gaseous exchange Flashcards
what do green plants trap during photosynthesis and what does it manufacture
they trap light energy and manufacture organic compounds
why cant animals and humans make use of energy directly from the sun
they do not have chlorophyll to trap the radiant energy
how do animals and humans get their energy
by eating plants and animals that in turn may have eaten plants in this way light energy is transferred from the sun to all living organisms
what do humans and animals have to do with the energy they obtained from the food they eat
they need to find some way of releasing the energy that is locked in the food they have eaten and digested
what do we require energy for
for various things we do such as walking running and growth
cellular respiration
the process by which energy is released
what do we require for cellular respiration to take place
we require oxygen
why is oxygen necessary
without oxygen we will not be able to make use of the energy that is within the food we eat
where does oxygen move in the body
from the lungs into the blood and from here into the cells, carbon dioxide moves in the opposite direction (gas exchange)
importance of gas exchange
it ensures that the oxygen from the air in the atmosphere or the air that is drawn into the body of an organism is able to pass through to the cells that require them for cellular respiration
what is the by product of cellular respiration
carbon dioxide
why cant carbon dioxide be allowed to accumulate in the body of an organism
it is toxic to the organism .if it would combine with water to form carbonic acid which reduces the pH
what will happen if the pH is reduced
it will affect the action of the enzymes which are sensitive to changes in pH
second importance of gas exchange
it helps to bring the carbon dioxide to the surface of the organism so that it can be eliminated
what does air passages consist of
the nostrils nasal passages the trachea bronchi bronchioles make up the air passages
where does the nostrils lead to
they lead to the nasal cavities
what is the purpose of nostril hair
remove dust from the inhaled air
what separates the two nasal cavities from each other
by a vertical septum
what is the nasal cavity further sub divided into
into three passages by the three turbinate bones
what are the nasal passages lined by
by a ciliated columnar epithelial cells with goblet cells
what is the air the passes through the nasal passages slowed down by
turbinate bones
why is air slowed down by turbinate bones
so that the air is warmed moistened and cleansed of dust and germs which are trapped in the mucus
fromthe nasal passage the air passes into the ?
pharynx
where does the pharynx lead to
into the trachea b means of and opening (glottis )
where does the pharynx lead to
it leads to the oesophagus
what happens when food is swallowed
the glottis is closed by means of a leaf shaped cartilage called the epiglottis
what is the purpose of the epiglottis
prevents food from going down the trachea and choking is thus avoided
where is the larynx or voice box
in the upper part of the trachea
what does the larynx contain
it contains the vocal cords
how is the rest of the trachea
it is a long tube strengthened by c shaped cartilage rings
what is the function of the cartilage rings
keeps the trachea open at all times
what does the incomplete portion of the cartilage ring in contact with the oesophagus allow
it allows the oesophagus to swell and project into the trachea when food passes through the oesophagus
what happens to the trachea in the thoracic or chest cavity
it divides to form two bronchi
what is the structure if the bronchus
it is the same structure as the trachea
where does the bronchus enter
enters one lung where it is sub divided into smaller and smaller bronchioles
characteristic of the smallest bronchioles
it has no cartilage
alveoli
air sacs with pouches
