Exchange & Transport In Animals Flashcards
1
Q
What is diffusion?
A
The net movement of particles from an area of higher concentration to an area of lower concentration, DOWN a concentration gradient, until an equilibrium is reached.
2
Q
Describe the relationship between surface area and SA:V
A
As the surface area increases, the SA:V decreases
3
Q
What challenges are encountered by large organisms in reference to gas exchange?
A
- Diffusion distance is too great
- Diffusion cannot occur fast enough in large enough quantities to meet metabolic demands
4
Q
What are 4 features of an effective exchange surface?
A
- Thin layers
- Increased surface area
- Good blood supply
- Ventilation to maintain diffusion gradient
5
Q
Why is an increased surface area a useful feature on an effective exchange surface?
A
-Increases the area in which diffusion can take place.
This can be seen in the alveoli in the lungs and the villi of the small intestines.
6
Q
How can you increase the surface area?
A
Increase the number of surfaces, e.g. increasing the number of alveoli
7
Q
Why are thin layers a useful feature on an effective exchange surface?
A
- Short diffusion distances, lessening the time taken for the substances to diffuse.
- This can be seen through the wall of the alveolus and the one cell thick wall of the capillary, and the thin villi of the small intestines.
8
Q
Why is good blood supply a useful feature of an effective exchange surface?
A
The continuous supply of red blood cells maintains a steep concentration gradient, allowing diffusion to constantly take place.
- This is as a result of the substances bring constantly removed and delivered.
9
Q
Why is ventilation a useful feature in a useful exchange surface?
A
Maintains diffusion gradient
10
Q
What type of process is inhalation?
A
An energy-using ACTIVE process.
11
Q
What is exhalation?
A
A passive process
12
Q
Describe features in the nasal cavity of the human respiratory system
A
- Hairy lining which secretes mucus
- Large surface area with a good bloody supply
- Moist surfaces, increasing humidity of incoming air
13
Q
What is the function of the hairy lining that secretes mucus in the nasal cavity?
A
Protecting delicate lung tissue from infection/irritation
14
Q
What is the function of moist surfaces in the nasal cavity?
A
Increases humidity of incoming air, which reduces evaporation from the exchange surfaces
15
Q
What is the function of the large surface area with a good blood supply in the nasal cavity?
A
To warm air to body temperature
16
Q
Describe the structure of the trachea
A
- Wide tube supported by incomplete rings made of cartilage
- Lined with ciliated epithelium with goblet cells
17
Q
Describe 2 properties of cartilage
A
- strong
- flexible
18
Q
What is the purpose of having cartilage in the trachea?
A
- Stop the trachea from collapsing
- Rings incomplete so food can move easily down the oesophagus so behind the trachea
19
Q
What lines the trachea?
A
- Ciliates epithelial cells
- Goblet cells
20
Q
What do ciliated epithelial cells do?
A
-Cilia beat and move mucus away from lungs
smoking can cause cilia to stop beating
21
Q
What do goblet cells do?
A
Secrete mucus onto the lining of trachea
Trap dust and microorganisms
22
Q
Describe the structure of the bronchus
A
Similar structure as trachea, however smaller rings of cartilage.
23
Q
Describe the parts of the human respiratory system.
A
Nasal cavity/Nose/Mouth Trachea Bronchus Bronchioles Alveoli
24
Q
How large is the diameter of bronchioles?
A
<1mm
25
Describe the structure of bronchioles (3 points)
- Lined with a thin layer of flattened epithelium
- No cartilage rings
- Walls of bronchioles constrain smooth muscle
26
Describe the use of smooth muscle in the bronchioles
* Smooth muscle - contract = Bronchioles constrict (airways close up)
* Smooth muscle relax = Bronchioles dilate (airways opens up)
27
Describe the structure of alveoli
Tiny air sacs - main gas exchange surfaces of the body (unique to mammalian lungs):
- Thin flattened epithelial cells
- Collagen
- Elastic fibres (composed of elastin)
0. 2mm in diameter
28
What is the function of elastic fibres in alveoli? (2 points)
- Designed to stretch as air is drawn in and return to resting size (elastic recoil).
- Helps squeeze out air
29
What are the 4 main adaptions of the alveoli?
- Increased SA
- Thin walls
- Good blood supply
- Ventilation
30
What are the 4 stages of Inhalation/Exhalation?
- Anatomical change
- Volume change
- Pressure change
- Air movement
31
Describe the anatomical changes that occur during inhalation
* Diaphragm contracts -flattens/moves down
| * External intercostal muscles contracts - rib cage moves up and out
32
Describe the volume change that occurs during inhalation
- Increases the volume of the thorax/thoracic cavity
33
Describe the pressure change that occurs during inhalation
- Decrease in pressure within the thorax below atmospheric pressure, creating a steep concentration gradient.
34
Describe the air movement that occurs during inhalation
- Air rushes in, down the pressure gradient
35
Describe the anatomical change that occurs during exhalation
* The diaphragm relaxes - moves up
| * External intercostal muscles relax - rib cage moves down and in
36
Describe the volume change that occurs during exhalation
- Decrease in the volume of the thorax/thoracic cavity.
37
Describe the pressure change that occurs during exhalation
- Increase in pressure in the thorax
- No longer below atmospheric pressure
- This leads to very shallow concentration gradient
38
Describe the air movement that occurs during exhalation
- Air moves out, into the atmosphere through the mouth and nasal cavity
39
What is Spirometry?
A pulmonary function test (PFT)
40
What is Spirometry used to measure?
- Volume
- Speed (flow)
[during inhalation and exhalation]
41
What body parts are involved in gas exchange in insects?
- Body surface (exoskeleton)
- Spiracles
- Tracheae
- Tracheoles
- Tracheal fluid
42
What role body surface (exoskeleton) play in gas exchange in insects?
- Tough surface in which little/no gas exchange can occur.
| - Doesn’t contain blood pigment which can carry oxygen, meaning there’s a need for another gas exchange system.
43
Where can spiracles be found?
On the thorax and abdomen of an insect
44
What is a spiracle?
A small opening in an insect’s thorax or abdomen
45
What is the function of a spiracle?
- Allow the movement of air to enter and leave the system
| - Another method of water control
46
What is a tracheae?
Tubes running from the spiracles into and along the body of the insect. They are the largest tubes in the insect respiratory system
47
Why are controlled sphincters closed for as much as possible?
- To reduce water loss
48
What are inside the tracheae?
Rings of chitin
| Chitonous rings
49
What are chitinous rings in the tracheae for?
- Chitin rings lines the tracheae to keep them open if they are pressed or bent.
- Relatively impermeable, meaning that little gas exchange takes place in the tracheae
50
What is the liquid in the tracheoles?
- There is tracheal fluid at the end of tracheoles.
- If there’s increased oxygen demands, lactic acid builds up in the tissues, causing water out of tracheoles by osmosis.
- This causes more exposure for gas exchange
51
What are adaptions in insects affecting gas exchange
- When spiracles are closed, oxygen and CO2 can diffuse into the body fluids of the insect where it is held in a process called buffering.
- When spiracles flutter, they move fresh air into the tracheae to renew supply of oxygen, WHILE minimising water loss.
- When CO2 levels build up really high in the body fluids of the insect, the spiracles open widely and CO2 diffuses out rapidly. There may also be pumping movements of the thorax and abdomen when the spiracles are open to maximise gas exchange.
52
What are the three stages in which water flows over the gills?
1. Environment into buccal cavity
2. Buccal cavity over the gills
3. Gills to out the operculum
53
What takes place in the first stage of the water flowing of gills - environment into buccal cavity?
- Mouth opens and the floor of the buccal cavity is lowered.
- Increases the volume of water intake in the buccal cavity.
- This leads to the pressure in the cavity dropping below the water pressure outside the fish.
- This causes water to move into the buccal cavity.
54
What takes place in the second stage of water flowing over gills - buccal cavity over gills?
- As water enters the buccal cavity, the operculum valve is shut.
- Operculum cavity containing gills expands.
- Lowers pressure in the operculum cavity containing the gills
- The floor of the buccal cavity moves up, increasing pressure so that more water moves from the buccal cavity over the gills.
55
What takes place during the third stage of water flowing over gills - gills to out the operculum?
- Mouth closes, the operculum opens and the sides of the opercular cavity move inwards.
- All three actions increase pressure in the operculum cavity.
- This forces water over the gills and out the operculum.
- The floor of the buccal cavity is steadily moved up, maintaining a flow of water over the gills.
56
What features are included in the gas exchange in bony fish?
- Gill filaments
- Gill lamellae
- Bony Gill Arch
- Deoxygenated and oxygenated blood vessels
57
What is the function of the bony Gill arch?
Supports the structure of the gills
58
What are Gill lamellae?
Disks with rich blood supply and large surface area, are the main site of gaseous exchange in the fish.
59
What are Gill filaments?
Occur in stacks and need a flow of water to keep them apart, exposing the large surface area needed for gaseous exchange.
60
Describe what countercurrent flow is?
A system where blood and water flow in opposite directions
61
Explain how countercurrent flow ensures efficient gas exchange
Countercurrent flow is more efficient that parallel flow, as, because the water and blood travel in opposite directions, therefore maintaining a concentration gradient across the whole gill.
This prevents equilibrium being established.
A much higher level of oxygen enters the blood, as the oxygen consistently counties to diffuse down a concentration gradient.
62
Why is there a need for a transport system in large multicellular organisms?
- SA:V is too small; metabolic demand is too high, diffusion distances
- Nutrients, waste and hormone transportation.
63
What is more efficient: open system or closed system? (why)
Closed system
| - High pressure of heart pump maintains diffusion gradient.
64
What is a single circulatory system?
Blood only travels through the heart once for a complete circulation of the body.
65
What is a double circulatory system?
Blood travels through the heart twice for a complete circulation of the body.
Heart to lungs
Lungs to heart
Heart to rest of body
66
Why does the blood return to the heart after travelling to the lungs?
To be pumped, which will lead to the blood travelling at high pressure again.
67
What are the three types of blood vessels?
Arteries
Veins
Capillaries
68
What is the function of the arteries?
Carry oxygenated blood away from the heart, except pulmonary artery and the umbilical cord.
69
Describe the tunica externa of an artery?
- Made of collagen
- Tough outer layer
- Prevents vessels from busting under high pressure
70
What parts of an artery are adapted to withstand high pressures?
- Thick outer layer, made of collagen
| - Elastic fibres can stretch
71
Describe the tunica media of an artery
- Made of elastic fibres and smooth muscle.
- Elastic fibres stretch in times of high pressure, to withstand it.
- Smooth muscle contracts and vessel constricts, making lumen small, and blood faster.
72
What is an example of an open circulatory system?
Invertebrate animals and insects
73
What is the blood equivalent from an insect called?
Haemolymph
74
Describe the lumen of an artery
- Narrow to maintain high pressure, so that blood can be transported faster.
75
How can the artery adapt during differing times of oxygen demand?
- Vasodilation occurs around areas in high demand of oxygen
| - Vasoconstriction in areas of low demand of oxygen
76
Describe the tunica externa of a vein
- Made of collagen
| - Less thick than an artery, as less likely to burst, due to low pressure
77
Describe the tunica media of a vein
- Made of smooth muscle and a little elastic fibre
- Thinner as there is less pressure to withstand
- Veins can be easily squashed
78
What is the function of a vein?
Carry deoxygenated blood towards the heart
79
Why do veins contain valves?
Prevent the back flow of blood
80
Describe the tunica interna of a vein
- Contains endothelium
81
What is the function of the endothelium in the tunica interna of a vein?
Provides a smooth thin layer, allowing blood to flow smoothly.
82
What is the function of the capillaries?
- Link arterioles with veules (arteries with veins)
83
Describe the capillary wall
- One endothelium cell thick
| - Efficient diffusion site as there is a short diffusion pathway
84
Why is the lumen so small in capillaries?
- Allows red blood cells to be in single file, maximising potential surface area for diffusion.
85
What is water potential?
The potential that water has to move freely
86
What is the kPa of pure water?
0
87
What affect will the addition of solutes have on water potential
Water potential becomes more negative, as it reduces its potential to move freely.
88
What is the aorta?
Where oxygenated blood leaves the heart to the rest of the body under high pressure
89
What is the (superior/inferior) vena cava
Deoxygenated blood travels into the heart, from the rest of the body, at a low pressure via the vena cava.
90
What is the right atrium?
The first chamber in which the blood passes
91
What is the right atrioventricular valve?
Valve separating atrium and ventricle on the right side
92
What are tendinous cords
Cords attached to the atrioventricular valves that prevent the flaps of the valves from folding the wrong way
93
What is the right ventricle?
The second chamber in which the blood passes. This is where the deoxygenated blood is pumped to the heart.
94
What is the pulmonary artery?
Deoxygenated blood travelling to the lungs, away from the heart.
95
What is the pulmonary vein?
Oxygenated blood travelling to the heart from the lungs
96
What is the role of the semilunar valves?
Prevents back flow of blood into ventricles
97
What is the role of the left atrioventricular valve?
Valve separating atrium and ventricle on the left side.
98
What is the left atrium?
The third chamber in which the blood passes
99
What is the left ventricle
Fourth chamber blood is in before being pumped around the rest of the body. Blood is oxygenated and under high pressure, in order to reach the rest of the body
100
What is the septum?
Thick, muscular wall in-between 2 sides of the heart and the wall of left ventricle.
- Allows high pressure to be exerted, in order to reach the rest of the body.
101
Why is the heart myogenic?
The heart is able to initiate its own contraction
102
What are the 2 nodes in the heart?
SAN - sino-atrial node
| AVN - atrioventricular node
103
Where is the SAN (sino-atrial node) situated?
Pacemaker area (in the right atrium)
104
Describe the stages of heart contraction
1. Basic rhythm is maintained via a wave of electrical excitation.
2. A wave of electrical excitation begins in the pacemaker area called the SAN (sino-atrial node). This causes the atria to contract initiation a heartbeat. A layer of no-conducting tissue prevents excitation reaching the ventricles.
3. The excitation then reaches the AVN (Atrioventricular node), which slightly delays the wave of excitation before stimulating bundle of His.
4. The bundle of His, is a bundle of conducting tissues containing purkyne fibres.
5. The bundle of his travels towards the apex of the heart, where it splits into two branches.
6. They travel up the walls of the ventricles from the apex, creating another contraction, this time of the ventricles.
7. By contracting from the bottom up, the ventricles are able to be fully emptied.
8. There is a delay between the contraction of the SAN and the AVN, to ensure that the atria have stopped contracting before the ventricles start.
105
What is an ECG?
Electrocardiogram
106
What is the purpose of delaying the stimulation at the AVN?
-To allow the atria to stop contracting before the ventricles start.
107
What does an ECG do?
Monitor the electrical activity of the heart
108
What three events can be identified on an ECG?
- Atrial excitation
- Ventricular excitation
- Ventricular repolarisation
109
What is haemoglobin?
- Globular protein (quaternary structure)
110
How many subunits does haemoglobin contain? - which does each contain?
4 - each consisting of a polypeptide (protein) chain and a haem (non-protein) group.
111
What does each haem group contain?
- Iron atom
| - An affinity for Oxygen
112
Write the word equation for oxygen and haemoglobin?
Oxygen + Haemoglobin = Oxyhaemoglobin
113
Describe the chains in a haemoglobin molecule
2 x beta chains
| 2 x alpha chains
114
What happens when oxygen binds to haemoglobin?
It is taken out of solution, therefore maintaining a steep concentration gradient.
115
What is partial pressure?
-The relative pressure a gas contributes to a mixture of gases (in kPa).
116
What is another term used to describe partial pressure for oxygen?
Oxygen tension
117
Describe cooperative binding
1. O2 molecule combines with first haem group.
2. This changes the shape of the haemoglobin molecule.
3. This stabilises the other subunits
4. Uptake of second O2 is made much easier
5. Further alteration leads to further amplification.
118
Describe the graph between partial pressure and saturation of oxygen
S - shape
119
Describe the difference in oxygen affinity between adult haemoglobin and foetal haemoglobin
Foetal haemoglobin has a higher oxygen affinity
120
What happens in the carriage of CO2?
- 5% remains in plasma
- 10% combines with animo groups in Hb (to forms carboaminohaemoglobin
- 85%
-85% forms carbonic acid, by combining with water. This then becomes hydrogen carbon ions, which diffuse out, causing chloride to enter (called chloride shift) and the hydrogen ion combines with haemoglobin to create haemoglobonic acid - which acts as a buffer.
121
What are the three stages in heart contraction? (In order)
- Atrial systole
- Ventricular systole
- Diastole
122
What is atrial systole?
The contraction of the atria, in which the blood is pumped into the ventricles.
123
What is ventricular systole?
The contraction of the ventricles, in which blood is pumped to the lungs and to the rest of the body.
124
What is diastole?
The heart relaxes - the atria and ventricles fill with blood. This allows the volume and pressure of the blood in the heart to build.
125
What are 4 types of arrhythmic heartbeats?
- Ectopic heartbeat
- Atrial fibrillation
- Tachycardic heartbeat
- Bradycardic heartbeat
126
What is an ectopic heartbeat?
“Heart hiccup”
| - An extra heart beat (usually experience 1 a day, however dangerous if more frequent).
127
What is atrial fibrillation?
Rapid contraction of atria, up to 400 times a min, however not contracting properly, meaning the heart isn’t able to be pump blood effectively.
128
What is a tachycardic heartbeat?
Rapid heartbeat - >100bpm.
Normal after exercise, or if angry, or have a fever.
However, if standard, then may need medication.
129
What is a bradycardic heartbeat?
Slow heartbeat - <60bpm.
Regular exercise can lead to resting heart rate under 60bpm, however severe bradycardia can leads to severe consequences.
This could lead to a pacemaker being needed.
130
What parts can an ECG be broken up into?
P,Q,R,S,T
131
What occurs a the P wave on an ECG?
Atria are contracting
132
What occurs at the QRS complex on an ECG?
Ventricular contraction
133
What occurs at the T wave on an ECG?
Atria and ventricles are relaxing - heart is filling with blood. (Diastole)
