B3.2 Flashcards
What are the 3 types of blood vessels?
~ Arteries
~ Veins
~ Capillaries
What do arteries do?
Take blood away from the heart
What do veins do?
Take blood to the heart
What do capillaries do?
~ Join up arteries and veins
~ Exchange oxygen and carbon dioxide
What do white blood cells do?
Defend our bodies against disease by removing any foreign organisms they see as a threat
What do platelets do?
Help our blood to clot at a wound
What is plasma?
A watery fluid in which all the different blood cells are suspended
What makes up half the volume of blood?
Red blood cells
What is haemoglobin?
A red pigment that can carry oxygen
What is oxyhemoglobin?
Haemoglobin combined with oxygen
What are alveoli?
Tiny sacs in the lungs where the exchange of oxygen and carbon dioxide take place
Why is the diffusion pathway in alveoli short?
Because the walls of the capillaries are only one cell thick
What happens when you inhale?
~ Intercostal muscles (between ribs) contract ~ Ribs move up and out ~ Diaphragm moves down / flattens ~ Volume of chest increases ~ Pressure inside decreases ~ Air is drawn in
What happens when you exhale?
~ Intercostal muscles (between ribs) relax ~ Ribs move down and in ~ Diaphragm moves up ~ Volume of chest decreases ~ Pressure inside increases ~ Air is forced out
Why do the walls of the arteries contain muscle and elastic fibres?
To go against pressure
Why are capillaries narrow with thin walls?
~ So the oxygen and glucose can diffuse into the cell
~ So the carbon dioxide and water can diffuse out the cell
What increases the surface area of the small intestine?
Villi
What is active transport?
When substances are absorbed against a concentration gradient. This requires energy from respiration
What does active transport allow cells to do?
Absorb ions from dilute solutions
When there is active transport, what is there also?
Mitochondria, because they release energy from respiration which is needed for the process to happen
What is gaseous exchange?
The exchange of carbon dioxide and oxygen between the blood and the air in the lungs
What is the diaphragm?
A muscle that separates the thorax and the abdomen
What is the artificial aid to breathing of negative pressure?
~ Air is pushed out of the iron chamber
~ This lowers the pressure in it
~ As there is a higher pressure outside, air is drawn into the lungs
What is the artificial aid to breathing of positive pressure?
~ Positive pressure bag pushes air into the lungs through a mask
~ Can be controlled by a machine to regulate breathing
What are advantages and disadvantages of positive pressure?
✅ Quick and easy to use
✅ Can be portable
❌ Patient needs to be hooked to the machine quickly
What are advantages and disadvantages of negative pressure?
✅ Breathes for the patient
❌ Patient has to lie in large machine
Where are red blood cells produced?
In bone marrow
What are coronary muscles?
Blood vessels supplying the muscles on the wall of the heart
What is heart disease caused by?
Blockages in coronary arteries caused by cholesterol
Why does high cholesterol cause heart disease?
The cholesterol narrows the artery so less blood can flow through and less sugars and oxygen can get to the heart
What do stents do?
They’re inserted into arteries and they widen them so that it is easier for blood to flow through
How does the heart pump blood?
~ Atria (both atrium) fill up
~ Atria contract and force blood into ventricles
~ Ventricles contract and force blood out through the major blood vessels at the top of the heart and it travels to other parts of the body
How do digested substances in the small intestine move into the blood?
~ In the small intestine are villi (sing. Villus)
~ On villi are microvilli, in the microvilli are mitochondria
~ The mitochondria release energy from respiration and carry out active transport, which moves digested substances into the blood
What do red blood cells do?
Transport oxygen
Why do red blood cells not have a nucleus?
So they can carry lots of haemoglobin
What do valves in the heart do?
Make sure blood flows in the right direction
What happens to haemoglobin when it’s exposed to oxygen?
It converts into oxyhaemoglobin
Why is there an interest in artificial blood?
- Lack of donors from normal blood
- Not all normal blood types are compatible with other people
- Risk of infection with normal blood
What are advantages of artificial blood?
- Artificial blood can be stored for 3 years or more
* Artificial blood can be used immediately
What are disadvantages with heart transplants?
- Lack of donors so you have to wait a long time
- Low success rate
- Risk of infection
