Zusammenfassung der Ressource
Exchange surfaces
and breathing
- Gas exchange
- Cells need to take
in oxygen and
excrete waste
products like CO2
- Small organisms have a large
SA:V ratio. Large organisms
have a small SA:V ratio.
- Small organisms can diffuse
directly into or out the surface
membrane. Small distance
and is quicker
- Large organisms have cells deep
within the body, large distance.
Difficult to exchange substance to
supple a large volume through a small
surface
- Trachea
2 bronchi
bronchioles
alveoli
- Gas
exchange
happens in
the alveoli
- Surrounded by capillaries. O2
diffuses out of the alveoli in the
blood and CO2 diffuses into the
alveoli from the blood
- Gas exchange systems
- How the lungs are adapted
- Many alveoli
provide large
surface area
- Alveolar and capillary
epithelium are one cell thick,
short diffusion pathway
- Alveoli have a good
blood supply, take away
O2 and bring back CO2.
- Breathing in and out
keeps a fresh supply of
air and concentration
gradient high
- Role of each tissue
- Goblet cells
- Secrete mucus
that traps
microorganisms
and prevents
them from
reaching alveoli
- Cilia
- Wafts the mucus
to the back of the
throat to prevent
lung infection
- Elastic fibres
- They stretch
and recoil to
help with
breathing in
and out
- Smooth muscle
- Allows the
diameter of the
lumen to be
controlled.
- Cartilage
- Provide
support and
stops the
trachea from
collapsing (in a
C shape)
- Breathing
- Inspiration
- Expiration
- Intercostal and diaphragm muscles relax.
Ribcage moves down and in, diaphragm
becomes curved. Decreases volume of thorax
and increases pressure in lungs. Air forced out
- Intercostal and diaphragm muscles contract.
Ribcage moves up and out, diaphragm
flattens. Increases volume of thorax. Lung
pressure decreases. Air flows into the lungs
- Terms
- Tidal volume:
volume of air in
each breath at
rest
- Vital capacity:
maximum volume of
air breathed in or out
- Breathing
rate: how
many
breaths
(p/min)
- Residual
volume: air
that
remains in
the lungs
(1.5dm3)
- Expiritory/Inspiritory
reserve: How much
more air can be
breathed in or out
- Spirometer
- Oxygen filled chamber,
person breaths through
a tube, movements
recorded (spirometer
trace), soda lime
absorbs CO2.
- Volume of air decrease because
CO2 in absorbed