Miss Palmer- Transport in Animals Flashcards
what is a circulatory system
uses blood to carry glucose and oxygen around the body which carries hormones, antibodies, and waste products ( co2 + urea)
what are features of multicellular organisms
relatively big so need transport system , low surface area: volume ratio, high metabolic rate ( speed reactions take place), very active as cells are constantly respiring so need constant oxygen and glucose and co2 removed
what is a single circulatory system
blood passes through the heart once each complete circuit of the body
what organism uses a single circulatory system
fish as they are less active so need less oxygen for respiration
what is a double circulatory system
passes through the heart twice in one circuit, right is deoxygenated blood
what is a closed circulatory system and what organisms have ne
all vertebrates ( fish and mammals) have closed systems- blood is enclosed in blood vessels
what is an open circulatory system and what organisms have one
blood isn’t enclosed in blood vessels all the time, instead flows freely through body cavity, all invertebrates ( insects) have an open system
what are arteries and how are they specialised to their function
carry blood away from the heart
walls are thick, muscular and elastic to withstand the pressure and allows it to stretch and recoil
endothelium is folded to allow it to expand under high pressure
all carry oxygenated blood except pulmonary arteries which takes deoxygenated blood to lungs
what are arterioles and what is their function
arteries branch into arterioles which are much smaller but have less elastic tissue
have a smooth layer of muscle to allow it to expand and contract, so controls the amount of blood
what are capillaries and what is their function
arterioles branch into capillaries
smallest blood vessels
glucose+ oxygen are exchanged between cell and capillaries - one cell thick for efficient diffusion
what are venules and what is their function
capillaries connect to venules
thin walls, muscle cells
join together to form veins
what are veins and what is their function
take blood back to heart
wider lumen as less pressure
valves to keep blood flowing in correct direction
all carry deoxygenated blood as it has been used up in the cells apart from pulmonary veins which carry oxygenated blood to heart from lungs
what is tissue fluid
surrounds cells in tissue
made from substances that leave blood plasma e.g. oxygen, water, nutrients
cells take oxygen and nutrients from tissue fluid which is made from substances that come out of capillary by pressure filtration
what is pressure filtration and how does it work
at start of capillary bed, nearest to arteries hydrostatic pressure is higher than tissue fluid so moves out of capillary into spaces around cell causing tissue fluid. this reduces hydrostatic pressure in the capillaries which means their is a lower water potential inside than outside but the oncotic pressure (plasma protein) is higher inside that outside so some water enters via osmosis to reach equilibrium.
what is a lymph vessel and how does it work
not all the tissue fluid re-enters the capillaries , so some tissue fluid left over this gets returned into the blood via the lymphatic system which is a drainage system made of lymph vessels
once inside the lymph, valves stop lymph going backwards , gradually moving towards lymph vessels in thorax
What side of the heart pumps deoxygenated blood
The right side
What does AV valves stand for and what does it do
Atrioventricular valves link atria to the ventricles
What does SL valves stand for and what do they do
Semi-lunar that link the ventricles to pulmonary artery and aorta
What do valves do
Stop backflow of blood as they only open one way
What makes the valves open
The Higher the relative pressure behind the valves
What causes the valves to close
If the pressure is higher at the front of the valve
What is the cardiac cycle
Ongoing sequence of contraction and relaxation of the atria and ventricles which changes the volume and therefore the pressure.
What is stage one of the cardiac cycle
Ventricles relax , atria contract
Decreases volume of chambers so the pressure increases , pushing blood out through the ventricle through AV valves
What is stage 2 of the cardiac cycle
Ventricles contract and atria relaxes
The pressure inside the ventricles is higher than atria which causes the AV valve to close to prevent back-flow and SL valves to open so blood is forced into arteries