Animal transport Flashcards
(63 cards)
1
Q
why do animals need circulatory systems?
A
- hormones and enzymes often produced in one part of the body and required in another part
- circulatory systems transport these substances
- digested food, absorbed in intestines is required by other cells in body
- high metabolic demands - oxygen needs to reach centre of organism and CO2 needs to be removed
- small SA:V ratio - not enough surface for enough substances to diffuse in
2
Q
components of a circulatory system
A
- heart - pumping mechanism
- fluid substances are transported in
- vessels fluids can flow in
3
Q
open circulatory system
A
- heart pumps transport medium through few vessels into large cavity called haemocoel (low pressure)
- in the haemocoel, transport medium directly bathes organs enabling diffusion of substances
4
Q
closed circulatory system
A
- blood is fully enclosed within vessels
- from heart, blood pumped through progressively smaller vessels, in capillaries, substances diffuse in and out of blood and into cells
- blood returns to heart
5
Q
single circulatory system
A
- blood passes through two- chambered heart just once per complete circuit of the body
- closed - blood passes through 1st set of capillaries - exchanging CO2 and O2, then 2nd set - exchanging substances between blood and cells
- low activity levels
6
Q
double circulatory system
A
- blood passes through four-chambered heart twice per complete circuit of the body
- 1st - heart to lungs to pick up O2 and unload CO2
- 2nd - heart to body to unload O2
7
Q
pulmonary circulation
A
- consists of all vessels involved in transporting blood between heart and lungs
8
Q
systemic circulation
A
- consists of all vessels involved in transporting blood between heart and body, not lungs
9
Q
disadvantages of single circulatory system
A
- low blood pressure - slow movement of blood
- activity level of animals tends to be low
10
Q
advantages of double circulatory system
A
- heart can pump blood further around body
- high pressure
- fast blood flow `
11
Q
characteristics of arteries and arterioles
A
- carry oxygenated blood under high pressure (except pulmonary artery from heart to lungs)
- narrow lumen - maintains pressure
- walls made of elastin, collagen and smooth muscle - strong
- elastic fibres - withstand high pressure from large blood volume, recoil to original shape
- endothelium (smooth) lines inside, so blood easily runs over it
12
Q
how are arterioles different from arteries?
A
- arterioles have more muscle and less elastic fibres as little pulse surge but constrict and dilate to move blood
13
Q
capillaries characteristics
A
- lumen only one blood cell thick - ensures red blood cells travel single file
- substances exchanged from blood cells to surrounding tissue through gaps in endothelium
- mostly carry oxygenated blood from arterioles to venules
14
Q
adaptations of capillaries
A
- large surface area - allow diffusion of substances in and out of capillaries
- small cross-sectional area - reduces rate of blood flow from arteriole supplying them
- endothelium is one cell thick - short diffusion pathway
15
Q
veins and venules characteristics
A
- carry deoxygenated blood (except pulmonary vein from lungs to heart)
- no pulses as blood pressure is low - pressure is lost as blood moves around body
- walls contain lots of collagen and few elastic fibres and muscle - greater proportion of vessel is lumen
- smooth endothelium so blood easily flows
16
Q
venules and veins differences
A
- venules have little elastin fibres or smooth muscles
- venules link capillaries to veins
- venules have narrower lumen
17
Q
functions of blood
A
- transporting oxygen to and CO2 from respiring cells
- cells and antibodies for immune response
- hormones
- food molecules
- maintains body temp
18
Q
composition of blood
A
- 55% - plasma containing RBCs, WBCs, platelets, plasma proteins, dissloved glucose, amino acids, hormones, mineral ions
- 45% - RBCs, platelets, WBCs
19
Q
specialised features of erythrocytes
A
- flattened biconcave disc shape - large surface area to volume ratio for gas exchange
- large amount of haemoglobin - oxygen transport
- no nucleus or organelles - maximises space for haemoglobin and oxygen
- larger diameter than capillary - slows blood flow to enable diffusion
20
Q
why does blood have a low water potential?
A
- large plasma proteins dissolved in blood eg. albunium can’t fit through endothelium gaps in capillary walls
- causes water to move into the capillary by osmosis
21
Q
tissue fluid composition
A
- same as plasma but without RBC and plasma proteins
22
Q
high hydrostatic pressure causes and effects
A
- caused when blood flows from arterioles to capillaries - high pressure from surge of blood when heart contracts
- arterial end of capillary - 4.6kPa
- higher than oncotic pressure so water is forced out of capillary into spaces between cells forming tissue fluid
- diffusion occurs between tissue fluid and cells
23
Q
high oncotic pressure cause and effect
A
- hydrostatic pressure falls to 2.3kPa as fluid has moved out
- oncotic pressure still -3.3kPa, so water moves back into capillaries
24
Q
what happens when not all tissue fluid returns to the capillaries?
A
- excess drains to the lymphatic system where it forms lymph
25
composition of lymph
- similar to tissue fluid but less oxygen and nutrients
- contains fatty acids
26
what would happen without the lymph system?
- there would be a build up of lymph fluid in tissues, making them swell and forming an odoema
27
lymphatic system
- lymphatic capillaries and lymph vessels with valves to prevent backflow, lymph nodes are found along the vessels
- lymph moves through vessels by squeezing of muscles
- lymph nodes - contain lymphocytes that build up when necessary and produce antibodies which are passed into the blood, intercept bacteria from lymph which are digested by phagocytes in the nodes
28
where is the semi-lunar valve?
going from the ventricles to the pulmonary artery or aorta
29
where are the atrioventricular valves?
going from the atrium to the ventricles
(also called tricuspid valve on right side)
30
cardiac muscle
- muscle in the heart
- contracts involuntarily - myogenic
- made up of cells connected by cytoplasmic bridges - enables electrical impulses
31
cardiac cycle - names of stages
- atrial systole
- ventricular systole
- diastole
32
blood flow through the heart
Right side (deoxygenated)
1. deoxygenated blood enters superior and inferior vena cava at low pressure - atria have thin muscular walls
2. slight pressure build up - AV valve opens and blood flows into right ventricle, atrium contracts to force all blood through
3. right ventricle starts to contract, tricuspid valve shuts, deoxygenated blood forced through semi-lunar valve into pulmonary artery and towards lungs
Left side (oxygenated)
1. oxygenated blood from lungs enters left atrium at pulmonary vein
2. pressure builds in left atrium and bicuspid valve open, blood fills the left ventricle, when ventricle and atrium are full, atrium contracts to force blood out atrium
3. left ventricle contracts to force blood through semilunar valve into aorta and around the body
33
why is the wall of left ventricle thicker?
- it has to overcome the resistance of the aorta and pump blood to the whole body
34
atrial systole
- muscles of atria contract
- pressure in atria increases
- tricuspid (right side) and bicuspid (left side) atrioventricular valves open, allowing blood into ventricles
- pressure decreases
- lasts about 0.1 sec
- depolarisation
35
ventricular systole
- muscles of ventricles contract
- pressure in ventricles increases
- tricuspid and bicuspid AV valves close
- semi-lunar valves in aorta and pulmonary arteries open
- pressure decreases
- lasts about 0.3 sec
36
diastole
- pressure in ventricles decreases
- semi-lunar valves close
- all heart muscles relax
- blood flows into atria from vena cava and pulmonary vein
- blood pressure in atria and ventricles remains low
37
cardiac output
- amount of blood pumped around body (ml/min or l/min)
- stroke volume x heart rate
38
what does it mean that the cardiac muscle is myogenic?
it has its own intrinsic rhythm - around 60 bpm
39
sinoatrial node
- in right atrium
- initiates electrical impulse that spreads across both atria causing them to contract
- a layer of non-conducting tissue prevents the impulse passing to the ventricles
- blood forced through bicuspid and tricuspid valves into ventricles
- (atrial systole)
40
atrioventricular node
- impulse from SAN reaches AVN and after a delay of 0.1 sec, impulse is transmitted along specialised muscle fibres called bundle of His (made up of Purkyne fibres), then reaches apex of heart
- delays impulse allowing ventricles to fill and atria to fully contract
41
stages when electrical impuse reaches bundle of His
- electrical impulse travels down it from the AVN so the ventricles can contract from the bottom up
- insulating layer prevents contractions until at the apex
- ensures all blood gets pushed out of ventricles
42
Purkinje fibres
- wave is transmitted from bundle of His through Purkinje fibres to myocytes in walls of ventricles
- causes them to contract and forcing blood out of ventricles into atria
43
repolarisation
- during diastole the heart relaxes and the chambers fill with blood
- nodes become polarised - positive charge builds up on inside of node and negative charge on outside
44
brachycardia
slow heart beat, less than 60bpm
45
tachycardia
fast heart rate, more than 100bpm
46
ectopic beat
extra beats followed by gaps
47
atrial fibrillation
irregular rhythm
48
what makes the 'lub-dub' heart sounds?
- 'lub' - atrio-ventricular valves closing (right and left side at same time)
- 'dub' - semi-lunar valves closing
49
normal ECG
- shows electrical activity in heart
- atrial systole - small bump followed by small dip then larger spike
- ventricle systole - wide, short bump
- diastole - flat line until the end
50
how to measure heart rate from an ECG
- measure distance between two identical points
- work out how many fit into 60 sec
51
how is oxygen transported in the blood?
- erythrocytes contain haemoglobin
- 1st oxygen loosely binds to haemoglobin to form oxyhaemoglobin, haemoglobin changes shape to make it easier for the next oxygen to bind
52
affinity for oxygen
tendency to combine with oxygen
53
partial pressure of oxygen
measure of concentration/proportion of oxygen - greater concentration of oxygen dissolved in the air, higher partial pressure
- pO2
54
describe the oxygen dissociation curve
low partial pressure (eg. at respiring tissues)
- haemoglobin has low affinity for oxygen, oxygen released rapidly to cells
- less oxyhaemoglobin
higher partial pressure (eg. at lungs)
- heamoglobins high affinity for oxygen so they bind which leads to large increase in oxyhaemoglobin
- once high saturation reached, molecules unable to take on more oxygen, rises in partial pressure make less difference so graph levels out
- 'S' shaped
55
partial pressure in lungs and effects
- high partial pressure (12-13 kPa)
- haemoglobin has 95-97% saturation
56
partial pressure of oxygen in respiring tissues and effects
- low partial pressure (1-4 kPa)
- haemoglobin has 20-25% saturation
57
what is the Bohr effect and why is it important?
- shows that in higher partial pressures of CO2, haemoglobin gives up oxygen more easily
- at lower partial pressures of CO2, haemoglobin accepts oxygen more readily
- the second line is drawn to the right of the original
- in respiring cells which are producing high levels of CO2, it means oxygen is given up easier
- at the lungs where the CO2 levels in the air are low, oxygen binds to haemoglobin more easily
58
what % of CO2 produced by respiring cells is transported in blood plasma, carboaminohaemoglobin and hydrogen carbonate ions?
blood plasma - 5%
carbaminohaemoglobin - 20%
hydrogen carbonate ions - 75-80%
59
transport of carbon dioxide in carbaminohaemoglobin
- each of haemoglobins' 4 polypeptide chains has a free amino group
- each amino group can react with a molecule of carbon dioxide
- carbon dioxide + haemoglobin<-----reversible-----> carbaminohaemoglobin
60
carbon dioxide transport as hydrogen carbonate ions in blood plasma
- when CO2 diffuses into RBC it combines with water to form carbonic acid - catalysed by carbonic anhydrase
- carbonic acid dissociates - hydrogen carbonate ion and hydrogen ion
- hydrogen carbonate ion diffuses out RBC into blood plasma - causes charge imbalance
- negative chloride ion diffuses into RBC - chloride shift - prevents charge imbalance
- hydrogen ions bind to haemoglobin (haemoglobonic acid) to prevent pH of blood falling - haemoglobin acts as a buffer
- at the lungs hydrogen carbonate ions diffuse back into RBC in exchange for chloride ions
- hydrogen carbonate ions combine with H+ to reform carbonic acid which is broken down by carbonic anhydrase forming CO2
- CO2 diffuses out of RBC into blood plasma - CO2 can be exhaled through lungs
61
equation to form carbonic acid
CO2 + H2O <---carbonic anyhydrase---> H2CO3
62
carbonic acid dissociation equation
H2CO3 <------> HCO3- + H+
carbonic acid<--->hydrogen carbonate + hydrogen ion
63
how is fetal haemoglobin different form adult haemoglobin?
- fetal haemoglobin - higher affinity for oxygen
- oxygenated blood from mother runs close to deoxygenated blood of fetus, needs to be able to be transferred from mothers blood to fetus' blood
