Transport in animals Flashcards
1
Q
What features do all transport systems in animals have
A
- a suitable medium in which to carry molecules
- a pump, such as the heart for moving blood
- valve to maintain the flow in one direction
2
Q
What do some transport system in animal have
A
- a respiratory pigment in vertebrates and some inverttebrates but not insects which increases the volume of oxygen that can be transported
- a ystem of vessels with a branching network to distribute the transport medium to all parts of the body
3
Q
What are open circulatory systems
A
- the blood does not move around the body in blood vessels but it bathes the tissues directly while held in a cavity called the haemocoel
- oxygen diffuses directly onto the tissues from the tracheoles so the blood does not tranport oxygen and has norespiratory pigment
4
Q
What is the transport system in insects like
A
- open circulatory system
- no respiratory pigment
- dorsal tubed shape like heart
- inssects have an open blod system. they have a long dorsal (top) tube shaped heat running the length of the body. It pumps blood out at low pressure into the haemocoel where materials are exchanged between the blood and body cells.
- Blood returns slowly to the heart and the open circulation starts again
5
Q
What is a closed circulatory system
A
- the blood moves in blood vesselss
- there are two types single and double circulation
6
Q
Describe the transport system in fish
A
- single closed circulatory system
- have a respiratory pigmment
- 1 atrium and 1 ventricle - heart
- the ventricle of the hearrt pumps deoxygenated blood to the gill where the well developed capillary network reduces its pressure. Oxygenated blood is carried to the tissues and from there, deoxygenated blood returns to the atrium of the heart
- blood moves to the ventrical and the circulation starts again
7
Q
What is single circulation
A
- the blood moves though the heart once in it passage around the body
8
Q
What is the transport system like in earthworms
A
- single closed circulatory system
- have a respiratory pigment
- (pseudohearts) - heart
- blood moves forward in the dorsal vessel and back in the ventral vesel
- five pairs of ‘pseuodohearts’ thickened, muscular blood vessels pump the blood from the dorsal to the ventral vessel and keep it moving
9
Q
What is a double circulatory system
A
the blood passes through the heart twice in the circuit around the body
10
Q
Describe the transport system in mammals
A
- Double closed circulatory system
- have a respiratory pigment
- 2 atria and 2 ventricles - heart
- blood is pumped by a muscular heart at a high pressure giving a rapid flow rate through blood vesse;s
- 0rgans are not in direct contact with the blood but are bathed by tissue fluid, which seeps out of the capillaries
- the blood pigment haemoglobin carries oxygen
11
Q
What is an advantage of double closed circulatory systems
A
- Blood pressures is reduced in the capillaries of the lungs and its pressure would be too low to make circulation efficient in the rest of the body
- instead the blood is returned to the hearrt which raises its pressure again to pump it to the rest of the body
- materials are then delivered quickly to the body cells
- oxygenated blood is pumped around the body at a higher pressure
12
Q
Describe the flow of blood in fish
A
organs -> veins - > heart -> afferen arteries -> gill capillaries -> efferent arteries -> organs
13
Q
Describe the flow of blood in mammals
A
organs -> vena cava -> heart -> pulmanoary artery -> lungs -> pulmonary vein -> heart -> aorta -> organs
14
Q
Describe the double circulatory system in mammals
A
- pulmanory circulation
- systematic circulation
- in each circuit the blood passes through the heart twice through the right side and once through the left side
15
Q
What is pulmonary circulation
A
- serves the lung
- the right side of the heart pumps deoxygenated blood to the lunds
- oxygenated blood returns from the lungs to the left side of the heart
16
Q
What is systematic circulation
A
- serves the body tissues
- the left side of the heart pumps oxygenated blood to the tissues
- deoxygenated blood from the body returns to the right side of the heart
17
Q
What are the three types of blood vessel
A
- arteries
- veins
- capillaries
18
Q
What are the three layers of arteries and veins
A
- tunica intima
- tunica media
- tunica externa
19
Q
What is the tunic intima
A
- the innermost layer
- which is a single layer of endotherlium in some arteries it is supported but elastic rich collagen
- it is a smooth lining reducing friction producing minimal resistance to blood flow
20
Q
What is the tunica media
A
- the middle layers
- contains elastic fibres and smooth muscle
- it is thicker in arteries than in veins
- the contraction of the smooth muscle regulated blood flow and maintain the blood pressure as the blood is transported further form the heart
21
Q
What is the function of the tunica media in arteries
A
- in arteries the elasic fibres allow stretching to accomodate changed in blood flow and pressure as blood is pumped from heart
- at a certain point stretched elastic fibres recoil pushing blood on throguh the a\rtery
- this is felt as the pulse and maintain the blood pressure
22
Q
Wha is the tunica externa
A
- the outer layer
- contains collagen fibres which resist overstretching
23
Q
What is the function of arteries
A
- carry blood away from the heart
- their thick muscular walls withstand the blood’s high pressure, derived from the heart
- arteries branch into smaller vessels called arterioled that further subdivide into capillaries
24
Q
What is the function of capillaries
A
- form a vast network that penetrated all the tissues and organs of the body
- blood from the capillaries collects into venules which take blood into veins which return it to the heart
25
What are the functions of veins
* have a larger diameter lumen and thinner walls with less muscle than arteries
* consequentlu the blood pressure and the flow rate are lower
* for veins above the heart blood return to the heart by gravity
* it moves through other veins by the pressure from the surrounding muscles
* veins have semi lunar valve along their length ensuring flow in onve direction and preventing backflow these are not present in arteries other than at the base of the aorta and pulmonary artery
* the fault functioning of the valves can contribute to the varicose veins and heart failure
26
What is the structure of capillaries
* thin walls which are only one layer of endothelium on a basement membrane
* pores between the cells make the capillary walls permeable to water and solutes such as glucose so exchange materials between the blood and the tissues take place
27
How are capillaries adapted to their function
* capillarie have a small diameter and the rate of blood flow slows down
* there are many capillaries in a capillary bed which reduces the rate of blood flow so that there is plenty of time for the exchange of materials with the surrounding tissue fluid
28
What is the heart and why is it thought as two seperate pumps
* a pump to circulate blood is essential for a circulatory system
* the heart can be thought of as two seperate pumps one dealing with oxygenated blood and the oher with deoxygenated blood
* these are two relativley thin walled collection chambers the atria whcih are above two thickeer walled pumping chambers
* the ventricalses allowing the complete seperation of oxygenated and deoxygenated blood
29
What does the heart consist of
* cardiac muscle a specialised tissue with myogenic contraction
30
why is cardiac muscle specialied for the heart
* cardiac muscle never tires
31
what is myogenic contraction
* the heartbeat is initiated within muscle cells themselves and is not dependent on nervous or hormonal stimulation
32
systole
A stage in the cardiac cycle in which heart muscle contracts
33
Diastole
A stage in the cardiac cycle in which heart muscle relaxes
34
What is the cardiac cycle
* describes the sequences of events of one heartbeat
* the action of the heart consists of alternation contractions (systole) and relaxations (diastole)
35
What are the three stages of the cardiac cycle
* atrial systole
* ventricular systole
* diastole
36
What is atrial systole
* The atrium walls contract and the blood pressure in the atria increases
* This pushes the blood through the tricuspid and bicuspid valves down into the ventricles which are relaxed
37
What is ventricular systole
* the ventricle walls contract and increase the blood pressure in the ventricles
* this forces blood up through the semi lunar valves out of the heart into the pulmonary artery and the aorta
* the blood cannot flow back from the ventricles into the atria because the tricuspid and bicuspid calces are closed by the rise in ventricular pressure
* the pulmonary artery carries deoxygennated blood to the lungs and the aorta carries oxygenated blood to the rest of the body
38
What is diastole
* pthe ventricles relax
* the volume off the ventricles inceases and so pressure in the ventrucles falls
* this risks the blood in the pulmonary artery and aorta flowing backwards into the ventricles
* that tendency to flow backwards causes the semi lunar valves at their bases to shut preventing blood re entering the ventricles
* the atria also relax during diastole so blood from the vena cava and pulmonary veins enter the atria and the cycle starts afain
39
Describe the flow of blood through the left side of the heart
* the left atrium relaxes and receives oxygenated blood from the pulmonary vein
* when full the pressure forces open the bicuspid valve between the atrium and ventricle
* relaxation of the left ventricle draws blood from the left atrium
* the left atrium contracts pushing the remaining blood into the left ventricle through the valve
* the left atrium relaxes and the left ventricle contracts its strong muscular wall exerts high pressure
* this pressure pushes blood up and out of the heart throguh the semi lunar valves into the aorta the pressure also closes the bicuspid valve preventing the backflow of blood into the left atrium
40
What happens to the heart in a heart beat
* the two sides of the heart work together the atria contract at the same time followed millisecond later by the ventricles contracting together. A complete contraction an relaxation of the whole heart is called a heartbeat
* when a chamber of the heart contracts it is emptied of blood when it relaxes it fills with blood again
* atria walls have litle muscle a the blood only has to go the ventricles. Ventricle walls contain more muscle and generate more pressure as they have to send the blood further either to the lungs or to the rest of the body
* the left ventricle has a thicker muscular wall than the right ventricle a it has to pump the blood all round the body whereas the right ventricle has only to pump the blood a short distance to the lungs
41
What are the functions of valves
* valves prevent backflow of blood
* the atrio ventricular valves (bicuspid and tricuspid) s
* semi lunar valves at the base of the aorta and pulmonary artery and the semi lunar valves in veins all operate by closing under high blood pressure preventing blood flowing backwards
42
How is a heartbeat controlled
* contraction of cardiac muscle is myogenic
* the wall of the rught atrium has a cluster of specialised cardiac cells called the sino atrial node that acts as a pacemaker
42
Sino atrial node (SAN)
An area of the heart muscle in the right atrium that initiates a wave of electrical excitation across the atria to generate contration of the heart muscle it is called the pacemaker
43
Atrio ventricular node (AVN)
The only conducting area of tissue in the wall of the heart between the atria and vetricles through which is electrical excitation passes from the atria to conducting tissue in the walls of the ventricle
44
What are the functions of the nodes to create a heartbeat
* a wave of electrical stimulation arise at and spreads over both atria so they contract together
* the ventricles are electrically insulated from the atria by a thin layer of connective tissue except at another specialised cluster of cardiac cells the AVN
* So the electrical stimulation only spreads to the ventricles from this point. The Avn introduces a delay in the transission of the electrical impulse
* the muscles of the ventricles do not start to contract intil the mucles of the atria have finished contracting
* The AVN passes the ecitation down the nerves of the bundle of His the left and right bundle branches and to the apex of the heart. The excitation is transmitted to the Purkinje fibres in the ventricle walls which carry it upwards thrgouh the muscles of the ventricle walls
* The impulsse cause the cardiac muscle in each ventricle to contract simultaneously from the apex upwards
* This pushs the blood up tot he aorta and pulmonary arteries and empties the ventricles completley
*
45
What is an electrocardiogram
is a trace of the voltage changes produced by the heart deteced by electrodes on the skin
46
What is the p wave
* is the first part of the trace and shows voltage change generated by the SAN associated with the contraction of the atria
* the atria have less muscle than the ventricles so the P wave is small
47
What i the time between the start of the P wave and the QRS complex
* The PR interval
* it is the time takes for the excitation to spread from the atria to the ventricles through the atrio ventricular node
48
What is the t wave
* repolarization of the ventricle muscles
* the St egment lasts from the end of the S wave to the beginning of the T wave
49
What does the QRS complex show
* the depolarisation and contraction of the ventricles
* ventricles have more muscel than atria and so the amplitude is bigger than the p wave
50
What is the line between the T wave and P wave of the net cycle
* is the baseline of the trace and is called the isoelectric line
51
How can the heart rate be calculated from the electrocardiogram
* reading on the horizontal axis
52
How does the rythm shown by the regularity of the pattern of the trace
* a person with the atrial fibrilation had a rapid heart rate and may lack a p wave
* a person who has had a heart attack may have a wide QRS complex
* a person with enlarged ventricle wallls may have a QRS complex shpowing greater voltage change
* Changes in the height of the ST segment and T wave may be realted to insufficent blood being delivered to the heart myscle and such as hapens in patients with blocked coronary arteries and athersclorosis
53
How does pressure change in the blood vessels
* the blood pressure is hgihgest in the aorta and large arteries it ries and falls rythmically and ventricular contraction
* friction between the blood and vessel walls and the karge total suurface area ncauases progressive drop in pressure in arterioles depite their nearrow lumen although their bllod pressure also depends on wether they are dialated or constricted
* the extenivecapillary bed further reduce blood pressure as fluid leaks from the capillarie to the tisue
* in arteries and capillaries the hgiher the blood pressure the faster the blood flows so both pressure and speed fall as the distance from the heart increases
* veins are not subject to pressure changes derived from the contraction of the ventricles so their blood pressre is low
* veins have a large diameter lumen so blood flows faster than in capullaries despite their low pressure
* blood does not return to the heart rythmically its return is enhances by the massaging effect of muscles around veins
54
What is blood roughly made up of
* blood is a tissue
* made up of cells -45%
* and in a solution called plasma - 55%
55
Why are red blood cells red
* (erythrocytes) they contain the pigment haemoglobin
56
What is the main function of red blood cells
to transport oxygen from the lungs to respiring tisues
57
What are the two main ways that blood cells are unusual
* they are bioconcave discs the surface area is larger than a plane disc so more oxygen diffues avross the membrane
* the thin centre makes them look paler in the middle it reduces the diffusiion distance making gas exchange further
* they have no nucleus that make more room for haemoglobin maximising the oxygen that can be carried
58
What is plasma and what is made of
* pale yellow liquid
* about 90% of water containing solutes such as good molecules (including glucose, amino acids , vitamins B and C, mineral ions)
* waste products (urea, hydrogen carbonate ions)
* hormones
* plamssma proteins (albumin, blood clotting proteins and antibodies)
* Plasma also distributes heat
59
What is the equation for haemoglobin binding to oxygen
* oxygen + haemoglobin -> oxyhaemoglobin
* 4O2 + Hb - > Hb. 4O2
60
Plasma
* fluid component of the blood compromising water and soluted
* plasma = blood - cells
61
Affinity
* the degree to which two molecules are attracted to each other
62
Co operative binding
* The increasing ease with which haemoglobin binds to the second and third oxygen molecules as the confromation of the haemoglobin molecules changes
63
How is oxygen transported efficienty
* haemoglobin must asssociate redily with oxygen where gas exchange takes place at the alveoli and readily dissociate from oxygen at the respiring tissues such as mucle
64
What is haemoglobin
* haemoglobin can perform contradictory requirements by changing it affinity for oxygen by changing shape
* each haemogloboin contains four haem group each haem contain an ion of iron.
65
how does oxygen bind to haemoglobin
* One oxygen molecule can bind to each iron ion so four oxygen molecules can bind to each haemoglobin molecule
* the firsst oxygen that attatches changes the shape of the haemoglobin molecule making it easier for the second molecule to attatch
* the second oxygen molecule attatching changes the shape again making it easier for the third molecule to attatch
* This is cooperative binding and it allows haemoglobin to pick up oxygen very rapidly in the lungs
* the third oxygen molecule does not induce a shape change so it take a large increae in oxygen partial pressure to bind to the fourth oxygen molecule
66
how does haemoglobin increase the partial pressure of oxygen
* if it absorbed oxygen evenly the fraph plotted would be linear but co operativ e binding means the haemoglobin is expossed to increasing partial pressure of oxygen shows a sigmoid curve ( s shape )
* at very low oxygen partial pressure it i difficult for haemoglobin to load oxygen but the steep part of the graph shows oxygen binding increasingly easily
* at high partial pessures of oxygen the percentage saturation of oxygen is very high
67
# ****
What is partial pressure of a gass
* is the pressure it would exert if it were the only one present
* normal atmospheric pressure is 100 KPa
68
What is the partial pressure of oxygen
* oxygen comprimises of 21% of the atmosphere so the partial pressure is 21 Kpa
69
What does the oxygen dissociation curve show
* the oxygen affinity of haemoglobin is high at hgih partial pressure of oxygen and oxyhaemoglobin does not release it's oxygen
* oxygen affinity reduces the partial pressure of oxygen decreases and oxygen is readily released meeting at respiraory deamsn the graph shows that a very small decrease in oxygen partial pressure leads to a lot of oxygen dissacoiating from haemoglobin
70
What would happen if the relationship between oxygen and partial pressure and % saturation of haemoglobin with oxygen linear
* a higher partial presure of oxygen
* haemoglobins oxygen affinity would be too low and so oxygen would be readily released and would not reach respiring tissues
* at lower partial pressure of oxygen haemoglobins oxygen affinity owuld be too high and oxygen would not be released in respiring tissue even at low oxygen partial pressures
71
what would the sigmodial graph of adult human haemoglobin show
* red blood cells load oxygen in the lungs where the oxygen partiial presure is hgih and the haemoglobin becomes saturated oxygen
* the cells carry the oxygen as oxyhaemoglobin to respiring tissues such as muscle
* there the partial pressure of oxygen is low because oxygen is being used in repsiration
* oxyhaemoglobin than unloads its oxygen that is it disociates
72
Decribe the dissociation curve of foetal haemoglobin
* the haemoglobin in the blood of a foetus must absorb oxygen from the maternal haemoglobin of the placenta
* the foetus has haemoglobin that differs in two of the four polypepetide chains from the haemoglobin of the adult
* This gives foetal haemoglobin a higher affinity for oxygen than the mother's haemoglobin at the same partial pressure of oxygen
* their blood flows very close in the placenta so oxygen transfers to the foestus's blood and at any partial pressure of oxygen the percentage saturation of the foetus' blood is higher than the mothers
* this moves the dissociation curve to the left
73
What is the transport of oxygen in other animals with a low oxygen environment
* the lugworm lives head down it is's burrown in th sand on the seashore a low oxygen environment
* it has a low metabolic rate and is haemoglobin has a dissociaition curve to the left of human haemoglobin this means it haemoglobin loads oxygen very readily but onlu releases it when the partial pressure of oxygen is very low which is the situation of its habitat
* with an increase in altitude the oxygen partial pressure in the atmosphere decreases this is significant for mountain anmals such as llama its haemoglobin has a dissociation curve that is to the left of human haemoglobin its haemoglobin has a higher affinity for oxygen at all oxygen partial pressures so loads oxygen more readily in the lungs and relases oxygen when the oxygen partial pressure is low in its respiring tissue
74
What is the effect of carbon dioxide concentration on haemoglobin and oxygen
* haemoglobin releases oxygen more rapidly as carbon dioxide concetration increases
* at any oxygen partial pressure the haemoglobin is less saturated with oxygen so the data points on the dissociation curve is lower
* this is described by aying the curve moves to the right
* the shift is the fraph i called the Bohr effect
* it accounts for the unloading of oxygen from the oxyhaemoglobin in respiring tissures where th aprtial pressure of carbon diosxide is high and oxygen is needed
75
Where on the graph would there be a low and high partial pressure of carbon dioxide
* the low partial pressure of carbon dioxide would be on the left of high partial pressure of carbon dioxide with the x axis being partial pressure of oxygen
76
summarise the effects of uptake and unloading of oxygen and haemoglobin
* when haemoglobin is exposed to an increase in oxygen partial presure it absorbs oxygen raapidly at low partial pressure but more slowly as the partial pressure rises this is shown in an oxygen dissociation curve
* when the oxygen and partial pressurre of oxygen is high as in lung capillaries oxygen combines with hameoglobin to form oxyhaemoglobin
* when the partial pressure of oxygen is low as in respiring tissue the oxygen dissociates from oxyhaemoglobin
* when partial pressures of carbon dioxide is hgih haemoglobin has a lower affinity for oxygen so it is less efficient at loading oxygen and more efficient at unloading it
77
How is carbon dioxide transported
* is solution in the plasma - 5%
* as the hydrogengcarbonate ion HCo3 - - 85%
* bound to haemoflobin as carbamino-haemoglobin -10%
* some carbon dioxide iss trasnsported in red blood cells but most is converted in the red blood cells to hydrogen carbonat which then diffuses into the plasms
78
What is the reaction that occurs in a red blood cell regarding carbon dioxide and oxygen
* carbon dioxide in gthe blood diffuses into red blood cells
* carbonic anhydrase catalyses the combination of carbon dioxide with water making carbonic acid
* carbonic acid dissociates into H+ and Hco3- ions
* HCO3 - ions diffuse out of the red blood cells into the plasma
* To balance the outflow of negative on and maintsain electrochenucal nuetraluty chloride ions diffuse into red blood cell from the plasma - this is called the chloride shift
* H+ ions cause oxyhaemoglobin to dissociate into oxygen and haemoglobin. The H + ions combine with the haemoglobin to make haemoglobonic acid HHb. this removes hydrogen ions and so the Ph of the red blood cell doesn't fall
* oxygen diffuses out of the red blood cell into the tissue
79
Write the equations in order of when they occur in red blood cells
* Co2 + H20 -> H2CO3
* H2Co3 -> HCO3- + H+
80
How are capillaries well adapted for exchange of materials
* they have thin permeable walls
* they provide a large surface area for exchange of materials
* blood flows very slowly through capillaries allowing time for exchange of materials
81
Chloride shift
the diffusion of chloride ions from the plasma into the red blood cell preserving electrical neutrality
82
Tissue fluid
* Plasma without the plasm proteins forced throguh capillary walls bathing cells and filling psaces beteen them
* Tissue fluid = plasma - plasma proteins
83
Lymph
Fluid absorbed from between cells into lymph capillaries rather than back into capillaries
84
What happens in the capillaries
* exchange between the blood and the body cells hapens at the capillaries
* plasma solutes and oxygen move from the blood to the cells and waste products such as cabon dioxide and in the liver urea move from the cells to the blood
* fluid from the plasma is forced throguh the capillary walls and as tissue fluid bathes the cells supplying them with olutes such as glucose, amino acids, fatty acids, salts, hormone and oxygen
* the tissue fluid removes waster made by the cells
85
What related to the blood hydrastic pressure and solute potential
* the diffusion of solutes in and out of the capillaries
86
What happens at the arterial end of a capillary bed
* blood is under pressure from pumping of the heart and muscle contraction in artey and arteriole walls. The high hydrostatic pressure pushes the liquid outward from the capillary to the spaces between the surrounding cells
* plasma is a solution and its low ssolute potential due mainly to the colloidal plasma proteims tends to pill water back into apillary by osomosis
* the hydrostatic pressure is greater than the plasma's solute poterntial so water and solutes are forced out through the capillary wall into spaces between cells
* solues such a glucoe oxygen and ions are used during cell metabolism of their concentration in and around the cells is low but the blood is higher this favour diffusion form the capillaries to the tisue fluid
87
What happens at venous end of capillary bed
* the blood's hydrostatic pressure is lower than at the arterial end because its volume has been reduced by fluid loss and because friction with the capillary walls resist it flow
* the plasma proteims are more concentrated in the blood because so much water has been lost the solute potential of the remaining plasma is therefore more negative the osmostic force pulling waer inwards is greater than the hydrostatic force pushing water outwards so water passes back into capillaries by osmosis
* tisue fluid surrounding cells picks up carbon dioxide and other wastes which diffuses down a concentration gradient form the cells where they are made and into capillaries where they are less concentrated
* not all of the fluid passes back into capillariies about 10% drains into the blindly eding lymph capillaries of the lymphatic system most of the lymph fluid eventually return of the venous system throguh the thoracic duct which empties into the left subclavian vein above the heart
88
What is the netflow outwards in a capillary bed
* high hydrostatic pressure of blood - oxygenated blood at arterial end of capillary bed
* solute potential pulling water inwards is less tan hydrostatic pressure
89
What is netflow inwards in capillary bed
* low hydrostatic pressure as fluid has been forced - deoxygenate blood at enous end of capillary bed out of capillary and friction with capillary wall
* solute potential a little moe negative at the arterial end
90
Describe plasma
* site - blood vessels
* associated cells - erythrocutes, granulocytes, lymphocytes
* respiratory gases - more oxygen less carbon dioxide
* nutrients - more than tissue fluid and lymph
* large protein molecules
* lower water potential
91
Describe tissue fluid
* site - surrounding body cells
* associated cells - granulocytes, lymphocyes
* respiratory gases - less oxygen more carbon dioxide
* fewer nutrients
* high water potential
92
describe the lymph
* site - lymph capillary vessel
* associated cells - granulocytes, lymphocyes
* respiratory gases - less oxygen more carbon dioxide
* fewer nutrients
* high water potential
