transport in animals Flashcards
(31 cards)
name and describe the two main features of a fish’s gas transport system
~gills= located within the body, supported by arches, along with multiple projections of gill filaments, which are stacked up in piles
~lamellae= at right angles to the gill filaments, give an increased surface area. blood and water flow across them in opposite directions (countercurrent)
explain the process of gas exchange in fish
~buccal cavity volume increased to enable water to flow in
~water is pumped over the lamellae by the operculum, oxygen diffuses into the bloodstream
~waste carbon dioxide diffuses into the water and flows back out of the gills
explain gas exchange in bony fish- constant water flow
~mouth opens, water flows into the buccal cavity
~floor of buccal cavity drops down, increasing the volume available
~fish shuts operculum increasing volume of opercular cavity, pressure in opercular cavity falls
~floor of the buccal cavity lifts upwards, increasing the pressure of the water causing water to flow over the gills
~mouth closes, operculum opens, sides of opercular cavity squeeze inwards - forcing it out the operculum
how does the counter current exchange system maximise oxygen absorbed by the fish
~maintains a steep concentration gradient, as water is always next to blood of a lower oxygen concentration. keeps rate of diffusion constant and enables 80% of available oxygen to be absorbed
~ means equilibrium is never reached
name and describe the three main features of an insects gas transport system
~spiracles= holes on the body’s surface which may be open or closed by muscular sphincter for gas or water exchange
~tracheae= large tubes extending through all the body tissues, supported by rings to prevent collapse
~tracheoles= smaller branches dividing off the tracheae
explain the processes of gas exchange in insects
~gas es move in and out trachea through the spiracles
~a diffusion gradient allows oxygen to diffuse into the body tissue while waste CO2 diffuses out
~contraction of muscles in the tracheae allows mass movement of air in and out
summarise the different types of circulatory systems
~open= blood can diffuse out of vessels eg insects
~closed= blood confined to vessels eg fish, mammals
-more efficient and can control amount of blood going to diff organs - vasoconstrictio/dialation
~single= blood passes through pump once per circuit of the body
~double= blood passes through heart twice per circuit of the body
relate the structure of arteries to there function
~carry blood away from heart at high pressure
~thick muscular wall to withstand pressure
~elastic fibres stretch and recoil as blood pulses through
~lumen is narrow to maintain pressure and lined with endothelium cells which reduce friction.
relate the structure veins to their function
~carry blood under low pressure
~lumen is larger as carry a greater deal of blood
~lined with endothelium to reduce friction
~valves to prevent backflow
~thin walled as blood under low pressure and doesn’t pulse
relate the structure of arterioles and venules to their function
~branch off arteries and veins in order to feed blood into the capillaries
~smaller than arteries and veins so that the pressure change is more gradual as blood passes through increasingly small vessels
relate the structure of capillaries to their function
~walls are one cell thick - short diff distance
~numerous and highly branched- providing a large sa
~lumen not much larger than RBC so it gets pressed against capillary wall, they must also pass through single file increasing gas exchange
what is tissue fluid
a watery substance containing glucose, amino acids, oxygen and other nutrients . it supplies these cells while also removing any waste materials
formation of tissue fluid
~at arteriole end - is under high hydrostatic pressure, which forces fluid out of the blood
- plasma proteins are hydrophilic so they lower the water potential of the plasma, this causes water to move back in - oncotic pressure
~hydrostatic pressure> oncotic pressure - pushes tissure fluid out gaps - ultrafiltration
~at venous end - hydrostatic pressure < oncotic pressure - causes tissue fluid to be reabsorbed back into the blood
how is tissue fluid formed basic
as blood is pumped through increasingly small vessels, hydrostatic pressure is greater than oncotic pressure, so fluid moves out of the capillaries
how does tissue fluid differ from blood and lymph
~tissue fluid is formed from blood but does not contain red blood cells, platelets, and various other solutes usually present in blood
~after tissue fluid has bathed cells it becomes lymph, and therefore this contains less oxygen and nutrients and more waste products
cardiac diastole
~the heart is relaxed. blood enters the atria, increasing the pressure and pushing open the atrioventricular valves. this allows blood to flow into the ventricles
atrial systole
the atria contract, pushing any remaining blood into the ventricles
ventricular systole
the ventricles contract. the pressure increases, closing the atrioventricular valves to prevent backflow. semilunar valves open. blood flows into the arteries
how do you calculate cardiac output
cardiac output= heart rate x stroke volume
myogenic meaning
the hearts contraction is initiated from within the muscle itself, rather than by nerve impulses
explain how the heart contracts
~SAN initiates and spreads an electricle impulse across the atria
~AVN receives, delays and then conveys the impulse down the bundle of his
~impulse travels into the purkinje fibres which branch across the ventricles, so they contract from the bottom up.
describe types of abnormal activity that may been seen on an ECG
~tachycardia= fat heart beat ( over 100BPM )
- short term - exercise, fear , panic
- long term problems with SAN node
~bradycardia= slow heartbeat ( under 60BPM )
- can be due to athletic training which increases the stroke volume of the heart
- developed due to disease may require artificial pace maker
~fibrillation= irregular waves of excitation pass over the atria , fast heartbeat
~ectopic= early or extra heartbeats
haemoglobin
~structure - 4 polypeptide chains, 4 prosthetic groups - haem contains iron ion fe2+ , is a conjugated protein
~o2 molecules ind to the haem groups and carry it round the body, then release them where they are needed in respiring tissues
