2.3 animal transport Flashcards
1
Q
2 types of circulatory systems
A
open
closed
2
Q
what is an open circulatory system
A
the transport medium is moved into a large space in the body cavity
(haemocoel)
blood does not flow in blood vessels
3
Q
who has an open circulatory system
A
insects
4
Q
what is a closed circulatory system
A
the blood flows in. blood vessels
respiratory gases are transported in the blood
5
Q
explain the circulatory system in an insect
A
blood is pumped from a dorsal tube-shaped heart and a dorsal vein that runs the length of the body into a large fluid filled body cavity known as the haemocoel
blood bathes the tissues directly and returns slowly to the heart
6
Q
two types of closed circulatory systems
A
single
double
7
Q
what is a single closed circulatory system
A
the blood moves through the heart once for each cycle around the body
8
Q
who has single circulation
A
earthworms and fish
9
Q
what is double circulation
A
the blood moves through the heart twice for each cycle around the body.
10
Q
closed circulation in an earthworm
A
blood flows forward in the dorsal vessel (back) and back in the ventral (front) blood vessels that run the length of the body. vessels are connected by five pseudo hearts
11
Q
what keeps blood pumping in earthworms
A
pumping action of the pseudo hearts and the thickened, muscular blood vessels
12
Q
advantages of closed circulation
A
-for larger animals it allows them to control the flow of blood to certain parts of the body
- greater blood pressure generated so blood can flow faster
13
Q
disadvantages of closed circulation
A
more energy is required
more complex as contains a network of vessels
14
Q
3 main layers of the walls of arteries and veins
A
-tunica externa
-tunica media
-tunica intima
15
Q
describe structure and function of tunica externa
A
made of collagen which resists overstreching
16
Q
structure and function of tunica media
A
made of smooth muscle tissue
contraction of which regulates blood flow and maintains blood pressure
also made of elastic fibres for elastic recoil and to maintain pressure
17
Q
structure and function of tunica intimacy
A
a single layer of smooth endothelium
which reduces friction and produces minimal resistance to blood flow
18
Q
what are the only arteries that contain valves
A
aorta and pulmonary artery
19
Q
structure of arteries
A
-thick muscle layer (can be constricted and dilated) to control the volume of blood
- thick elastic layer
-no valves as blood is under high pressure
-lumen is small
20
Q
structure of capillaries
A
-one cell thick endothelium on a basement membrane
-smaller diameter which slows the rate of blood flow
-lots of capillaries=large total cross sectional area= large reduction in blood flow due to increased restriction
21
Q
structure of arterioles
A
small arteries
-smooth muscle
- can constrict and dilate
22
Q
structure of veins
A
-larger diameter, thinner walls, blood is at a lower pressure
-larger lumen
-valves to prevent back flow of blood
23
Q
properties of the heart
consist of…..
A
-cardiac muscle walls
-coronary arteries (own blood supply)
-4 chambers (2 atria/2 ventricles)
- valves
24
Q
role of the pump on the left
A
pumps out oxygenated blood to the body
25
role of the pump on the right
pumps out deoxygenated blood to the lungs
26
direction of blood : atria
artery to body
27
direction of blood: vena cava
vein from the body
28
direction of blood: pulmonary artery
artery to the lungs
29
direction of blood: pulmonary vein
vein from the lungs
30
where is the highest blood pressure (blood vessels)
aorta and arteries
rise and fall in pressure here= contraction and relaxation of the ventricles in the heart
31
blood pressure changes
arterioles
friction with vessel walls causes a pressure drop. have a large surface area and are narrow so there's a substantial drop in pressure
32
what does pressure in the arterioles depend on
whether they are dilated or contracted.
33
blood pressure changes
capillaries
have a huge cross-sectional surface area, reduces pressure slows blood flow
34
what does reduced blood pressure do
slows blood flow
35
what does reduced blood pressure in the capillaries allow for
time for the exchange of substances
36
blood pressure changes in veins
pressure is low
37
what do the coronary arteries transport
oxygen, glucose and other metabolites
38
explain the journey deoxygenated blood takes
returns to the heart through the vena cava and enters the right atrium. once the right atrium has filled with blood the wall of the atrium contracts (increase in blood pressure) forces the tricuspid valve open and blood enters the right ventricle. once the right ventricle is full of blood, wall of the ventricle contracts from the apex which forces blood up. tricuspid valve shuts and the semi-lunar valve is forced open. blood is transported to the lungs
39
explain the journey of oxygenated blood
returns to the heart via the pulmonary vein. the left atrium fills with blood and then contracts. the bicuspid valve is forced open allowing blood to fill the left ventricle. once the left ventricle is full it contracts and forces blood upwards. (increases blood pressure) closes the bicuspid valves and forces the semi-lunar valve open. blood is forced into the aorta and onwards to the body at high pressure
40
what does the cardiac cycle describe
the sequence of events of one heartbeat
0.8 seconds
3 stages
41
what is the cardiac muscle contraction
myogenic which means it beats on its own. contraction is stimulated from the muscles. it does not need impulses from nerves to make it contract
42
systole
=
contraction
43
diastole
=
relaxation
44
3 stages of the cardiac cycle
atrial systole (ventricles in diastole)
ventricular systole (atria in diastole)
diastole (atria & ventricles) ventricles first
45
explain what happens in atrial systole
-atria contract
-blood flows through the atria-ventricular valves into the ventricles
-pressure is low (thin atrial walls)
- back flow is prevented (valves closing)
46
explains what happens in ventricular systole
- ventricles contract
- atrio-ventricular valves close (greater pressure in ventricles)
-semi-lunar valves in aorta & pulmonary arteries open
-blood flows into the arteries
-thick muscle walls generate greater pressures in the ventricles
-the left ventricular wall is partially thick and strong
47
why is the left ventricular wall thick and strong
it has to pump blood around the whole body
48
explain ventricular diastole
and then diastole
VD
-heart relaxes and pressure in the ventricles drops
- semi-lunar valves shut to prevent back flow of blood from the arteries
other:
-whole of the heart muscle relaxes
-blood flow from the veins flows into the atria
-cardiac cycle begins again
49
changes in pressure within the heart
(atrial systole)
-walls of atria contract, increases pressure in the atria. (still low)
trio-ventricular valves close as pressure in ventricles begin to increase
50
changes in pressure within the heart
(ventricular systole)
51
electrical cardiac cycle
explain
electrical impulse SAN initiates tje contraction of the atria (at the same time)
the AVN causes a 0.1 second delay (time for the atria to fill and blood to go to the ventricles)
AVN speeds to the bundle of his
ventricles contract when impulse moves to the Purkinjee fibres
52
how is the heartbeat initiated
in a specialised region of the right atrium called the Sino-atrial node
53
what do ECGs measure
the electrical activity that spreads through the heart during the cardiac cycle can be detected using electrodes on the skin
54
what are the electrocardiogram a record of
voltage changes in the heart detected using the sensors on the skin
55
what can the electrical signals of a heart be tested by
chart recorder
56
what does the P wave show
the depolarisation of the atria during atrial systole
57
why is the P wave smaller than the QRS wave
because the atria have less muscle than the ventricles
58
what does the QRS wave show
the spread of depolarisation through the ventricles resulting in ventricular systole
59
what does the T wave show
the depolarisation of the ventricles during ventricular diastole
60
what does the part between t and p show
isoelectric line and is the baseline
61
effect of high blood pressure
more likely to have a stroke
62
systolic (pressure)
pressure in the artery as the heart contracts
top number
63
diastolic pressure
pressure in the artery as the heart relaxes
bottom number
64
what does affinity mean
the degree to which two molecules are attracted to eachother
65
what do we use the words loading/assocating
when oxygen binds to haemoglobin
66
when do we use the words unloading or dissociating
when oxygen unbinds from haemoglobin
67
how can haemoglobin change it's affinity
by changing its shape
68
why does haemoglobin change it's affinity
- so that it has a high affinity and associates readily with oxygen at the site of gas exchange, alveolus in humans
-so that it has a lowered affinity and dissociates readily from oxygen at respiring tissues
69
how is oxygen carried in the blood
oxyhaemoglobin
70
where does oxygen assosciate/dissociate
associates with oxygen at surface gas exchange
dissociates with oxygen at respiring tissue
71
explain oxygen affinity when in the gas exchange surface
high 02 concentration
low CO2 concentration
high affinity of haemoglobin for oxygen
so oxygen attaches
72
explain oxygen affinity when in respiring tissue
low o2 concentration
high CO2 concentration
low affinity of haempglobin for oxygen
so oxygen released
73
explain co-operative binding
- The increasing ease after the first oxygen molecules bind
- haeoglobin binds it's second and third oxygen molecules, as the shape of the haemoglobin molecules change.
- the thirds oxygen molecule doesn't alter the shape of haemoglobin so a very large concentration is needed to bind the fourth molecule.
74
what happens to haemoglobin at high partial pressures vs low
at high (in lungs) haemoglobin strongly binds to oxygen
at low partial pressure (capillaries)
oxyhaemoglobin dissociates to release oxygen
75
what shape are oxygen dissociating curves
sigmoid
76
describe haemoglobin
has an affinity (attraction) oxygen
1 haemoglobin molecule can carry 4 oxygen molecue
77
what does the curve on oxygen dissociation curves show
that at low partial pressures of oxygen, the percentage saturation of haemoglobin is very low, it has combined with very little oxygen. at high a partial pressures of oxygen, the percentage saturation is very high haemoglobin has combined with lots of oxygen
78
what is the partial pressure of oxygen in the lungs
how saturated will haemoglobin be
high
95-98% saturated, almost every haemoglobin will be combined with 8 atoms of oxygen
79
what will the partial pressure of oxygen be in respiring tissue
how saturated will haemoglobin be
low
be about 20-25% saturated will carry only a quarter of the possible oxygen
80
what does partial pressure of oxygen mean
the concentration of oxygen in the lungs or body tissues
81
why is the sigmoid shape more efficient
a small drop in oxygen partial pressure leads to a large decrease in haemoglobin saturation so the oxygen is more readily released to the tissues
82
what would happen at higher partial pressure if there's a linear relationship (without co-operative binding)
haemoglobin oxygen affinity would be too low and so oxygen affinity would be too low and oxygen would be readily released so would not reach respiring tissues
83
what would happen at lower partial pressure if there's a linear relationship
haemoglobin oxygen affinity would be too high and oxygen would not be released in respiring tissues, even at very low partial pressures
84
difference between normal and foetal haemoglobin
foetal haemoglobin has a higher affinity of oxygen at the same partial pressure
85
how would foetal haemoglobin be seen on a dissociation curve
it will be shifted to the left
86
why does foetal haemoglobin have a higher affinity for oxygen
because at all partial pressures in the placenta, the mothers haemoglobin releases oxygen
87
what do lugworm and llamas have and why
have a high affinity of oxygen
because they live in a low oxygen environment
88
explain llama and lugworm in terms of the dissociation curves
lower availability of oxygen so will be shifted to the right
89
what is myoglobin
a pigment that binds to oxygen which is only found in muscle cells
90
what does myoglobin have
a high affinity of oxygen even at low partial pressures
91
when does myoglobin release its oxygen
at very low partial pressures
92
what does extra oxygen from myoglobin do
can help to maintain aerobic respiration in muscles
93
what does the line moving to the right on the dissociation curve show
more readily haemoglobin disassociated its oxygen
94
what is the effect carbon dioxide have on oxygen transport called
the Bohr effect
95
what will c02 do to dissociation curves
will shift to the right
96
what happens if the concentration of carbon dioxide increases
haemoglobin releases oxygen more readily
97
what affect does carbon dioxide have at any oxygen partial pressure
the haemoglobin is less saturated with oxygen
98
explain when the carbon dioxide levels are high
haemoglobin has a lower affinity for oxygen, so it is less efficient at loading oxygen and more efficient at unloading it
99
2 reasons why oxygen is more readily unloaded by haemoglobin
1. partial pressure of oxygen is lower, causes the haemoglobin to have a lower affinity for oxygen
2. the partial pressure of carbon dioxide is higher, this also causes haemoglobin to have a lower affinity for oxygen (Bohr effect)
100
what does the curve to the left show
haemoglobin is better at loading oxygen (foetal, llama, lugworm, myoglobin)
101
what does the curve to the right show
haemoglobin is better at releasing (unloading) oxygen (in the presence of more carbon dioxide)
102
explain the Bohr effect (in a red blood cell)
diagram..
1. carbon dioxide defuses from the tissues into the plasma and the cell
2. carbonic anhydrase catalyses the reaction between water and carbon dioxide to get carbonic acid.
3. carbonic acid dissociates and forms H+ and HCO3- ions.
4. HCO3- ions diffuses out of the RBC into the blood. this causes the chloride shift to balance the charge and maintain the electrochemical neutrality
5. oxyhemoglobin releases oxygen and combines with H+ ions to form haemoglobin acid. oxygen diffuses out of the RBC and into the plasma and is passes to respiring tissue by diffusion
103
what does the Bohr effect allow
haemoglobin to release oxygen more readily
104
what does haemoglobin combined with H+ ions have
a buffering effect which maintains the pH of the RBC cytoplasm
105
what is the chloride shift
the diffusion of chloride ions from the plasma into the red blood cell, maintain electrical neutrality
106
how is carbon dioxide transported in the blood
5% in dissolved solution in the plasma
10% is combined with haemoglobin in RBC
85% is in the form of hydrogen carbonate ions dissolved in the plasma
107
what does the blood transport in the plasma
urea and carbon dioxide
nutrients
hormones
proteins
salts
heat
108
3 types of proteins found in the plasma
albium
fibrinogen
antibodies
109
what is albium involved in
helping to maintain osmotic balance
110
what is fibrinogen involved in
involved in blood clotting
111
what are antibodies for
immunity
112
what are the products of digestion that are found in the plasma
glucose, amino acids, fatty acids, glycerol and vitamins
113
examples of salts found in the plasma
sodium
potassium
chloride
114
adaptations of capillaries
thin permeable walls
large SA
blood flow slowly allowing time for exchange of material
115
what is hydrostatic pressure
blood is under pressure from the pumping of the heart and muscle contraction in artery and arteriole walls
116
definition of tissue fluid
is plasma without the plasma proteins, forced through capillary walls, bathing cells and filling the spaces between them
117
what causes diffusion of solutes in and out of capillaries
- bloods hydrostatic pressure
- solute potential/osmotic pressure
118
what is the hydrostatic pressure in blood vessels
is the pressure of the blood against the capillary wall (opposing force to osmotic pressure)
119
what does the osmotic pressure do as blood travels along capillaries/ how is it created
remains constant by the presence of circulating hydrophilic plasma proteins which are too large to diffuse out of the capillaries
120
what is the hydrostatic pressure in capillaries
its higher them the opposing osmotic pressure in blood
121
what does the high hydrostatic pressure do at the arteriolar end of the capillaries
forces fluid/water and nutrients from the plasma out of the capillaries and into surrounding tissues.
122
what happens to the fluid/water and the cellular wastes in the tissues
they enter the capillaries at the venue end, where the hydrostatic pressure is less than the osmotic pressure
123
what is lymph
the fluid absorbed from between cells into lymph capillaries, rather than back into capillaries
