Biology (Exchange Surfaces and lungs) Flashcards
(44 cards)
Organisms need exhange surfaces to absorb?
oxygen
glucose
minerals
Organsim need o remove?
C02 (animals)
02 (plants)
ammonia/urea
Single-celled organisms can use.?
simple diffusion to absorb and remove these gasses/oriducts bvecuase they have a large SA:V
As the size of an organism increases the SA:V ..?
decreases- the SA isnt large ebough to absorb/remove these products fast enough
need a larger SA- often combine with a transport system
Good exchange surfaces have..?
- large SA to allow more molecules to pass through (fold walls/membranes)
- short diffusio patrhway
- steep concentration gradient
Some exchnage surafces use…?
An exaple in the human body is..?
active transport to transport molecules
liver- to control blood sugar levels
Air travels into the nose> along the..?
trachea> long the brochi and bronchioles>alveloi (air sacs) where exchange takes place
Breathing in (Inspiration)
ribcage moves up and out diaphram contracts (flattens) external interocastel msuicles contract The volume in thoriac cavity increases pressure decreases>when pressur ei lower than atmospheric pressure air moves in
Breathing out (expiration)
ribcage moves down and in/diaphram relaxes (rises)/interbnal intercoastel musicles relax/volume in thoraic avity decreases/pressure increases/air is forced out of lungs when higher than atmospheric pressure
02 passes from alveloi to
tissues
C02 passes from tissues t0
alveloi
He large surafce area in lungs is due to..?
even though alveloi are tiny thoudands of them make up a large surface area
what allows the difrusion of gasses?
permable barrier (plasma memberane surrounding cyrtoplas)
How does the thin barrier reduce the diffusion pathway?
The capillary wall is only once cellt hick
The alevolousb wall is only one cell thick
They are both made up flattened (squashed) endotherlial cells
Red blood cell is same size as capillary cell so red blood is squeezed part makeing ti close to the alveloi.travel theere quicker
How is the diffusion gradient maintained?
THe concentration of C02 in th blood is kept lower than that in the alevloi so it dissues into the alveloi
The concentration o 02 is always kept lower ij t he blood so that it diffuses from the alveloi uinto the blood
How does the blood travel from the heart>tissues via the lungs?
Heart pumps blood from pulmonary artery>lungs>here, artery diviedes up into arterioles>carry blood to capillaries>red blood cells are squeezed past-forcingthem to give up blood to tissues
The breathing movements of the lungs ?
ventilate them/replace used air with fresh air
Trachea brochi and brochioels have to be..?
strong to stop collapsing whjen iside pressur is low (inspriation)
large enough to let air flow
flexible
Cartilage in the trachea and bronchi is used for?
strength (to prevent collapsing during inspiration)
C rings in trachea (not complete rings to provide some flexibility)-less regular in bronchi
oesphogus allowed to expand
The smooth mucle?
contracts which constrict the lumen>makes it narrower>limits flow of air to and from the alveloi
important to do this if there are harmful substances in the air
most obvious effect in brochioles
involuntary cause asthma atatcks
Elastic fibres..?
When smooth muscle contracts>constricts the artery
This deforms the elastic fibres in the loose tissue( inner surace of cartilage)
When smooth tissue relaxes, elastic fibres recoil helping to widen the artery
Goblet cells and glandular tissue?
These are jsut below the epithelium (thin inner lining)
secrete mucus>trap pathogens>reduce risk of infection
Ciliated cells?
They are hair-like projections from membrane which move in synchronisd motion to waft msucus up airwar>back of throat>swallowed>killed by acid in the stomach
Tidal volume is
volume of air breathed in or out per breath
