Haemoglobin

Question 1

What is haemoglobin?

Answer 1

A protein that carries oxygen around the body.

It has a quaternary structure

Question 2

Why do we need haemoglobin?

Answer 2

• Oxygen does not dissolve well so we need a molecule to carry it around the body.
• It cannot be carried into the blood plasma
• the red blood cells contain molecules of haemoglobin which will readily take on oxygen
• 1 haemoglobin molecule carries 4 molecules of oxygen

Question 3

What is oxygen loading/ unloading?

Answer 3

• The process by which haemoglobin binds to oxygen is known as loading or associating. This takes place in the lungs of mammals and forms oxyhemoglobin
• The process by which haemoglobin releases oxygen is called unloading or dissociating. In mammals it takes place in the tissues
• Oxygen leaves haemoglobin at the body cells, turning back to Hb, the allows oxygen to diffuse into the body cells for respiration. The red blood cells have a biconcave shape and no nucleus, this surface area allows it to carry more oxygen

Question 4

What is the oxygen saturation of blood?

Answer 4

The normal range for oxygen saturation levels is 95-99%, below this can indicate there is a problem. Emphysema and cystic fibrosis can both lead to low saturation levels

Question 5

What is used to measure oxygen saturation levels?

Answer 5

We use pulse oximeters to measure the oxygen saturation of the blood. This is a non-invasive method
It works by placing it over a finger, toe or earlobe. It uses wavelength of light to measure the amount of oxyhemoglobin compared to deoxyhaemoglobin

Question 6

What is emphysema?

Answer 6

A lung condition that causes shortness of breath.
In people with emphysema the air sacs in the lungs (alveoli) are damaged.
Over time the inner walls of the air sacs weaken and rupture, creating large air spaces instead of small ones.
This reduces the surface area of the alveoli and therefore the diffusion of oxygen - this leads to oxygen saturation.

Question 7

What is cystic fibrosis?

Answer 7

A genetic disorder that affects mostly the lungs, but also the pancreas, liver, kidneys and intestine.
Long-term issues include difficulty in breathing and coughing up mucus as a result of frequent lung infections, meaning reduction of oxygen saturation

Question 8

What are the symptoms of low oxygen saturation?

Answer 8

• shortness of breath
• headache
• dizziness