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3 main factors that affect the exchange system ?
size
surface area : volume
levels of activity
explain how size affects the exchange system ?
in smaller organisms such as single-celled organisms, diffusion is sufficient for gas exchange due to their high surface area to volume ratio.
Larger organisms require specialized systems to efficiently transport materials across longer distances.
explain how surface area to volume ratio affects the exchange system ?
A higher surface area to volume ratio allows for more efficient diffusion of substances, enabling faster exchange of gases and nutrients.
larger organisms have a lower ratio, necessitating specialized structures or systems to facilitate adequate exchange.
explain how the level of activity affects the exchange system ?
Higher levels of activity increase the demand for oxygen and nutrients, requiring more efficient exchange systems to meet metabolic needs. Active organisms often have adaptations, such as larger respiratory surfaces or enhanced blood flow, to support their energy requirements.
what are the features of a good exchange system ?
large surface area,
thin barriers for diffusion,
a moist environment,
good blood supply to maintain concentration gradients,
ensuring efficient exchange of gases and nutrients.
describe the structure of the mammalian gaseous exchange system ?
the trachea made of rings of cartilage that prevent collapsing during inspiration
trachea branches into the bronchi, leading to bronchioles and alveoli
alveoli walls contain elastic fibres to allow stretch and recoil during inhalation and exhalation
the lungs are protected by the ribcage which are made of intercostal muscles and a diaphragm that aids in ventilation.
The alveoli provide a large surface area for gas exchange and are surrounded by capillaries to facilitate diffusion of oxygen and carbon dioxide.
how is the mammalian gaseous exchange system adapted ?
alveolus one cell thick (squamous epithelium tissue)
capillary walls one cell thick
capillaries are in close contact with alveolus walls
to maximize diffusion efficiency, enhancing gas exchange.
how is a good blood supply maintained within the mammalian exchange system ?
breathing movements ventilate the lungs by bringing in more o2 and removing co2 and ensures
conc of O2 in air of alveolus remains higher than in the blood
conc of CO2 remains lower in alveoli than in the blood
describe inhalation ?
diaphragm contracts down and becomes flattened
external intercostal muscles contract to raise ribcage
volume of thorax increases
thorax pressure decreases below atmospheric pressure
air moves into the lungs
describe exhalation
diaphragm relaxes and becomes dome shaped
external intercostal muscles relax and ribs fall
internal intercostal muscles contract to forcefully push more air out, usually only happens during exercise coughing or sneezing.
volume of thorax decreases
pressure in lungs increases
air moves out of the lungs
what are the tissue in the gaseous exchange system ?
lung tissue have alveoil