Blood Flashcards
Describe the composition of red blood cells (5)
Biconcave, disc-like cells without nucleus. Transport of oxygen - contain mainly haemoglobin, which loads oxygen in lungs and unloads it in other parts.
Describe the composition of white blood cells
Lymphocytes: produce antibodies to destroy microorganisms
Phagocytes: engulf bacteria and other microorganisms that have infected the body.
Describe the composition of platelets
Release chemicals to make blood clot when we cut ourselves
Describe the composition of plasma
Carries blood cells around the body; carries dissolved nutrients, hormones, Carbon dioxide, and urea; also distributes heat around the body.
Explain how red blood cells are suitable for the transport of oxygen
No nucleus so more room for haemoglobin
Biconcave shape allows efficient exchange of oxygen in and out of cell.
Have high surface area to volume ratio therefore larger area for diffusion
Thinness gives a short diffusion distance to the centre of the cell
Thin cell surface membranes allows oxygen to diffuse through easily
Pathogens
May be fungi, bacteria, protocols or viruses.
How immune system responds to disease using white bloods:
Phagocytes
Change their shape, producing extensions of their cytoplasm, called pseudopodia. This surrounds and encloses the pathogen in a vacuole. Then phagocyte secretes an enzyme and breaks down pathogen. (Phagocytosis)
How immune system responds to disease using white blood cells:
Lymphocytes
Make chemicals called antibodies, which are soluble proteins that pass into the plasma. Pathogens have ‘markers’ which the antibodies recognise. These markers are called antigens. The antibodies stick to the antigens and destroy the pathogen.
AND AND AND AND AND
lymphocytes can develop into memory cells that make us immune to diseases.
Structure and role of:
Arteries
Carry blood from the heart to organs of the body. This blood (arterial blood) has been pumped out by the ventricles and puts a lot of pressure on the walls or the arteries.
Structure and role of:
Veins
Carry blood from organs back towards the heart. The pressure of this blood (venous blood) is much lower than that in the arteries. Veins must be able to allow the blood to pass through easily and prevent it from flowing in the wrong direction.
Structure and role of:
Capillaries
Carry blood through organs, bringing the blood close to every cell in the organ. Capillaries must be small enough to fit between cells.
The structure of the heart and how it functions
The human heart pumps blood around the body at different speeds and at different pressures according to the body’s needs blood is moved through the heart by a series of contractions and relaxation a of cardiac muscle in the walls of the four chambers.
Vaccinations results in…
The manufacture of memory cells, which enable future antibody production to the pathogen to occur sooner, faster and in greater quantity.
