3.3 Organisms exchange substances with their environment - SA ratio + Gas Exchange Flashcards
What is the relationship between the size of an organism and its surface area to volume ratio?
The size of an organism influences its surface area to volume ratio, affecting its adaptations.
What is a key adaptation of exchange surfaces in organisms?
Exchange surfaces have adaptations to make transport across the surface more efficient.
What is the surface area to volume ratio of an organism with a surface area of 6 cm² and a volume of 2 cm³?
SA:Vol = 3
What is the surface area to volume ratio of an organism with a surface area of 54 cm² and a volume of 27 cm³?
SA:Vol = 2
Small organisms have a _______ surface area in comparison to their volume.
large
How do small organisms like amoeba exchange substances?
They exchange substances across their surface by diffusion.
Why can small organisms efficiently exchange substances?
They have a large surface area relative to their volume and a smaller distance from the outside to the interior.
What happens to the surface area compared to volume as organisms increase in size?
The surface area becomes smaller compared to its volume.
What is a key factor that increases with the size of larger organisms?
Higher metabolic rate.
What is the significance of metabolic rate in larger organisms?
It demands efficient transport of waste out of cells and reactants into cells.
Name an adaptation that helps in the efficient absorption of digested food.
Villi and microvilli.
Which adaptations are used for efficient gas exchange in mammals?
Alveoli and bronchioles.
What structures do terrestrial insects use for efficient gas exchange?
Spiracles and tracheoles.
Which adaptations are involved in efficient gas exchange in fish?
Gill filaments and lamellae.
What adaptation do plants have for efficient gas exchange?
Thin wide leaves.
What is the role of many capillaries in larger organisms?
Efficient exchange at tissues.
Fill in the blank: The larger an organism is, the larger the distance from the ______ to the outside.
[middle]
True or False: Larger organisms do not require adaptations for efficient substance exchange.
False.
What are the key structures involved in human gas exchange?
• alveoli
• bronchioles
• bronchi
• trachea
• lungs
These structures facilitate the process of gas exchange in the respiratory system.
What is the role of the diaphragm in ventilation?
The diaphragm contracts and relaxes to control inhalation and exhalation.
The diaphragm is a key muscle involved in the mechanics of breathing.
What are the muscles involved in ventilation?
• Diaphragm
• External intercostal muscles
• Internal intercostal muscles
These muscles work together to expand and contract the thoracic cavity.
Define ventilation in the context of human respiration.
Ventilation is inhaling and exhaling in humans.
It involves the movement of air into and out of the lungs.
What happens during inspiration?
• Thoracic cavity expands
• External intercostal muscles contract
• Diaphragm contracts
These actions result in air being drawn into the lungs.
What occurs during expiration?
• Thoracic cavity reduces
• External intercostal muscles relax
This process pushes air out of the lungs.
What does the term ‘antagonistic’ refer to in the context of muscle function?
Muscles that work in opposition to each other.
For example, the external intercostal muscles oppose the internal intercostal muscles during breathing.
Fill in the blank: The _______ is a muscle that plays a crucial role in the process of ventilation.
diaphragm
The diaphragm is essential for inhalation and exhalation.
True or False: The pleural membranes are involved in the gas exchange process.
False
The pleural membranes provide a protective layer around the lungs but do not directly participate in gas exchange.
What is the function of the pharynx in the respiratory system?
The pharynx serves as a passageway for air moving from the nasal cavity to the larynx.
It plays a role in both the respiratory and digestive systems.
What is the role of the diaphragm in respiration?
Contracts to move down and flattens for inspiration; relaxes to move up and dome-shaped for expiration
The diaphragm is a key muscle in the process of ventilation.
What are antagonistic muscles in the context of respiration?
Muscles that work in opposition to each other, such as external and internal intercostal muscles
They facilitate the processes of inspiration and expiration.
How do external intercostal muscles contribute to inspiration?
Contract to pull the ribs up and out
This action increases the volume of the thoracic cavity.
What happens to the internal intercostal muscles during expiration?
Contract to pull the rib down and in
This helps decrease the volume of the thoracic cavity.
What is the initial change in air pressure in the lungs during inspiration?
Initially drops below atmospheric pressure
This allows air to flow into the lungs.
What is the change in lung volume during expiration?
Decreases
This is caused by the contraction of the internal intercostal muscles and diaphragm.
What is the function of capillary networks around alveoli?
To remove exchanged gases and maintain a concentration gradient
This is essential for efficient gas exchange.
How many alveoli are there in each human lung?
300 million
This large number creates a significant surface area for gas exchange.
What is the primary purpose of alveolar epithelial cells being very thin?
To minimize diffusion distance
This facilitates faster gas exchange between air and blood.
Fill in the blank: Air moves into the lungs as the atmospheric pressure is _______ than that of the thorax.
higher
Fill in the blank: Each alveolus is surrounded by a network of _______ to facilitate gas exchange.
capillaries
True or False: The mucosal lining plays a role in the respiratory system.
True
It helps in protecting and moistening the airways.
What structures are involved in the gas exchange process?
Alveoli, capillary beds
This exchange occurs between the alveolar epithelium and the blood.
What happens to the air pressure in the thorax during expiration?
It becomes higher than atmospheric pressure
This drives air out of the lungs.
What is the significance of the large surface area provided by alveoli?
Facilitates efficient gas exchange (diffusion)
More surface area allows for greater amounts of oxygen and carbon dioxide to be exchanged.
What is the primary gas exchange surface in fish?
Gills
Gills allow fish to extract oxygen from water.
Why do fish require a specialized gas exchange surface?
Because they are waterproof and have a small surface area to volume ratio.
How much less oxygen is available in water compared to air?
30 times less.
What adaptation do fish have to maintain the concentration gradient for gas diffusion?
Countercurrent flow.
What are the key terms associated with fish gill anatomy?
- Gills
- Gill filament
- Gill lamellae
- Large surface area
- Diffusion
How many layers of gills do fish have on each side of their head?
Four layers.
What is the structure that covers each gill filament?
Gill lamellae.
What positioning of gill lamellae contributes to a large surface area?
Positioned at right angles to the filament.
What happens when fish open their mouths?
Water rushes in and over the gills.
Fill in the blank: Fish obtain oxygen from the water through their _______.
gills.
True or False: Fish can directly breathe air like terrestrial animals.
False.
What is the primary purpose of gill filaments?
To create a large surface area to volume ratio for diffusion
This adaptation facilitates efficient gas exchange in aquatic organisms.
What structure in gills is responsible for maintaining a short diffusion distance?
Capillary network in every lamella
The thinness of the gill lamellae also contributes to reduced diffusion distance.
What mechanism maintains the concentration gradient in gills?
Countercurrent flow mechanism
This mechanism is essential for effective gas exchange.
Define countercurrent flow mechanism.
Water flows over the gills in the opposite direction to the flow of blood in the capillaries
This arrangement prevents equilibrium and maintains a diffusion gradient.
True or False: Countercurrent flow allows equilibrium to be reached in the gills.
False
Countercurrent flow ensures that equilibrium is not reached, which is crucial for gas exchange.
What are gill lamellae?
Thin structures that increase surface area for gas exchange
They are covered by gill filaments.
Fill in the blank: The __________ is a network of capillaries found in gill lamellae.
Capillary network
This structure is important for short diffusion distances.
List the key terms related to gas exchange in gills.
- Gills
- Gill filaments
- Gill lamellae
- Equilibrium
- Countercurrent flow
- Branchial arteries
Understanding these terms is essential for comprehending the gas exchange process.
What is the primary function of the tracheal system in insects?
Gas exchange
What are the main components of the tracheal system in insects?
- Trachea
- Tracheoles
- Spiracles
What are spiracles?
Round, valve-like openings that allow gas exchange
Where are spiracles located in insects?
Along the length of the abdomen
What is the role of the trachea in the insect respiratory system?
A network of internal tubes that transport gases
What structural feature do trachea tubes have to maintain their shape?
Rings of cartilage
What are tracheoles?
Smaller tubes that branch from the trachea and deliver oxygen to tissues
True or False: Insects have lungs for gas exchange.
False
Fill in the blank: Insects have an exoskeleton made from _______ material.
hard fibrous
What is the purpose of the lipid layer in the insect exoskeleton?
To prevent water loss
How do oxygen and carbon dioxide enter and leave the insect’s body?
Via the spiracles
What is the significance of the tracheal system in relation to respiring cells?
It delivers oxygen to all respiring cells
What is the main process by which gases are exchanged in terrestrial insects?
Diffusion
What are the three key adaptations for efficient gas exchange in terrestrial insects?
- A large number of fine tracheoles
- Thin walls of tracheoles for short diffusion pathway
- Steep diffusion gradients due to oxygen use and carbon dioxide production
What is the role of anaerobic respiration in gas exchange for insects?
Produces lactate, lowering water potential and drawing more air into tracheoles
How does mass transport contribute to gas exchange in insects?
Insects contract and relax abdominal muscles to move gases en masse
What adaptation do insects have to minimize water loss by evaporation?
- Small surface area to volume ratio
- Waterproof exoskeleton
- Spiracles that can open and close
Fill in the blank: The walls of the tracheoles are very _______ and there is a short distance between spiracles and tracheoles.
thin
True or False: The concentration gradient established during respiration causes oxygen to move from the atmosphere into the tracheoles.
True
What happens to the volume in the tracheoles when muscle cells respire anaerobically?
It decreases, drawing more air from the atmosphere
What is the effect of evaporation on terrestrial insects?
It can lead to water loss, necessitating adaptations to reduce it
What is the significance of the large surface area provided by tracheoles?
Enhances gas exchange efficiency
What is the process called when water moves from the tracheoles into the cells by osmosis?
Osmosis
What are the key structures involved in gas exchange in plants?
The mesophyll layers (palisade and spongy mesophyll) and the stomata created by guard cells
These structures facilitate the exchange of gases necessary for photosynthesis and respiration.
What is the function of the palisade mesophyll?
The site of photosynthesis, where lots of oxygen is produced and carbon dioxide is used up
This process creates a concentration gradient that drives gas exchange.
How does oxygen move during gas exchange in plants?
Oxygen travels through the air spaces in the spongy mesophyll and diffuses out of the stomata
This occurs due to the concentration gradient established by photosynthesis.
How does carbon dioxide enter the plant?
Carbon dioxide diffuses in through the stomata
This is essential for photosynthesis to occur.
What happens to stomata at night?
Stomata close to reduce water loss by evaporation
This occurs when photosynthesis is not taking place.
What are guard cells?
Cells that control the opening and closing of stomata
Guard cells can swell to open stomata or shrink to close them.
Fill in the blank: The palisade mesophyll is the site of _______.
photosynthesis
True or False: The spongy mesophyll is involved in photosynthesis.
True
The spongy mesophyll assists in gas exchange and contains chloroplasts for photosynthesis.
What is the role of evaporation in gas exchange?
Evaporation can lead to water loss, prompting stomata to close
This is a protective mechanism to prevent dehydration in plants.
What are xerophytic plants adapted to survive in?
Environments with limited water
Xerophytes have evolved specific adaptations to conserve water.
Name one example of a xerophytic plant.
Marram grass
Marram grass is known for its adaptations to sandy coastal environments.
What is one adaptation of xerophytes to limit water loss?
Curled leaves
Curled leaves trap moisture and increase local humidity.
How do sunken stomata help xerophytes?
They trap moisture to increase local humidity
This adaptation reduces water loss through evaporation.
What is the function of hairs on xerophytic plants?
To trap moisture to increase local humidity
Hairs create a microenvironment that reduces evaporation.
What is the purpose of a thicker cuticle in xerophytes?
To reduce evaporation
A thicker cuticle provides a barrier against water loss.
Fill in the blank: Xerophytes have a _______ root network to reach more water.
Longer
Longer roots allow xerophytes to access deeper water sources.
