Exchange Surfaces Flashcards
Tidal Volume
The volume of air inspired or expired in a normal (resting) breath.
Pulmonary Ventilation
Volume of air inspired or expired in a minute (at normal breath)
Ventilation Rate
Number of breaths taken per minute
difference between endothelium vs epithelium?
Endothelium in blood vessels, Epithelium in alveoli.
Inspiration…
- Diaphragm contracts, external intercostal muscles contract
- thorax volume increases
- air moves into lungs down air pressure gradient
Expiration
- Diaphragm relaxes, internal intercostal muscles contract
- volume of thorax decrease
- air moves out of lungs.
How to find oxygen usage?
Gradient of trace on spirometer graph.
How do we maintain a steep concentration gradient across the alveoli and capillaries?
Constant inhalation replaces CO2 in alveoli with O2, so the concentration of O2 in alveoli is always higher than that of the blood.
What does the spirometer draw with?
A kymograph
Volume of air breathed in per min
Pulmonary ventilation
Pulmonary ventilation equation
Tidal vol x ventilation rate
why do fish need such adapted exchange surfaces?
Less oxygen dissolved in water than thre is in air.
Process of ventilation in FISH?
- mouth opens
- buccal cavity floor drops
Water rushes into fishes mouth - opercular cavity expands
- mouth closes
- buccal cavity floor rises
- water rushes into opercular cavity and across gills.
- water flows out of operculum
Why is countercurrent used across gill lamellae?
Maintains a favourable concentration gradient across the entire diffusion surface.
Explain the movement of fluid in ventilation system of insects?
Fluid moves into tracheoles when at rest. when muscles are not at rest, fluid is drawn into muscle.
Movement of oxygen between cells and tracheoles?
Cells use oxygen for respiration.
Oxygen concentration is low in cells.
Oxygen diffuses into cells.
How are spiacles adapted to reduce water loss?
- Close in non-optimal conditions
- hairs that trap humid air
what are trachea lined with?
CHITIN
what are the tracheoles not made of?
CHITIN
How does oxygen get to cells?
Diffuses into a fluid medium
Why is tracheal fluid in tracheoles not ideal in times of high oxygen demand?
It limits the surface area of the tracheoles.
explain how tracheal fluid moves into muscle cells?
Lactic acid builds up in muscle cells, reduces water potential, tissue fluid moves into muscle cells.
explain mechanical ventilation of tracheal system?
Muscles of the abdomen and thorax change the volume of the body of the insect. This changes the pressure inside the trachea, forcing air in and out.
what is used as a resevoir of air in insects?
air sacs or collapsable enlarged trachea.
How do air sacs in insects store air?
Thorax and abdomen created ventilating movement that inflates these air-resevoirs! now the insect can close its spiracles, yay !
What does DGC stand for?
Discontinuous gas exchange cycles
Name the 3 stages of DGC
Closed spiracles
Fluttering spiracles
Open spiracles
what happens at “closed spiracles” DGC?
oxygen moves into cells, CO² moves out and is held in tissue fluid (buffering).
What happens at “spiracles fluttering” DGC?
Spiracles open and close rapidly. moves oxygen into trachea whilst minimising water loss.
What happens at “open spiracles” DGC?
CO² build up in tissue fluid leads to rapid flush of CO² out of trachea
Give the safety precautions for using a spirometer…
- sterilised mouthpiece
- refreshed soda lime
- no asthmatics
- no air leaks in the apparatus.
What does smooth muscle in bronchioles do?
conract to restrict airways. relax to dilate airways
What is the shape of the cartilage in the trachea and why?
C shaped
It allows food to pass down an esophagus
Define residual volume…
The air that remains in the lungs even after forced expiration.
define vital capacity..
The maximum volume of air that can be exhaled.
Usual range for vital capacity…
2.5 to 5.0
Adaptations of nasal cavity
- large surface area, good blood supply. warms air to body temperature.
- moist surfaces increase humidity and reduce evaporation from exchange surfaces.
- hairy lining that produces and secretes mucus to trap pathogens.
Residual volume
volume of air left in the lungs after forced expiration.
what are tracheoles?…
single elongated cells with no chitin.
Total lung capacity calculation
Vital capacity + residual volume
Where is smooth muscle found in the lungs…
in the trachea, bronvhi abd brinchioles up to the bronvhioles ending.
Why do larger organisms need a circulatory system?
- high metabolic demand
- low surface area to volume ratio
- longer diffusion pathway
- a slow rate of diffusion
- slow rate of respiration
