Topic 3 Flashcards
Describe the need for specialised exchange surfaces in multicellular organisms.
Multicellular organisms require specialised exchange surfaces due to their larger size and lower surface area to volume ratio, which makes it difficult for substances to diffuse efficiently across their cells.
Define the characteristics of an efficient
exchange surface.
An efficient exchange surface should have a
large surface area, be thin to minimize the
distance for diffusion, and have a good blood
supply or ventilation to maintain a steep
concentration gradient.
How do fish achieve gas exchange despite
having a small surface area to volume ratio?
Fish have specialised gas exchange surfaces,
specifically gills, which consist of multiple gill
filaments and lamellae that facilitate gas
exchange through a counter current flow of
blood and water.
Explain the role of the operculum in fish
ventilation.
The operculum acts as a valve and pump in
fish, allowing water to be expelled and
creating pressure differences that facilitate
the flow of water over the gills for gas
exchange.
Describe the process of ventilation in fish.
Ventilation in fish begins with the opening of
the mouth and lowering of the buccal cavity
floor, allowing water to flow in. The mouth
then closes, raising the buccal cavity floor
and increasing pressure to force water over
the gill filaments by the differnece in the pressure between the mouth cavity and opercular activity. The operculum acts as a valve and pump and lets water out and pumps it in.
How do gill filaments contribute to gas
exchange in fish?
Gill filaments, which are covered in lamellae,
increase the surface area for gas exchange
and allow for efficient oxygen uptake from
water due to the counter current flow of blood
and water.
Define the importance of maintaining a steep
diffusion gradient in gas exchange.
Maintaining a steep diffusion gradient is
crucial for maximizing the amount of oxygen
that diffuses into deoxygenated blood,
enhancing the efficiency of gas exchange.
Explain why fish cannot survive long out of
water.
Fish cannot survive long out of water because
their gill filaments stick together in the
absence of water, preventing effective gas
exchange and leading to suffocation.
Describe the adaptations of root hair cells for
gas exchange.
Root hair cells have a large surface area that
enhances their ability to absorb water and
nutrients from the soil, facilitating efficient
gas exchange.
How do folded membranes, such as those in
mitochondria, contribute to exchange
surfaces?
Folded membranes in mitochondria increase
the surface area available for biochemical
reactions, enhancing the efficiency of gas
exchange and energy production.
Describe the role of stomata in plant leaves.
Stomata are small holes in plant leaves that
allow gases to enter and exit, facilitating
efficient gas exchange.
How do air spaces in leaves contribute to gas
exchange?
Air spaces in leaves allow gases to move
around and come into contact with
photosynthesizing mesophyll cells, enhancing
gas exchange.
Define the structure and function of the lungs
in mammals.
The lungs are lobed structures with a large
surface area located in the chest cavity,
responsible for gas exchange and protected
by the rib cage.
Explain the function of the diaphragm in the
respiratory system
The diaphragm separates the lungs from the
abdominal area and plays a crucial role in the
process of inhalation and exhalation.
How do intercostal muscles assist in
breathing?
External intercostal muscles contract to raise
the ribcage during inhalation, while internal
intercostal muscles contract to lower it during
exhalation.
Describe the pathway of air entering the
lungs.
Air enters through the nose, travels along the
trachea, bronchi, and bronchioles before
reaching the alveoli for gas exchange.
What is the significance of alveoli in the
respiratory system?
Alveoli are tiny air-filled sacs where gaseous
exchange occurs, and they are adapted to
maximize efficiency due to their thin walls.
How are the trachea and bronchi structurally
similar?
The trachea and bronchi are similar in
structure, both composed of several layers
including cartilage, but differ in size, with
bronchi being narrower.
Explain the difference between bronchi and
bronchioles.
Bronchi are larger air passages that contain
cartilage, while bronchioles are narrower and
primarily composed of smooth muscle and
elastic fibers.
Define the composition of the walls of the
trachea and bronchi.
The walls of the trachea and bronchi are
mostly composed of cartilage, glandular and
connective tissue, elastic fibers, smooth
muscle, and blood vessels.
What is the role of ciliated epithelium in the
respiratory system?
Ciliated epithelium helps to trap and move
particles out of the airways, protecting the
lungs from debris and pathogens.
How do alveoli facilitate efficient gas
exchange?
Alveoli are very thin, only one cell thick,
which allows for rapid diffusion of gases
between the air and blood.
How do the bronchioles differ in structure
from the bronchi?
Bronchioles are narrower than bronchi and
only the larger bronchioles contain cartilage;
their walls are made of smooth muscle and
elastic fibers.
What prevents friction between the rib cage
and lungs during breathing?
A lubricating substance is secreted to prevent
friction between the rib cage and lungs during
inflation and deflation.
