transport in man Flashcards
(51 cards)
plasma constituents
- is 55% of the blood volume
- contains 90% water, 10% dissolved solutes
what are dissolved in the blood plasma
mineral ions (sodium, potassium, calcium, magnesium, chloride, bicarbonate)
soluble food substances
metabolic waste products
plasma proteins
hormones
red blood cell (erythrocyte)
produced in bone marrow destroyed in liver and spleen
lifespan of 120 days, no nucleus for cell growth/repair
white blood cells (leucocytes)
cells are colourless, no haemoglobin, irregularly shaped, presence of nucleus
phagocyte: carries out phagocytosis, engulfs and digests bacteria
lymphocyte: produces antibodies
antibodies
- neutralise toxins produced by bacteria
- bind to the surface of bacteria, causing them to rupture
- bind to the surface of bacteria and tag them for phagocytosis by phagocytes
- cause bacteria to clump together so it can be easily injected by phagocytes
what has antigens
surfaces of RBCs
where are antibodies found
WBCs/plasma
agglutination
clumping of cells
when does agglutination occur
when antibody A recognises and binds to antigen A on the surface of RBCs
type O RBCS
have no antigens on its surface -> universal donor
type AB blood
no antibodies in the blood plasma of type AB blood -> universal recipient
Blood type A
Antigen A on RBC, antibody B in plasma
Blood type B
Antigen B on RBC, antibody A in plasma
Blood type AB
A and B antigens on RBC, no antibodies in plasma
Blood type O
No antigens on RBC, antibodies A and B in plasma
platelets (thrombocytes)
not true cells, just fragments
temporary clot
- temporary clot forms where platelets gather and release substances that attract platelets
- platelets become sticky and forms a platelet plug
blood clot benefits
- defends the body by preventing excessive blood loss from wound
- preventing entry of bacteria into body
clotting step 1
damaged platelets and tissues release thrombokinase (inactive enzymes)
clotting step 2
in the presence of calcium ions, thrombokinase converts inactive prothrombin (from blood plasma) into active thrombin
clotting step 3
thrombin converts soluble fibrinogen into insoluble fibrin threads
clotting step 4
fibrin threads form mesh that trap blood cells
blood vessel structures
innermost layer: endothelium
middle: smooth muscle tissue, elastic fibres (for arteries and arterioles -> smooth muscle in them bring about vasoconstriction and vasodilation)
outer: connective tissue
artery
- thick muscular walls
- allows diameter of blood vessel to be adjusted by contracting/relaxing)
- controls blood pressure inside vessel, regulates blood flow - numerous elastic fibres
- elasticity for blood vessels to dilate, stretch and recoil to enable it to withstand increases in blood pressure in vessel, prevents it from bursting
- stretch and recoil to help maintain high pressure of blood flowing through artery