Blood vessels and blood Flashcards
Name the 3 blood vessels?
arteries, capillaries and veins.
Describe structure of arteries
Thick muscular wall to withstand high blood pressure
can stretch to prevent bursting from high blood pressure
Elastic fibre stretch when surge of blood passes through and recoils between surges to keep blood moving.
Describe structure of capillaries
Really close to every cell in the body to exchange substances.
permeable walls so substances can diffuse in and out.
supply food and oxygen and take away waste like CO2
one cell thick increases rate of diffusion by decreasing distance over which it occurs.
very small lumen
Describe structure of veins
Thin wall-blood pressure is low
Contains valves to prevent backflow of oxygenated blood.
Bigger lumen to help blood flow.
What is the function if the arteries?
Carry deoxygenated blood away from the heart
What is the function of the veins?
Carries oxygenated blood to the heart
What is the function of the capillaries?
Involve exchange of materials in tissues.
What is the equation for the rate of blood flow?
Volume of blood divided number of minutes.
What is plasma?
Pale straw-coloured liquid that carries everything in the blood.
What is the function of plasma?
Carries red blood cells, white blood cells and platelets
Transports soluble digestion products eg glucose.
transport carbon dioxide (produced by aerobic
respiration) from organs to lungs
transports urea from liver to kidneys to be excreted by urine.
What is the function of red blood cells?
carries oxygen from lungs to all cells in body.
shaped like biconcave gives large surface area for oxygen to be absorbed.
contain haemoglobin which attaches to oxygen and forms oxyhaemoglobin. In body tissues oxyhaemoglobin splits up haemoglobin and oxygen to release oxygen to cells.
no nucleus allows more room to carry oxygen.
What is the function of white blood cells?
Engulf and destroy pathogens (phagocytosis)
produce antibodies to fight against pathogens.
Produce antitoxins to neutralise toxins produced by pathogens.
Remain in the blood for a long time and can protect us if we get infected again by the same pathogen.
What are red blood cells?
carry oxygen around the body.
What are white blood cells?
Defend us against infections
What are platelets?
Small fragments of cells
