Chapter 7- Exchange surfaces Flashcards
What do all specialised exchange surfaces have in common?
Increased surface area- overcomes limitations of SA:V ratio
Thin layers- decrease diffusion surfaces
Good blood supply- the steeper the concentration gradient the more effective the diffusion is
Ventilation- to support and maintain diffusion gradienrts
What happens to the body when you inhale?
Ribcage moves up and out
Diaphragm contracts and moves down
Intercostal muscles move up and out
Pressure reduces
Define tidal volume
The volume of air that moves into and out of the lungs with each resting breath
Around 500cm3 in most adults at rest which uses around 15% of lung capacity.
Define vital capacity
Volume of air that can be breathed in when the strongest possible exhalation is followed by the deepest possible intake of breath
Define inspiratory reserve volume
The max. volume of air that you can breathe in over and above a normal exhalation
Define expiratory reserve volume
The extra amount of air you can force out of your lungs over and above the normal tidal volume that you breathe out
Define residual volume
The volume of air left in your lungs when you have exhaled as hard as possible
Define breathing rate
The number of breaths taken per minute
Define ventilation rate and give its equation
The total volume of air inhaled in one minute
Ventilation rate= tidal volume x breathing rate
What is mechanical ventilation of the tracheal system?
Air is actively pumped into the system by muscular pumping in movements of the thorax and/or abdomen
What are spiracles made up of and their separate functions?
Trachae- largest tube of insect respiratory system, carries air into body and lined by spirals of chitin which prevents collapse
Tracheoles- smaller tubes, single elongated cells, no chitin and freely permeable to gases, sit of gaseous excahnge
Sphincters- open and close the spiracles
Tracheal fluid- towards end of tracheoles, limits air for diffusion- when there is an increase in O2 demands lactic acid builds in cells and H2O moves out of the tracheoles so exposes more SA for GE
What is a collapsible enlarged trachea?
Used to increase the amount of air moved through the exchange system
Usually inflated or deflated by movement of the thorax or abdomen
What are the main difficulties that bony fish have to overcome?
all cause low rate of diffusion
water is 1000x denser than air
it is also 100x more viscus than air
has a lower O2 content
What are the main components of the gills?
Gill fillaments- large stacks, need constant flow of water to keep apart, exposing large SA for GE
Gill lamellae- main site of GE, large SA, rich blood supply
Gill arch- both the gill lamellae and fillaments
What is the overflow of water like when a fish is swimming and not swimming?
Swimming- keeps water flowing over gills by opening mouth and operculum
Not swimming- flow of water stops but operculum movement allows a constant flow
