SB8c Circulatory System Flashcards
What do red blood cells (erythrocytes) do and what do they contain?
.they carry oxygen
.contain haemoglobin which is red dye that binds to oxygen
How are red blood cells adapted?
.have dips on both sides (biconcave) - maximise their surface area to absorb oxygen as quickly as possible
.have no nucleus - can carry more oxygen
What do white blood cells do? (identify the two cells)
.phagocytes - engulf and digest pathogens
.lymphocytes - release antibodies
What is plasma?
.liquid that carries blood cells, glucose and carbon dioxide
What do platelets do?
.they allow blood to clot
What do arteries do?
takes blood away from the heart.
State 3 features of arteries.
.narrow lumen to maintain blood pressure
.thick elastic wall - allows stretch and recoil
.strong outer wall
What do veins do?
they carry blood back to the heart.
Explain 2 features of veins.
.wide lumen with valves - valves prevent backflow
.thin walls as blood is under lower pressure
What do capillaries do?
they conect veins and arteries.
Explain 1 feature of capillaries.
.their one cell thick - short diffusion distance
How is blood pumped? (4)
.the heart pumps blood at high pressure into the arteries
.artery walls stretch as the blood moves through (pulse)
.veins are at lower pressure
.muscles push the blood back to the heart and valves prevent backflow
How is oxygen transported from the lungs to a tissue? (3)
.oxygen enters the blood through the alveoli and into the capillaries
.the capillaries join veins which flow to the heart
.the heart then pumps the blood through arteries towards capillaries that surround tissue
what does Alveoli do?
move oxygen into bloodstream and carbon dioxide out of bloodstream
