module three Flashcards
(32 cards)
countercurrent flow
water flows opposite to blood over gill lamellae
what is countercurrent flow needed to do?
maintain concentration gradient for diffusion
open circulatory systems
few transport vessels, pumped at low pressure and doesnt transport gases
single circulatory system
one per cycle, one circuit and 2 sets of capillaries.
works for fish due to countercurrent mechanism
capillaries
lumen just slightly bigger than red blood cell, red blood cell squashed against walls and walls one cell thick in order to create a short diffusion distance and maximise diffusion
smooth muscle
thicker in arteries than veins, but thickest in arterioles. none in capillaries. helps constrict the arteries so blood can flow through at high pressure.
elastic layer
thicker in arteries and veins to maintain high blood pressure. none in capillaries, thickest in arteries.
collagen layer
lots of collagen in walls of veins for strength.
hydrostatic pressure
pressure exerted by liquid
oncotic pressure
tendancy of water to move into the blood by osmosis
where abouts in the capillaries has high hydrostatic pressure?
arteriole end due to small diameter.
this pressure forces water, glucose, fatty acids, amino acids, ions and oxygen out of the capillaries at the arterial end.
tissue fluid reabsorption
large molecules e.g. plasma proteins remain in the capillaries and therefore lower the water potential of the blood remaining in the capillary.
this lower water potential results in a higher oncotic pressure towards the venule end of the capillaires
hydrostatic pressure low due to loss of liquid , water potential very low
what happens to the remaining liquid in the capillaries?
absorbed into lymphatic system, eventually drained back into the bloodstream near the heart.
spiracles
open and close for gas exchange and to prevent water loss
why do insect abdominal muscles contract and relax?
for pumping mechanism to moce gases in and out of spiracles and trachea
what does many tracheoles allow the insect to have?
large surface area
what do the tracheoles being thin-walled and close to the muscle mean?
short diffusion distance
what happens when an insect is in flight?
anaerobic respiration to produce lactate.
this lowers the water potential of the cells so water moves from tracheoles to the cells by osmosis
this decreases volume of liquid in the tracheoles, so more air from the atmosphere moves in
what do the coronary arteries supply the cardiac muscle with?
oxygenated blood for aerobic respiration, provides ATP so the cardiac muscle can continually contract and relax
preicardial membranes
surrounds the heart and are inelastic which prevents the heart from filling and swelling with blood
why is the left ventricle thicker than the right one?
so it can contract with more force and pump blood at a higher pressure as it needs to reach all around the body.
why do the atria have thin walls
blood only needs to be pumped to the ventricles
atrial systole
atrial muscles contract, increasing pressure further. AV valves open and blood flows to the ventricles
ventricular systole
ventricular muscles contract, increasing pressure. AV valves close and SL valves open. blood is pushed out of the ventricles and into the arteries
