Exchange Flashcards
Equation for diffusion
SA x diffrence in concentration
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Length of diffusion path
Explain gas exchange in insects
Have an ineternal network of tubes called the TRACHEAE made up of tiny spores called spiracles
Treacheae divides into tracheoles
They go through all body tissues of the insect
3 ways gases move in and out of tracheal system in insects
1) along a diffusion gradient
2) mass transport -muscles can contract to squares out trachea enabling movements of air in and out.
3)end of tracheoles fill up with water
When in major activity , anaerobic respiration occurs. This produces lactate. It’s soluble and lowers the water potential : water moves in via osmosis. This water decreases in volume and draws air Into them. This means the final diffusion phase is in a gas state, this increases rate of diffusions
Structure of gill
Gill filaments-make up the gill.
At right angles to them are the gill lamellae, this increase SA.
How are gills countercurrent flow
Flow of water over gill is opposite to the flow of blood.
Counter current exchange principle
Water pass over the Blood that is already oxygenated, this mean that the oxygenated blood wil get to a maximum concentration.
The water with now little O2 passed over the blood with little oxygen and diffusion takes place.
Structure of leaf
Top-bottom
Waxy cuticle
Upper epidermis
Palisade mesophyll layer
Spongy mesophyll layer
Air
Lower epidermis
Limiting water loss in insects
-Small SA to volume ratio
-Water Portfield coverings
-spiracles
They are openings in tracheae, they can be closed and therefore reduces water loss but will mean less O in so will only happen when insect is at rest
Limiting water loss in plants
Thick waxy cuticle-stops water loss, the thicker the better
Rolling up of leaves - cleared a high water potential area around the stomata’s so less water loss
Hairy leaves- trap moist air to less water lost by evaporation
What do each intercostal muscles lead to
1) internal intercostal lead to exhalation
2) external intercostal lead to inhalation
What happens during inspiration
External intercostal muscles contract
Ribs pulled up and out increasing volume
Diaphragm muscles contract, increases the volume (it flattens)
Less pressure in lungs
Atmospheric pressure now forced into lungs
Expiration
Internal intercostal muscles contract
Ribs move down and inwards
Diaphragm muscles relax , decreasing volume
Higher pressure in lungs
Pressure inside lungs is greater than outside so air leaves
Digestive system
Oesophagus
Stomach-store and digest food
Ileum-enzymes released, lots of villi and microvilli
Large intestine- absorbs water
Rectum- water removed via egestion
Salivary glands- hydrolyses starch into maltose
Pancreas-contains pancreatic juice, contains protease and lipase and amylase
How is starch digested
Amylase from silavairly glands hydrolyse starch into maltose
Stomach denatures the amylase to prevent hydrolysis of starch
Pancreatic amylase hydrolysis the last remaining starch
Iluem releases maltase into the cells on its lumen (membrane bound)
This hydrolysis maltose to a-glucose
Where are sucrose and lactose found and how hydrolysed
Sucrose- fruits
Hydrolysed by sucrase which breaks the glycosidic bond - products are glucose and fructose
Lactose - milk
Hydrolysed by lactase which breaks the glycosidic bond- products are glucose and galactose
How are lipids digested
Lipase hydrolyse the ester bind in tryglcerides (fatty acids). Lipids are slip up into micelles by bile salts (emulsification) this increases SA for faster reaction
Protein digestion
Endopeptiades- hydrolyse peptide bond between amino acid and central region of protein molecule
Exopeptiades-hydrolyse the peptide bonds between terminal amino acid, releases dipeptidrs and single amino acids
Dipeptidases- hydrolyse the bind between 2 amino acids
Why type of structe does damaging have?
Quaternary
Pulmonary vein/artey , aorta and vena cava - where to and from
Pulmonary artery :
From left ventricle (de oxygenated blood) to lungs
Vein: from lung (oxygenated) to left atrium
Aorta : left ventricle to rest of body
Vena cava from rest of body to right atrium
What prevents back flow of blood in heart?
Bicuspid valve (left side)
Tricuspid valve (right side)
What do semi lunar valves do?
In the Aorta and pulmonary artery
Prevent back flow into ventricles
