gas exchange + circulatory systems Flashcards
(37 cards)
why do large organisms need transport systems
- low SA:V
- long diffusion distance
- more active than single celled organisms need more oxygen and more glucose
so can’t rely on diffusion alone
breathing mechanism
- allows movement of air (with O2) to enter longs
- air low in O2 and high in CO2 to leave lungs
inhaling
- diaphragm contracts
- ribs move up/out
- intercostal muscles contract
increases volume of chest cavity
pressure decreases
so air rushes in due to concentration gradient
exhaling
- diaphragm relaxes
- ribs move down/in
- intercostal muscles relax
volume decreases
pressure increases
air rushes out
alveoli adaptation
- large number - large surface area
- walls one cell thick - shirt diffusion distance
- surrounded by capillaries - maintain high concentration gradient
- moist - dissolve gases - efficient diffusion
open circulatory system
insects
blood not in vessels
one main blood vessel
blood leaves main vessel and enters chest cavity
closed circulatory system
fish/ mammals
blood in vessels
2 diff types - single/double
single circulatory system
fish
blood flows through heart once each circuit of the body
double circulatory system
humans
blood passes through the heart twice in one circuit of the body
2 circuits - pulmonary (lungs) - systemic (body)
+ of double circulation
- simultaneous high pressure delivery of oxygenated blood to all regions of the body
- oxygenated blood reaches respiring cells undiluted by deoxygenated blood
artery
- away from heart
- high pressure/pulse
- thick walls - not permeable
- small lumen
- no valves
- oxygenated blood (except pulmonary artery)
vein
- to heart
- low pressure/no pulse - smooth flow
- thin walls - not permeable
- large lumen
- has valves
- deoxygenated blood (except pulmonary)
capillary
- from arteries to veins
- pressure falls
- one cell thick walls - permeable
- lumen one cell wide
- no valves
blood loses O2
thick artery walls
WITHSTAND high pressure
large vein lumen
reduces friction (low flow resistance)
valves in veins
prevent BACKFLOW of blood
capillary network
large exchange surface
thin capillary walls
short diffusion distance for substances
heart made of
cardiac muscle
heart has own blood supply
made of muscle
in order to contract need oxygen supply
provided by coronary arteries
purpose if septum
to keep oxygenated and deoxygenated blood separate
left - oxygenated - thick wall (pressure)
right - deoxygenated
left ventricle wall is
thicker to generate high pressure
ensures delivery to whole body
diastole
heart relaxed
- SL valves closed - AV valves open
blood forced into ventricles
atrial systole
both atria contract
- SL valves closes - AV valves open
blood forced into ventricles
