3.1- exchange surfaces and breathing Flashcards
what are the 3 main factors that affect the need for an exchange system?
size, SA to V ratio and level of activity
what advantages do small organisms have compared to larger organisms when it comes to gaseous exchange?
Cytoplasm very close to the outside
short diffusion pathway
how would you describe to SA:V ratio in a small organisms
Large, SA is larger than their volume
how would you describe the SA:V ratio in a large organisms
Small, smaller SA compared to their
volume.
how do some animals increase their SA?
Give an example of an animal that does this.
By adopting a different shape.
e.g. flat worm have a thin and flat body
what does metabolic activity require?
energy from food and oxygen to release the energy in anaerobic respiration.
name the needs for energy in a active organism
movement and for warmth
name the 3 features of a good exchange surface plus examples
- large SA:V ratio for more space for diffusion. e.g folding membranes in root hair cells.
- thin permeable barrier. e.g. alveoli in the lungs
- Good blood supply. helps maintain a steep conc. gradient.
name the tissues/organs that air flows through after it reaches the nose down to the lungs hint- t,b,b,a
trachea(windpipe) then bronchi and bronchioles (small air sacs) finally the alveoli.
what protects the lungs?
ribcage
what are the ribs held together by?
intercostal muscles
how is ventilation produced?
through the action of the intercostal muscle and diaphragm.
how small are alveoli?
100-300 micrometers
what must the lungs produce to reduce cohesion forces between water molecules that can cause alveoli to collapse?
surfactant
name the thin barriers that reduce diffusion distance in gaseous exchange
- alveolus wall one cell thick
- capillary wall one cell thick
- both walls have squamous cells (thin)
- capillaries in close contact with alveolus walls.
why is having a good blood supply in gaseous exchange important? hint- CO2 and O2
blood transports CO2 from tissues to lungs. ensuring conc of CO2 in the blood is higher than that in the air. making it diffuse through alveoli.
blood transports O2 from lungs to tissues. so conc is lower in blood.
what happens to the diaphragm during inhalation?
The diaphragm contracts and moves down.
what happens to the diaphragm during exhalation
diaphragm relaxes and moves up
what happen to elastic fibres during inspiration?
stretch
what happen to elastic fibres during exhalation
recoil to push air out
what are some requirements of an effective airway?
- Be large for sufficient airflow without constriction.
- be supported to prevent collapsing when the air pressure is low.
- be flexible
what are airways lined with also its function?
ciliated epithelium (helps keep lungs healthy, and move mucus
what do goblet cells release ?
mucus
describe structure of trachea and bronchi
they have similar structure. but bronchi is more narrow than trachae. also contain cartilage to prevent collapsion.
why is the cartilage in the trachea c- shaped
flexibility and space for food to pass.
describe the strucutre of brioncholes
narrower than bronchi, no cartilage and wall is compromised by smooth muscle and elastic fibers.
role of smooth muscles
constrict air ways
how do we measure lung volumes
spirometer- movement of the chamber is recorded on a datalogger.
what absorbs the CO2 after exhalation in a spirometer.
a chamber of soda lime. which also allows measurment of oxygen consumption
name precautions that must be taken before using a spirometer.
- individual must be healthy
- soda lime is fresh
- no air leaks
- mouth piece is sterilised
- water chamber is not overfilled
definition of vital capacity
maximum air that can be moved through one breath usually 2.5-5.0 dm3
what are the factors that affect vital capacity
- size of a person
- age and gender
- level of regular exercise
definition of residual volume
air that stays in the lungs even after exhalation usually 1.5 dm3
volume of tidal volume
volume of air moved in and out with each breath. usually 0.5 dm3
how do we measure oxygen uptake in a spirometer?
the gradient of decrease in volume
how do bony fish absorb the oxygen dissolved in water ?
they use their gills
how many pairs of gills do most fish have
5
what do each gills in a bony fish consist of ?
2 rows of gill filaments attached to a bony arch.
how do gills in a fish gain a large SA?
through the folding of the many secondary lamellae.
definition of counter current flow
when 2 fluids flow in opposite directions
how do bony fish keep water flowing over the gills
by using a buccal-opercular pump.
describe the ventilation in bony fish
- first buccal cavity changes volume
which draws water in. - cavity closes and pushes water towards the gills.
- movements of operculum reduces pressure directing the water.
what type of circulatory system do insects have
?
they have an open circulatory system.
what role does the body fluid obtain in insects ?
both the blood and tissue fluid.
insects possess what type of air filled system
tracheal system
how does air enter through the tracheal system in insects
pores called spiracles
what is the name for the tubes that transport air in the body of an insect ?
trachae
What are the ends of tracheoles filled with?
tracheal fluid
