3.2)Transport in animals Flashcards
what are the 3 factors that affect the need for a transport system?
- size
2.SA/V ratio - metabolic activity
how does size affect the need for a transport system?
-small animals=cells close to the environment
-large animals=longer diffusion distance=diffusion rate is slow
how does SA/V affect the need for a transport system?
-small animal=large SA/V ratio
-large animal= small SA/V ratio
how does the level of metabolic activity affect the need for a transport system?
-active=need a good supply of oxygen and nutrients for movement=need energy
-warmth
what are the features to a good transport system?
1.fluid
2.pump
3.exchange surfaces
why is fluid necessary for a good transport system?
carries nutrients, oxygen and waste around the body–blood
why is a pump necessary for a good T.S?
create pressure to push the fluid arounf the body
why are exchange surfaces necessary for a good T.S?
allow substances to enter and leave
what is a double circulatory system?
consists of 2 separate circuits
what is pulmonary circulation?
carry blood to the lungs to pick up oxygen
what is systemic circulation?
carry oxygen to the body
what are some disadvantages of a single circulatory system?
-low blood pressure
-slow flow
-limited rate of nutrients and oxygen delivered
what are some advantages of a double circulatory system?
-not too high pressure=could damage vessels
-high pressure=flow quickly
-systemic circulation has a higher pressure than pulmonary circulation
what is an open circulatory system?
-the blood circulates through blood cavities
-tissues and cells are bathed in the blood
how does an open circulatory system work in insects?
-pumping organ=long muscular tube
-blood from the body enters the heart through pores=ostia
-heart pumps blood to the head=peristalsis
-blood pours into the body cavity
what are some disadvantages of an open circulatory system?
-low blood pressure
-slow flow
-lack of body movement can affect blood circulation
what ia closed circulatory system?
-blood stays entirely in vessels
-cells and organs bathe in tissue fluid
what are some advantages of an closed circulatory system?
-high pressure=quick flow
-faster delivery of oxygen and nutrients
-faster removal of CO2 and O2
which direction does an artery transport blood?
carry blood away from heart
what are some features of an artery?
-thick artery wall=high pressure could cause damage
-small lumen=maintain pressure
-folded inner wall=lumen can expand as blood flow increases
-wall has 3 layers
what are the 3 layers of the artery wall?
1.inner layer=tunica intima
2.middle layer=tunica media
3.outer layer=tunica adventitia
what are the component of the tunica intima?
-thin layer of elastic tissue=stretch and recoil=maintain pressure
what are the component of the tunica media?
-thick layer of smooth muscle
what are the components of the tunica adventitia?
-thick layer of collagen=strength
-layer of elastic tissue=stretch and recoil=maintain pressure
what are arterioles?
small blood vessels that distribute blood from the artery to capillaries
what are some features of arterioles?
-layer of smooth muscle=reduce friction
-ability to constrict=reduce diameter of arteriole=higher resistance=slower R.O.F
-construction=allows blood to be directed too areas which demand more O2
what are capillaries?
thin blood vessels that help with the exchange of materials between the blood and tissue fluid
what are some features of capillaries?
-thin walls
-narrow lumen
-single layer of flattened endothelial cells
-leaky walls
how are thin walls useful to capillaries?
-shorter diffusion pathway=faster exchange of substances
how is a narrow lumen useful for a capillary?
RBC are squeezed against the wall=shorter diffusion pathway + increased resistance=slower R.O.F
how is a single layer of flattened endothelial cells useful for capillaries?
shorter diffusion pathway
how are leaky walls useful capillaries?
blood plasma and dissolved substances can leave the capillary
what are venules?
vessels that transport blood from the capillaries to the veins
what are the components of the walls of venules?
layer of collagen,muscle and elastic tissue
where do veins carry blood to?
towards the heart
what are some features of veins?
-thinner walls than artery=low pressure
-large lumen=ease flow
-thin layers of collagen and smooth muscle and elastic tissue (do not need to stretch or recoil
-not actively constricted
-valves=prevent blood flow in opposite direction
-can be flattened=changes the pressure of the blood
what is blood plasma?
plasma=dissolved substances
what are erythrocytes?
RBC
what are leucocytes?
WBC
what is tissue fluid?
-plasma leaking from capillaries
-surrounds cells and tissues=supplies O2 and nutrients
what is mass flow?
as blood plasma leaks=carries dissolved substances into tissue fluid
what is hydrostatic pressure?
the pressure created when blood is forced through the capillary
what is osmotic pressure?
-the movement out of the capillary
-water potential of capillary becomes more negative=h2o moves down the water gradient
how is tissue fluid formed?
1.hydrostatic pressure is higher in the capillary than the tissue fluid
2.h2o and small molecules are pushed out
3.as h2o leaves the capillary the hydrostatic pressure drops
4.the water potential is lower at the venule end of the capillary than the tissue fluid=fluid enters capillary
5.tissue fluid lost most of its o2 but gained co2 and waste
6.excess fluid is drained into the lymphatic system
what are the external features of the heart?
-cardiac muscle
-ventricles
-atria
-coronary arteries
-tubular blood vessels
what is the cardiac muscle?
-main part of the heart
-firm
-dark red
what are the ventricles?
-2 main pumping chambers
-bottom of heart
what is the atria?
-2 thin walled chambers
-smaller than ventricles
-above ventricles
what are the coronary arteries?
-supply oxygenated blood to the heart
-on the surface
what happens if the coronary arteries become constricted?
-restricted blood flow
-less delivery of o2 and nutrients
-angina or myocardial infarction (heart attack)
what are tubular blood vessels?
-carry blood into the atria and the artery (which carries blood away from heart)
-top of the heart
what are the internal features of the heart?
-4chambers=atria and ventricles
-septum
what is the atria?
-receives blood from the major veins
1.deoxygenated blood–>vena cava–>right atrium
2.oxygenated blood–>pulmonary vein–>left atrium
-blood flows from the atria into the ventricles through the atrio-ventricular valves
-valves have tendinous cords=prevent valves from turning inside out
what is the septum?
-separates the ventricles from each other
-ensures deoxygenated blood and oxygenated blood are on separate sides
what is the flow of deoxygenated blood through the ventricles?
-deoxygenated blood leaves the right ventricle and flows into the pulmonary artery
what is the flow of oxygenated blood through the ventricles?
leaves the left ventricles and flows into the aorta
what and where are the semilunar valves located?
-base of major arteries
-prevent blood flowing back to the ventricle when they start to relax
what creates blood pressure?
contraction of cardiac muscle
what is the blood pressure like in the atria?
-low pressure=only need to push blood to ventricles=small distance
-thin walls
what is the blood pressure in the right ventricle?
-high pressure
-thick walls=pump blood out of the heart
-alveoli is delicate=high pressure=damage
-blood doesn’t need to travel far–> lungs
what is the blood pressure in the left ventricle?
-2~3 times thicker wall than right
-pumped out through the aorta
-high pressure=overcome the resistance of systemic circulation
what is the structure of the cardiac muscle?
-branched fibres=cross bridges
-spreads the stimulus around the heart
-ensure muscle can produce a squeezing action
-mitochondria=energy for contraction
-muscle cells separated by intercalated discs=allow for synchronised contraction
-each cell divided into its own unit=sarcomeres
what is the cardiac cycle?
when all 4 chambers all contract in a coordinated sequence
what is diastole?
relaxing phase of the cardiac cycle
what are valves for?
-ensure blood flows in correct direction
-open and close due to pressure
what is the ventricular systole?
-right and left pump together
-contraction begins at base
-blood pushed up toward arteries
what is diastole?
-muscular walls of all 4 chambers relax
-elastic recoil=increase in volume
-blood flows in from veins
what is atrial systole?
-right atria contract
-thin muscle=small pressure
-push blood into the ventricles=full of blood
how to the atrio-ventricular valves work?
1.after the systole the walls relax=pressure in ventricles is less than atria
2.the blood flows from the atria to the ventricles=pushes the atrio-ventricular valves open
3. pressure in both ventricles and atria rises
4. the valves open when the atria contract and close when it relaxes
5. the ventricles start to contract=increases in pressure=valve closes
how do the semilunar valves work?
1.pressure in the atria is higher than the ventricles=valves closed
2.then during the ventricular systole the pressure increases
3.pressure in ventricles is higher than atria= valves open
4.blood has high pressure=powerful spurt
5.the heart relaxes
6.elastic recoil=heart returns to original shape=pressure in ventricle drops
7.when the pressure drops below the pressure in the stria the blood tries to flow to the ventricles but the valves close=prevent flow
what are the pressure changes in blood of the aorta?
-as blood moves down the aorta the pressure drops
-less obvious fluctuations
what is elastic recoil for?
maintain blood pressure
why is it important to maintain the pressure gradient between the aorta and arterioles?
to keep blood flowing towards the tissue
what does myogenic mean?
the heart can initiate its own contraction
what is special about the coordination of the heart ?
it can contract and relax rhythmically even when not connected to the body
what is fibrillation?
insufficient of pumping if contractions are not synchronised
what is the sino-atrial node?
-patch of tissue that generates electricity
-initiates the wave of excitation at regular intervals
-“pacemaker”
what happens during the contraction of the atria?
1.wave of excitation quickly spreads over the walls
2.travels along the walls of the muscle tissue
3.causes the muscle cells to contract
4.atrial systole
how does the wave of excitation pass to the ventricles?
1.atrio-ventricular node conducts the wave to the ventricles
2.the wave is delayed=allow time for atria to finish contracting+blood flow to the ventricles
what is the purkyne tissue?
specialised conducting tissue down the interventricular septum
what happens during the contraction of the ventricles?
1.after delay the wave is carried down from the AVN to the purkyne tissue
2.at the base of the septum=the wave spreads=muscles contract
ventricles contract base upwards=push blood up
what are electrocardiograms?
monitor the electrical activity of the heart by attaching sensors to the skin
how do electrocardiograms work?
1.electrical activity spreads from the tissue to the skin
2.sensors pick up the excitation
3.convert into trace
what are the letters used to describe a wave?
P=excitation of atria
QRS=excitation of ventricles
T=diastole
what is a slow heartbeat called?
bradycardia
what is a fast heartbeat called?
tachycardia
what type of heartbeat is it when the P waves are not obvious?
atrial fibrillation
what type of heartbeat is it when there are “missed” heartbeats?
ectopic
what is haemoglobin?
(Hb)
-water soluble globular protein
-2 alpha and 2 beta polypeptide chains
-each contain haem group
-carries o2
-binds to the haem (Fe2+)
-can carry 4 o2
what are the adaptations of the RBC?
-Biconcave shape=increased SA
-small and flexible=pass through narrow capillaries
-no nucleus=more room for o2
-packed with Hb
what is affinity?
attraction for o2
what is oxyhaemoglobin?
-when the Hb become oxygenated
-haemoglobin+oxygen=oxyhaemoglobin
what is the transport of o2?
- o2 diffuses into the blood plasma=down the conc. gradient into the erythrocytes
2.o2 binds to Hb=maintain conc. gradient
3.o2 binds to the haem group=oxyhaemoglobin
4.at respiring tissue=o2 disassociates from oxyHb
5.o2 diffuse out the RBC and into the respiring tissue
what is the partial pressure for o2?
(po2)
amount of o2 in the tissue
what is po2 measured in?
kpa
what are the pressure changes during the transport of o2?
-during ventilation=lung tissue has a high po2
-high po2= higher number of o2 associate with Hb=% of Hb saturation is the highest
-at the respiring tissue=po2 decreases=o2 disassociates from the oxyHb=diffuse int respiring cells
what are the 3 ways in which co2 can be transported?
1.dissolved in plasma
2.associated with Hb
3.hydrogen carbonate ions
how is co2 transported as hydrogen carbonate ions?
1.co2 dissolves in h2o=carbonic acid
2.carbonic acid releases h+ protons
3.carbonic acid diffuses out of RBC
4.cl- diffuse into cell to balance the charge–>chloride shift
describe the o2 disassociation curve?
-s shaped curve
-% Hb saturation is not directly proportional to po2
-difficult to achieve 100% saturation
-as o2 associates with Hb=conformation of Hb changes=changes the ability to associate
what are the difference between all 4 of the associations?
-first=conformation changes
-2&3=easier to associate due to the conformational change
-4=difficult=Hb if “full”
-curve plateaus below 100%
what are the effects of co2 on o2 transport?
-o2 dissociates when the po2 is low=hb ions can bind the the Hb THEREFORE they compete with the o2
-in the respiring tissue:⬆️ co2 produced=⬆️ carbonic acid formed=⬆️ h+ dissociated=⬆️ competition for Hb=⬆️ o2 disassociation
-the higher co2 in environment=⬆️ o2 disassociation
-curve shifts to the right=BOHR EFFECT
What causes P. Fluctuation as blood flows along the aorta?
