transport in animals- cardiac cycle and circulation Flashcards
what is an open circulatory system
blood does not flow through vessels but pumped into large spaces in body cavity
name a group of organisms with an open circulatory system
Insects
assess the similarities and differences in vascular systems between earthworms and insects
Earthworms:
- closed circulation
- pumps
- vascularisation
- carriage of respiratory gases in blood
Insects:
- Open circulatory system
- dorsal tube shaped heart
- blood does not carry respiratory gases
what is a single circulatory system and where is it found
blood passes throught the heart once in a total circuit of the body
deoxygenated blood pumped to gills (oxygenated) then goes directly to the organs and back to the heart
Fish
what are the three main types of blood vessels
Arteries
veins
capillaries
through which blood vessels does the blood pass after leaving the heart until it returns back to the heart
Artery Arteriole Capillary venule vein
describe the physiology of an artery
carries blood away from the heart under high pressure
relatively small lumen
endothelium
lots of elastic tissue
thick smooth muscle
outer layer-collagen +elastic fibres
describe the physiology of a veins
carries blood to the heart
relatively large lumen
endothelium
thin smooth muscle
outer layer-collagen +elastic fibres
explain how the semi lunar valve works in veins and what its purpose is
blood has enough pressure to open the valve
back flow of blood causes the valve to shut
this prevents the blood flowing backwards in the vein
what is a double circulation system
blood passes through the heart twice in each circuit of the body
(lungs and somatic)
which vessels go into the right atrium
(superior and inferior) vena cava
which vessel goes out from the right ventricle
pulmonary artery
which vessels go into the left atrium
pulmonary vein
which vessels go into the left ventricle
aorta
explain the cardiac cycle
Atrial systole
the atria is full of blood and ventricles are relaxed
atria contract
atrio-ventricular valves opens due to pressure of blood
ventricular systole
- atria relaxes
- the ventricles contract- forcing blood into the pulmonary artery and aorta
- av valve closed by pressure of ventricular contraction so that blood doesnt go back into the atria (lub)
- semi lunar valve opens
- blood flows into the pulmonary artery and aorta
Diastole
ventricles relax
pressure in ventricles drops below arteries
semi lunar valve closes (dub)
all heart muscle relaxes
blood from pulmonary veins and vena cava flow into atria
explain how the heart is myogenic
myogenic meants that it can cause its own contraction without innervation
sino-atrial node (pace maker of heart) depolarises sends impulse to both atria and atrio ventricular node (AVN).
AVN generates its own impulse which pass down Bundle of His (in septum) and Purkinje fibres to the apex of the heart.
this causes the contraction of the ventricles
what is the function of red blood cells
carry oxygen around the body
how is carbon dioxide carried around the body
CO2 diffuses into the red blood cell
reacts with H2O to form H2CO3 which dissociates into H+ and HCO3-
the H+ combines with Hb to make HHb (haemoglobonic acid) this decreases the affinity for O2 which is released from Hb
HCO3 diffuses out of the cell down its concentration gradient.
cl- ions diffuse into the rbc to balance the loss of charge (chloride shift)
what is the bohr effect
oxygen dissociation curve- move to the right - lower affinity for O2
move to the left higher affinity for O2
higher CO2 partial pressures lowers the affinity of Hb to O2 (moves the dissociation curve to the right)
