Gas Exchange Flashcards
(126 cards)
1
Q
What is the total oxygen requirement of an organism proportional to?
A
Its total volume
2
Q
What is proportional to the organisms surface area?
A
The rate of absorption of oxygen
3
Q
What has an organism done if it has increased in size?
A
Developed different adaptations to overcome these problems
4
Q
What are the 5 common features of surface areas?
A
- Large surface area relative to volume
- Permeable
- Thin
- Moist - potential region of water loss
- Mechanism to maintain diffusion gradients
5
Q
How can large surface area be obtained in small organisms?
A
The large surface area can be formed by the folding of the exchange surface
6
Q
Why is being permeable important to an exchange surface?
A
This allows easy diffusion of gases
7
Q
Why is being thin important to an exchange surface?
A
It creates a short diffusion pathway, as diffusion is only effective across less than 1mm.
8
Q
How far is diffusion effective?
A
Less than 1mm
9
Q
Why is being moist important to an exchange surface?
A
O2, CO2 and nutrients diffuse in solution
10
Q
Why is having a mechanism to maintain diffusion gradients important to an exchange surface?
A
Transport system, ventilation mechanism or creation of currents across surface allows for exchange.
11
Q
What are the 3 mechanisms to maintain diffusion gradients?
A
- Transport System
- Ventilation Mechanism
- Creation of currents across a surface
12
Q
What adaptation have terrestrial vertebrates made for gas exchange with air?
A
Internal Lungs
13
Q
What is the epiglottis?
A
a flap of cartilage behind the root of the tongue, which is depressed during swallowing to cover the opening of the windpipe.
14
Q
What are the similarities and differences between the trachea and bronchi?
A
Similar in structure
Different in size
15
Q
What is the inner surface of the trachea and bronchi covered in?
A
Ciliated Epithelium
16
Q
What is the function of ciliated cells?
A
Rhythmic wave like movement moves mucus to top of trachea where it is swallowed
17
Q
What are the 3 functions of goblet cells?
A
- Secrete sticky mucus containing glycoprotein
- Protects from dehydration, traps microbes and dust
- Lysozyme also present which causes bacterial lysis
18
Q
What is the function of cartilage ?
A
Holds the airway open during inhalation and exhalation throughout the pressure changes to prevent collapse.
19
Q
Where is cartilage found?
A
In the trachea and bronchi
20
Q
What shape is the cartilage found in the trachea?
A
C- shaped rings
21
Q
What shape is the cartilage found in the bronchi?
A
In irregular blocks
22
Q
What is found on the inside of the cartilage?
A
Smooth muscle
23
Q
What is the function of the smooth muscle in cartilage during exercise?
A
Relax during exercise to allow more air into the lungs
24
Q
What causes asthma attacks?
A
Contracts during asthma which causes constriction and breathlessness
25
What recoils during exhalation?
Elastic Fibres
26
What are the three features of the alveoli that make them good for gaseous exchange?
1. They provide an enormous surface area
2. Their surface is moist so gases can dissolve in the moisture and diffuses through the epithelial lining
3. The walls are thin providing a short diffusion pathway
27
Why is it important that alveoli are well ventilated?
Because ventilation movement ensure air is inhaled and exhaled from the lungs
28
Why do alveoli have a good blood supply?
Because they are covered with an extensive network of capillaries
29
Why do the alveoli have a maintained diffusion gradient?
Because blood is always moving taking oxygen away and bringing carbon dioxide
30
What three structural features of alveoli walls are important?
1. They are a single layer of squamous epithelium cells
2. Thin flattened cells
3. Adjacent blood capillaries are also lined with squamous endothelium
31
What allows alveoli to stretch and why is this so important?
Its elastic fibres, alveoli stretch during inhalation and recoil during exhalation to force the air out
32
What acts as a lubricant on the alveoli to maintain the moisture on its surface? What is its function?
Surfactant (detergent) lubricant, which reduces cohesion of water molecules and so prevent collapse of alveoli when breathing out.
33
What type of ventilation do mammals use?
Mammals ventilate their lungs by creating a negative pressure in the lungs which draws air in
34
What is the purpose of negative pressure ventilation?
The negative pressure created in the lungs draws air in
35
What does a positive pressure in the lungs cause?
Forces air out of the lungs
36
What are the lungs surrounded by in humans?
Two membranes called the pleural membrane
37
What is the function of the fluid in the pleural membrane?
Acts as a lubricator and a shock absorber
38
What is the function of the pleural membrane?
Ensures the thorax in air tight which allows for the change in pressure during ventilation
39
What is inspiration?
Inhalation- when a fresh supply of O2 is brought in to maintain the O2 concentration gradient
40
What is expiration?
Exhalation - removes waste air with its cargo of CO2 to maintain the CO2 gradient
41
What is the first step of inspiration ? HINT: (Ribs)
External intercostal muscles contract, pulling the ribcage upwards and outwards
42
What occurs with the pleural membrane during inspiration?
This pulls out the pleural membrane, reduces pressure in the pleural cavity and the inner pleural membrane moves outwards. This pulls on the surface of the lungs and causes the alveoli to expand.
43
What does the diaphragm do during inhalation?
Diaphragm contracts, pulling it from a domed shaped into a flattened shape.
44
What are the three combined effects of inspiration?
1. Volume of the thorax and lungs increase
2. Alveolar pressure is reduced to below atmospheric pressure
3. Air is drawn into the lungs (goes down the pressure gradient)
45
What is the first stage of relaxed expiration? HINT: Ribs
Externals intercostal muscles relax and the ribcage falls under its own weight
46
What happens to the diaphragm during relaxed expiration?
Diaphragm relaxes and gut pressure pushes it back into its domed shape
47
What happens in the lungs during relaxed expiration?
Elastic recoil of lung tissue
48
What is the combined effect of relaxed expiration?
1. Volume of the thorax and lungs decrease
2. Pressure is increased
3. Air is forced out
49
What happens to the intercostal muscles and ribcage during forced expiration?
Internal intercostal muscles contract, pulling the ribcage down and in
50
What happens to the abdominal muscles during forced expiration?
Abdominal muscles contract pushing the diaphragm upwards
51
What is the combined effect of forced expiration?
1. Volume of the thorax and lungs decrease
2. Pressure is increased
3. Air is forced out
52
When is forced expiration used?
Playing an instrument, singing etc
53
What are three features of water?
1. Contains a low concentration of oxygen, 0.7%
2. Denser than air
3. More viscous than air
54
Why can fish not carry out gas exchange through their body surface?
They have gills which are impermeable
55
Where are the fish's gills located?
In the opercular cavity
56
What provides a fish with a large surface area for gas exchange?
Gills contain numerous gill plates and filaments providing a large surface area for gas exchange
57
How is a concentration gradient maintained in a fish?
Using an extensive network of capillaries and counter current flow to maintain concentration gradient
58
What separates a fish's blood from the water stream and why is this important?
A thin layer of cells which allows for a short diffusion pathway
59
How many gills does a fish have?
4 pairs of gills in the pharynx (throat)
60
What supports each gill?
A bony gill arch
61
What is along each gill which adds to surface area?
Gill lamellae
62
How is oxygen passed into the blood stream of a fish?
The gill plates contain blood capillaries. The oxygen passes through the gill plates into the capillaries and is carried by haemoglobin. The CO2 passes into the water.
63
What is the function of gill rakers?
Filter water and trap prey
64
Why can fish not survive out of water?
Fish cannot survive out of water because the change in density from water to air results in the gill plates and filaments to be bought together which reduces the surface area for diffusion.
65
What is the counter current system?
Blood in capillaries flows in the opposite direction from the water in the adjacent channels.
66
Why is the counter current system effective?
Dissolved gasses diffuse faster between fluids with a large difference in gas concentration than between fluids with only a small difference.
67
What are the 5 mechanical steps to inhalation in fish?
1. The mouth opens
2. The operculum closes the opening at the back of the pharynx
3. The floor of the mouth cavity is lowered.
4. The volume of the mouth cavity increases and the pressure falls
5. Water flows in
68
What adaptations have occurred to increase the surface area to volume ratio in Amoeba?
'Pseudopodia' - projections that increase their surface area
69
What adaptations have occurred to increase the surface area to volume ratio in Flatworm?
Thin and flat, so large surface area to volume ratio.
Approx- 2mm thick
70
What adaptations have occurred to increase the surface area to volume ratio in Earthworm?
Elongated and round
71
What is the method of oxygen delivery to each cell in Amoeba?
Simple diffusion
72
What is the method of oxygen delivery to each cell in flatworms?
Simple Diffusion
73
What is the method of oxygen delivery to each cell in earth worms?
Simple Diffusion
74
What is the habitat of Amoeba and how does it aid with gas exchange?
Fresh water, ponds and stagnant water where oxygen is minimal. 02 dissolves in water.
75
What is the habitat of Flatworm and how does it aid with gas exchange?
Aquatic, fresh water or salt water.
| 02 dissolves in water
76
What is the habitat of Earthworm and how does it aid with gas exchange?
Damp soil to maintain moisture on the worms skin to allow gases to dissolve
77
What is the function of Goblet cells?
Secrete sticky mucus containing glycoprotein, keeps lungs moist which protects from dehydration.
Contains lysozyme which causes bacterial lysis
78
Where are Goblet Cells found?
Trachea, Bronchi and Bronchioles
79
What is the function of Ciliated Epithelial Cells?
Waft mucus and dirt upwards toward trachea to be swallowed for digestion
80
Where are ciliated Epithelial cells found?
Trachea, Bronchi and bronchioles
81
What is the function of cartilage?
Holds airways open during respiration. 'C' shaped to provide flexibility.
82
Where is cartilage found?
Trachea is 'c' shaped cartilage
Bronchi has irregular blocks
No cartilage in bronchioles
83
What is the function of Elastic fibres?
Stretch during inhalation and recoil during exhalation
84
Where are Elastic fibres found?
Alveoli, Trachea, bronchi and bronchioles
85
What is the function of smooth muscle?
To adjust the diameter of the airway
86
Where is smooth muscle found?
Between the trachea, bronchi, bronchioles and cartilage.
87
State 5 ways in which alveoli are efficient at gas exchange?
1. Large surface area for gas exchange
2. Moist so gases can dissolve for diffusion
3. The cell lining is thin so provides a short diffusion pathway,
4. Permeable
5. Maintain diffusion gradient as alveoli are well ventilated, alveoli have a good blood supply.
88
Why do organs for gas exchange need to be retained in the body in terrestrial organisms?
To prevent heat and water loss
89
What is the transition into an adult called for amphibians ?
Metamorphosis
90
Where do amphibians live?
.They live in water for fertilisation
.Larvae (tadpoles) live in water and have gills
.Adults live near aquatic environments
91
What gas exchange surface do amphibians' have?
. Larvae have gills
| . Adults use moist skin as its exchange surface during rest and its lungs during exercise
92
What are the 3 key features of the surface of a amphibian?
1. Undergo metamorphosis
2. The larvae have gills
3. Adults use their skin for gas exchange at rest and the lungs when active.
93
Are reptiles aquatic or terrestrial?
Terrestrial
94
What gas exchange surface does reptiles use?
.'In and out' bellow-like arrangement with more complex lungs with in-growth of tissue increasing surface area with NO diaphragm
95
What is the key feature of a reptiles gas exchange surface?
Movement of the ribs aid in the ventilation of the lungs
96
Are birds aquatic or terrestrial?
Terrestrial
97
What are the gas exchange surfaces used by birds?
A bird breaths air in, air moves into rear air sacs, which is then expelled into lungs and flows through to the front air sacs. NO diaphragm. COUNTER CURRENT EXCHANGE.
98
What is the key feature of a birds respiratory system?
Attached to the lungs are air sacs which act as bellows. When the bird breathes in any air that remains in the lungs form the last breath gets sucked into the air sacs meaning that the lungs are always filled up with fresh air.
99
What is counter current exchange?
When blood picks up oxygen from the lungs and flows in the opposite direction to the air.
100
What is the respiratory system in Insects called?
The tracheal system
101
What is involved in the respiratory system of insects?
It involves the diffusion of oxygen directly from the atmosphere into the air-filled sacs and tubes.
102
How many spiracles does a grasshopper have and where are they located?
10 pair of spiracles, located laterally on the body surface. 2 pairs on the thorax and 8 pairs on the abdomen.
103
What guards spiracles?
Fine Hairs
104
Why do fine hairs guard spiracles?
To prevent the entry of dust and other foreign particles
105
What do the spiracles open into?
A series of long tubes called the lateral tracheal trunk that link to air sacs and tracheae.
106
What are tracheae?
Long tubes that have a wall of single layered epithelial cells.
107
What do the cells in the insects tracheal system secrete?
Spiral cuticle thickenings around the tube that gives support to the tube.
108
What do tracheal tubes branch further into ?
Finer tracheoles that enter all tissue
109
What is at the end of the tracheoles and why is this important?
Fluid and a lack of cuticle thickening to allow gases to dissolve for diffusion
110
What can larger insects do in reference to air flow?
Larger insects can create a one way airflow through their major tracheae.
111
What happens during inhalation in insects?
1. The thoracic spiracles open
2. The abdominal spiracles are closed
3. The abdomen expands causing a decrease in pressure so air flows in.
112
What happens during exhalation in insects?
1. The thoracic spiracles close
2. The abdominal spiracles open
3. The abdomen contracts causing an increase in pressure so air flows out
113
What happens to insects respiratory system during flight? Why does it do this?
When muscles are active during flight the fluid is drawn into the tissue supplying oxygen.
This is effective because it creates a larger surface area for gas exchange and a shorter diffusion pathway.
114
What is the mouth cavity of a fish called?
Buccal Cavity
115
What are the 5 steps of mechanisation of fish exhalation?
1. The mouth closes
2. The operculum is forced open at the back of the pharynx
3. The floor of the mouth cavity is raised.
4. The volume of the mouth cavity decreases and the pressure increases
5. Water flows out
116
Diffusion of oxygen between water and blood occurs until what happens?
The bloods and water have an equal percentage saturation of oxygen
117
What is the main photosynthetic tissue in a leaf?
Palisade Mesophyll
118
What is the upper epidermis and what is its purpose?
A thin, transparent layer of cells which prevent the loss of heat and water
119
What is the function of the spongy mesophyll layer?
Provides air spaces for respiration
120
What is the significance of having a large surface area in respect to respiration?
Creates a larger number of stomata
121
What is the significance of having a large surface area in respect to photosynthesis?
Allows to capture more light
122
What is the significance of being thin in respect to respiration?
Creates a short diffusion pathway
123
What is the significance of being thin in respect to respiration?
Light can penetrate through the leaf
124
Does being transparent effect gas exchange in leaves?
No
125
How does transparency effect photosynthesis in leaves?
The light can pass through the cuticle to the palisade mesophyll layer
126
How are palisade cells structured to maximise the harvest of light energy during photosynthesis?
They are elongated and packed full of moving chloroplast
