Exchange And Transport Flashcards
Why do multicellular organismsrequire specialised gas exchange surfaces
The distance that needs to be crossed is too large and substances cannot easily enter the cells as in a single celled organism
How is surface area to volume ratio calculated
Ratio=surface area/ volume
Name three features of an efficient gas exchange surface
Large surface area
Thin/ short distance
Steep concentration gradient
Describe trachea and its function
Wide tube supported by c- shaped cartilage
Lined by ciliated epithelium cells
Carries air to bronchi
Decide bronchi and their function
Supported by cartilage lined by ciliated epithelium cells
Allow passage of air into the bronchioles
Describe the bronchioles and their function
Smooth muscles and elastic fibres
Allow passage of air into the alveoli
Describe alveoli and their function
Mini Air sacs epithelium cells site of gas exchange
Walls only one cell thick covered with capillaries
Explain the process of inspiration
External intercostal muscles contract
Diaphragm contracts and flattens
Volume increases
Air pressure outside the lungs is higher so air moves in
Explain the process of expiration
External intercostal muscles relax
Diaphragm relaxes and domes upward
Volume decreases
Air pressure outside is lower so air moves out
Spirometer
Measures lung volume breathe into airtight chamber leaves a trace on a graph which shows the volume of the breaths
Vital capacity
Max volume of air can be expelled in one breath
Tidal volume
Vol of air breath in and out during each breath at rest
Breathing rate
Number of breaths each minute
Two main features of a fish’s gas transport system
Gills
Lamellea
Gas exchange in a fish
Buccal cavity volume increased to enable water to flow in reduced to increase pressure
Water is pumped over lamellae by opurculum oxygen diffuses into the bloodstream
Waste carbon dioxide diffuses into the water and flows back out of the Gills
Countercurrent system
Maintains a steep concentration gradient as water is always next to blood of a lower oxygen concentration. Keeps rate of diffusion constant and enables 80% of available oxygen to be absorbed
Three features of an insects gas transport system
Spriracles
Tracheae
Thracheoles
Process of gas exchange- insects
Gases move in and out of tracheae though the spiracles
Diffusion gradient allows oxygen to diffuse into body tissue while waste co2 diffuses out
Contraction of muscles in the trachea allows movement of air in and out
Different types of circulatory system
Open- blood diffuses out of vessels
Closed- blood confined to vessels
Single- blood passes though pump once per circuit
Double- blood passes through heart twice per circuit
Structure and function of arteries
Thick muscular walls to handle high pressure
Elastic tissue allows recoil to prevent pressure surges
Narrow lumen to maintain pressure
Structure and funtion- veins
Thin walls- lower pressure
Valves- blood doesn’t flow backwards
Less muscular and elastic tissue- don’t have to control blood flow
Structure and function cappilaries
Walls only one cell thick- short diffusion pathway
Narrow- can permeate tissues and red blood cells can lie flat against the wall
Numerous and highly branched providing a large surface area