Circulatory System Flashcards
types of circulatory system
gastrovascular cavity
open circulatory system (haemolymph (tissue fluid+blood), animal movement/heart = pumping)
closed circulatory system
advantages of a closed circulatory system
blood flows more rapidly through vessels than intracellular spaces
possible to selectively direct blood to specific areas
transport facilitating molecules stay within vessels
-> support higher metabolic activity
what is the blood made up of?
Connective tissue Plasma: water + gases, nutrients, ions, proteins Red blood cells White blood cells Platelets
What does erythropoetin do?
stimulates the increase in production of red blood cells
what does to renin-angiotensin-aldosterone pathway do?
the regulation of the plasma sodium concentration and arterial blood pressure.
when is the renin-angiotensin-aldosterone pathway activated?
When blood volume or sodium levels in the body are low, or blood potassium is high, cells in the kidney release the enzyme, renin - causes blood pressure to increase
what are red blood cells also known as?
erthyrocytes
what is haemoglobin made out of?
2 x α subunits
2 x β subunits
Each has haem (Fe) group
how is haemocyanin different to haemoglobin?
2 subunits only with Cu groups instead of Fe
which animals use haemocyanin?
some crustaceans
what are platelets?
Fragments of megakaryocytes
Collagen fibres -> sticky spiky ball
Stimulates clotting cascade
what happens to tissue fluid that is not drawn back into capillaries?
merge into larger vessels or drain into superior vena cava
fish heart structure
Two chambers 1 atrium 1 ventricle Low pressure in aorta Skeletal muscle helps pump
amphibian heart structure
Three chambers 2 atria 1 ventricle, but partially separated Minor mixing of oxygenated and deoxygenated blood High pressure in aorta
reptile heart structure
Three(ish) chambers 2 atria 1 ventricle with complex division Switch lung supply on and off 2 aortas
