Gas Exchange Flashcards
what is an open circulatory system
where blood does not remain within the vessels at all times
what is the order of structures that air is transported through in an insect
spiracle, tracheae, tracheoles, tracheal fluid
what is the process of gas exchange in an insect
air enters the insect through a pore in each segment known as spiracles.
these openings are connected to the tracheae which then divide into smaller and smaller tubes called trachioles.
the end of the tubes are filled with tracheal fluid and oxygen diffuses into the respiring cells that are bathed in this fluid.
what happens in resting insects
the end of the tracheoles fill with water because the membranes are permeable
how does blood flow in a single circulatory system
through the heart once for each circuit of the body
what is counter current flow
where fluids flow in opposite directions to each other to maximise oxygen uptake
what is transpiration
the loss of water vapour from a plant through the stomata of the leaves
what do oxygen and carbon dioxide move through in the alveoli
they move by simple diffusion through the hydrophobic tails of the lipid bilayer
what five factors increase rate of simple diffusion
a larger surface area
a higher temperature
a short diffusion pathway
small diffusing molecules
steep concentration gradient
how do the epithelial cells reduce diffusion pathway
they’re thin and flattened (squamous) cells
explain the mechanism of inhalation at rest
the diaphragms contracts and moves in a downward direction
the external intercostals muscles contract which acts to move the rib cage up and out
this increases the volume of the thoracic cavity
which decreases the pressure
this creates a pressure gradient between the atmosphere and alveolus so a flow of air comes from the higher pressure in the atmosphere into the gas exchange system
air then inflates the lungs before reaching the alveoli for gas exchange
explain what would happen if carbon dioxide was allowed to build up in the red blood cells
there would be an increase in the concentration of H+ ions and a decrease in pH and would cause enzymes to denature
explain the mechanism of exhalation at rest
the diagram relaxes and moves in an upward direction
the internal intercostal muscles expand which moves the rib cage down and in
this decreases the volume of the thoracic cavity which increases pressure
so a pressure gradient is created which causes air to flow from higher pressure in the alveolus to lower pressure in the atmosphere through the nose and mouth
