transport in animals qp3 Flashcards
what is the inner layer made of and what is it called
tunica intima- is folded and can stretch and recoil to maintain blood pressure
what is the medium layer made of and what is it called
tuncia media- thick layer of smooth muscle which can contract (vasoconstriction) or relax
what is the outer layer made of and what is it called
tunica adventitia- a thick layer of collagen and elastic tissue which provides the strength to withstand high pressure and recoil to maintain high pressure
what are ways in which arteries are different to the wall of a vein
arteries have:
-no valves
-endothelim/tunica intima is folded
-more / thicker muscle/ elastic tissue/ tunica media
-more/ thicker collagen
why does hydrostatic pressure drop as the blood moves away from the heart
- more (smaller) vessels
- vessels have a larger total lumen/ cross sectional area
-reduced resistance to blood flow
-arteries stretch/ expand - loss of fluid/ plasma from capillaries
what is tissue fluid used to exchange
tissue fluid is used to exchange nutrients and gasses between cells and the body
-cells can take up oxygen and nutrients from the tissue fluid and release metabolic waste into it by diffusion
what does the oncotic pressure of blood tend to do
the oncotic pressure of blood tend to pull water back into the blood
what does the oncotic pressure of the tissue fluid tend to do
the oncotic pressure of the tissue fluid tends to pull water into the tissue fluid
what does hydrostatic pressure of the blood tend to do
hydrostatic pressure of the blood tends to push fluid back into the tissues
define single circulatory system
blood passes through the heart once for each circulation/ circuit of the body
once reaching the AVN after atrial systole has occurred, where does the wave of excitation spread down
the excitation spreads down the septum
why is there a short delay between the excitation of the atria and the excitation of the ventricles
so ventricles do not contract before they are fully full
explain why the excitation wave is spread to the apex
- to ensure that the ventricles contract from the bottom upwards
-to push blood upwards
-complete/ efficient emptying of ventricles
what does the P wave represent
excitation of the atria
what does the QRS complex represent
electrical stimulation of the ventricles
