composition of blood Flashcards
Plasma is important for the transport of many substances including:
Carbon dioxide - the waste product of respiration, dissolved in the plasma as hydrogencarbonate ions and transported from respiring cells to the lungs
Digested food and mineral ions - dissolved particles absorbed from the small intestine and delivered to requiring cells around the body
Urea - the waste substance produced in the breakdown of proteins by the liver. Urea is dissolved in the plasma and transported to the kidneys
Hormones - chemical messengers released into the blood from the endocrine organs (glands) and delivered to target tissues/organs of the body
Heat energy - created in respiration (an exothermic reaction), heat energy is transferred to cooler parts of the body or to the skin where heat can be lost
red blood cells are adapted to carry oxygen in 3 ways:
They are full of haemoglobin, a protein that binds to oxygen to form oxyhaemoglobin
They have no nucleus which allows more space for haemoglobin to be packed in
The shape of a red blood cell is described as being a ‘biconcave disc’ this shape gives them a large surface area to volume ratio to maximise diffusion of oxygen in and out
