Gas exchange and blood proteins

where does gas exchange occur?

lungs - in tiny sacs aka alveoli

what are alveoli surrounded by?

a network of capillaries to help with gas exchange

gas exchange at the lungs process

move via diffusion (high concentration to low concentration)

oxygen diffuses from air in the alveoli into the blood

co2 diffuses from the blood into the air in the alveoli

how are alveoli adapted for gas exchange?

thin

large surface area

gas exchange at the lungs diagram

erythrocytes

red blood cells

role of haemoglobin in red blood cells

loads o2 at the lungs and unloads it at respiring tissues

loads co2 at respiring tissues and unloads it at the lungs

percentage of oxygen and carbon dioxide in inhaled air

21% oxygen

0.04% carbon dioxide

percentage of oxygen and carbon dioxide in exhaled air

16% oxygen

4% carbon dioxide

types of blood proteins

haemoglobin, myoglobin, foetal haemoglobin

where is haemoglobin found?

in red blood cells

function of haemoglobin

carries 4 oxygen molecules

transports oxygen around the body

removes co2 as a waste product

oxyhaemoglobin

oxygenated form of haemoglobin

where is myoglobin found?

in muscle cells

myoglobin function

an oxygen and iron binding protein which releases oxygen to muscle cells when oxygen conc. is low

carries one oxygen molecules

acts as an oxygen store

oxymyoglobin

oxygenated form of myoglobin

foetal haemoglobin

foetus cannot use its lungs, so relies on exchanging oxygen and co2 via diffusion from its mother’s blood

has a higher affinity for oxygen, so is more efficient at extracting oxygen from maternal circulation

what causes an increase in co2 in the blood?

increased rates of respiration

what happens to co2 in the blood?

it dissolves and forms carbonic acid

how does carbonic acid affect blood pH?

lowers it (makes it more acidic)

how does low pH affect haemoglobin?

causes haemoglobin to release more oxygen

why is the Bohr effect important during exercise?

ensures muscles receive more oxygen so they can continue working at a high rate

what is the Bohr effect?

the concept that a decrease in blood pH (due to increased CO2) reduces haemoglobin’s affinity for oxygen, causing more oxygen to be released to tissues