Exchange Surfaces And Breathing Flashcards
Why can large or multicellular organisms not use diffusion alone to absorb nutrients?
They have a greater metabolic activity and more demands which means more oxygen and other nutrients are needed. This means they have specialised transport systems
What is the equation for the surface area and circumference of a circle?
Area-π𝒓²
Circumference-2π𝒓
What is the equation for the surface area and volume of a cuboid?
Surface area-2 (bh+bl+hl)
Volume of cuboid-hbl
What are the three characteristics of a well adapted exchange surface?
Large surface area
Thin barriers for a short diffusion pathway
Concentration gradient is maintained by molecules being constantly supplied and removed
What is the role of the alveoli?
They are tiny air sacs in the lungs that facilitate gaseous exchange. They transport oxygen into the bloodstream and take in carbon dioxide.
How are the lungs adapted to their function?
-The alveoli provide a large surface area for gaseous exchange
-Surfactant prevents the alveoli from sticking together and allows gases to dissolve
-Permeable to oxygen and carbon dioxide as they can diffuse across the membrane
-Thin barriers reduce diffusion distance-alveolar and capillary walls are one cell thick
-Concentration gradient is maintained by blood flow and ventilation
Explain the mechanisms of ventilation when inhaling
-The diaphragm contracts and moves down
-External intercostals contract which moves ribs up and out while the internals contract
-Volume of the chest increases
-Pressure in the lungs falls below atmospheric pressure to allow air to move in
Explain the mechanics of ventilation when exhaling
-Diaphragm relaxes and moves up
-External intercostals relax which causes the ribs to move down and in while the internals contract
-Volume of the chest decreases
-Pressure in the lungs rises above atmospheric pressure to allow air to move out
What muscle is used during forced exhalation?
Abdominals
What tissues and cells make up a bronchiole?
Smooth muscle,
Ciliated epithelium,
Goblet cells,
Blood vessels,
Loose tissue with elastic fibres
What tissues and cells make up a bronchus?
Cartilage,
Smooth muscle and elastic fibres,
Blood vessels,
Ciliated epithelium with goblet cells
What is the role and shape of cartilage in the trachea?
C-shaped cartilage rings
Used to prevent collapse and bursting of the trachea during pressure changes,
Flexible to allow movement of the neck and expansion of the oesophagus when swallowing
What is the role of cartilage in ventilation?
Used to keep the airways open and prevent them from being damaged by pressure changes or air flow
What is the role of smooth muscle in ventilation?
It can contract or relax to open or close the airways and change airflow
What is the role of elastic fibres in ventilation?
Allows the airways to stretch and recoil which helps prevent damage
What is the role of goblet cells in ventilation?
They produce mucus which traps dust and microorganisms that have been inhaled to protect the alveoli
What is the role of ciliated cells?
They line the airways and waft mucus towards the throat to be swallowed
Define vital capacity and tidal volume
Vital capacity- The maximum volume of air that can be inhaled or exhaled in one breath
Tidal volume- The volume of air that is inhaled or exhaled in one breath at rest (around 15% of vital capacity)
Define residual volume and how you can calculate total lung capacity
The volume of air left in the lungs after hardest possible exhale
Lung capacity can be calculated by
Vital capacity + residual volume
Define oxygen uptake and breathing rate
Oxygen uptake- Rate of oxygen consumption (dm³/min)
Breathing rate- Number of breaths per unit of time
What are the average vital capacities of males and females in normal and athletic conditions
Normal:
Male- 4.6 dm³
Female- 3.1 dm³
Athlete:
Male- 6.0 dm³
Female- 4.6 dm³
What is the function of a peak flow meter?
Measures the rate at which air can be expelled and taken into the lungs (L/min)
What is the function of vitalograpghs?
Advanced version of the peak flow meter that puts data onto a graph
What is the function of a spirometer?
Measures volume of the lungs and can be used to check breathing patterns
Explain how a spirometer produces a graph
When inhaling the spirometer chamber goes down,
This causes a pen to go down of graph paper,
This means when the trace goes down it represents inhalation
And when it goes up it represents exhalation
What are 4 precautions to take when setting up a spirometer
There is enough oxygen in the chamber,
The mouthpiece is disinfected,
The person wears a nose clip to ensure all air breathed out come from the chamber
There is a counterbalance in place
What chemical can be used to remove CO2 from a spirometer
Soda lime
Why does a spirometer graph gradually drop and what does this allow us to do?
Soda lime absorbs CO2 in the spirometer,
This reduces the total volume of gas in the chamber,
Causing the graph to drop as more CO2 is absorbed,
CO2 being absorbed tells us how much O2 is used up so we can calculate O2 usage
How do you calculate oxygen uptake?
Measure the reduction in the chamber between two points,
Calculate the time taken between these two points,
Divide the reduction by the time then times by 60,
Reduction in chamber
——————————– X 60
Time taken
This gives oxygen consumption in dm³/min and the same value applies to carbon dioxide removed
Define breathing rate and ventilation rate
Breathing rate- The number of breaths per minute
Ventilation rate- The total volume of air inhaled in one minute
What is the buccal cavity?
The mouth on a fish
Explain the process of ventilation in a bony fish
The fish opens its mouth and lowers the floor of the buccal cavity,
Volume of the buccal cavity increases which decreases pressure as water enters the mouth,
The fish closes its mouth which raises the floor of the buccal cavity which decreases volume and increases pressure,
This forces water out across the fill filament,
The operculum is then forced open and water leaves the gills
Explain the role of the operculum
It is a gill covering made of bone that is involved in the protection of the gills,
It allows water pressure to build when the fish opens its mouth resulting in it being forced open when the mouth closes allowing water to flow through the gills
Explain the key characteristics of the gills
The gill arch contains an artery which transports deoxygenated blood to the gill,
The gill arch also contains vessels that carry oxygenated from the gill,
The gill arch has primary lamellae attached to it and secondary lamellae line the top
State and explain how the gills are adapted for gas exchange
Each gill is made of many primary lamellae which results in a large SA- this is helpful because a larger SA means there is more space for oxygen to diffuse onto,
The primary lamellae are covered in secondary lamellae which further increases the SA- this means there is more space for oxygen to diffuse onto
Secondary lamellae have a lot of capillaries and a thin layer of cells- this means oxygen can diffuse across quickly and then transported away quickly due to the high blood supply
The arch has an artery and multiple vessels to carry oxygenated and deoxygenated blood- this means that oxygen can be transported in larger quantities due to the larger vessel size
Explain the counter current system
Blood flows through the gills in the opposite direction to the water flow which maintains a steep concentration gradient,
This results in the net movement of oxygen by diffusion is always into the blood
What are the steps involved in a fish dissection?
1)Ensure you are wearing an apron and gloves as it can be messy
2)Place your chosen fish in a dissection tray or cutting board
3)Push back the operculum and use scissors to carefully remove the gills. Cut each gill arch through the bone at the top and bottom
4)Look closely to identify the fill filaments (primary lamellae) and then draw and label
Explain how gas exchange occurs in an insect
Air moves in the spiracles and then into tiny air filled tracheae,
The tracheae branch off into smaller tracheoles which have thin permeable walls,
Oxygen goes from the air, to the tracheae, to the tracheoles, to the cells,
Carbon dioxide diffuses the opposite way,
Insects use rhythmic abdominal movements and wing movements when flying to move air in and out of the spiracles
How are insects adapted for gas exchange?
The tracheae and tracheoles give a large surface area for more diffusion,
The tracheoles are lines with singular cells to minimise diffusion distance while also providing a larger SA
What can an insect do to further increase SA?
They can withdraw a fluid from within the tracheoles when active
