3.1.1 exchange surfaces Flashcards
what is a specialised exchange surface
adapted to maximise the rate of diffusion across it
what type of organisms need specialised exchange surfaces
multicellular that have small SA:volume ratios
long diffusion rates
high metabolic rates
Ficks law
( SA x concentration difference) / diffusion distance
what conditions for diffusion rate to be maximium
large surface area
large concentration gradient
short diffusion difference
how does large surface area increase rate of diffusion
increase area over which diffusion can occur
how does thin feature of the organism increase rate of diffusion
keeps diffusion distance short
how does good blood supply increase rate of diffusion
maintains steep concentration gradient of repiratory gases
how does well ventilated increase rate of diffusion
maintains steep concentration gradient of repiratory gases
what is gas exchange
swapping CO2 for O2 by diffusion
function of trachea
non-collapsible tube through which air is drawn into the lungs
function of alveoli
microscopic air sacs adapted for gas exchange
function of bronchus
flexible tubes which deliver air from trachea to bronchioles
function of pleural membrane
double membrane that surrounds lungs and protects them from friction during breathing
function of diaphragm
flexible sheet of muscle involved in ventiallation
function of bronchioles
flexible,narrow tubes which deliver air to the alveoli
function of intercoastal muscles
muscles between ribs involved in ventilation
function of ciliated cells
sweep mucus out trachea
function of goblet cells
produce mucus
function of smooth muscle cells
constrict bronchioles
function of squamous epithelium cells
short diffusion distance
why is ventilation of the lungs important
increase the concentration gradient and pressure
what happens during inspiration
diaphragm contracts,flattens and lowers
external intercoastal muscles contract to move ribs up
volume of chest cavity increases
lower pressure in chest cavity
air is drawn into lungs
lungs swell
what happens during expiration
diaphragm relaxes to dome shape
external intercoastal muscles relax to move ribs down
volume of chest cavity decreases greater than atmosphere pressure in chest cavity
air moves out of lungs
lungs shrink
what is forced expiration
requires energy to forcablly push ribs down hard and fast to expel air quickly
occurs during exercise
closed circulatory system
blood is enchased in vessels
high pressure so blood flows quickly
where are single closed circulatory systems found
fish and annelid worms
key features of single closed circulatory system
blood passes through 2 sets of cappillaries
low pressure
flows through heart once
slow flow
key features of double closed circulatory system
travels through heart twice
1 capillary network
high pressure
fast blood flow
where is double closed circulatory system found
birds and most mammals
where is open circulatory system found
invertebrate
key features of open ciirculatory system
split by membrane
hemolymph
what does open circulatory system transport
food,cells in defence against disease
nitrogenous waste products
function of heart
generate blood vessels
function of blood vessels
maintain and regulate pressure
function of pulmonary capillary bed
exchange surfaces - O2 into blood
- CO2 into lungs
function of systemic capillary beds
exchange surfaces - O2 into cells
- CO2 into blood
