1What do insects have on the outside?
Exoskeleton which provides protection and is water proof
2Ways insects prevent wwater loss
Small surface area to volume ratio
Water proof exoskeleton
Sphincters which can close spiracles
3What are spiracles?
Respiratory openings in which gases can enter and leave the insect.
4What is insect tracheal system?
Spiracles are attached to a network of trachea which are internal tubes with rings of chitin which branch into tracheoles which extend between cells to exchange gasses.
5Why are tracheoles filled with tracheal fluid?
During intense activity, cells do anaerobic respiration creating lactic acid, reducing the water potential. This causes water in tracheal fluid to move in cells. This reduces volume of tracheal fluid but leads to more air being drawn in.
6Ways gases move in and out of tracheal sysetm
- Down a concentration gradient
- Contraction of muscles squeeze trachea, enabling mass movement of gases
- Movement of tracheal fluid to cells causing air to be drawn
7What is operculum
bony plate that covers the gills and which water leaves through opercular opening
8Strucuture of gills
Made up of stacks of gill filaments and at right angles to filaments are lamellae which increase surface area and have capillaries.
9what is counter current
Mechanism in which blood and water flows in opposite directions to each other to maintain a concentration gradient throughout ENSURING equilibrium is never reached
10How do guard cellswork( potassium decreases water potential)
Closing stomata:
1)Potassium ions move out of vacuole and out of cell
2)Water moves out of cell
3)Guard cell shrinks and closes stomata.
Opposite for opening stomata
11Features of xerophytic plants for reducing water loss
thick cuticle
smaller surface area to volume ratio
These 3 trap still air reducing water potential gradient:
- Rolling of leaves
- Hairy leaves
- stomata in grooves
12What happeneds during inspiration(opposite happened for expiration)
-External intercostal muscles contract and pull ribs upwards and outwards
- internal intercostal muscles relax
-diaphragm contracts and pulls downwards
- Air pressure in lungs initially drops
- Lung volume increases
So air moves into lungs
13What is spirometer
Instrument which measures tidal volume
14What is tidal volume
volume of air that enters and leaves at rest
15Whats ventilation rate
number of breaths taken per minute
16Pulmonary ventilation? (total volume of air move in lungs in one minute)
tidal volume x ventilation rate
17General adaptions of gas exchange
Good blood supply
High surface area to volume ratio
Short diffusion pathway
Mechanism for maintaining gradient.