Transport in Animals Flashcards
what is the need for transport systems
- need to exchange substances with their surrounding environment
- singed celled organisms have a high SA:V
- exchange substances via diffusion
- multicellular organisms have a smaller SA:V as their size increases there is a longer diffusion distance
what is an open system
- blood isn’t contained within blood vessels but is pumped directly into the body cavity (haemocoel)
- haemocoel comes into direct contact with tissues and cells where exchange takes place between the transport medium and cells
what is a closed system
- blood is pumped around the body and is always contained within a network of blood vessels
what is a single system
- blood passes through the heart once during one complete circuit of the body
what is a double system
- blood passes through the heart twice during one complete circuit of the body
how does the circulatory system in fish work
- single system
- deoxygenated blood is pumped to the gills from the heart
- gills are the exchange site where oxygen and carbon dioxide are exchanged with the atmosphere and blood
- oxygenated blood flows from the gills to the body
- blood returns to the heart
- heart has one atrium and one ventricle
how does the circulatory system in animals work
- blood in the right side of the heart leaves and travels to the lungs
- blood returns to the left side of the heart before being pumped around the body
how does the circulatory system in insects work
- tubular heart pumps haemoglobin into the dorsal vessels
- dorsal vessel delivers haemolymph into haemocoel
- haemolymph re enters the heart via a one way valve called ostia
what are the components of blood vessels
- elastic fibres
- smooth muscle
- collagen
what are elastic fibres
stretch and recoil providing walls with flexibility
what is smooth muscle
contracts and relaxes which changes lumen size
what is collagen
provides structural support to maintain the shape and volume of the vessel
what are arteries
- transport blood from the heart to the rest of the body
- walls are thick, muscular, elastic fibres to stretch and recoil as the heart beats to maintain high pressure
- endothelium is folded allowing artery to expand
- narrow lumen
what are arterioles
- branch from arteries, transport blood into capillaries
- smooth layer allowing them to expand and contract which controls the amount of blood flow into tissues
- muscular layer allows them to partially cut off blood flow to specific organs
what are veins
- return blood to the heart under low pressure
- wide lumen so blood returns faster with less friction between blood and endothelial layer
- valves prevent the backflow of blood
what are venules
- connect capillaries to veins
- few/no elastic fibres
- large lumen
what are capillaries
- leaky thin walls allowing substances to leave the blood to reach body tissues
- small lumen so blood moves slowly for more diffusion
- thin walls allow for a short diffusion distance
what is hydrostatic pressure
pressure exerted by a fluid
what is oncotic pressure
- osmotic pressure exerted by plasma proteins within a blood vessel
how is tissue fluid formed at the arterial end
- blood at arterial end
- hydrostatic pressure forces fluid out of capillary
- proteins are large and remain in blood
- increased protein content creates water potential gradient between capillary and tissue fluid
- hydrostatic pressure is greater than oncotic pressure, movement of water is out of capillaries into tissue fluid
how is tissue fluid formed at the venous end
- hydrostatic pressure within the capillary is reduced due to increased distance from the heart
- water potential gradient stays the same
- oncotic pressure greater than hydrostatic
- water flows into capillary from tissue fluid
what is the lymphatic system
- excess tissue fluid passes into lymph vessels
- becomes lymph inside
- valves prevent lymph from going backward
- lymph moves to lymph vessels in thorax
- lymph re-enters bloodstream through veins
what is the mammalian heart structure
- protected in chest by pericardium
- left and right side separated by septum
- interatrial septum separates atria’s
- interventricular septum separates ventricles
what does the tricuspid valve separate
right atria and ventricle
what does the pulmonary valve separate
right ventricle and pulmonary artery
what does the bicuspid valve separate
left atria and ventricle
what does the aortic valve separate
left ventricle and aorta
what brings blood to the heart
vena cava and pulmonary vein
what takes blood away from the heart
pulmonary artery and aorta
what are coronary arteries
- receives blood through arteries
- supply cardiac muscle with nutrients
- removes waste products
what is atrial systole
-atrial walls contract - atrial volume decreases and pressure increases
- pressure forces atrioventricular valves open
- blood forced into ventricles
what is ventricular systole
- ventricle walls contract - ventricular volume decreases and pressure increases
- atrioventricular valves forced closed
- force semi-lunar valves open
- blood forced into arteries and out of the heart
what is diastole
- ventricles and atria are relaxed
- pressure in ventricles drops below pressure in the aorta and pulmonary artery forces semi-lunar valves closed
- pressure in atria rises forcing atrio-ventricular valves open
- blood flows into ventricles
what is cardiac output and how do you calculate it
- volume of blood that is pumped by the heart per minute
heart rate x stroke volume
heart rate = number of times a heart beats per minute
stroke volume = volume of blood pumped out of the left ventricle
what is the electrical activity in the heart
- starts in sino atrial node in wall of right atrium
- SAN sets rhythm of heartbeat by sending out waves of electrical activity to atrial walls
- right and left atria contract at the same time
- band of non-conducting collagen tissue prevents waves of electrical activity passing directly from atria to ventricles
- waves of activity transferred from SAN to AVN
- bundle of His conducts waves of activity to purkyne tissue in right and left ventricular walls contracting simultaneously
what are electrocardiograms
- used to monitor and investigate electrical activity of the heart
- use electrodes placed on the chest
what is tachycardia
- heart beats too fast
- resting heart rate of 100bpm
what is bradycardia
- heart beats too slow
- resting heart rate of 60bpm
what is an ectopic heartbeat
- early heartbeat then pause
what is fibrillation
irregular heartbeat
what are the adaptations of erythrocytes
- flattened biconcave shape increases surface area and maximises diffusion
- no nucleus to maximise space for haemoglobin
- large diameter to slow blood flow to enable the diffusion of oxygen
what is haemoglobin
- protein that makes up 95% of red blood cells
- 4 polypeptide chains each bound to a haem group
- each haem group combines with one oxygen molecule
- 1 molecule of haemoglobin can bind to 4 oxygen molecules = oxyhaemoglobin
how does oxygen bind to haemoglobin
- oxygen binds to haemoglobin at a high oxygen concentration
- oxygen dissociates from haemoglobin at a low oxygen concentration
what is partial pressure
- mixture of gases that has an overall pressure
- each gas in the mixture is contributing
what is the bohr shift
- describes the effect of high carbon dioxide concentration on haemoglobin affinity to oxygen
- low amount of partial pressure of carbon dioxide increases the affinity
- high amount of partial pressure of oxygen decreases the affinity
- as proportion of carbon dioxide increases the oxygen dissociation curve for HB moves to the right
what is foetal haemoglobin
- higher affinity for oxygen
- helps maximise oxygen uptake from the mother’s bloodstream
what is myoglobin
- 1 haem group
- high affinity for oxygen even at low partial pressures
- oxymyoglobin will only ever dissociate when oxygen levels are low
how is carbon dioxide transported
- 5 % produced by respiring cells
- diffuses into the cytoplasm
- carbonic anhydrase produces carbonic acid
- 10-20% combines with amino groups to form carbaminohaemoglobin
- 75-80% converted to hydrogen carbonate
what is hydrogen carbonate
- carbon dioxide reacts slowly with water to form carbonic acid
- weak acid - partially dissociates to form hydrogen carbonate and hydrogen ions
- sped up by high levels of carbonic anhydrase
what is haemoglobinic acid
- hydrogen ions produced by dissociation binds with haemoglobin to form haemoglobinic acid
- haemoglobin acts as a buffer
what is the chloride shift
- negatively into charged hydrogen carbonate ions move out of the cell and red blood cells become positive
- chloride ions move into red blood cells
