Module 3 - Exchange Surfaces Flashcards
Suggest why goblet cells have a large number of mitochondria
To provide lots of energy
Suggest the role of golgi apparatus in the function of goblet cells
Golgi apparatus packages protein and allows mucus to be secreted
Sjogren’s syndrome is a rare condition that can reduce the production of mucus.
Suggest how the upper respiratory tract of a person with Sjogren’s syndrome might be affected
They may be coughing to attempt to remove the mucus
Why do large multicellular animals have a specialised exchange surface
They have a large surface area to volume ratio, therefore simple diffusion cannot be used to meet the body’s metabolic demands, and nutrients as it is a long path and will be too slow.
State the roles of cartilage and elastic fibres in mammalian gas exchange
Cartilage - stops the trachea from collapsing
Elastic fibres - recoil of alveoli
Bony fish and insects have different gas exchange systems. Both can be observed by dissection.
Describe how you would carry out the dissection to display maximum detail of either gas exchange system
Fish - remove the operculum and observe the gills
Insects - cut open the exoskeleton and observe the tracheae
Describe how the trachea of a mammal is different from the trachea in an insect
Mammals have just one trachea , insects have multiple tracheae
Mammals trachea have smooth muscle, goblet cells. Individual insect tracheae do not.
What does surfactant do in the alveoli
It reduces the cohesive action between water molecules.
It prevents alveoli from collapsing.
Alveoli are located in the lungs of mammals.
Explain how alveoli are adapted for efficient gas exchange (6)
Alveoli have thin wall, one cell thick, so diffusion can occur rapidly, as shorter diffusion path
Larger number of alveoli so larger volumes of gas exchanged/higher rate of diffusion
Alveoli is well ventilated as oxygen is constantly replenished and CO2 is constantly removed. So maintains the concentration gradient.
Alveoli have elastic fibres which stretch and recoil. Stretching increases surface area and recoil helps force air out.
Describe and explain how one feature of the lungs provides an efficient gas exchange surface
Large surface area for maximum diffusion.
Squamous epithelium cells provide a short diffusion rate
What do the abbreviations FEV1 and PEFR stand for?
FEV1 - Forced Expiratory Volume
PEFR - Peak Expiratory Flow Rate
The walls of the alveoli consist of squamous epithelial cells.
How does the structure of these cells differ from the epithelial cells lining bronchioles?
They do not have cilia and have fewer mitochondria
Bronchiole walls contain smooth muscle and elastic fibres.
Describe the role of each of these tissues
Smooth Muscle - Controls lumen size
Elastic fibres - Allow stretch and recoil
Outline the process of gaseous exchange in the alveoli of mammalian lungs
Gases move by diffusion down a concentration gradient
Oxygen diffuses from alveoli into blood
Carbon Dioxide diffuses from blood into alveoli
State the correct term for the definition
A group of organs working together to perform an essential function
Organ System
Many teachers use models to demonstrate and explain breathing and lung function in mammals.
When the rubber sheet is pulled down the balloons expand.
Explain why the balloons expand
Volume inside the jar increases and the pressure inside the jar decreases, lower than atmospheric pressure so air is forced into the balloons causing it to expand.
Explain how the structure of the lungs provides humans with an efficient gaseous exchange
There are many alveoli which provide a large surface area
Squamous epithelial cells are thin so shorter diffusion path
Capillary wall is only one cell thick
Thin walls for gasses to diffuse quicker
Dense capillary network around alveoli
Bony fish absorb dissolved oxygen from the water using gills. Water is passed through the buccal cavity and over the gill lamellae. The oxygen saturation of the blood a water changes as the water passes over the gills.
Describe the way oxygen is transferred in the blood at the gills
Blood and water flow in a countercurrent system with a constant concentration gradient between them
Describe how the structures of the insect tracheal system and fish gills provide large surface area for gas exchange
Insect tracheal system has many branched tracheae
Fish have many filaments
Which of the muscles in the mammalian ventilation system contract to force air out of the lungs
Internal intercostal muscle
What structural features are present in Trachea Bronchi Bronchioles Alveoli
Trachea - cartilage, goblet cells elastic fibres
Bronchi - cartilage, goblet cells, elastic fibres
Bronchioles - elastic fibres
Alveoli - elastic fibres
Compare and contrast between normal expiration and forced expiration (6)
Normal expiration is a passive process, the diaphragm moves up, external intercostal muscle relax, ribs move down and in, elastic fibres recoiled and the volume of thorax reduced.
In forced expiration is an active process, it requires energy, the internal intercostal muscles contract and the ribs pulled down hard.
Name a piece of apparatus that may be used to monitor lung function and outline how a vital capacity measurement may be taken using this apparatus.
spirometer
Vital capacity can be taken by one deep breath in and one full expiration. The height of peak to trough of the trace shows vital capacity.
Explain the meaning of the term tidal volume
Volume of air inhaled/exhaled in one breath during regular breathing
Suggest how the teacher may use a glass jar and rubber sheets to demonstrate tidal volume
Move the rubber sheet up and down
Explain the meaning of the term vital capacity
Maximum volume of air inhaled and exhaled in one breath
Show how gills are adapted for efficient gas exchange
The lamellae provide large surface area
Short distance between blood and water
Blood maintains diffusion gradient
Why can expiration be a passive process?
It does not use muscle contraction, muscle relaxes
Some chemicals act as allergens. If these allergens are inhaled, they can cause breathing problems. Allergens cause the smooth muscle in the walls of the airway to contract.
Suggest the effects that this muscle contraction has on ventilation
Harder to exhale
Harder to inhale
More air remains in the lungs
what is the function of smooth muscle cells in gaseous exchange system
Reduces diameter of airway
What is the function of squamous epithelial cells in the gaseous exchange system
Provide short diffusion distance
Explain why using standard deviation would increase the confidence in any conclusion made
Standard deviation is the spread of data around the mean. Reduces the effect of an anomaly.
What is the formula for tidal volume
when ventilation rate and breathing rate is given
Tidal volume = ventilation rate (cm^3) / breathing rate
CPF can affect lung function in dogs. CPF can reduce the tidal volume of a dog’s lungs. Explain how the high occurrence of CPF in West Highland Terriers could have been a result of artificial selection
Inbreeding reduces genetic diversity
Explain how DNA sequencing could help scientists understand how a dogs genes affect its probability of developing CPF
Compare genomes of dog breeds
Identify dogs that carry the allele for CPF.
Explain why a booster vaccination is needed
Produce more memory cells as they may have reduced in number
Asthma is a condition in which the bronchioles become reduced in diameter
Suggest how diameter might become reduced
Contraction of smooth muscle
Extra mucus production
Explain why it is difficult to expel air from the lungs if the bronchioles become reduced in diameter
Exhalation is passive so reduced diameter means force may be needed - breathing harder
Which muscle contracts to force air out of the lungs
Internal intercostal muscle
Explain how grasshopper pumps air in and out of its body
Gasses, O2 and CO2 are dissolved in trachea fluid and is diffused through trachéales.
The changes in volume of its body by rhythmic abdominal movements
Explain why a parallel flow gas exchange system would be less efficient than a counter current gas exchange system
In a parallel flow system, the oxygen concentration gradient between the water and the blood decreases with distance along gill plate, which will mean that the rate of oxygen diffusion will also decrease.
Less oxygen diffuses into the blood than with a counter current system, where the concentration gradient is maintained.
Explain how the concentration gradients of oxygen and carbon dioxide are maintained between the alveoli and the blood in a healthy person.
Alveoli surrounded by rich capillary network which means blood constantly takes O2 and brings CO2
Emphysema is a lung disease that leads to the breakdown of the alveoli walls.
Suggest why a person with emphysema would have difficulty expelling air from the lungs.
Break down of the alveoli walls would mean less elastic fibres from the alveoli.
Harder for lungs to recoil and expel air
