7 Exchange surfaces Flashcards
equation of Fick’s Law (rate of diffusion)
rate of diffusion = Area of diffusion surface * difference in concentration / Thickness of surface over which diffusion takes place.
What is osmosis
The diffusion of water across a partially permeable membrane
What is water potential + its measure
The pressure exerted by water molecules as they collide with a membrane or container
Pascals (Pa)/ Kilopascals (KPa)
What is the water potential of pure water
0 KPa
What happens to the water potential when a solute is added
Lowers the water potential
Are all solutions negative or positive water potentials?
Negative
The more concentrated the solution the more …… the water potential (what is ……)
Negative
information flashcard
When solutions of different concentrations (different water potentials) are separated by a partially permeable membrane the water molecules can move between solutions but the solutes usually cannot. There will then be a net movement of water from the solution with HIGHER water potential (less concentrated) to the solution with the LOWER water potential (more concentrated). This will continue until the water potential on both sides of the membrane is equal (equilibrium).
What is a pinocytosis
liquid
what is a phagocytosis
Solid
what is a hypOtonic solution
lOwer sucrose
higher water potential
What is a hypERtonic solution
HighER sucrose
lower water potential
In osmosis does the water move from a hypotonic solution to a hypertonic solution
HypOtonic —> HypERtonic
Why can single celled organisms use diffusion alone
Low metabolic rate
large SA:V ratio
What organisms can use diffusion through the cell surface
Amoeba
The bigger the organism the ….. the SA:V ratio
Smaller
What makes effective exchange surfaces (4)
- increased SA
- thin layers
- good blood supply
- ventilation
Mammals have a …. SA:V ratio and a ….. metabolic rate
small
high
A few reasons why mammals have a high metabolic rate (2)
- active
- maintain their own body temperature
Key structures in the respiratory system (5)
-Nasal cavity
-Trachea
-Bronchus
-bronchioles
-Alveoli
Info about the nasal cavity (4)
-large SA
-hairy lining
-secretes mucus to trap dust and bacteria
-Moist surfaces (+humidity)
Info about the Trachea (2)
-supported by incomplete rings of cartilage (C rings)
-Lined with ciliated epithelium and goblet cells
-Goblet cells = secrete mucus
-Cilia = beat mucus upwards up the trachea
Info about the bronchus (3)
-also called bronchi
-2 of them connected to the trachea
-same supportive incomplete cartilage rings but smaller
Info about the bronchioles (4)
-divide from bronchus
-no rings of cartilage
-lined with epithelium
-diameter 1mm>
Info about the Alveoli (6)
-300-500 million alveoli per adult lung
-unique to mammalian lungs
-diameter of 200-300um
-Thin layer of epithelial cells
-one cell thick (alveolus + capillary wall)
-Capillary’s in close contact with alveolus wall.
what’s the Abdomen
Lower half of the body
(liver intestine ect)
What’s the thorax
The top half of the body
(lungs etc)
what is ventilation
The process of moving air into and out of the lungs, bringing in oxygen + removing carbon dioxide
is the contracted diaphragm flat or curved upwards
flat
(relaxed = curved upwards)
does the diaphram contract or relax when the lungs are inflated
contract (flat diaphram)
Info about insects gas exchange
-they are very active during parts of their life cycle
-mainly land dwelling animals
-relatively high oxygen requirements
-have a tough exoskeleton
What’s the order of the parts in an insects respiratory system (3) (+2 extra details)
-spiracle
-tracheae
-tracheoles
-then reaches muscle
-water in tracheoles
what’s the diameter of the tracheae and what is it made of in insects
1mm
spirals of chitin
What do spiracles do
-allows air to enter + leave
-can be opened and closed to reduce water loss
-closed most of the time
-open when the oxygen demand builds or carbon dioxide levels build up.
what’s the diameter of tracheoles in insects
0.6 - 0.8um
How does tracheal fluid work
+at the end of tracheoles
-oxygen demand is high (insect flying)
-lactic acid build up in the tissue
-results in the water moving out of the tracheoles by
osmosis
-more area exposed for gaseous exchange
water facts (3)
water is 100 times denser than air
water is 100 times more viscous
much lower oxygen content
Gill facts (4)
-they maintain a flow of water in an opposite direction over the gills compared to the blood flow
-large SA
-good blood supply
-thin layers
Shape of chitin
continuous circular spiral
