3.2 circulatory sytems Flashcards
state the features of an open circulatory system
-no blood vessels
-haemolymph
-less efficient (low blood pressure, flow affected by body movement)
what makes the double circulatory system more efficient
-blood pressure in lungs not too high
-heart can boost pressure before blood to the body
-body circulation at higher pressure
features of an artery
small lumen
thick elastic fibres
thick smooth muscle
collagen
features of vein
wide lumen
thin elastic fibres
thin smooth muscle
collagen
contain valves
features of a capillary
endothelium can be fenestrated in different levels of porosity
how is tissue fluid made and reabsorbed
-at arteriole end: hydrostatic pressure > oncotic pressure ,
net movement out
-at venule end: oncotic pressure > hydrostatic pressure,
net movement in
what is the lymphatic system
overflow of the tissue fluid which is drained to the heart.
what is the AVN
-atrioventricular node
-sends wave of depolarisation down bundle of his and up ventricle walls
what is the SAN
-sinoatrial node
-pacemaker
-this is what makes the heart myogenic
role of purkyne fibres
spread electrical impulse
what is p on an ECG
atrial excitation
what is QRS on an ECG
ventricle excitation
what is T on an ECG
repolarisation
what is the bohr shift
if co2 is present graph of affinity of oxygen is shifted down
explain how the bohr shift happens
CO2 + H2O > H2CO3- > H+ + HCO3- (TO PLASMA)
H+ > HHb
haemoglobin oxide dissociates in the presence of haemoglobinic acid
