Chapter 7 - Exchange Systems And Breathing Flashcards
(129 cards)
1
Q
Do single celled organisms have high or low SA:V
A
High
2
Q
Need for larger multicellular animals to have specialised exchange surfaces
A
- small SA:V = diffusion distance too long = time taken for diffusion would be too long
Specialised exchange surfaces needed for oxygen/carbon dioxide
3
Q
Outline how respiratory systems in bony fish are adapted to maximise ventilation
A
- water enters mouth when flaw of buccal cavity lowered
- volume change in buccal cavity
- buccal cavity raised when mouth shut = pressure increase
- water flows over gills
- water leaves via operculum
- one direction flow
4
Q
Outline how respiratory systems in insects are adapted to maximise ventilation
A
- abdominal pumping + pressure change in abdomen
- thorax shape change = air drawn in/forced out
- spiracle size changes
- large SA:V = diffusion may be sufficient
5
Q
Why do maggots not need well developed exchange surfaces and transport systems
A
- smaller so greater SA:V
- shorter diffusion distance
- less active so lower metabolic demand for O2
- no exoskeleton so can absorb oxygen by diffusion through skin
6
Q
Explain how nasal cavity increases efficiency of gaseous exchange
A
- large SA and good blood supply
- mucus secreting cells, trap dust and microbes
- moist surfaces = increase humidity + reduce evaporation from surfaces in lung
7
Q
How are gills adapted for efficient gas exchange
A
- many lamellae = large SA = faster diffusion
- secondary lamellae on main lamellae provide large surface area
- good blood supply = maintains steep concentration gradient
8
Q
Outline how respiratory systems in bony fish are adapted to gaseous exchange
A
- gill = larger surface area
- thin = short diffusion distance
- counter current system = gills have good blood supply = steep concentration gradient
9
Q
Outline how respiratory systems in insects are adapted to maximise gaseous exchange
A
- gas diffuses along tracheae
- oxygen dissolves in tracheal fluid at tracheoles + diffuse into surrounding cells
- many tracheoles so large SA
10
Q
What holds the tracheae open
A
Spirals of chitin
11
Q
Explain how trachea increases efficiency of gaseous exchange
A
- cartilage rings = stop it from collapsing
- Ciliated epithelium + goblet cells secrete mucus, trap dust and microbes and move them towards stomach
12
Q
Explain how bronchi/bronchioles increases efficiency of gaseous exchange
A
Smooth muscle = allows air to move in and out and maintains high concentration gradient of oxygen / co2
13
Q
Explain how alveoli increases efficiency of gaseous exchange
A
- thin wall = reduces diffusion distances
- elastic fibres = elastic recoil to help squeeze air out during exhalation
- large number = large SA = increased rate of diffusion
- surfactant = reduces friction and prevents alveoli from collapsing
- good blood supply = maintains high concentration gradient
14
Q
Explain how diaphragm increases efficiency of gaseous exchange
A
- contract to increase volume in lungs, reduce pressure and cause inspiration
15
Q
Advantage of high SA:V
A
allows for the exchange of substances to occur via simple diffusion
16
Q
What is BMR
A
metabolic rate of an organism when at rest
17
Q
The greater the body mass…
A
higher the metabolic rate
o Therefore, a single rhino consumes more oxygen within a given period of time compared to a single mouse
18
Q
Effective exchange surfaces in organisms have …
A
o Large surface area
o Short diffusion distance (thin)
o Good blood supply
o Ventilation mechanism
19
Q
Adaptations of root hair cells = effective exchange
surface
A
• Root hair cells = increase surface area
20
Q
How does extensive capillary network effect efficiency of gas exchange in alveoli
A
constant flow of blood through the capillaries means that oxygenated blood is brought away from the alveoli and deoxygenated blood is brought to them
o This maintains the concentration gradient necessary for gas exchange to occur
21
Q
How does ventilation effect efficiency of gas exchange in alveoli
A
maintain gradient = ensure that there is always a higher concentration of oxygen
in the alveoli than in the blood
22
Q
Examples of organisms with good blood supply / ventilation
A
Gills / alveolus
23
Q
How do gills have good blood supply / maintain concentration gradient
A
Counter current system
24
Q
What is counter current system
A
extensive capillary system that covers the gills ensures that the blood flow is in the opposite direction to the flow of water
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Key feature of the counter current system
water with the highest oxygen concentration is found next to the most deoxygenated blood
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Where does gas exchange take place in humans
human thorax
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What is the human thorax
Collection of organs and tissues in chest cavity
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What is cartilage
strong and flexible tissue
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Where can cartilage be found
in rings along the trachea
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What are these rings of cartilage called
Tracheal rings
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Purpose of tracheal rings
help to support the trachea and ensure it stays open while allowing it to move and flex while we breathe
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What are Ciliated epithelium
Specialised tissue
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Where is ciliated epithelium found
along the trachea down to the bronchi
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Purpose of Ciliated epithelium
Each cell has small projections of cilia which sweep mucus, dust and bacteria upwards and away from the lungs and the epithelium itself
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Where are goblet cells found
scattered throughout the ciliated epithelium in the trachea
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Function of goblet cells
Secrete mucus to trap dust, bacteria and prevents them from reaching the lungs
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Where is the mucus swept tk
Swallowed and destroyed in stomach by acid
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What is squamous epithelium
Lining of alveoli = forms structure of alveolar walls
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Features of squamous epithelium
very thin and permeable for the easy diffusion of gases
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Where is smooth muscle found
throughout the walls of the bronchi and bronchioles
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Function of smooth muscle
helps to regulate the flow of air into the lungs by dilating when more air is needed and constricting when less air is needed
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Where are elastic fires found
All lung tissues
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Functions of elastic fibres
enable the lung to stretch and recoil = what makes expiration a passive process
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Purpose of capillary lumen being small = only able to fit one blood cell at a time
ensures that there is sufficient time and opportunity for gas exchange to occur
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What produces the mucus
Mucous glands in goblet cells
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Where are elastic fibres actually found
In the squamous epithelium of alveolar walls
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List the components of the gas exchange system = humans
Nasal cavity
Trachea
Bronchi
Bronchioles
Alveoli
Diaphragm
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What is the trachea
channel that allows air to travel to the lungs
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What shape are tracheal rings
C shapes
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Why are they c shaped
prevent any friction from rubbing with the esophagus located close behind
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What is the bronchus
Extensions of the tracheae that split into two for the left + right lung
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Structure of bronchus
Very similar structure to trachea but smaller = thinner walls + smaller diameter
• The cartilage rings in the bronchi are full circles
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What are bronchioles
narrow self-supporting tubes with thin walls
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Features of the bronchioles
get smaller as they get closer to the alveoli
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What do the larger bronchioles have that the smaller ones don't
Smooth muscle
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Function of this elastic fires and smooth muscle in the large bronchioles
adjust the size of the airway to increase or decrease airflow = constrict
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Where is the alveoli found
At the ends of the bronchioles
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What does the alveoli wall consist of
single layer of epithelium
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Purpose of single layer of epithelium in alveolus walls
o Elastic fibres are located in the extracellular matrix
o Elastic fibres = cause recoil = helps move air out of alveoli
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Where does the trachea lead to and from
From mouth and nose to bronchi
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What is ventilation
Mass flow of gases
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What is ventilation brought about by
pressure differences in the thoracic cavity
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What is the passage of air
1. Nose / mouth
2. Trachea (windpipe)
3. Bronchi
4. Bronchioles
5. Alveoli
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What type of process is breathing in = mammals
Active
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How do mammals breathe in
- EXTERNAL INTERCOSTAL MUSCLES CONTRACT
- RIBCAGE MOVES UP AND OUT
- DIAPHRAGM CONTRACTS AND moves down and FLATTENS
- VOLUME OF thorax INCREASES
- PRESSURE INSIDE thorax DECREASES below atmospheric
- AIR IS DRAWN IN
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What is breathing in called
Inspiration
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Why is inspiration active
We are contracting muscles
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What is breathing out called
Expiration
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Process of breathing out
- diaphragm relaxes and is pushed up
- external intercostal muscles relax = rib cage moves down and inwards
- volume of thorax decreases and pressure increases above atmospheric
- air moves out of the lungs
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Is expiration active or passive
Passive
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When is expiration an active process
- when forced e.g. coughing, blowing
- because internal intercostal muscles contract instead of external intercostal muscles relaxing
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Labelled diagram of gas exchange
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When we talk about pressure in ventilation = mammals = what should we say
Thoracic pressure
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What is vital capacity
the maximum volume of air that could be inhaled or exhaled after taking a deep breath
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What is tidal volume
volume of air that is breathed in or out during normal breathing (at rest) = in a
single breathe
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What is breathing rate
Number of breaths taken in one minute
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What counts as one breath
taking air in and breathing it back out again
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What is oxygen uptake
volume of oxygen used up by someone in a given time
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What is residual volume
amount of air that remains in the alveoli + airways after forced exhalation
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Normal breathing rate of humans
12-18 breaths per minute
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Label this
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What is the process of using a spirometer
Pen records the movement of the lid = as you breathe in the lid moves down and vice versa because the pen would be going down when you breathe in and up when you breath out.
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Purpose of soda lime in spirometer
Carbon dioxide is absorbed from the exhaled air by soda lime in order to stop the concentration of carbon dioxide in the re-breathed air from getting too high = can cause respiratory distress
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How to measure oxygen uptake be measured
o Carbon dioxide is removed from the exhaled air, meaning that the total volume of air available in the spirometer gradually decreases, as oxygen is extracted from it by the subject's breathing
o This change in volume is used as a measure of oxygen uptake
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Label this
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Precautions before using a Spirograph
- subject should be healthy = no breathing problems like asthma
- The soda lime should be fresh
- There should be no air leaks = closed system
- The mouthpiece should be steriled
- The water chamber shouldn’t be overfilled otherwise it will enter the pipes
- Make sure subject is wearing a nose clip
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What is breathing rate usually measured in
Breaths min^-1
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Formula for ventilation rate
Ventilation rate = tidal volume X breathing rate
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How to calculate vital capacity
inspiratory reserve + expiratory reserve + tidal volume = approx. 4 to 4.5 dm3 =
peak to trough
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How to calculate breathing rate
peak to trough is one breath = count the number of
peaks in a minute
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How to calculate oxygen consumption
air breathed into the spirometer has CO2 removed by soda lime = volume of gas
decreases = decrease is equivalent to oxygen consumption = LINE GRADIENT IS
OXYGEN CONSUMPTION = gradient steeper in exercise
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How to double rate of diffusion
surface area or concentration difference is doubled or
2. thickness of the exchange membrane is halved.
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Features of the exchange system in insects
•spiracle
•trachea
•tracheoles
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Why can't insects just use simple diffusion through skim and why is this an advantage + disadvantage
• rigid exoskeleton with a waxy coating = impermeable to gases
o prevents water loss but also means no gas exchange
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What is a spriacle
opening in the exoskeleton of an insect which has valves
96
Purpose of spiracle
allows air to enter the insect and flow into the system of tracheae
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What are trachea/tracheoles
tubes within the insect respiratory system which lead to tracheoles (narrower tubes)
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What di the trachea have in insects
origid rings of cartilage / chitin that keep the tracheae open
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Passage of air in insects
Spiracle = trachea = air sac = tracheoles = muscle
cels
100
For smaller insects is this okay
Yes = sufficient oxygen via diffusion
101
How does the oxygen get from tracheoles to muscle cels
• Lactic acid / tracheal fluid - oxygen dissolves into this fluid, where it reaches individual cells to start simple diffusion / gas exchange
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When inactive, what happens to the fluid
tracheal fluid builds up at the bottom of the tracheoles, causing slower diffusion.
103
When active, what happens to the fluid
muscles draw up tracheal fluid
• Faster diffusion
• Tracheal fluid being drawn up = less pressure = draws air from spiracles
104
What's the problem with larger insects + how do we fix this
• Need more rapid supply of oxygen = create mass flow of air = ventilation
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Expiration in insects
• muscles contract & flatten the body
• volume of the tracheal system decreases
• air is forced out
106
Inspiration in insects
• Closing the spiracles
• Using abdominal muscles to create a pumping movement for ventilation
107
Why do fish have a problem with gas exchange
• Oxygen dissolves less readily in water = must pass large volumes of water over their gas exchange systems relative to the volumes of air ventilated by land animals.
108
Structure of fish gills in bony fish
gills = 4 = on each side of the head
• Each gill arch is attached to two stacks of filament
• On the surface of each filament, there are rows of lamellae
• The lamellae surface consists of a single layer of flattened cells that cover a vast network of capillaries
• lie between the mouth cavity and the opercular flaps
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All questions 😠
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128
Explain how Fig. 1.1 shows that gills are adapted for efficient gas exchange.
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