Exchange Flashcards
An effective gas exchange surface has
Large SA, thin , efficient blood supply, ventilated
SA of small intestine increased by
Villi
Villi
Produce extensive network of capillaries to absorb products of digestion by diffusion and active transport and large SA
Roots SA increase by
Root hairs
Stomata exchange in plants
Carbon dioxide and water
Guard cells
Control water loss
Xylem transport
Water and mineral ions up plant
Phloem carries
Dissolved sugars from leaves to rest if plant
Arteries (flow)
Blood flows from heart to organs-away
Veins (flow)
Blood to heart
Differnace between arteries and veins
Arteries-thick walls containing muscle and elastic fibres
Veins -thinner walls and valves to prevent back flow of blood
In blood?
Plasma with rbc and wbc and platelets suspended in it. A tissue
Red blood cells
No nucleus and packed with haemoglobin, biconcave shape
White blood cells
Have nucleus and defend against microorganisms
Lungs haemoglobin combines with
Oxygen to form oxyhaemoglobin and in other organs this splits back up
What’s Exchanged between an organism ?
Respiratory gases, nutrients and excretory products and heat
Effective exchange surface has
Large surface area to volume ratio (small organisms)
Larger organisms need
Special Ed exchange surfaces with large areas to increase ratio
sA of sphere
4 pie r squared
Volume of sphere
4/3 pie r 3(cubed)
SpecialisEd exchange surfaces have
Large SA compared to vol, thin and selectively permeable and movement of environmental medium like air and a transport system for movement of internal medium
Relationship of diffusion to other factors
Diffusion-directly proportional - to SAxdiff in conc /length of diffusion path
Gas exchange in single celled organisms
O2 diffused through cell surface membrane of body surface and co2 disffuses out body surface through cell wall. Large SA:V as small
How does the surface area required for insects conflict with conserving water
Because the large surface area required for exchange conflicts as it makes it easier for water to evaporate from it
Insects internal network of tubes strengthened by rings to prevent them from collapsing
Tracheae
Tracheae divide into smaller dead end tubes called?
Tracheoles
Tracheoles role
Extend throughout all body tissues of insect and so atmospheric air is directly braught to respiring tissues due to the short diffusion pathway to the body cell from it
Respiratory gases move in and out of tracheal system -3ways
Along a diffusion gradient , mass transport , the ends of the Tracheoles are filled with water
Gases enter and leave tracheae through tony pores called
Spiracles
Spiracles on the body surface are opened or closed by
Valves
Tracheal system limits insects as
Have to be small due to need for short diffusion between environment and cells
