- Thin, permeable walls (1 cell thick) -> Maximise diffusion
What are the 4 MAIN parts of the blood?
- Red blood cells
- White blood cells
- Platelets
- Plasma